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TR6 U.K./US Engine?


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Hi, new to the forum and need a little help identifying some details of a car I’m looking at please. The car is a 1972 with a CP76 chassis number which I believe represents a U.K. P.I. ? This car however has a twin carb SU/Stromberg engine with a manual lift pump with an Engine number of CF4895UE. 
I guess the questions that I’d appreciate help with are:-

1, Is the engine fitted a U.K. engine that has been modified to twin carbs from PI? 
2, Is this a U.S. spec engine and if so would it be the 104 bhp version.

3, Are the carbs SU or Stomberg?
4, In your opinion if it’s a U.K. car with a U.S engine would it significantly impact on its valuation? 
5, Is it feasible or sensible to restore it to PI spec? 
 

Thanks in advance for any advice. I’d like to be an owner soon!!!

 

39C3717E-96A0-4478-A576-01C06FDA0929.jpeg

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Lucas Pi may be fitted to any Triumph six cylinder - indeed four cylinder version, eight and twelve were produced, if you can find them, and fitted to Ford Capris, Maseratis etc.etc.       Pi sets appear on eBay sometimes, or the usual suspects (dealers) will have reconditioned sets.  Try Carl at TRtraders who no ow runs Prestige, as Malcolm Jones has retired.

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1 hour ago, Adrian Pettitt said:

Hi, new to the forum and need a little help identifying some details of a car I’m looking at please. The car is a 1972 with a CP76 chassis number which I believe represents a U.K. P.I. ? This car however has a twin carb SU/Stromberg engine with a manual lift pump with an Engine number of CF4895UE. 
I guess the questions that I’d appreciate help with are:-

1, Is the engine fitted a U.K. engine that has been modified to twin carbs from PI? 
2, Is this a U.S. spec engine and if so would it be the 104 bhp version.

3, Are the carbs SU or Stomberg?
4, In your opinion if it’s a U.K. car with a U.S engine would it significantly impact on its valuation? 
5, Is it feasible or sensible to restore it to PI spec? 
 

Thanks in advance for any advice. I’d like to be an owner soon!!!

 

39C3717E-96A0-4478-A576-01C06FDA0929.jpeg

Hi Adrian,

My feedback as follows:

 

1. CF is an American block. Chances are it has been rebuilt over the years, so difficult to advise what components have been used, unless you strip it.

2. USA spec engines produced 104bhp when new, yes.

3. Believe Stombergs were original USA equipment.

4. If it is a USA block, but built to UK spec, and Lucas PI, then it is marginal in the grand scheme of things with regards to value. Obviously it will not be a all matching numbers car, etc. The money is in the body and chassis, relatively speaking.

5.  It is feasible to strip and rebuild to UK spec, with Lucas PI, yes.  It is not just a case of installing Lucas PI though to the existring engine (although it would run), as you don't know the CR or type of cam fitted.  Don't forget fuel tank is different, etc.

 

If you're looking for more power, and originality is not high on the agenda, look at webers as an alternative. Would work out cheaper than souring a complete Lucas system, and then having it rebuilt. Same applies again, head removal and cam change as a minimum.

 

Cheers.

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5 minutes ago, TRTOM2498PI said:

Hi Adrian,

My feedback as follows:

 

1. CF is an American block. Chances are it has been rebuilt over the years, so difficult to advise what components have been used, unless you strip it.

2. USA spec engines produced 104bhp when new, yes.

3. Believe Stombergs were original USA equipment.

4. If it is a USA block, but built to UK spec, and Lucas PI, then it is marginal in the grand scheme of things with regards to value. Obviously it will not be a all matching numbers car, etc. The money is in the body and chassis, relatively speaking.

5.  It is feasible to strip and rebuild to UK spec, with Lucas PI, yes.  It is not just a case of installing Lucas PI though to the existring engine (although it would run), as you don't know the CR or type of cam fitted.  Don't forget fuel tank is different, etc.

 

If you're looking for more power, and originality is not high on the agenda, look at webers as an alternative. Would work out cheaper than souring a complete Lucas system, and then having it rebuilt. Same applies again, head removal and cam change as a minimum.

 

Cheers.

 

6 minutes ago, TRTOM2498PI said:

Hi Adrian,

My feedback as follows:

 

1. CF is an American block. Chances are it has been rebuilt over the years, so difficult to advise what components have been used, unless you strip it.

2. USA spec engines produced 104bhp when new, yes.

3. Believe Stombergs were original USA equipment.

4. If it is a USA block, but built to UK spec, and Lucas PI, then it is marginal in the grand scheme of things with regards to value. Obviously it will not be a all matching numbers car, etc. The money is in the body and chassis, relatively speaking.

5.  It is feasible to strip and rebuild to UK spec, with Lucas PI, yes.  It is not just a case of installing Lucas PI though to the existring engine (although it would run), as you don't know the CR or type of cam fitted.  Don't forget fuel tank is different, etc.

 

If you're looking for more power, and originality is not high on the agenda, look at webers as an alternative. Would work out cheaper than souring a complete Lucas system, and then having it rebuilt. Same applies again, head removal and cam change as a minimum.

 

Cheers.

Hi Thank you for the info. These look like SU’s to me?  Is there a preference? 
Cheers

Adrian

7 minutes ago, TRTOM2498PI said:

Hi Adrian,

My feedback as follows:

 

1. CF is an American block. Chances are it has been rebuilt over the years, so difficult to advise what components have been used, unless you strip it.

2. USA spec engines produced 104bhp when new, yes.

3. Believe Stombergs were original USA equipment.

4. If it is a USA block, but built to UK spec, and Lucas PI, then it is marginal in the grand scheme of things with regards to value. Obviously it will not be a all matching numbers car, etc. The money is in the body and chassis, relatively speaking.

5.  It is feasible to strip and rebuild to UK spec, with Lucas PI, yes.  It is not just a case of installing Lucas PI though to the existring engine (although it would run), as you don't know the CR or type of cam fitted.  Don't forget fuel tank is different, etc.

 

If you're looking for more power, and originality is not high on the agenda, look at webers as an alternative. Would work out cheaper than souring a complete Lucas system, and then having it rebuilt. Same applies again, head removal and cam change as a minimum.

 

Cheers.

 

1B02EA12-F04B-4E4C-B8C2-D2F69EF1A147.jpeg

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 My guess is that the original engine was beyond repair and replaced with a rebuilt CF (ex US) engine. Difficult to know the spec of the engine if the current owner hasn't got any records but you could measure the height of the head to see if its been skimmed and check the head number. This will give you idea if its been skimmed to raise the CR up to UK spec. Also does it run OK? If the owner will let you check the needles in the carbs - this could also be a clue to any engine mods.

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5 minutes ago, DRD said:

 My guess is that the original engine was beyond repair and replaced with a rebuilt CF (ex US) engine. Difficult to know the spec of the engine if the current owner hasn't got any records but you could measure the height of the head to see if its been skimmed and check the head number. This will give you idea if its been skimmed to raise the CR up to UK spec. Also does it run OK? If the owner will let you check the needles in the carbs - this could also be a clue to any engine mods.

Thanks, so the lower CR on US spec engines was just a deeper swirl pot in the head and the pistons are the same? Would the BHP be similar to PI with the U.K. CR and SU’s? Is there much difference in practice on the road between the different engine variants and outputs? 

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No because there are several differences between the UK and US engines, not just the PI system. Also the PI system will in itself provide better power than carbs, everything else being equal. However with other engine improvements a carb engine can be improved to perform as well as a PI or better.

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52 minutes ago, Adrian Pettitt said:

Thanks, so the lower CR on US spec engines was just a deeper swirl pot in the head and the pistons are the same? Would the BHP be similar to PI with the U.K. CR and SU’s? Is there much difference in practice on the road between the different engine variants and outputs? 

The PI CP engine will generate about 137 BHP in good condition and not 150 as listed by BL. To convert a CF USA engine up to !50 quite a lot of work has to be done to the engine and expense!

Modified head + gas flowing.

Cam shaft change to a BL S2 type, Newman make a copy of this cam as did SAH.

6 branch exhaust manifold + big bore system.

Carburation: Triple Weber DCOE's or Triple SU's or modern PI like Emerald.

Bruce

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Judging by the thickness of the corner flange, thats a low compression head, probably original with the  block. Can be shaved to raise comp ratio to PI-spec. That and ahotter cam will work nicely with SUs. But wehn buying the sole consideration is rust, and rust again. And an overdive 'box is a bonus.

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1 hour ago, john.r.davies said:

Just been to RevintonTR for a rolling road check.    I know RRs are not gospel, but 160bhp!    From my self built engine!  WooHoo!  So it is possible!

John

IMG_20210430_105012.jpg

Likewise John,

2yrs ago my TR6 equipped with Lucas Pi went on Revington's rollers and it produced around 170hp at the flywheel and they reckon around 140hp at the rear wheels.

Modified head, +0.040" bores, Phoenix manifold and a slightly wilder than standard Pi camshaft from Newman.

I'm thinking of dialling down on camshaft choice over next winter, in favour of a smoother tick over and low down torque.

Richard.

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16 minutes ago, Richard71 said:

Likewise John,

2yrs ago my TR6 equipped with Lucas Pi went on Revington's rollers and it produced around 170hp at the flywheel and they reckon around 140hp at the rear wheels.

Modified head, +0.040" bores, Phoenix manifold and a slightly wilder than standard Pi camshaft from Newman.

I'm thinking of dialling down on camshaft choice over next winter, in favour of a smoother tick over and low down torque.

Richard.

Hi Richard,

 

Be interested to know which Newman can you have.

I have a Newman hybrid cam, which idles smoother than a CP cam, and will pull from 1000rpm to an accurate 6000+rpm (electronic speedo). It has all the road manners of a standard car, but does accelerate when requested very nicely.  This is based on Lucas PI, but now Emerald EFI.

 

Cheers.

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16 minutes ago, TRTOM2498PI said:

Hi Richard,

 

Be interested to know which Newman can you have.

I have a Newman hybrid cam, which idles smoother than a CP cam, and will pull from 1000rpm to an accurate 6000+rpm (electronic speedo). It has all the road manners of a standard car, but does accelerate when requested very nicely.  This is based on Lucas PI, but now Emerald EFI.

 

Cheers.

Hi Tom,

It isn't listed on their website, 284 degrees  duration & .412" lift.

I'm keen to more about your cam, I'm also interested in the camshaft that TRGB have advertised on their website & eBay, they're quite secretive about it's profile. It promises what I might be looking for in the future.

Richard.

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On 4/30/2021 at 3:39 PM, Richard71 said:

Hi Tom,

It isn't listed on their website, 284 degrees  duration & .412" lift.

I'm keen to more about your cam, I'm also interested in the camshaft that TRGB have advertised on their website & eBay, they're quite secretive about it's profile. It promises what I might be looking for in the future.

Richard.

Richard,

 

If the cam you mention on the TRGB website is a Piper 'yellow' or 'red', send me a message. These cam profiles were done for my company :) 

Tom

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35 minutes ago, Tom Boyd said:

Richard,

 

If the cam you mention on the TRGB website is a Piper 'yellow' or 'red', send me a message. These cam profiles were done for my company :) 

Tom

Blydenstein did it years ago I got one in mine 

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On 4/30/2021 at 3:39 PM, Richard71 said:

Hi Tom,

It isn't listed on their website, 284 degrees  duration & .412" lift.

I'm keen to more about your cam, I'm also interested in the camshaft that TRGB have advertised on their website & eBay, they're quite secretive about it's profile. It promises what I might be looking for in the future.

Richard.

Hi Richard,

If you go for it make sure that it is not a re-grind and made from a new blank. Over the last 10 years there are plenty of tales of woe on re-ground camshafts!

Bruce.

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2 hours ago, Andy Moltu said:

Never understood the obsession with lumpy tickler and the CP engine.

So long as they tick over the "lumpiness" is irrelevant as long as they pull well enough. 

+1  Bruce.

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4 hours ago, Andy Moltu said:

I think the use of reprofiled cams has reduced now that new blanks are more widely available.

 

Moss certainly caught a big cold with re-grinds it cost them £££££££'s and they then rejected their stock back to their suppliers????? I believe its Newman only now??? As they use only new blanks for automotive applications!

Bruce.

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That low compression head is ideal for supercharging, and that needs no cam change. Pity Moss did not persevere with the kit.

Peter

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On 4/30/2021 at 11:13 AM, DRD said:

 My guess is that the original engine was beyond repair and replaced with a rebuilt CF (ex US) engine. Difficult to know the spec of the engine if the current owner hasn't got any records but you could measure the height of the head to see if its been skimmed and check the head number. This will give you idea if its been skimmed to raise the CR up to UK spec. Also does it run OK? If the owner will let you check the needles in the carbs - this could also be a clue to any engine mods.

Thanks, so the lower CR on US spec engines was just a deeper swirl pot in the head and the pistons are the same? Would the BHP be similar to PI with the U.K. CR and SU’s? Is there much difference in practice on the road between the different engine variants and outputs? 

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