USA TR6 power increase and tuning

[Saphire TR6]

I have a USA imported 1971 TR6 which is running on stromberg carbs which is misfiiring when the engine is wormed up.

 

I have a haynes manual detailing the carb adjustment requires a special tool and also a distant memory from reading Traction that these carbs are difficult to tune.

 

I am thinking of SU carbs, triple weber or converting the engine to PI to get more HP as well.

 

Looking through the techy stuff I have read to increase the power I will need a new cam and increase the compression.

 

Can anyone help with the best thing to do to increase the power and tune easily with an indication on price.

[foster461]

I have a USA imported 1971 TR6 which is running on stromberg carbs which is misfiiring when the engine is wormed up.

 

I have a haynes manual detailing the carb adjustment requires a special tool and also a distant memory from reading Traction that these carbs are difficult to tune.

 

I am thinking of SU carbs, triple weber or converting the engine to PI to get more HP as well.

 

Looking through the techy stuff I have read to increase the power I will need a new cam and increase the compression.

 

Can anyone help with the best thing to do to increase the power and tune easily with an indication on price.

 

Welcome to the forum..

 

There seems to be two approaches to increasing the power output of the US spec engines. They are capable of over 200HP although to get that far can be very expensive because we are talking about special pistons etc. For most of us the choice is to go down the normally aspirated path with increased compression, different cam, different headers and exhaust system etc or to supercharge (a days work bolting the supercharger on assuming you have a solid engine). These are mutually exclusive as once you increase the compression beyond a certain point the supercharger is not an option. In my experience both approaches cost about the same (starting at around $4000 US) for parts, machining etc assuming you do the bulk of the non-specialist work. If you add in roller rockers and other toys you can easily add another $1500 to $2000 in parts.

 

A good approach is to decide which path you plan to take and then build a phased project plan that say takes care of the core engine (head, cam, lifters etc) and lets you bolt on further updates later as budget and time allow (headers, exhaust, roller rockers, carbs etc).

 

For carbs triple strombergs are popular and very shortly someone is going to tell you that triple Webers are also a great option.

 

I'm pondering the same question and I'm still paralyzed at the aspirated vs supercharged question.

 

Someone from the UK can help with UK pricing estimates.

 

Stan

[rpurchon]

I have a USA imported 1971 TR6 which is running on stromberg carbs which is misfiiring when the engine is wormed up.

 

I have a haynes manual detailing the carb adjustment requires a special tool and also a distant memory from reading Traction that these carbs are difficult to tune.

 

I am thinking of SU carbs, triple weber or converting the engine to PI to get more HP as well.

 

Looking through the techy stuff I have read to increase the power I will need a new cam and increase the compression.

 

Can anyone help with the best thing to do to increase the power and tune easily with an indication on price.

 

 

send for a moss catologue lots of good info on uping the engine . shop around for prices though. richard

[stephen cooper]

If you are going down the naturally aspirated route you will want to change the cam and up the compression as you've already mentioned. Depending on how fast you want to go TR5 cam is a good start and a 9.5:1 compression ratio.

 

Fit a 6-3-1 - The phoenix one can be improved on vastly but it will cost more. HS6s with free flow air filters + richer needles on the 2500s manifold would work well, but PI or Webers would give you quite a bit more with the above spec. Note with the above mods you'd need a recalibrated MU or to visit the rollers with a set of DCOEs.

 

Re. your strombergs when warm it sounds like it might be the temperature controllers giving you grief.

 

Cheers Steve

[foster461]

Welcome to the forum..

 

There seems to be two approaches to increasing the power output of the US spec engines. They are capable of over 200HP although to get that far can be very expensive because we are talking about special pistons etc. For most of us the choice is to go down the normally aspirated path with increased compression, different cam, different headers and exhaust system etc or to supercharge (a days work bolting the supercharger on assuming you have a solid engine). These are mutually exclusive as once you increase the compression beyond a certain point the supercharger is not an option. In my experience both approaches cost about the same (starting at around $4000 US) for parts, machining etc assuming you do the bulk of the non-specialist work. If you add in roller rockers and other toys you can easily add another $1500 to $2000 in parts.

 

A good approach is to decide which path you plan to take and then build a phased project plan that say takes care of the core engine (head, cam, lifters etc) and lets you bolt on further updates later as budget and time allow (headers, exhaust, roller rockers, carbs etc).

 

For carbs triple strombergs are popular and very shortly someone is going to tell you that triple Webers are also a great option.

 

I'm pondering the same question and I'm still paralyzed at the aspirated vs supercharged question.

 

Someone from the UK can help with UK pricing estimates.

 

Stan

 

I should also have added the fuel injection is also an option, either converting to the original Lucas mechanical injection along with the required engine mods or a more modern EFI system. One quite elegant solution is the throttle body injection system that uses adapted Stromberg bodies. I really dont know that this would have any compelling power advantage of say the triple Webers but it is another option.

 

Stan

[Bald Rick]

Looking through the techy stuff I have read to increase the power I will need a new cam and increase the compression.

 

Can anyone help with the best thing to do to increase the power and tune easily with an indication on price.

 

Hi

 

Based on my own experiece from the last couple of years:

 

Camshaft - From about £130 reprofiled or at lot more for a chilled cast iron one (new)

 

Cylinder head - Stage 2 modified using your head - from about £500

 

Pair of rebuilt SU HS6 carbs on manifold with linkage - about £230

 

Distributor (a lot of people forget this) - about £150

 

Exhaust manifold and system in Stainless Steel - About £500

 

That's assuming your engine is in top condition to start with. Extra compression and more power puts the reciprocating parts under more stress.

 

So you may need crank reground, new shells and thrustwashers, re-bore and pistons, oil pump (I went for an uprated pump @ £65) timing chain & sprockets and so on and so on. plus gaskets, nuts and bolts, washers, leads, fan belt and dozens of other things you never thought you'd need when you started.

 

While the engine is apart its a good idea to have the flywheel lightened and the crank and flywheel balanced as an assembly.

 

I could have bought a second hand 2.5PI saloon engine (135 bhp) in good order for about a half of what I have spent. Probably with an overdrive box thrown in. It would have fitted with a little bit of work. So don't rule anything out until you have checked out the condition of your engine and the cost of going down your chosen route.

 

Good luck

 

Tony

[Saphire TR6]

Hi

 

Based on my own experiece from the last couple of years:

 

Camshaft - From about £130 reprofiled or at lot more for a chilled cast iron one (new)

 

Cylinder head - Stage 2 modified using your head - from about £500

 

Pair of rebuilt SU HS6 carbs on manifold with linkage - about £230

 

Distributor (a lot of people forget this) - about £150

 

Exhaust manifold and system in Stainless Steel - About £500

 

That's assuming your engine is in top condition to start with. Extra compression and more power puts the reciprocating parts under more stress.

 

So you may need crank reground, new shells and thrustwashers, re-bore and pistons, oil pump (I went for an uprated pump @ £65) timing chain & sprockets and so on and so on. plus gaskets, nuts and bolts, washers, leads, fan belt and dozens of other things you never thought you'd need when you started.

 

While the engine is apart its a good idea to have the flywheel lightened and the crank and flywheel balanced as an assembly.

 

I could have bought a second hand 2.5PI saloon engine (135 bhp) in good order for about a half of what I have spent. Probably with an overdrive box thrown in. It would have fitted with a little bit of work. So don't rule anything out until you have checked out the condition of your engine and the cost of going down your chosen route.

 

Good luck

 

Tony

 

 

I have had a look on the internet and will be going with a new cam and head to increase compression.

 

Do you know where I can get my cylinder head and cam altered?

Who could supply the distributor?

 

Thanks everyone for their advise

[Don Elliott]

In 2002 there were about 10 Brits who invaded the Mid-Ohio track with their TRs and one Spitfire. The fastest TR in the feature race with 47 Triumphs was a red TR5 from Manchester. He had removed all the PI and he had replaced this with carbs.

[Bald Rick]

I have had a look on the internet and will be going with a new cam and head to increase compression.

 

Do you know where I can get my cylinder head and cam altered?

Who could supply the distributor?

 

Thanks everyone for their advise

 

Hi

 

Difficult one for me as I live pretty far south from York. However, there are a whole load of companies specialising in Triumphs.

 

I got my head from TRGB in Huntingdon Cambs. but I also talked TR Enterprises in Blidworth Notts and several other companies much further south, Revingtons, Moss & Rob Walker amongst others. There are loads more, you can look up suppliers on the TR Register main pages and search the net. Also search this forum, there is a lot of good info on here which I have found invaluable.

 

Camshaft came from Chris Witor, a Triumph saloon specialist who does a lot for carburated engines, Helpful and knowledgeable if you can get hold of him! But again there are any number of options. Any of the companies mentioned above can advise you.

 

Distributor is best from Martin Jay, I think most people use him. Provided you give him your head and camshaft details he can make a distributor with an advance curve to suit. You will find him on the web: http://www.distributordoctor.com/

 

Your carbs can be overhauled and tuned. The tuning tool is not expensive and there is information about them here:

http://web.archive.org/web/20020605024956/...yetriumphs.org/

also check the diaphragms for holes and splits first.

 

Unless you are a complete masochist (or like me are a few sandwiches short of a picnic ) it is a very good idea to get the whole package from one supplier, then you can be sure all components will match and work together, and if they don't, you can go back to them and say help!

 

One important point, If your car is an early TR6 (pre CC67893) and has its original head, it will have different inlet ports. It can be identified by the number 516323 stamped on the head. If you go for an exchange head you have to make sure it is the same otherwise the ports will not line up properly and performance will be badly affected. If you have an exchange head of a later type you must get the later manifold (or a saloon manifold like the 2500S or TC) to go with it. I speak from personal experience. If you are going to get a different head then try and get a 219016 head as per this atricle: http://www.tr6.org/cylheads/index.html

 

Good luck

 

Tony

[Tom Fremont]

In 2002 there were about 10 Brits who invaded the Mid-Ohio track with their TRs and one Spitfire. The fastest TR in the feature race with 47 Triumphs was a red TR5 from Manchester. He had removed all the PI and he had replaced this with carbs.

 

I saw that too! The car belonged to Chris Petch and had Weber 45s on it - beating out TR6s with modern fuel injection set-ups claiming ~260 HP. I might add that Chris wrecked the car a couple of days prior in testing and mangaged to cobble it back together and win - all the more impressive!

 

Now to the point of this thread - here's a 100,000 mile recipe for 150+ BHP on your TR6:

 

1. Get the short block rebuilt to standard spec by a TR specialist.

2. Get a proper gas-flowed head ( this is where you get the most improvement for your money according to Racetorations )

3. Get a new 150 camshaft and competition followers

4. Get a set of triple Weber 40 DCOEs - these can be had reasonably second hand, but make sure they're all of the same type and free from corrosion, and the manifold and linkage kit ( you got me there, Stan! )

5. Get a Phoenix Sport exhaust / manifold set up.

You can get a low-advance distributor if you want, but I found it suffices to use the standard one with the static timing set back to ~5 degrees and no vacuum advance.

 

Once you get this done you'll be in TR6 nirvana with a 100,000 mile lease all paid for. I think Stan's about right on the cost ( note that's $, not £ ).

[foster461]

I saw that too! The car belonged to Chris Petch and had Weber 45s on it - beating out TR6s with modern fuel injection set-ups claiming ~260 HP. I might add that Chris wrecked the car a couple of days prior in testing and mangaged to cobble it back together and win - all the more impressive!

 

Now to the point of this thread - here's a 100,000 mile recipe for 150+ BHP on your TR6:

 

1. Get the short block rebuilt to standard spec by a TR specialist.

2. Get a proper gas-flowed head ( this is where you get the most improvement for your money according to Racetorations )

3. Get a new 150 camshaft and competition followers

4. Get a set of triple Weber 40 DCOEs - these can be had reasonably second hand, but make sure they're all of the same type and free from corrosion, and the manifold and linkage kit ( you got me there, Stan! )

5. Get a Phoenix Sport exhaust / manifold set up.

You can get a low-advance distributor if you want, but I found it suffices to use the standard one with the static timing set back to ~5 degrees and no vacuum advance.

 

Once you get this done you'll be in TR6 nirvana with a 100,000 mile lease all paid for. I think Stan's about right on the cost ( note that's $, not £ ).

 

 

Thanks Tom, I knew I could count on you to hold up the Weber end of this discussion :-)

 

Re the Exhaust system, it seems that a better set of headers and a free flow exhaust is mandatory to get the best out of any TR6 engine, tuned or not, and looking at Moss and TRF in the US it is not clear whose products they are selling although both seem to have the Monza exhaust. The Moss headers seem to just converge all six pipes at a single junction while the TRF unit appears to go from three into 2 (for the dual pipe Exhaust). Do you have a pointer to the Phoenix setup ?, I'm curious to see how these designs compare.

 

TRF headers: http://www.zeni.net/trf/TR6-250GC/61.php

 

Moss US headers: http://www.mossmotors.com/Shop/ViewProduct...teIndexID=29778

 

Monza dual pipe Exhaust: http://www.mossmotors.com/Shop/ViewProduct...teIndexID=29783 (Moss and TRF seem to have the same units)

 

Stan

[stephen cooper]

Exhaust manifolds have been pretty well covered on here before. The second link is the awful 6-2 probably worse than standard! Ideally you want a single pipe exhaust system, splitting into 2 costs power. Certainly for road applications the best configuration is a 6-3-1 the phoenix one has nasty collectors and unequal primaries.

 

What you really want is this... the original 6-3-1 with equal primaries and real pipe-pipe joins as designed by Gareth Thomas

Edited April 10, 2007 by stephen cooper

[RobinTR6]

Exhaust manifolds have been pretty well covered on here before. The second link is the awful 6-2 probably worse than standard! Ideally you want a single pipe exhaust system, splitting into 2 costs power. Certainly for road applications the best configuration is a 6-3-1 the phoenix one has nasty collectors and unequal primaries.

 

What you really want is this... the original 6-3-1 with equal primaries and real pipe-pipe joins as designed by Gareth Thomas

 

and where do you get one then

[stephen cooper]

Contact Gareth, emails at the bottom http://www.jagclub.ru/triumph_evo.html

[Andy Moltu]

Aren't these fancy manifods a grand or so? The Phoenix ones vastly cheaper.

 

As a starting point you are right in thinking that to tune a USA spec engine upping the compression ratio is the first step.

If you have got the engine out it's worth checking the bottom end is sound. It may prove a sound investment to lighten the flywheel (or fit a spider type alternative) and get the bottom end balanced. These don't add power but will allow it to be used more reliably.

 

When I got my car it ws running twin Strombergs with a CP (150) cam & I'm not convinced that the two are a good match. The CP cam works well with injection. You might be well worth a chat with one of the tuning specialists as some of the after market profiles suit the twin carb approach better.

 

Twin SUs would be a better option than the Strombergs as it's far easier to get hold of different needles to suit.

Edited August 19, 2007 by andymoltu

[TR674]

Andy

I discussed this with my mechanic a few months ago. We get a few USA imports here too and he does a conversion to PI for around AU$950. From memory that is a new speced cam, higher compression and all the PI gear fitted. It may be an idea to locate a specialist Triumph mechanic and ask the question?

Regards

Craig