Tappet clearnace on TC (1949)

[Robert FzMG]

Al Moss welded the holes in a spare oil banjo bolt that goes into the head. Robert Ford TC9851. TA2692 San Jose, California.

On Feb 21, 2018, at 3:37 PM, Duncan morelists@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: Norman, if a spray of hot oil is a concern, the usual go around is a modified spare valve cover with access slot or holes punched out on the top of it.   Al Moss said  he would temporarily block oil flow of feeder tube to head.    From: "'Norman Verona' norman@frenchblat.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: 'Duncan' morelists@yahoo.com>; 'MG-TABC List' mg-tabc@yahoogroups.com>; 'CLIVE SHERRIFF' csherriff99@gmail.com>  Sent: Wednesday, February 21, 2018 2:23 PM Subject: RE: [mg-tabc] Re: Tappet clearnace on TC (1949)   Duncan,    I sometime adjust tappets with the engine running, on other engines. However, with The TC with standard rockers there would be a lake of oil if I did that.     Norman Verona 11 Cherry Close, Royston, South Yorkshire S71 4LZ Phone: 0044 (0)1226 728811 Mob: 0044 (0)741 9905 741 Web: www.frenchblat.com   From: mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] On Behalf Of Duncan morelists@yahoo.com [mg-tabc] Sent: 21 February 2018 18:55 To: MG-TABC List mg-tabc@yahoogroups.com>; CLIVE SHERRIFF csherriff99@gmail.com> Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)     The mg-tabc.org "resources" section has an interesting article about adjusting valves.  [url=http://www..mg-tabc.org/library/valve_adjust.htm]http://www.mg-tabc.org/library/valve_adjust.htm[/url] Jerry Austin mentions the importance of setting points and correct ignition timing prior to adjusting valves.  He even mentions adjusting the valves with the engine running!    Below the article is a comment by Al Moss.  He claims the engine running adjustment can be done entirely by ear, with no feelers of any kind, and you do not need to have any prior knowledge of what sort of cam is in there.  He ends the comment by suggesting doubter's check the results with a vacuum gauge!    Duncan- TC9866- From: "CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: Norman Verona norman@frenchblat.com>  Cc: Bill Hyatt usaj24@earthlink.net>; David James dr.david.james@gmail.com>; yahoogroups mg-tabc@yahoogroups.com> Sent: Wednesday, February 21, 2018 3:20 AM Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)      Norman,    NEVER, but NEVER make assumptions.  If your engine had so much wear that it needed rebores up to 0.040 before you bought it, I'd say it might well have needed, and had, a new cam too.     TRY THIS,  note uin last paragraph "  An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter"   So:-   Camshaft -  Determination   Two different camshafts were supplied as original equipment for the XPAG and XPEG engines. The earliest type, part number AAA5776 (earlier numbers MG862/171 or X24084), was used in all TB and TC engines, and in TD engines up to engine number XPAG/TD2/24l15. This early cam requires a valve clearance of 0.019 in.    The later type, part number AAA3096 (earlier number 168553) was used in all later TD and TF engines and requires a valve clearance of 0.012 in.   Unfortunately, now that even the newest TF is almost 40 years old, the engine numbers quoted above are not necessarily a valid guide for purpose of camshaft identification. Engines originally equipped with AAA5776 may have been fitted with AAA3096 in the course of an overhaul.      With the engine cold, remove the rocker cover and turn the engine over with the crank until #1 intake valve (2nd valve from front of engine) is wide open. At this point, #4 intake valve (7th from front) will be fully closed and on the exact center of the heel of the  cam lobe. Set #4 intake to 0.021 in. clearance. This is the correct checking clearance for both cams, regardless of whether you use the degree wheel and dial indicator method or the simplified method which follows.   Now, wipe all the accumulated gook off the crankshaft pulley, and get out your measuring tape and a piece of chalk. Measuring around the rim of the pulley. make one chalk mark between 1/32 in. and 3/64 in. to the right (as seen from the front) of the top dead centre mark on the pulley. This corresponds to 5 BTDC, which is when the intake opens on the later cam (AAA3096).    Make a second chalk mark 23/64 in. to the right of the TDC mark. This corresponds to 11 BTDC, which is when the intake opens on the earlier cam (AAA5776).   Next, turn the engine over with the crank (it's easier with the spark plugs out) until the pushrod for #4 intake valve just barely locks up enough so that you can't spin it between your fingers. At this point, the timing pointer on the timing chain cover should be more or less aligned with one or the other of the chalk marks.      If the pointer aligns with the 11 mark, then you have the early cam (AAA5776) and you should set the valve clearance to 0.019 in. with the engine hot. If the pointer aligns with the 5 mark then you have the later cam (AAA3096) and you should set the valve clearance to 0.012 in. hot. If the pointer does not align with either mark, go back through the entire procedure again to make sure you did it right.      What effect does the wrong valve clearance setting have on the engine? This is a bit difficult for the novice to pinpoint unless he can compare performance to a properly set up car. In general, however, an engine equipped with AAA5776, but with the valve clearance set at 0.012 in. will be very low on power. An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter. You should also bear in mind the fact that while clearance which is too large is noisy, it doesn't necessarily produce any mechanical damage. On the other hand, burnt exhaust valves will almost surely result from unduly small valve clearance, as in the case of an AAA5776 cam set at 0.012 in.     Clive, Oxford, UK   [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1522512021&sig=MPFa8VQ6a_OGAgb80fOFbA--~D[/img] Virus-free. www.avast.com   On Sun, Feb 18, 2018 at 2:30 PM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:    Bill,   New timing chain, timing wheels & tensioner, new cam followers, the clatter is definitely from the tappets. I m pretty sure the camshaft is original as it hasn t been changed the mid 1950 s. I doubt it would have been changed in its first 6 or 7 years on the road.     Norman Verona 11 Cherry Close, Royston, South Yorkshire S71 4LZ Phone: 0044 (0)1226 728811 Mob: 0044 (0)741 9905 741 Web: www.frenchblat.com   From: Bill Hyatt [mailto:usaj24@earthlink.net]  Sent: 18 February 2018 14:05 To: Norman Verona norman@frenchblat.com> Cc: David James dr.david.james@gmail.com>; mg-tabc@yahoogroups.com Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)   Guys,  Clatter can also come from timing chain tensioner as it translates back and forth axially -Bill Hyatt Sent from my iPhone On Feb 18, 2018, at 6:01 AM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:    David,   My clatter is from the tappets. The tappet faces are good (I ve fully rebuilt the engine) As far as I know it s a 0.017 camshaft..   I ll try reducing them to m0.015 and if the clatter is the same open them back up to 0.017 .   I don t over rev the engine, 4000 rpm is about as high as I take it. It s as standard as it can be apart from 0.040 oversize pistons from a rebore before I bought the car.   I don t need speed from this car, I have a manic Caterham with 220 BHP weighing 500 kgs. That s for the time I want to shake some cobwebs. Also my everyday car is a 189 bhp Lotus Elise. The TC is for driving sedately along country roads.     Norman Verona 11 Cherry Close, Royston, South Yorkshire S71 4LZ Phone: 0044 (0)1226 728811 Mob: 0044 (0)741 9905 741 Web: www.frenchblat.com   From: mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] On Behalf Of David James dr..david.james@gmail.com [mg-tabc] Sent: 18 February 2018 10:10 To: mg-tabc@yahoogroups.com Subject: [mg-tabc] Re: Tappet clearnace on TC (1949)      I had noticed play in the distributor shaft of my 1948 TC, along with quite a lot of oil in the distributor top, and thought this might be the cause of the noisy engine. So I replaced the bushes in the distributor body. This cured the oil problem, but not the clatter. So I used the method given on the MGCC Y-Type Register web site to determine that the camshaft was still of the type that required a 19thou tappet clearance. On the basis that there are indents on the rockers that my feeler gauge would not detect, I set the clearance to 17thou. It is still noisy, but I am reluctant to reduce the clearance further. David (TC4985)

   

[Bill Hyatt]

-Bill HyattSent from my iPhone Begin forwarded message:

[b]From:[/b] Bill Hyatt usaj24@earthlink.net> [b]Date:[/b] February 21, 2018 at 8:02:24 PM EST [b]To:[/b] Duncan morelists@yahoo.com> [b]Subject:[/b] [b]Re: [mg-tabc] Re: Tappet clearnace on TC (1949)[/b]

Group,  It is disconcerting to see such ill informed discussion re adjusting valves. This is not rocket science, it is basically about valve train not locking up as various metal components in v. train expand from engine heat, at whatever heat generating RPM!All the methodologies presented assume that components in valve train are per OEM spec. Not necessarily so. The cam circle base may be worn, lifter bases could be concave, if the cam chain is sloppy worn,  the base circle location needed, could be erroneous by many degrees even if tensioner shoe spring is in spec (unlikely). Then there are related issues due to wear in push rod ends, wear in rocker assembly including rocker shoe face. A worn timing chain can have a big effect on ignition timing as Al Moss succinctly points out. Alas, it seems to be overlooked that ideal valve clearance is moving target and a function of internal component wear along with thermal heat potential to expand valve train components locking v.train up. The base solution should be that there is enough  clearance to insure that valve train has enough room to heat expand & not lock up engine valve train,  along with adequate clatter producing safety margin extra clearance. -Bill Hyatt   TC 4926 Sent from my iPhone On Feb 21, 2018, at 6:37 PM, Duncan morelists@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:   Norman, if a spray of hot oil is a concern, the usual go around is a modified spare valve cover with access slot or holes punched out on the top of it.   Al Moss said  he would temporarily block oil flow of feeder tube to head.    From: "'Norman Verona' norman@frenchblat.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: 'Duncan' morelists@yahoo.com>; 'MG-TABC List' mg-tabc@yahoogroups.com>; 'CLIVE SHERRIFF' csherriff99@gmail.com> Sent: Wednesday, February 21, 2018 2:23 PM Subject: RE: [mg-tabc] Re: Tappet clearnace on TC (1949)   Duncan,  I sometime adjust tappets with the engine running, on other engines. However, with The TC with standard rockers there would be a lake of oil if I did that.    [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b]  [b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]Duncan morelists@yahoo.com [mg-tabc] [b]Sent:[/b] 21 February 2018 18:55 [b]To:[/b] MG-TABC List mg-tabc@yahoogroups.com>; CLIVE SHERRIFF csherriff99@gmail.com> [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949)    The mg-tabc.org "resources" section has an interesting article about adjusting valves.  [url=http://www..mg-tabc.org/library/valve_adjust.htm]http://www.mg-tabc.org/library/valve_adjust.htm[/url]Jerry Austin mentions the importance of setting points and correct ignition timing prior to adjusting valves.  He even mentions adjusting the valves with the engine running!   Below the article is a comment by Al Moss.  He claims the engine running adjustment can be done entirely by ear, with no feelers of any kind, and you do not need to have any prior knowledge of what sort of cam is in there.  He ends the comment by suggesting doubter's check the results with a vacuum gauge!   Duncan-TC9866-From: "CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: Norman Verona norman@frenchblat.com> [b]Cc:[/b] Bill Hyatt usaj24@earthlink.net>; David James dr.david.james@gmail.com>; yahoogroups mg-tabc@yahoogroups.com> Sent: Wednesday, February 21, 2018 3:20 AM Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)    Norman,  NEVER, but NEVER make assumptions.  If your engine had so much wear that it needed rebores up to 0.040 before you bought it, I'd say it might well have needed, and had, a new cam too.    TRY THIS,  note uin last paragraph " [b] An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter"[/b]  [b]So:-[/b]  [b]Camshaft -  Determination   Two different camshafts were supplied as original equipment for the XPAG and XPEG engines. The earliest type, part number AAA5776 (earlier numbers MG862/171 or X24084), was used in all TB and TC engines, and in TD engines up to engine number XPAG/TD2/24l15. This early cam requires a valve clearance of 0.019 in. [/b][b] [/b][b]The later type, part number AAA3096 (earlier number 168553) was used in all later TD and TF engines and requires a valve clearance of 0.012 in.   Unfortunately, now that even the newest TF is almost 40 years old, the engine numbers quoted above are not necessarily a valid guide for purpose of camshaft identification. Engines originally equipped with AAA5776 may have been fitted with AAA3096 in the course of an overhaul.   [/b][b] [/b][b]With the engine cold, remove the rocker cover and turn the engine over with the crank until #1 intake valve (2nd valve from front of engine) is wide open. At this point, #4 intake valve (7th from front) will be fully closed and on the exact center of the heel of the  cam lobe. Set #4 intake to 0.021 in. clearance. This is the correct checking clearance for both cams, regardless of whether you use the degree wheel and dial indicator method or the simplified method which follows.   Now, wipe all the accumulated gook off the crankshaft pulley, and get out your measuring tape and a piece of chalk. Measuring around the rim of the pulley. make one chalk mark between 1/32 in. and 3/64 in. to the right (as seen from the front) of the top dead centre mark on the pulley. This corresponds to 5 BTDC, which is when the intake opens on the later cam (AAA3096). [/b][b] [/b][b]Make a second chalk mark 23/64 in. to the right of the TDC mark. This corresponds to 11 BTDC, which is when the intake opens on the earlier cam (AAA5776).   Next, turn the engine over with the crank (it's easier with the spark plugs out) until the pushrod for #4 intake valve just barely locks up enough so that you can't spin it between your fingers. At this point, the timing pointer on the timing chain cover should be more or less aligned with one or the other of the chalk marks.   [/b][b] [/b][b]If the pointer aligns with the 11 mark, then you have the early cam (AAA5776) and you should set the valve clearance to 0.019 in. with the engine hot. If the pointer aligns with the 5 mark then you have the later cam (AAA3096) and you should set the valve clearance to 0.012 in. hot. If the pointer does not align with either mark, go back through the entire procedure again to make sure you did it right.   [/b][b] [/b][b]What effect does the wrong valve clearance setting have on the engine? This is a bit difficult for the novice to pinpoint unless he can compare performance to a properly set up car. In general, however, an engine equipped with AAA5776, but with the valve clearance set at 0.012 in. will be very low on power. An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter. You should also bear in mind the fact that while clearance which is too large is noisy, it doesn't necessarily produce any mechanical damage. On the other hand, burnt exhaust valves will almost surely result from unduly small valve clearance, as in the case of an AAA5776 cam set at 0.012 in.[/b]    Clive, Oxford, UK  [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1522512021&sig=MPFa8VQ6a_OGAgb80fOFbA--~D[/img]Virus-free. www.avast.com  On Sun, Feb 18, 2018 at 2:30 PM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:  Bill, New timing chain, timing wheels & tensioner, new cam followers, the clatter is definitely from the tappets. I m pretty sure the camshaft is original as it hasn t been changed the mid 1950 s. I doubt it would have been changed in its first 6 or 7 years on the road.  [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b] [b]From:[/b] Bill Hyatt [mailto:usaj24@earthlink.net] [b]Sent:[/b] 18 February 2018 14:05 [b]To:[/b] Norman Verona norman@frenchblat.com> [b]Cc:[/b] David James dr.david.james@gmail.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949) Guys, Clatter can also come from timing chain tensioner as it translates back and forth axially-Bill HyattSent from my iPhone On Feb 18, 2018, at 6:01 AM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:  David, My clatter is from the tappets. The tappet faces are good (I ve fully rebuilt the engine) As far as I know it s a 0.017 camshaft.. I ll try reducing them to m0.015 and if the clatter is the same open them back up to 0.017 . I don t over rev the engine, 4000 rpm is about as high as I take it. It s as standard as it can be apart from 0.040 oversize pistons from a rebore before I bought the car. I don t need speed from this car, I have a manic Caterham with 220 BHP weighing 500 kgs. That s for the time I want to shake some cobwebs. Also my everyday car is a 189 bhp Lotus Elise. The TC is for driving sedately along country roads.  [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b] [b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]David James dr..david.james@gmail.com [mg-tabc] [b]Sent:[/b] 18 February 2018 10:10 [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Re: Tappet clearnace on TC (1949)   I had noticed play in the distributor shaft of my 1948 TC, along with quite a lot of oil in the distributor top, and thought this might be the cause of the noisy engine. So I replaced the bushes in the distributor body. This cured the oil problem, but not the clatter. So I used the method given on the MGCC Y-Type Register web site to determine that the camshaft was still of the type that required a 19thou tappet clearance. On the basis that there are indents on the rockers that my feeler gauge would not detect, I set the clearance to 17thou. It is still noisy, but I am reluctant to reduce the clearance further. David (TC4985)    

[Duncan]

That's a good point Bill.  A certain amount of clatter on cold startup is to be expected. The "engine running" method Al Moss described is for accurate adjustment of each valve on a hotengine.   Duncan- From: "Bill Hyatt usaj24@earthlink.net [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: mg-tabc@yahoogroups.com [b]Sent:[/b] Thursday, February 22, 2018 8:40 AM [b]Subject:[/b] Fwd: [mg-tabc] Re: Tappet clearnace on TC (1949)   -Bill HyattSent from my iPhone Begin forwarded message:

[b]From:[/b] Bill Hyatt usaj24@earthlink.net> [b]Date:[/b] February 21, 2018 at 8:02:24 PM EST [b]To:[/b] Duncan morelists@yahoo.com> [b]Subject:[/b] [b]Re: [mg-tabc] Re: Tappet clearnace on TC (1949)[/b]

Group,  It is disconcerting to see such ill informed discussion re adjusting valves. This is not rocket science, it is basically about valve train not locking up as various metal components in v. train expand from engine heat, at whatever heat generating RPM!All the methodologies presented assume that components in valve train are per OEM spec. Not necessarily so. The cam circle base may be worn, lifter bases could be concave, if the cam chain is sloppy worn,  the base circle location needed, could be erroneous by many degrees even if tensioner shoe spring is in spec (unlikely). Then there are related issues due to wear in push rod ends, wear in rocker assembly including rocker shoe face. A worn timing chain can have a big effect on ignition timing as Al Moss succinctly points out. Alas, it seems to be overlooked that ideal valve clearance is moving target and a function of internal component wear along with thermal heat potential to expand valve train components locking v.train up. The base solution should be that there is enough  clearance to insure that valve train has enough room to heat expand & not lock up engine valve train,  along with adequate clatter producing safety margin extra clearance. -Bill Hyatt   TC 4926 Sent from my iPhone On Feb 21, 2018, at 6:37 PM, Duncan morelists@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:   Norman, if a spray of hot oil is a concern, the usual go around is a modified spare valve cover with access slot or holes punched out on the top of it.   Al Moss said  he would temporarily block oil flow of feeder tube to head.    From: "'Norman Verona' norman@frenchblat.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: 'Duncan' morelists@yahoo.com>; 'MG-TABC List' mg-tabc@yahoogroups.com>; 'CLIVE SHERRIFF' csherriff99@gmail.com> Sent: Wednesday, February 21, 2018 2:23 PM Subject: RE: [mg-tabc] Re: Tappet clearnace on TC (1949)   Duncan,  I sometime adjust tappets with the engine running, on other engines. However, with The TC with standard rockers there would be a lake of oil if I did that.    [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b]  [b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]Duncan morelists@yahoo.com [mg-tabc] [b]Sent:[/b] 21 February 2018 18:55 [b]To:[/b] MG-TABC List mg-tabc@yahoogroups.com>; CLIVE SHERRIFF csherriff99@gmail.com> [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949)    The mg-tabc.org "resources" section has an interesting article about adjusting valves.  [url=http://www..mg-tabc.org/library/valve_adjust.htm]http://www.mg-tabc.org/library/valve_adjust.htm[/url]Jerry Austin mentions the importance of setting points and correct ignition timing prior to adjusting valves.  He even mentions adjusting the valves with the engine running!   Below the article is a comment by Al Moss.  He claims the engine running adjustment can be done entirely by ear, with no feelers of any kind, and you do not need to have any prior knowledge of what sort of cam is in there.  He ends the comment by suggesting doubter's check the results with a vacuum gauge!   Duncan-TC9866-From: "CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: Norman Verona norman@frenchblat.com> [b]Cc:[/b] Bill Hyatt usaj24@earthlink.net>; David James dr.david.james@gmail.com>; yahoogroups mg-tabc@yahoogroups.com> Sent: Wednesday, February 21, 2018 3:20 AM Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)    Norman,  NEVER, but NEVER make assumptions.  If your engine had so much wear that it needed rebores up to 0.040 before you bought it, I'd say it might well have needed, and had, a new cam too.    TRY THIS,  note uin last paragraph " [b] An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter"[/b]  [b]So:-[/b]  [b]Camshaft -  Determination   Two different camshafts were supplied as original equipment for the XPAG and XPEG engines. The earliest type, part number AAA5776 (earlier numbers MG862/171 or X24084), was used in all TB and TC engines, and in TD engines up to engine number XPAG/TD2/24l15. This early cam requires a valve clearance of 0.019 in. [/b][b] [/b][b]The later type, part number AAA3096 (earlier number 168553) was used in all later TD and TF engines and requires a valve clearance of 0.012 in.   Unfortunately, now that even the newest TF is almost 40 years old, the engine numbers quoted above are not necessarily a valid guide for purpose of camshaft identification. Engines originally equipped with AAA5776 may have been fitted with AAA3096 in the course of an overhaul.   [/b][b] [/b][b]With the engine cold, remove the rocker cover and turn the engine over with the crank until #1 intake valve (2nd valve from front of engine) is wide open. At this point, #4 intake valve (7th from front) will be fully closed and on the exact center of the heel of the  cam lobe. Set #4 intake to 0.021 in. clearance. This is the correct checking clearance for both cams, regardless of whether you use the degree wheel and dial indicator method or the simplified method which follows.   Now, wipe all the accumulated gook off the crankshaft pulley, and get out your measuring tape and a piece of chalk. Measuring around the rim of the pulley. make one chalk mark between 1/32 in. and 3/64 in. to the right (as seen from the front) of the top dead centre mark on the pulley. This corresponds to 5 BTDC, which is when the intake opens on the later cam (AAA3096). [/b][b] [/b][b]Make a second chalk mark 23/64 in. to the right of the TDC mark. This corresponds to 11 BTDC, which is when the intake opens on the earlier cam (AAA5776).   Next, turn the engine over with the crank (it's easier with the spark plugs out) until the pushrod for #4 intake valve just barely locks up enough so that you can't spin it between your fingers. At this point, the timing pointer on the timing chain cover should be more or less aligned with one or the other of the chalk marks.   [/b][b] [/b][b]If the pointer aligns with the 11 mark, then you have the early cam (AAA5776) and you should set the valve clearance to 0.019 in. with the engine hot. If the pointer aligns with the 5 mark then you have the later cam (AAA3096) and you should set the valve clearance to 0.012 in. hot. If the pointer does not align with either mark, go back through the entire procedure again to make sure you did it right.   [/b][b] [/b][b]What effect does the wrong valve clearance setting have on the engine? This is a bit difficult for the novice to pinpoint unless he can compare performance to a properly set up car. In general, however, an engine equipped with AAA5776, but with the valve clearance set at 0.012 in. will be very low on power. An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter. You should also bear in mind the fact that while clearance which is too large is noisy, it doesn't necessarily produce any mechanical damage. On the other hand, burnt exhaust valves will almost surely result from unduly small valve clearance, as in the case of an AAA5776 cam set at 0.012 in.[/b]    Clive, Oxford, UK  [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1522512022&sig=uUMyHEn5bv8f71uRXE6H3g--~D[/img]Virus-free. www.avast.com  On Sun, Feb 18, 2018 at 2:30 PM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:  Bill, New timing chain, timing wheels & tensioner, new cam followers, the clatter is definitely from the tappets. I m pretty sure the camshaft is original as it hasn t been changed the mid 1950 s. I doubt it would have been changed in its first 6 or 7 years on the road.  [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b] [b]From:[/b] Bill Hyatt [mailto:usaj24@earthlink.net] [b]Sent:[/b] 18 February 2018 14:05 [b]To:[/b] Norman Verona norman@frenchblat.com> [b]Cc:[/b] David James dr.david.james@gmail.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949) Guys, Clatter can also come from timing chain tensioner as it translates back and forth axially-Bill HyattSent from my iPhone On Feb 18, 2018, at 6:01 AM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:  David, My clatter is from the tappets. The tappet faces are good (I ve fully rebuilt the engine) As far as I know it s a 0.017 camshaft.. I ll try reducing them to m0.015 and if the clatter is the same open them back up to 0.017 . I don t over rev the engine, 4000 rpm is about as high as I take it. It s as standard as it can be apart from 0.040 oversize pistons from a rebore before I bought the car. I don t need speed from this car, I have a manic Caterham with 220 BHP weighing 500 kgs. That s for the time I want to shake some cobwebs. Also my everyday car is a 189 bhp Lotus Elise. The TC is for driving sedately along country roads.  [b][i]Norman Verona[/i][/b]11 Cherry Close, Royston, South Yorkshire S71 4LZPhone: 0044 (0)1226 728811Mob: 0044 (0)741 9905 741[b][i]Web: www.frenchblat.com[/i][/b] [b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]David James dr..david.james@gmail.com [mg-tabc] [b]Sent:[/b] 18 February 2018 10:10 [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Re: Tappet clearnace on TC (1949)   I had noticed play in the distributor shaft of my 1948 TC, along with quite a lot of oil in the distributor top, and thought this might be the cause of the noisy engine. So I replaced the bushes in the distributor body. This cured the oil problem, but not the clatter. So I used the method given on the MGCC Y-Type Register web site to determine that the camshaft was still of the type that required a 19thou tappet clearance. On the basis that there are indents on the rockers that my feeler gauge would not detect, I set the clearance to 17thou. It is still noisy, but I am reluctant to reduce the clearance further. David (TC4985)     #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436 -- #ygrps-yiv-79588548yiv2346962436ygrp-mkp { border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;} #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436ygrp-mkp hr { border:1px solid #d8d8d8;} #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436ygrp-mkp #ygrps-yiv-79588548yiv2346962436hd { color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;} #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436ygrp-mkp #ygrps-yiv-79588548yiv2346962436ads { margin-bottom:10px;} #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436ygrp-mkp .ygrps-yiv-79588548yiv2346962436ad { padding:0 0;} #ygrps-yiv-79588548 #ygrps-yiv-79588548yiv2346962436 #ygrps-yiv-79588548yiv2346962436ygrp-mkp .ygrps-yiv-79588548yiv2346962436ad p { margin:0;} 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[Norman Verona]

Bill,

 

You re forgetting the gap required by the camshaft to avoid excess wear on the cam and follower. The XPAG camshaft has a steep rise on the cam and requires a larger than normal gap to allow the cam not to hit the follower. Later cams had this steep rise lowered allowing a lower gap.

 

To be honest, if all we re talking about is a gap for heat expansion of the metal then 0.005 would probably be sufficient.

 

I once tested a BMC A series engine (Mini and 1970 s Midget) to see what the lowest gap I could get to allow enough for heat expansion. It was 0.003 The standard gap is 0.012

 

 

[b][i]Norman Verona[/i][/b]

11 Cherry Close, Royston, South Yorkshire S71 4LZ

Phone: 0044 (0)1226 728811

Mob: 0044 (0)741 9905 741

[b][i]Web: www.frenchblat.com[/i][/b]

 

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]Bill Hyatt usaj24@earthlink.net [mg-tabc] [b]Sent:[/b] 22 February 2018 16:40 [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] Fwd: [mg-tabc] Re: Tappet clearnace on TC (1949)

 

 

 

-Bill Hyatt

Sent from my iPhone

Begin forwarded message:

[b]From:[/b] Bill Hyatt usaj24@earthlink.net> [b]Date:[/b] February 21, 2018 at 8:02:24 PM EST [b]To:[/b] Duncan morelists@yahoo.com> [b]Subject:[/b] [b]Re: [mg-tabc] Re: Tappet clearnace on TC (1949)[/b]

Group, 

It is disconcerting to see such ill informed discussion re adjusting valves. This is not rocket science, it is basically about valve train not locking up as various metal components in v. train expand from engine heat, at whatever heat generating RPM!

All the methodologies presented assume that components in valve train are per OEM spec. Not necessarily so. The cam circle base may be worn, lifter bases could be concave, if the cam chain is sloppy worn,  the base circle location needed, could be erroneous by many degrees even if tensioner shoe spring is in spec (unlikely). Then there are related issues due to wear in push rod ends, wear in rocker assembly including rocker shoe face. A worn timing chain can have a big effect on ignition timing as Al Moss succinctly points out. Alas, it seems to be overlooked that ideal valve clearance is moving target and a function of internal component wear along with thermal heat potential to expand valve train components locking v.train up.

The base solution should be that there is enough  clearance to insure that valve train has enough room to heat expand & not lock up engine valve train,  along with adequate clatter producing safety margin extra clearance.

 

-Bill Hyatt

   TC 4926

Sent from my iPhone

On Feb 21, 2018, at 6:37 PM, Duncan morelists@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

 

Norman, if a spray of hot oil is a concern, the usual go around is a modified spare valve cover with access slot or holes punched out on the top of it.   Al Moss said  he would temporarily block oil flow of feeder tube to head.   

 

 

From: "'Norman Verona' norman@frenchblat.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: 'Duncan' morelists@yahoo.com>; 'MG-TABC List' mg-tabc@yahoogroups.com>; 'CLIVE SHERRIFF' csherriff99@gmail.com> Sent: Wednesday, February 21, 2018 2:23 PM Subject: RE: [mg-tabc] Re: Tappet clearnace on TC (1949)

 

 

Duncan,

 

I sometime adjust tappets with the engine running, on other engines. However, with The TC with standard rockers there would be a lake of oil if I did that.

 

 

[b][i]Norman Verona[/i][/b]

11 Cherry Close, Royston, South Yorkshire S71 4LZ

Phone: 0044 (0)1226 728811

Mob: 0044 (0)741 9905 741

[b][i]Web: www.frenchblat.com[/i][/b]

 

[b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]Duncan morelists@yahoo.com [mg-tabc] [b]Sent:[/b] 21 February 2018 18:55 [b]To:[/b] MG-TABC List mg-tabc@yahoogroups.com>; CLIVE SHERRIFF csherriff99@gmail.com> [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949)

 

 

The mg-tabc.org "resources" section has an interesting article about adjusting valves.  [url=http://www..mg-tabc.org/library/valve_adjust.htm]http://www.mg-tabc.org/library/valve_adjust.htm[/url]

Jerry Austin mentions the importance of setting points and correct ignition timing prior to adjusting valves.  He even mentions adjusting the valves with the engine running! 

 

Below the article is a comment by Al Moss.  He claims the engine running adjustment can be done entirely by ear, with no feelers of any kind, and you do not need to have any prior knowledge of what sort of cam is in there.  He ends the comment by suggesting doubter's check the results with a vacuum gauge!   

Duncan-

TC9866-

From: "CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> To: Norman Verona norman@frenchblat.com> [b]Cc:[/b] Bill Hyatt usaj24@earthlink.net>; David James dr.david.james@gmail.com>; yahoogroups mg-tabc@yahoogroups.com> Sent: Wednesday, February 21, 2018 3:20 AM Subject: Re: [mg-tabc] Re: Tappet clearnace on TC (1949)

 

 

Norman,

 

NEVER, but NEVER make assumptions.  If your engine had so much wear that it needed rebores up to 0.040 before you bought it, I'd say it might well have needed, and had, a new cam too.

 

 

TRY THIS,  note uin last paragraph " [b] An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter"[/b]

 

[b]So:-[/b]

 

[b]Camshaft -  Determination   Two different camshafts were supplied as original equipment for the XPAG and XPEG engines. The earliest type, part number AAA5776 (earlier numbers MG862/171 or X24084), was used in all TB and TC engines, and in TD engines up to engine number XPAG/TD2/24l15. This early cam requires a valve clearance of 0.019 in. [/b]

[b] [/b]

[b]The later type, part number AAA3096 (earlier number 168553) was used in all later TD and TF engines and requires a valve clearance of 0.012 in.   Unfortunately, now that even the newest TF is almost 40 years old, the engine numbers quoted above are not necessarily a valid guide for purpose of camshaft identification. Engines originally equipped with AAA5776 may have been fitted with AAA3096 in the course of an overhaul.   [/b]

[b] [/b]

[b]With the engine cold, remove the rocker cover and turn the engine over with the crank until #1 intake valve (2nd valve from front of engine) is wide open. At this point, #4 intake valve (7th from front) will be fully closed and on the exact center of the heel of the  cam lobe. Set #4 intake to 0.021 in. clearance. This is the correct checking clearance for both cams, regardless of whether you use the degree wheel and dial indicator method or the simplified method which follows.   Now, wipe all the accumulated gook off the crankshaft pulley, and get out your measuring tape and a piece of chalk. Measuring around the rim of the pulley. make one chalk mark between 1/32 in. and 3/64 in. to the right (as seen from the front) of the top dead centre mark on the pulley. This corresponds to 5 BTDC, which is when the intake opens on the later cam (AAA3096). [/b]

[b] [/b]

[b]Make a second chalk mark 23/64 in. to the right of the TDC mark. This corresponds to 11 BTDC, which is when the intake opens on the earlier cam (AAA5776).   Next, turn the engine over with the crank (it's easier with the spark plugs out) until the pushrod for #4 intake valve just barely locks up enough so that you can't spin it between your fingers. At this point, the timing pointer on the timing chain cover should be more or less aligned with one or the other of the chalk marks.   [/b]

[b] [/b]

[b]If the pointer aligns with the 11 mark, then you have the early cam (AAA5776) and you should set the valve clearance to 0.019 in. with the engine hot. If the pointer aligns with the 5 mark then you have the later cam (AAA3096) and you should set the valve clearance to 0.012 in. hot. If the pointer does not align with either mark, go back through the entire procedure again to make sure you did it right.   [/b]

[b] [/b]

[b]What effect does the wrong valve clearance setting have on the engine? This is a bit difficult for the novice to pinpoint unless he can compare performance to a properly set up car. In general, however, an engine equipped with AAA5776, but with the valve clearance set at 0.012 in. will be very low on power. An engine equipped with AAA3096, but with the clearance met at 0.019 in. will be slightly down on power and will produce a really awful amount  of valve clatter. You should also bear in mind the fact that while clearance which is too large is noisy, it doesn't necessarily produce any mechanical damage. On the other hand, burnt exhaust valves will almost surely result from unduly small valve clearance, as in the case of an AAA5776 cam set at 0.012 in.[/b]

 

 

Clive, Oxford, UK

 

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On Sun, Feb 18, 2018 at 2:30 PM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

 

Bill,

 

New timing chain, timing wheels & tensioner, new cam followers, the clatter is definitely from the tappets. I m pretty sure the camshaft is original as it hasn t been changed the mid 1950 s. I doubt it would have been changed in its first 6 or 7 years on the road.

 

 

[b][i]Norman Verona[/i][/b]

11 Cherry Close, Royston, South Yorkshire S71 4LZ

Phone: 0044 (0)1226 728811

Mob: 0044 (0)741 9905 741

[b][i]Web: www.frenchblat.com[/i][/b]

 

[b]From:[/b] Bill Hyatt [mailto:usaj24@earthlink.net] [b]Sent:[/b] 18 February 2018 14:05 [b]To:[/b] Norman Verona norman@frenchblat.com> [b]Cc:[/b] David James dr.david.james@gmail.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: Tappet clearnace on TC (1949)

 

Guys, 

Clatter can also come from timing chain tensioner as it translates back and forth axially

-Bill Hyatt

Sent from my iPhone

On Feb 18, 2018, at 6:01 AM, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

 

David,

 

My clatter is from the tappets. The tappet faces are good (I ve fully rebuilt the engine) As far as I know it s a 0.017 camshaft..

 

I ll try reducing them to m0.015 and if the clatter is the same open them back up to 0.017 .

 

I don t over rev the engine, 4000 rpm is about as high as I take it. It s as standard as it can be apart from 0.040 oversize pistons from a rebore before I bought the car.

 

I don t need speed from this car, I have a manic Caterham with 220 BHP weighing 500 kgs. That s for the time I want to shake some cobwebs. Also my everyday car is a 189 bhp Lotus Elise. The TC is for driving sedately along country roads.

 

 

[b][i]Norman Verona[/i][/b]

11 Cherry Close, Royston, South Yorkshire S71 4LZ

Phone: 0044 (0)1226 728811

Mob: 0044 (0)741 9905 741

[b][i]Web: www.frenchblat.com[/i][/b]

 

[b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]David James dr..david.james@gmail.com [mg-tabc] [b]Sent:[/b] 18 February 2018 10:10 [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Re: Tappet clearnace on TC (1949)

 

 

I had noticed play in the distributor shaft of my 1948 TC, along with quite a lot of oil in the distributor top, and thought this might be the cause of the noisy engine. So I replaced the bushes in the distributor body. This cured the oil problem, but not the clatter. So I used the method given on the MGCC Y-Type Register web site to determine that the camshaft was still of the type that required a 19thou tappet clearance. On the basis that there are indents on the rockers that my feeler gauge would not detect, I set the clearance to 17thou. It is still noisy, but I am reluctant to reduce the clearance further. David (TC4985)