Jump to content

TR6 U.K./US Engine?


Recommended Posts

10 hours ago, Mike C said:

Thanks Mike, much appreciated. I’ll try and spend a bit of time assessing what I’ve got when it arrives! If it runs and performs reasonably in its current form I’ll use it a bit first to see what needs attention generally. It should come with a large history folder which might give me some more insight into its restoration and current engine. 

Link to post
Share on other sites
11 minutes ago, Adrian Pettitt said:

Thanks Mike, much appreciated. I’ll try and spend a bit of time assessing what I’ve got when it arrives! If it runs and performs reasonably in its current form I’ll use it a bit first to see what needs attention generally. It should come with a large history folder which might give me some more insight into its restoration and current engine. 

see this discussion

 

Link to post
Share on other sites
15 hours ago, Adrian Pettitt said:

Hi Peter, That Moss kit looks interesting are their alternatives that are available? 
Thanks Adrian

Adrian, No other kit as far as I know.  Moss USA discintinued the kit as the Holley carb became NLA. Maybe thay have unsold stock eg the manifold that could be the basis of a diy installation. DIY is feasible if you can machine and weld ali components eg pulleys, manifolds, or know a friendly engineering workshop that does not demand drawings or CAD. The easiest way to do it is to fit the blower and carb on the disy side of the engine and take a duct across the front of the block to mate with a plenum chamber bolted to a carb inlet manifold. Eaton M62 blowers can be found on ebay and you have an SU that can be retuned to suit.  It is entirely  bolt-on and so reversible. But it is a major departure from fitting ready made parts, you have to engineer your own parts and design them as well eg pulley diameters. The alternator is moved to the exhaust side, with a new idlder pulley and longer belt. However other have done it and can help with design basics, and sourcing oddments such as back-fire valves etc.

Peter

Link to post
Share on other sites

135K miles and counting on the last rebuild of my TR250 with triple Weber DCOEs. Unsurpassed reliability with CP+ performance. Will idle at 550 rpm:

Wonder what these and the TR6s would fetch in today's market had they left the factory with Webers...

 

Tom

 

Link to post
Share on other sites
10 minutes ago, SpeedFreak said:

I know I am a bit late adding to this thread but please don't forget that the US spec. head has different port spacing to the UK type so PI inlet manifolds will not fit.

RW.

Only the earlier type CC heads, the CF heads are the same spacing as the CR cars.

Link to post
Share on other sites
  • 3 months later...
On 5/7/2021 at 4:08 PM, Tom Fremont said:

135K miles and counting on the last rebuild of my TR250 with triple Weber DCOEs. Unsurpassed reliability with CP+ performance. Will idle at 550 rpm:

Wonder what these and the TR6s would fetch in today's market had they left the factory with Webers...

 

Tom

 

Hi Tom,

I often read your positive posts about Weber carburettors and learn from your knowledge and experience. My recently purchased TR3 is fitted with Weber DCOE 45s, a bit big for the 4-cylinder TR engine?

So, from what I can gather, you know how to configure Webers in such a way as to get an excellent idle and decent fuel economy. Most on this Forum are very possesimistic about Webers, but I will give them the benefit of the doubt.

I suspect mine are poorly set up. As I understand it, these carburettors are like an empty alloy casting where you have great versatility built in.

Yes, as most do, you can use them to obtain more bhp, power and speed. But you could also reconfigure them to work efficiently for a road car with no ambition for track and racing.

I have been reading up on Webers, including TerriAnn's guide on her website.

What do you think of this configuration for a 2138cc engine, with extractor exhaust, electronic distributor?

Choke 30 or 32

Aux choke 3.5

Idle jet 45 F8

Main jet 130

Air correction jet 180

Emulsion tube F15

Accelerator pump jet 40

Accelerator pump intake/discharge valve 50

Needle valve 2.00

Float setting ?

Thanks in advance,

David

Link to post
Share on other sites
10 hours ago, DavidBee said:

Hi Tom,

I often read your positive posts about Weber carburettors and learn from your knowledge and experience. My recently purchased TR3 is fitted with Weber DCOE 45s, a bit big for the 4-cylinder TR engine?

So, from what I can gather, you know how to configure Webers in such a way as to get an excellent idle and decent fuel economy. Most on this Forum are very possesimistic about Webers, but I will give them the benefit of the doubt.

I suspect mine are poorly set up. As I understand it, these carburettors are like an empty alloy casting where you have great versatility built in.

Yes, as most do, you can use them to obtain more bhp, power and speed. But you could also reconfigure them to work efficiently for a road car with no ambition for track and racing.

I have been reading up on Webers, including TerriAnn's guide on her website.

What do you think of this configuration for a 2138cc engine, with extractor exhaust, electronic distributor?

Choke 30 or 32

Aux choke 3.5

Idle jet 45 F8

Main jet 130

Air correction jet 180

Emulsion tube F15

Accelerator pump jet 40

Accelerator pump intake/discharge valve 50

Needle valve 2.00

Float setting ?

Thanks in advance,

David

I know nothing about the TR 4 cylinder engine so I looked up this engine in my old SAH tuning book. The use of 45 webers requires quite extensive mods to the engine to get the best out of them i.e. Modified head to stage 3, GT Silencer system, fast road cam shaft, cam follower lightened. This will give power in the region of 135+ BHP. Your Choke size looks small as they start off with 34mm size and state that the car engine needs to be set up on a rolling road? Has your engine got these other mods a well?

Bruce.

Link to post
Share on other sites

USA block, is, I believe the same as a UK block

You can fit the heads, camshaft etc etc to replicate UK spec

YES go back to PI

It can be a faff to get set up, but, once it's right, it's right and you won't be disappointed

Link to post
Share on other sites

David,  The very best of luck sorting all those variables without handing the TR over to a Weber specialist. Personally I'd sell them and fit a pair of SUs, the performance difference is marginal in road driving and tuning is easy. The other option is to seek out another road-going 3 with Weber 45s and copy that, if it exists.

At cruise where  a road car spend 90% of driving the main jet does not flow fuel and tuning involves the auxilliary jets, emulsion tubes etc to obtain the correct fuel flow and quality (atomisation). For racing all these circuits need only be approx right ( ie rich) and tuning involves only one parameter, changing the main jet.  Taking a guess at component sizes will probably work after a fashion, but only because of the great leeway in rich mixture combustibilty. But for optimum "green" mpg the cruise mixture and its quality, along with correct vac advance, will need a lot of experimentation by substituting components, assuming the rolling road knows how to tune at cruise loads. With SUs cruise optimisation can be done while driving, DIY.

With 10% ethanol in fuel and all those tiny orifices in Webers we may start to see issues with corrosion and jet blockage. SUs jets will be immune.

 

Peter

Link to post
Share on other sites
10 hours ago, astontr6 said:

I know nothing about the TR 4 cylinder engine so I looked up this engine in my old SAH tuning book. The use of 45 webers requires quite extensive mods to the engine to get the best out of them i.e. Modified head to stage 3, GT Silencer system, fast road cam shaft, cam follower lightened. This will give power in the region of 135+ BHP. Your Choke size looks small as they start off with 34mm size and state that the car engine needs to be set up on a rolling road? Has your engine got these other mods a well?

Bruce.

Thanks Bruce!

I am learning more by the day. Modified, yes, to a point, but doesn't feel like a racing engine (as if I'd know!): gas-flowed head, most probably skimmed, 4 into 1 s/s exhaust, non standard cam (but not a racing cam) and the Spanish-built Weber 45s 152.

I managed to speak with Mark Mason, who rebuilt a TR4 first, before restoring my TR3. Truth be told, yes it was long ago, but he seemed a bit cagey. I learned that Racetorations had supplied a TR4 or 4A engine which threw a con rod, if I understood him correctly. He got a replacement TR4 engine, but didn't say which company it was from. The only clue was his reccomendation to use semi-synthetic oil, due to tight tolerances, so definitely not 83mm pistons.

Be that as it may, my impression is that fuel guzzling aside, which I want to reduce by retuning and checking for leaks, this engine set up would be, or might be, great fun on a track day event, but not competitive for racing. I get the impression he didn't go that far. Even if I wanted to do hill climbing, there's a lack of TR torque that almost defines TRs. So it is a half way house.

I want to do what is possible to make it work better at cruising speeds. It is not lumpy, pick up is not that bad, but fuel economy is a disaster and just unacceptable.

Wasn't the glorious SAH advice for tuning to get more bhp? That was their angle. But all I want is a more flexible engine, getting some of the torque back.

The Weber manuals and other sources all agree you can configure these carbs either for road or for track. I think TerriAnn's advice, endorsed by Stuart, is convincing. She distinguishes between normal city and road use/cruising (before the main jet gets involved) rally use and flat out racing, and suggests different baseline setups accordingly. But I am still dithering about what exactly to do.

 

 

Edited by DavidBee
Link to post
Share on other sites

You may well be correct poolboy, the Strombergs were working, but they are not as good as SU's, never were and never will be, fitted to USA cars for Californian regulations as the injected six would have caused some environmentalists to contemplate the end of the world was nigh:D

Link to post
Share on other sites

My experience is same as Poolboy:

I removed the Strombergs from a US-spec TR6 I had around 1990, and replaced them by SU’s. It did not give any noticable improvement.

Waldi

Link to post
Share on other sites
On 8/16/2021 at 1:01 PM, Chris59 said:

Got to be carefull with the push rods lengh ;)

 

As I found out when I skimmed my US TR6 head to match a UK compression ratio quite a bit of metal to come off and the US push rods become too long :wacko:

Link to post
Share on other sites
On 8/15/2021 at 11:19 PM, DavidBee said:

Hi Tom,

I often read your positive posts about Weber carburettors and learn from your knowledge and experience. My recently purchased TR3 is fitted with Weber DCOE 45s, a bit big for the 4-cylinder TR engine?

So, from what I can gather, you know how to configure Webers in such a way as to get an excellent idle and decent fuel economy. Most on this Forum are very possesimistic about Webers, but I will give them the benefit of the doubt.

I suspect mine are poorly set up. As I understand it, these carburettors are like an empty alloy casting where you have great versatility built in.

Yes, as most do, you can use them to obtain more bhp, power and speed. But you could also reconfigure them to work efficiently for a road car with no ambition for track and racing.

I have been reading up on Webers, including TerriAnn's guide on her website.

What do you think of this configuration for a 2138cc engine, with extractor exhaust, electronic distributor?

Choke 30 or 32

Aux choke 3.5

Idle jet 45 F8

Main jet 130

Air correction jet 180

Emulsion tube F15

Accelerator pump jet 40

Accelerator pump intake/discharge valve 50

Needle valve 2.00

Float setting ?

Thanks in advance,

David

To set up DCOEs properly they have  be done on a rolling road by someone who knows what he is doing with Webers! There is no short cut to this? Your weber settings are way off my old SAH book. I quote: 34 Choke Standard or mildly tuned

36 Choke, Fast road, Modified head, Road cam shaft, Extractor Manifold, GT exhaust

38 Choke, Full race preparation/Sprint Tune

Bruce.

 

Link to post
Share on other sites
3 hours ago, astontr6 said:

To set up DCOEs properly they have  be done on a rolling road by someone who knows what he is doing with Webers! There is no short cut to this? Your weber settings are way off my old SAH book. I quote: 34 Choke Standard or mildly tuned

36 Choke, Fast road, Modified head, Road cam shaft, Extractor Manifold, GT exhaust

38 Choke, Full race preparation/Sprint Tune

Bruce.

 

Thanks Bruce,

Thank you for taking an interest in my plight.

If I may say so, the settings you refer to are those suggested by TerriAnn who has a website with a guide to Webers. It is based on a survey of books and her own experience as a TR 3A owner who runs Webers.

Sincerely yours,

David

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.