TC rocker shaft

[Robert Grunau]

I have just stripped my TC rocker shaft and it shows typical "X" wear on the bottom after 39,000 miles. Wear is about 0.003" ( 3 thou. ). I am using TC valve springs. Can anyone explain why the oil feed holes on the rocker shaft feed oil to the top unloaded side of the rockers instead of the loaded bottom? Has anyone tried flipping the rocker shaft over so the oil feed holes point down to the contact area on the underside? Of course a new oil feed hole from the rear pedestal is required Bob Grunau --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.323 / Virus Database: 180 - Release Date: 2/8/02

[cameron@magma.ca]

Bob Gruneau wrote: "... Can anyone explain why the oil feed holes on the rocker shaft feed oil to the top unloaded side of the rockers instead of the loaded bottom? ...." Could it be that the designer was accustomed to putting the oil feed holes on the unloaded side of rotating shafts with hydrodynamic lubrication, and did the same on the rocker shaft without pausing to think about it ? David Cameron Metcalfe, Ont

[Eric Worpe]

Hi Bob and t-abc listers, The rocker bush should have an X pattern oil groove machined in it. The centre section of the X should be adjacent to the oil hole in the rocker shaft when the rocker is at rest. This should enable oil to circulate around some of the load area. When the rocker is operated, the small hole in the top of the rocker should align itself with the oil feed hole in the rocker shaft, allowing a spurt of oil through the hole to provide general lubrication to the internals of the rocker box. Some of the oil should also find its way to the rocker adjustment screw through a longitudinal hole to lubricate the ball and socket on top of the push rod. Problems with rocker bushes could be due to the bushes not being aligned correctly in the rockers. I only offer this as a possible explanation as I need to look into the issue a bit more thoroughly. Regards, Eric.

[Roger Furneaux]

Re: [mg-tabc] TC rocker shaft hi Bob - have you seen the latest "Octagon Bulletin"? Very interesting comments on this subject - basically the oil feed holes are [b]not needed,[/b] without them there will be a higher pressure of oil film, and the top end is quieter! oc[b]T[/b]agonally Roger

[quote]I have just stripped my TC rocker shaft and it shows typical "X" wear on the bottom after 39,000 miles. Wear is about 0.003" ( 3 thou. ). I am using TC valve springs. Can anyone explain why the oil feed holes on the rocker shaft feed oil to the top unloaded side of the rockers instead of the loaded bottom? Has anyone tried flipping the rocker shaft over so the oil feed holes point down to the contact area on the underside? Of course a new oil feed hole from the rear pedestal is required Bob Grunau

[/quote]

[Robert Grunau]

Re: [mg-tabc] TC rocker shaft Hi Roger,

No, do not yet have that OCC Bulletin.

But, I am talking about the oil feed holes in the rocker SHAFT. These normally point upwards to the unloaded side of the rocker bush, WHY?? Seems to me better lubrication to flip the shaft, drill a new single feed hole for the rear pedastel, feed oil under pressure to the contact area of the rocker bush.

And yes, I doubt the oil holes in the rockers themselves are necessary, surely the oil will escape out the sides of the bushes..

England type weather here today, 8 C, cool and rainy and I see green grass. Spring can t be too far away.

Regards, Bob Grunau

-----Original Message----- [b]From:[/b] Roger Furneaux [mailto:Roger.46TC@virgin.net] [b]Sent:[/b] Wednesday, February 20, 2002 1:31 PM [b]To:[/b] cgrunau@pathcom.com [b]Cc:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] TC rocker shaft

hi Bob - have you seen the latest "Octagon Bulletin"? Very interesting comments on this subject - basically the oil feed holes are [b]not needed,[/b] without them there will be a higher pressure of oil film, and the top end is quieter! oc[b]T[/b]agonally Roger

I have just stripped my TC rocker shaft and it shows typical "X" wear on the bottom after 39,000 miles. Wear is about 0.003" ( 3 thou. ). I am using TC valve springs. Can anyone explain why the oil feed holes on the rocker shaft feed oil to the top unloaded side of the rockers instead of the loaded bottom? Has anyone tried flipping the rocker shaft over so the oil feed holes point down to the contact area on the underside? Of course a new oil feed hole from the rear pedestal is required Bob Grunau

[Robert Grunau]

Thanks Eric, All the rockers and bushes are as you describe. I just checked all the bleed holes and they are now all clear to the rocker adjusting screws ( a couple were plugged ). I probably did not clear then out when I first restored the car in 1970/71. I still think the oil pressure would be better directed to the lower side of the rockers where the load occurs rather than the top. The stock situation puts oil pressure to the top, unloaded and clearanced side. I have decided to try flipping the shaft using the old shaft and directing the 8 feed holes in the shaft downwards. I have a new Crane cam and new cam followers so will remove the followers after about five thousand miles to check condition of followers and cam lobes. I will also check rocker shaft wear at that time. We will see! Regards, Bob Grunau . -----Original Message----- From: Eric Worpe [mailto:E.Worpe@surrey.ac.uk] Sent: Wednesday, February 20, 2002 7:42 AM To: cgrunau; mg-tabc@yahoogroups.com Subject: Re: [mg-tabc] TC rocker shaft Hi Bob and t-abc listers, The rocker bush should have an X pattern oil groove machined in it. The centre section of the X should be adjacent to the oil hole in the rocker shaft when the rocker is at rest. This should enable oil to circulate around some of the load area. When the rocker is operated, the small hole in the top of the rocker should align itself with the oil feed hole in the rocker shaft, allowing a spurt of oil through the hole to provide general lubrication to the internals of the rocker box. Some of the oil should also find its way to the rocker adjustment screw through a longitudinal hole to lubricate the ball and socket on top of the push rod. Problems with rocker bushes could be due to the bushes not being aligned correctly in the rockers. I only offer this as a possible explanation as I need to look into the issue a bit more thoroughly. Regards, Eric. Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.323 / Virus Database: 180 - Release Date: 2/8/02 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.323 / Virus Database: 180 - Release Date: 2/8/02