MGC Forum
Partial rebuild underway
Posted by tjh
Topic Creator (OP)
Mar 19, 2018 10:27 AM
Joined 10 years ago
68 Posts
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Hi all
The long awaited partial rebuild of my C is now firmly underway and I am finding a few interesting anomalies as I go. One of these is the fact on a UK spec car manual with overdrive there is no angle drive the cable is screwed straight into the gear box. Could this explain a previous post issue where my speedo seems to hopelessly overstate the speed. The needle on the dial is quite steady. Do all UK models have an angle drive and what would be the impact of not having one.
For those interested the engine and Gearbox are out and the engine in the hands of an expert to tear down and do what is necesary. Planning a few tweaks to the motor nothing too intrusive.
- Lighten the flywheel
- Convert head for lead free and gas flow the head.
- Tublar branch exhaust manifold.
- Street CAM to 270 dergrees opening
- Electronic distributor.
Any thoughts and recommendations appreciated.
Thanks all Trevor
The long awaited partial rebuild of my C is now firmly underway and I am finding a few interesting anomalies as I go. One of these is the fact on a UK spec car manual with overdrive there is no angle drive the cable is screwed straight into the gear box. Could this explain a previous post issue where my speedo seems to hopelessly overstate the speed. The needle on the dial is quite steady. Do all UK models have an angle drive and what would be the impact of not having one.
For those interested the engine and Gearbox are out and the engine in the hands of an expert to tear down and do what is necesary. Planning a few tweaks to the motor nothing too intrusive.
- Lighten the flywheel
- Convert head for lead free and gas flow the head.
- Tublar branch exhaust manifold.
- Street CAM to 270 dergrees opening
- Electronic distributor.
Any thoughts and recommendations appreciated.
Thanks all Trevor
Mar 19, 2018 10:44 AM
Joined 7 years ago
366 Posts
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If I recall correctly when I had the angle drive out and I was spinning it by hand, the ratio seemed to be 1:1 so I don't think that the angle drive introduces any increase or decrease in spinning the cable. I know my non-OD right hand drive manual trans car has an angle drive. The parts catalog does not list an angle drive for the OD transmission, just a "bearing speedometer" which appears to be a straight-through unit.
Cheers,
Joel
MGC "how-to's" available on YouTube:
https://www.youtube.com/playlist?list=PLSuil-nCBffJwKeCv5ZKF02CgPkp1sVvj
Cheers,
Joel
MGC "how-to's" available on YouTube:
https://www.youtube.com/playlist?list=PLSuil-nCBffJwKeCv5ZKF02CgPkp1sVvj
Mar 19, 2018 10:56 AM
Joined 13 years ago
526 Posts
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kirks-auto
Robert Kirk (RIP)
Davenport, IA, USA
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Mar 19, 2018 11:46 AM
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Joined 15 years ago
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Most all after market distributors are from China....ALL Lucas replacements are from China. Given your location you may or maynot have a competent service but a rebuilt Lucas original would be my choice given the failures of Chinese goods over the long haul. There are experts in both the UK and USA who can tweek your unit and avoid the mostly unnecessary cost of "no lead head". FWIW, British cars are built to run on just about any sort of petrol found around the world as the world was the market place for these cars and the heads are very well made as OEM units. Valve seat inserts that fail can cause a lot of damage should they fall loose.
270 degrees seems rather aggressive for the street cam and ditto above about where new units are made.
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
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270 degrees seems rather aggressive for the street cam and ditto above about where new units are made.
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
Beat or match most retail/delivered quote
JMA
John Anderson
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Mar 19, 2018 04:16 PM
Top Contributor
Joined 7 years ago
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Trevor,
Depending on how you will be driving your car I am agreeing with Robert on the cam.
270° duration is a very aggressive cam, even for me a horsepower tragic. I'm in a similar position to you and currently doing set up for fuel injection, the cam I have chosen is "only" 240° duration and I wouldn't want my cam for a carburettor equipped street engine.
The rest of your list is highly recommended.
John
Depending on how you will be driving your car I am agreeing with Robert on the cam.
270° duration is a very aggressive cam, even for me a horsepower tragic. I'm in a similar position to you and currently doing set up for fuel injection, the cam I have chosen is "only" 240° duration and I wouldn't want my cam for a carburettor equipped street engine.
The rest of your list is highly recommended.
John
kirks-auto
Robert Kirk (RIP)
Davenport, IA, USA
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Mar 19, 2018 04:20 PM
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Joined 15 years ago
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270 is an all out race cam IMHO and the car will never idle with that duration FWIW. 240 or 250 are street driven cam profiles and 250 still lopes a lot at idle...rather rough.
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
Beat or match most retail/delivered quote
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
Beat or match most retail/delivered quote
windjammerusn40
windjammerusn40 McCord
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Mar 19, 2018 04:32 PM
Joined 15 years ago
887 Posts
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kirks-auto
Robert Kirk (RIP)
Davenport, IA, USA
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Mar 19, 2018 04:53 PM
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Joined 15 years ago
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In the USA (NA spec) manual trans have two angle drives...one at each end of the cable.
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
Beat or match most retail/delivered quote
Regards,
Robert Kirk
kirkbrit@yahoo.com
E-mail PLEASE for quote/questions/orders
Business phone 563 323 1017
http://kirks-auto.com/
Moss distributor/UK importer
Beat or match most retail/delivered quote
Mar 19, 2018 05:40 PM
Joined 13 years ago
526 Posts
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My reference was for UK cars. Just for clarity UK cars don't have an angle drive at the gearbox end or the speedo end either except autos which have it at the gearbox end ONLY.
US cars ALWAYS have it at the speedo end no matter what gearbox but NO angle drive on Overdrive gearboxes at the Gearbox end. Like UK cars US auto cars have an angle drive at the gearbox end. I'm not sure about US manual non overdrive gearboxes. I will have to check it out.
Hope this all helps. Brian.
US cars ALWAYS have it at the speedo end no matter what gearbox but NO angle drive on Overdrive gearboxes at the Gearbox end. Like UK cars US auto cars have an angle drive at the gearbox end. I'm not sure about US manual non overdrive gearboxes. I will have to check it out.
Hope this all helps. Brian.
Mar 20, 2018 01:16 AM
Joined 7 years ago
366 Posts
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In reply to # 3700164 by mgcbrian
My reference was for UK cars. Just for clarity UK cars don't have an angle drive at the gearbox end or the speedo end either except autos which have it at the gearbox end ONLY.
Are we sure about this? My UK car has an angle drive on the gearbox end. My trans is manual, non-OD.
Cheers,
Joel
MGC "how-to's" available on YouTube:
https://www.youtube.com/playlist?list=PLSuil-nCBffJwKeCv5ZKF02CgPkp1sVvj
Mar 20, 2018 02:50 AM
Joined 13 years ago
526 Posts
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Mar 20, 2018 12:25 PM
Joined 13 years ago
526 Posts
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Mar 20, 2018 06:10 PM
Top Contributor
Joined 16 years ago
2,667 Posts
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Cams what a wonderful subject,
I run a 312 and soon 320 , 270 is now a fast road cam . The 312 in the injection car idles at 800 no problem.
I run a 312 and soon 320 , 270 is now a fast road cam . The 312 in the injection car idles at 800 no problem.
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MGC Racing , Alloy parts and uprated items for the C, Engine rebuilds to full race or EFI. Secondhand parts available. Facebook page "Holmes racing"
www.holmesracing.co
Topic Creator (OP)
Mar 21, 2018 02:05 AM
Joined 10 years ago
68 Posts
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Thankyou for the many posts it would seem the UK variant for overdrive manual does not have an angle drive at either end and even if it did on a 1 to 1 gearing would not answer my problem on speedo reading. so I will service the cable and possibly get the gauge done as well.
As far as cam shaft goes so appreciate the posts and insights but I must confess I am somewhat confused. In readings that I have been doing it would seem a standard CAM has a lift of .254 inches and duration of 252 degrees and that a good street duration without impacting lift is about 270 and race spec 285 to 320. I guess I need to do more research into the matter and would appreciate any other insights. My sources Are Derek Welch motorsport, Roger Williams how to improve MGB, MGC, MGV8. Keep the views coming either way I reckon I do not want to enhance it more than 5-7% from where it is now.
Chormy's post seems in line with my understanding.
Regards
Trevor
As far as cam shaft goes so appreciate the posts and insights but I must confess I am somewhat confused. In readings that I have been doing it would seem a standard CAM has a lift of .254 inches and duration of 252 degrees and that a good street duration without impacting lift is about 270 and race spec 285 to 320. I guess I need to do more research into the matter and would appreciate any other insights. My sources Are Derek Welch motorsport, Roger Williams how to improve MGB, MGC, MGV8. Keep the views coming either way I reckon I do not want to enhance it more than 5-7% from where it is now.
Chormy's post seems in line with my understanding.
Regards
Trevor
Topic Creator (OP)
Mar 21, 2018 02:11 AM
Joined 10 years ago
68 Posts
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