Converting TC/S to PI engine

[JimEB]

Hi all,

I'm investigating the idea of converting a TC/S spec engine into a PI one, along with all of the obvious fuel system changes required.

Using a couple of Chris Witor's technical briefings, I've figured out that the camshaft, cylinder head, pushrods and distributor are different, but is there anything else I've missed?

I guess it might be uneconomical to convert and easier to find a PI engine... ;D

[Nick Jones]

Harder part will be putting all the fueling bits & bobs in place (pump, filter, various pipes, pump wiring, inertia switch).  Lots of funny little odd& sods needed and maybe different fuel tank?  Not so bad if you have a donor car, but a bit of a horror in isolation.

I have a later (125bhp) PI engine here on the garage floor.  It needs a bottom end freshen-up at least, but was dragging my car around until quite recently.  No PI gear with it.

Nick

[HNJ1N]

have you considered going the triple weber route?,
   cheers,
      Laurence

[JimEB]

6780 wrote:

have you considered going the triple weber route?,
   cheers,
      Laurence

I have indeed... :)

Trouble (in a very positive sense) is that there are many options for the straight six, from mild (cam, jets) to wild (PI/EFI/Webers, cam, forged pistons/conrods/crank, 6:3:1 manifold, flywheel...).  It'd be quite fun to build a Q car, plain Jane on top but a real Porsche frightener  ;D

[HNJ1N]

and that ,for me Jim , is the interest in the mk1 . Transforming a classic 'slippers and pipe' saloon into something that will give any contemporary bmw et al a good run for its money gives me a real buzz.My own project will hopefully provide a few smiles, and that will be set up with triple webers,
   cheers,
     Laurence.
ps i also love a stock Mk1 , always great to see a factory original

[TedTaylor]

I have plans to eventually rebuild and fit my triple Webers to my Mk1 but that is an early pre-PI 2000 so would not have had the injection option when new, and it is what the works cars fitted around this period.  Apart from that it has to be PI for me - which can be made to perform to match/beat Webers and have better torque. After all the works only did one excursion into Webers for a rally (1970 Scottish) for the Mk2 and the rest of the time they stuck with PI.

Knowing what you are after Jim it depends whether you want to change a nice original car - and with lots of fiddle getting it set up correctly.  Surely an original PI would suit your needs better.  Also anyone who has used and driven a PI saloon knows that it may look like a 'slippers and pipe' car but it is not - loved mine and could see off Beemer drivers no problem plus knowing I am using a 1970s car ........  Often wish I had not sold it but an estate better suits my needs.

Ted  

[piman]

Hello HNJ1N,

unless you have a lot of spare cash, forget Webers, it will go very well on a pair of S.U.s and be more tractable and probably more economical to run. I prefer a P.I., but it is a big job to convert a non P.I. car unless you get a donor car.

Alec

[DJB_Harvey]

I'd say the biggest part of the job is the tank and associated pipework , some items are getting hard to find and donor cars that are complete are rare . Converting the engine is the easy bit ! ... However I'd still say it's worth it in the long run .
Not so sure I'd want to go the Weber route .. Very expensive and always thirsty in my experience ... Best left for a race car ?

[Spitfire2500]

piman wrote:

unless you have a lot of spare cash, forget Webers, it will go very well on a pair of S.U.s and be more tractable and probably more economical to run

I've never noticed any loss of tractability with Webers, otherwise I completely agree with the general sentiment. SUs will be more economical.

FWIW Webers is one of things I'd do differently on the 2.5 Spit if I was doing it all over again. A lot of money for not much benefit in a road car.

[dazzer]

Don't ignore twin 175 Strombies either with the addition of ram pipes (they just fit with homemade filters) . We've trounced a few Porsche 911s in the historic series and the Strombies have been 100% reliable over 30k or so, so far. You can also pick up an old pair for £25 tops. early TR4 are the best as the standard jetting works perfectly although a little rich on tick over. They bolt straight onto the early short manifolds if you open everything up and mill the carb flange to affix with just two bolts (don't use the convertors as you then cant fit the ram pipes). Plenty of youtube action of our 2000 MK1 and the sound they make is something else, makes the hairs stand up on the back of your neck.

I would have to say, and not trying to be controversial but the sound track from a well set up lightly filtered carb derivative surpasses anything a PI set up could hope to produce... There I've said it now... I'd also be confident in a carbie/PI dual with our current power plant.

MK1s at dawn it is then

Cheers
Dazzer

[Englishbull]

570 wrote:

Don't ignore twin 175 Strombies either with the addition of ram pipes (they just fit with homemade filters) . We've trounced a few Porsche 911s in the historic series and the Strombies have been 100% reliable over 30k or so, so far. You can also pick up an old pair for £25 tops. early TR4 are the best as the standard jetting works perfectly although a little rich on tick over. They bolt straight onto the early short manifolds if you open everything up and mill the carb flange to affix with just two bolts (don't use the convertors as you then cant fit the ram pipes). Plenty of youtube action of our 2000 MK1 and the sound they make is something else, makes the hairs stand up on the back of your neck.

I would have to say, and not trying to be controversial but the sound track from a well set up lightly filtered carb derivative surpasses anything a PI set up could hope to produce... There I've said it now... I'd also be confident in a carbie/PI dual with our current power plant.

MK1s at dawn it is then

Cheers
Dazzer

MMMMMMMMMM.............think you have defintely laid the gauntlet down there  ;)..................and not by myself  ;D

PS why didn't the works MK1's go down this route instead of PI?.

[venturer]

My conversion involves a 2500cc lump transplant into the mk1.I considered the pi route but with nearly 40k miles over six reliable years behind me with the TR5 using webersx3 ,including last years 10CR, i decided to use this engine/ancilleries as my template for the mk1 project. It will  be built with the emphasis on power at the lower to mid range rather than out and out top speed. Webers are juicy, but then the well sorted  pi 6  i had in the nineties was not any better, but then i do have a rather heavy right foot..,
    cheers,
      Laurence

[dazzer]

LEE_GODFREY wrote:

MMMMMMMMMM.............think you have defintely laid the gauntlet down there  ;)..................and not by myself  ;D

PS why didn't the works MK1's go down this route instead of PI?.

Looking at the early MK1 works cars they went down the route of triple webbers. I'm not knocking this because I've not tried it but you can get amazing results as kas kastner demonstrated with twin Strombergs, CW reports that they are quicker to respond as well, so it was with interest that I tried it and now I'd agree. Current historic regs in the catagories I run in also stipulate no more than two chokes and triples would also exclude us from most night events, so I guess necessity also pushed me in the direction of the Strombergs which most enthusiast including TR owners look upon with distain... which is great if you want some, most people just want rid of them!

The works cars also used 15" wheels for ground clearance... I've tried them with the specified issue 70 profiles and the handling is wooden... drop them down to 13" and the car is transformed. They did some gruelling events back then though and ground clearance was much more important I guess.

It will be interesting to see other big saloons on the HRCR or NESCRO events in the future perhaps even a PI which would be classed as a Cat 2 I believe if injection was given a waiver.

[Richard B]

1526 wrote:

to my Mk1 but that is an early pre-PI 2000 so would not have had the injection option when new, and it is what the works cars fitted around this period.

I'm sure I heard that they rallied a MkI 2000 PI whilst in development (circa 65 - 67). Not as good on torque as a 2.5 though.

[Englishbull]

Richard_B wrote:

I'm sure I heard that they rallied a MkI 2000 PI whilst in development (circa 65 - 67). Not as good on torque as a 2.5 though.

Yeah correct.

Pages below courtessy of The 2000/2500/2.5 Register pages written by Jonathan Lewis:-


As early as 1965, moves had been made towards grafting the 2-litre six-cylinder engine into the TR chassis but, at first, results were unpromising.  All this changed when an engine was equipped with Lucas petrol injection, first as a straightforward power-boosting exercise for competition purposes but then as a possible means of complying with the reduced exhaust emission levels which would be required in order to keep selling cars into the American market in the 1970s whilst retaining some semblance of performance and economy.  Although the idea of petrol-injected cars for the US would lose favour after Triumph’s importers there indicated their reluctance to accept the cost burdens associated with the new technology, PI-equipped engines had another important attribute and, for TRs sold outside the US, this was to prove decisive.  As Jaguar had discovered with its sports-racing D-Types a decade earlier, the flexibility (not to mention economy) of a PI-equipped engine could be significantly increased over that from a comparable carburetted unit, even with a racing-style ‘wild’ cam profile.  So-equipped, the six-cylinder Triumph engine could be made to produce the sort of power outputs only previously seen from the works rally cars, whilst retaining sufficient tractability for everyday road use.  The one key aspect in which the prototype 2-litre PI units were deemed to compare unfavourably with the old four-cylinder TR engine was in terms of bottom-end torque, and so swept capacity was boosted to 2498cc by increasing crankshaft throw and piston stroke.  As launched in the Triumph TR5 in October 1967, the latest version of the straight-six was claimed capable of a power output of 150bhp at 5,500rpm and torque of 164lb/ft at 3,500rpm, representing considerable gains on the parent 2000 engine (though North American customers would have to make do with a specially carburetted ‘emissions control’ version – the TR250 – which was nowhere near as potent).

[andy thompson]

6780 wrote:

and that ,for me Jim , is the interest in the mk1 . Transforming a classic 'slippers and pipe' saloon into something that will give any contemporary bmw et al a good run for its money gives me a real buzz.My own project will hopefully provide a few smiles, and that will be set up with triple webers,
   cheers,
     Laurence.
ps i also love a stock Mk1 , always great to see a factory original

Can't wait to see it Laurence,  not that much room for decent filters with webers in a saloon due to the strut tower - I'm sure you will overcome it :) maybe a PI style plenum with very short ram pipes?

[Ridgetone Triumph]

I have had 6 PI's in my time, 2 MK1's the rest Mk2's albeit one of the MK2's on SU's and 1 mk1 on Stromberg's ??) Most of the PI's ran ok but nothing special (I guess these one's had been fiddled with before my purchase, however 1 of the PI's I had was, I believe, untouched and went like stink 8) It returned about 26 mpg and would rev to 6500rpm in 1st,2nd and third gear everytime. This car went on to be my race car for the next 16 years and apart from running the engine bearings often (2.5 don't like being revved past 7000rpm) the only issue I had with the injection was the pump got hot, after I fitted another std pump I kept it cool via air flow, I never had any other PI issues, the fuel filter I replaced once that I can remember,  after about the 5th or 6th engine I had the engine worked on to stop the bearings packing up after every race ( I was also told by my mechanic NOT TO REV PAST  6000 rpm) To cut a long story short the metering unit was slightly alter to match the new engine (I guess this was richened up) and when it was back up running again I was able to pass many fast cars on the track and although the mpg was as low as 8-10 at high pace, I would still get up to 33mpg driven sensibly on the public highway (13.8mpg if entering a 12 rally :X) So if you are wondering what this is leading to,

JimEB PI IT  ;)

[venturer]

All being well Andy the car should be my entry in next years 10CR. 6 months is my time frame for this project,-once delivered work should start soon on the engine, courtesy of Tom Key. Strip down and prep for paint will begin at the same time.Good point on the trumpets and filters ,am sure we will find a satisfactory solution clearing the towers. My 5 runs without filters and short trumpets and has run fine over the past six years.
  The debate, re pi and carbs, will no doubt rumble on, i think we all have opinions on what is the best application, thats what makes having these cars interesting,
    cheers,
       Laurence.

[Ridgetone Triumph]

3100 wrote:

  The debate, re pi and carbs, will no doubt rumble on, i think we all have opinions on what is the best application, thats what makes having these cars interesting,
    cheers,
       Laurence.

Yes quite agree with you there, it like any car, you get a bad one and it is never forgotten and usually poison one against that car, get a good one and it's the best car ever made ;D  

[Slimboyfat]

Richard_B wrote:

I'm sure I heard that they rallied a MkI 2000 PI whilst in development (circa 65 - 67). Not as good on torque as a 2.5 though.

That would be Bill Bradleys 1966 factory 2 ltr PI race car.

[Slimboyfat]

Its this car we have to thank for duplex timing chain and gears.

The problem of rapid chain stretch due to the extra load of the metering unit drive had not manifested itself with other prototype PI cars at the factory.

Bill found himself wearing out a set of simplex chains, and gears every race until resolved by Ray Henderson and his team with a duplex set up.

[Slimboyfat]

Purely co-incidently Bill and I were talking about this very car, and its lack of success a couple of days ago.

The car was simply to heavy, and it didn't have enough grunt from the 2 ltr engine to keep up with the Lotus Cortinas.

[CRAJ]

More coincidence, Bill's car (with it's 2000 pi engine) will be on the 2000 Register stand at the NEC later this month. So come along and see it in the flesh.

Colin

[Slimboyfat]

No it will not!

Bills 66 race car, is not the same as the rally car FHP993C he now owns, and is making an appearance at the NEC (once I have got it out and given it a once over).

[JimEB]

Slimboyfat wrote:

No it will not!

Bills 66 race car, is not the same as the rally car FHP993C he now owns, and is making an appearance at the NEC (once I have got it out and given it a once over).

Oh...not seen Roy Fidler's car for...oh...fifteen years? Feeling old... ;D