Carburettor butterflies

[frenchblatter]

This isn't my TC but a friends. The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone. I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now. However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn. In over 50 years of working on SU's I've never seen oval throats. Any thoughts? In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Peter Cole]

Norman Mike Sherry Lloyd talks about carb bodies in TCs Forever. They don't wear, but they do distort due to the pot metal early bodies were made from. For once repros from Burlen are better than old ones. Other problems to look for is leaking shafts and the butterfly being fitted a.a.f. As I'm sure you know they have a chamfered rim to help effect a seal in the throat. If they are fitted incorrectly to the spindle they won't seal well. Regards Peter Cole

On 23 Nov 2017 18:43, "norman@frenchblat.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]

This isn't my TC but a friends. The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone. I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now. However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn. In over 50 years of working on SU's I've never seen oval throats. Any thoughts? In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Rothgene]

Check for air leaks at the intake manifold   [b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies     This isn't my TC but a friends. The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone. I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now. However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn. In over 50 years of working on SU's I've never seen oval throats. Any thoughts? In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[M. P.]

Air leaks? Exactly!!!   While the throttle shafts and butterflies are proper items to check on a complete rebuild, it is very hard sometimes to convince one to keep one's hands off of the carbs when the engine starts running poorly.  A check on proper valve lash, then distributor settings including point gap and timing and finally idle speed.   Air leakage checks at the base of the carbs to manifold and manifold to block by spraying carb cleaner in and around the interfacings.  A spray of carb cleaner at both ends of the carb throttle shaft as well.  An engine stumble and recovery indicates an air leak.  Once you have checked all of that then you can proceed to the carbs and the normal course of action including float bowl height, air flow balanced carb to carb, needle height, fuel flow, fuel filter and so on.   Sent from Yahoo Mail on Android

On Thu, Nov 23, 2017 at 4:27 PM, Rothgene rothgene@msn.com [mg-tabc]mg-tabc-noreply@yahoogroups.com> wrote:   Check for air leaks at the intake manifold   [b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies     This isn't my TC but a friends. The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone. I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now. However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn. In over 50 years of working on SU's I've never seen oval throats. Any thoughts? In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies. #ygrps-yiv-1792238365 #ygrps-yiv-1792238365yiv5338118814 #ygrps-yiv-1792238365yiv5338118814 -- #ygrps-yiv-1792238365yiv5338118814ygrp-mkp { border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;} #ygrps-yiv-1792238365 #ygrps-yiv-1792238365yiv5338118814 #ygrps-yiv-1792238365yiv5338118814ygrp-mkp hr { border:1px solid #d8d8d8;} #ygrps-yiv-1792238365 #ygrps-yiv-1792238365yiv5338118814 #ygrps-yiv-1792238365yiv5338118814ygrp-mkp #ygrps-yiv-1792238365yiv5338118814hd { color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;} #ygrps-yiv-1792238365 #ygrps-yiv-1792238365yiv5338118814 #ygrps-yiv-1792238365yiv5338118814ygrp-mkp #ygrps-yiv-1792238365yiv5338118814ads { margin-bottom:10px;} #ygrps-yiv-1792238365 #ygrps-yiv-1792238365yiv5338118814 #ygrps-yiv-1792238365yiv5338118814ygrp-mkp .ygrps-yiv-1792238365yiv5338118814ad { padding:0 0;} #ygrps-yiv-1792238365 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[Norman Verona]

There are no leaks at the manifold, the flanges aren’t bowed, the butterflies are in the correct way (but weren’t fully centralised).

 

Just for the record, I started work on January 1st at University Motors and on the Thursday was shown how to overhaul a pair of SU’s  on a TC.  That was 1961.However, after all these years of messing about with cars I’ve never come across a distorted carb body. As I’ve said before, it doesn’t matter how much you know, you’ll always learn more.

 

 

[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] Rothgene [mailto:RothGene@msn.com] [b]Sent:[/b] 23 November 2017 23:27 [b]To:[/b] mg-tabc@yahoogroups.com; norman@frenchblat.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies

 

Check for air leaks at the intake manifold   

 

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies

 

 

This isn't my TC but a friends.

 

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.

 

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.

 

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.

 

In over 50 years of working on SU's I've never seen oval throats.

 

Any thoughts?

 

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Norman Verona]

All that s been checked and tested. For the record this is the car worked on by John Twist at the recent UK seminar on how to tune a TC John couldn t get the tickover below (approx.) 1500 rpm. The owner said he was going to take it back to the chap who had done the carbs. Several of us thought that probably wasn t a good idea see how poorly the engine had been before John went through everything.

 

I have taken the carbs off and centralised the butterflies, they now close fully but there are visible gaps either side by the spindles. I will assume that the bodies are warped and deal with that.

 

Thanks

 

 

[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]'M. P.' imabystander@yahoo.com [mg-tabc] [b]Sent:[/b] 24 November 2017 00:14 [b]To:[/b] mg-tabc-noreply@yahoogroups.com; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies

 

 

Air leaks? Exactly!!!   While the throttle shafts and butterflies are proper items to check on a complete rebuild, it is very hard sometimes to convince one to keep one's hands off of the carbs when the engine starts running poorly.  A check on proper valve lash, then distributor settings including point gap and timing and finally idle speed.   Air leakage checks at the base of the carbs to manifold and manifold to block by spraying carb cleaner in and around the interfacings.  A spray of carb cleaner at both ends of the carb throttle shaft as well.  An engine stumble and recovery indicates an air leak.  Once you have checked all of that then you can proceed to the carbs and the normal course of action including float bowl height, air flow balanced carb to carb, needle height, fuel flow, fuel filter and so on.  

Sent from Yahoo Mail on Android

 

On Thu, Nov 23, 2017 at 4:27 PM, Rothgene rothgene@msn.com [mg-tabc]

mg-tabc-noreply@yahoogroups.com> wrote:

 

Check for air leaks at the intake manifold   

 

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies

 

 

This isn't my TC but a friends.

 

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.

 

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.

 

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.

 

In over 50 years of working on SU's I've never seen oval throats.

 

Any thoughts?

 

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Trevor Burnett]

Whilst on the discussion, I was given a body with a badly distorted flange, I placed the body in my hydraulic press with light pressure then heated it up with a heat gun slowly applying add. pressure, between the gentle press application and the heat gun and leaving the body to cool down with the applied pressure, the flange only required light lapping to achieve perfect “flatness”.

 

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Norman Verona' norman@frenchblat.com [mg-tabc] [b]Sent:[/b] 2017/11/24 11:11 AM [b]To:[/b] 'Rothgene'; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies

 

 

There are no leaks at the manifold, the flanges aren’t bowed, the butterflies are in the correct way (but weren’t fully centralised).

 

Just for the record, I started work on January 1st at University Motors and on the Thursday was shown how to overhaul a pair of SU’s  on a TC.  That was 1961.However, after all these years of messing about with cars I’ve never come across a distorted carb body. As I’ve said before, it doesn’t matter how much you know, you’ll always learn more.

 

 

[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] Rothgene [mailto:RothGene@msn.com] [b]Sent:[/b] 23 November 2017 23:27 [b]To:[/b] mg-tabc@yahoogroups.com; norman@frenchblat.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies

 

Check for air leaks at the intake manifold   

 

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies

 

 

This isn't my TC but a friends.

 

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.

 

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.

 

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.

 

In over 50 years of working on SU's I've never seen oval throats.

 

Any thoughts?

 

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Norman Verona]

I’ve heard that many think the distortion to the flange is from overtightening whereas it’s from heat. It happens far less on cars with plastic insulating blocks hence why, after getting my flanges flat (no comments please) I fitted longer studs and plastic blocks as per the MGA.

 

 

 

 

 

[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]'Trevor Burnett' trevor@safxmarine.co.za [mg-tabc] [b]Sent:[/b] 24 November 2017 10:40 [b]To:[/b] 'Norman Verona' norman@frenchblat.com>; 'Rothgene' RothGene@msn.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies

 

 

Whilst on the discussion, I was given a body with a badly distorted flange, I placed the body in my hydraulic press with light pressure then heated it up with a heat gun slowly applying add. pressure, between the gentle press application and the heat gun and leaving the body to cool down with the applied pressure, the flange only required light lapping to achieve perfect “flatness”.

 

[b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Norman Verona' norman@frenchblat.com [mg-tabc] [b]Sent:[/b] 2017/11/24 11:11 AM [b]To:[/b] 'Rothgene'; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies

 

 

There are no leaks at the manifold, the flanges aren’t bowed, the butterflies are in the correct way (but weren’t fully centralised).

 

Just for the record, I started work on January 1st at University Motors and on the Thursday was shown how to overhaul a pair of SU’s  on a TC.  That was 1961.However, after all these years of messing about with cars I’ve never come across a distorted carb body. As I’ve said before, it doesn’t matter how much you know, you’ll always learn more.

 

 

[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] Rothgene [RothGene@msn.com] [b]Sent:[/b] 23 November 2017 23:27 [b]To:[/b] mg-tabc@yahoogroups.com; norman@frenchblat.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies

 

Check for air leaks at the intake manifold   

 

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies

 

 

This isn't my TC but a friends.

 

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.

 

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.

 

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.

 

In over 50 years of working on SU's I've never seen oval throats.

 

Any thoughts?

 

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.

[Peter Cole]

Norman, We seem to be discussing two different problems here. If the butterflies don't close properly then the car is likely to tick over too fast as you report due, to an excess of fuel and air entering the engine. If there are any leaks from the spindles, the inlet manifold or due to lack of flatness of the flanges air will certainly be sucked in, but no fuel with it, so the engine will run weak and probably stall. Regards Peter Cole.

On 24 November 2017 at 11:07, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u] I ve heard that many think the distortion to the flange is from overtightening whereas it s from heat. It happens far less on cars with plastic insulating blocks hence why, after getting my flanges flat (no comments please) I fitted longer studs and plastic blocks as per the MGA.[u][/u][u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

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

11 Cherry Close, Royston, South Yorkshire S71 4LZ[u][/u][u][/u]

Phone: 0044 (0)1226 728811[u][/u][u][/u]

Mob: 0044 (0)741 9905 741[u][/u][u][/u]

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

[u][/u] [u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Trevor Burnett' trevor@safxmarine.co.za [mg-tabc] [b]Sent:[/b] 24 November 2017 10:40 [b]To:[/b] 'Norman Verona' norman@frenchblat.com>; 'Rothgene' RothGene@msn.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

[u][/u] [u][/u]

[u][/u][u][/u]

Whilst on the discussion, I was given a body with a badly distorted flange, I placed the body in my hydraulic press with light pressure then heated it up with a heat gun slowly applying add. pressure, between the gentle press application and the heat gun and leaving the body to cool down with the applied pressure, the flange only required light lapping to achieve perfect flatness .[u][/u][u][/u]

[u][/u][u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Norman Verona' norman@frenchblat.com [mg-tabc] [b]Sent:[/b] 2017/11/24 11:11 AM [b]To:[/b] 'Rothgene'; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

[u][/u][u][/u]

[u][/u][u][/u]

There are no leaks at the manifold, the flanges aren t bowed, the butterflies are in the correct way (but weren t fully centralised).[u][/u][u][/u]

[u][/u][u][/u]

Just for the record, I started work on January 1st at University Motors and on the Thursday was shown how to overhaul a pair of SU s on a TC. That was 1961.However, after all these years of messing about with cars I ve never come across a distorted carb body. As I ve said before, it doesn t matter how much you know, you ll always learn more.[u][/u][u][/u]

[u][/u][u][/u]

[u][/u][u][/u]

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

11 Cherry Close, Royston, South Yorkshire S71 4LZ[u][/u][u][/u]

Phone: 0044 (0)1226 728811[u][/u][u][/u]

Mob: 0044 (0)741 9905 741[u][/u][u][/u]

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

[u][/u][u][/u]

[b]From:[/b] Rothgene [RothGene@msn.com] [b]Sent:[/b] 23 November 2017 23:27 [b]To:[/b] mg-tabc@yahoogroups.com; norman@frenchblat.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

[u][/u][u][/u]

Check for air leaks at the intake manifold[u][/u][u][/u] [u][/u][u][/u] [u][/u][u][/u]

[u][/u][u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies [u][/u][u][/u]

[u][/u][u][/u]

[u][/u][u][/u]

This isn't my TC but a friends.[u][/u][u][/u]

[u][/u][u][/u]

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.[u][/u][u][/u]

[u][/u][u][/u]

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.[u][/u][u][/u]

[u][/u][u][/u]

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.[u][/u][u][/u]

[u][/u][u][/u]

In over 50 years of working on SU's I've never seen oval throats.[u][/u][u][/u]

[u][/u][u][/u]

Any thoughts?[u][/u][u][/u]

[u][/u][u][/u]

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.[u][/u][u][/u]

[u][/u][u][/u]

[Norman Verona]

Peter, there are no airleaks and the butterfies are closing fully. The problem is the bodies are warped and air is paasing the butterflies at the sides. The top and bottom are fully closed

On 24 Nov 2017, at 12:19, "Peter Cole pcoleuk@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> wrote:   Norman, We seem to be discussing two different problems here.  If the butterflies don't close properly then the car is likely to tick over too fast as you report due, to an excess of fuel and air entering the engine.  If there are any leaks from the spindles, the inlet manifold or due to lack of flatness of the flanges air will certainly be sucked in, but no fuel with it, so the engine will run weak and probably stall. Regards Peter Cole.    On 24 November 2017 at 11:07, 'Norman Verona' norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]   I ve heard that many think the distortion to the flange is from overtightening whereas it s from heat. It happens far less on cars with plastic insulating blocks hence why, after getting my flanges flat (no comments please) I fitted longer studs and plastic blocks as per the MGA.[u][/u][u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

[u][/u] [u][/u]

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

11 Cherry Close, Royston, South Yorkshire S71 4LZ[u][/u][u][/u]

Phone: 0044 (0)1226 728811[u][/u][u][/u]

Mob: 0044 (0)741 9905 741[u][/u][u][/u]

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

[u][/u] [u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Trevor Burnett' trevor@safxmarine.co.za [mg-tabc] [b]Sent:[/b] 24 November 2017 10:40 [b]To:[/b] 'Norman Verona' norman@frenchblat.com>; 'Rothgene' RothGene@msn.com>; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

[u][/u] [u][/u]

  [u][/u][u][/u]

Whilst on the discussion, I was given a body with a badly distorted flange, I placed the body in my hydraulic press with light pressure then heated it up with a heat gun slowly applying add. pressure, between the gentle press application and the heat gun and leaving the body to cool down with the applied pressure, the flange only required light lapping to achieve perfect flatness .[u][/u][u][/u]

 [u][/u][u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com [mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Norman Verona' norman@frenchblat.com [mg-tabc] [b]Sent:[/b] 2017/11/24 11:11 AM [b]To:[/b] 'Rothgene'; mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

 [u][/u][u][/u]

  [u][/u][u][/u]

There are no leaks at the manifold, the flanges aren t bowed, the butterflies are in the correct way (but weren t fully centralised).[u][/u][u][/u]

 [u][/u][u][/u]

Just for the record, I started work on January 1st at University Motors and on the Thursday was shown how to overhaul a pair of SU s  on a TC.  That was 1961.However, after all these years of messing about with cars I ve never come across a distorted carb body. As I ve said before, it doesn t matter how much you know, you ll always learn more.[u][/u][u][/u]

 [u][/u][u][/u]

 [u][/u][u][/u]

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

11 Cherry Close, Royston, South Yorkshire S71 4LZ[u][/u][u][/u]

Phone: 0044 (0)1226 728811[u][/u][u][/u]

Mob: 0044 (0)741 9905 741[u][/u][u][/u]

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

 [u][/u][u][/u]

[b]From:[/b] Rothgene [RothGene@msn.com] [b]Sent:[/b] 23 November 2017 23:27 [b]To:[/b] mg-tabc@yahoogroups.com; norman@frenchblat.com [b]Subject:[/b] Re: [mg-tabc] Carburettor butterflies[u][/u][u][/u]

 [u][/u][u][/u]

Check for air leaks at the intake manifold[u][/u][u][/u]  [u][/u][u][/u]  [u][/u][u][/u]

 [u][/u][u][/u]

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of norman@frenchblat.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] Thursday, November 23, 2017 6:43 PM [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Carburettor butterflies [u][/u][u][/u]

 [u][/u][u][/u]

  [u][/u][u][/u]

This isn't my TC but a friends.[u][/u][u][/u]

 [u][/u][u][/u]

The engine will not run slower than 1500 rpm, even with all adjustments screws fully undone.[u][/u][u][/u]

 [u][/u][u][/u]

I diagnosed, remotely that the new butterflys fitted by the chap who'd sold him the car wern't centalised. I went there today and took the carbs off. The butterflys weren't correctly centaliseed and the throttles close fully now.[u][/u][u][/u]

 [u][/u][u][/u]

However I notice that there is a large gap on the sides of the butterfly's and, when refitted, the engine is still running fast. Jerry, the owner says the chap who's been working on says it needs new carbs because the "throats" are worn.[u][/u][u][/u]

 [u][/u][u][/u]

In over 50 years of working on SU's I've never seen oval throats.[u][/u][u][/u]

 [u][/u][u][/u]

Any thoughts?[u][/u][u][/u]

 [u][/u][u][/u]

In the meantime I'm ordering new spindles and butterflys as I suspect the throttle adjusting arms have been drilled in the wrong plalce and the slot in the spindle is too far over one way stopping the butterfly being fitted. To overcome this it looks like he's filed the sides of the butterflies.[u][/u][u][/u]

[u][/u][u][/u]