2500-M V8 motor swap

[Dogsharks]

Hi guys,

I'm new here so don't flame me if I'm asking a question that's been asked a million times, etc.

I have a '74 2500-M with webers and a hot cylinder head/cam setup. The car is quick, but I want to put a V8 in the car and go through all the running gear to essentially bring the chassis up to GTU status, and keep a streetable motor in it. This means a fairly well tweaked 302 or 289, maybe stroked, and even perhaps a 427 FE as I have two of them in the grage on rollers now, just waiting for something to power. If I go the FE route I'll have to use aluminum heads and intakes to keep the weight on a par with the 302, and of course, the ENTIRE drivetrain will need a LOT of attention, as it will essentially be a 427 Cobra in TVR clothing.

Any comments are welcome. If I'm nuts, tell me so. If someone out there has done this, lemme hear from you. I'm in Tennessee, and have been running a '83 928-S 5-speed, a '84 944, and a '90 944 S2 Cabriolet for the last few years, and the TVR is sleeping in the basement, about to be reawakened.

Next time it comes out of the garage, it will be time to hide the women and children, just like the last time this car saw daylight ten years ago!!!

Regards, P

"dogsharks"

[dogsharks]

This would be one heck of a motor for a 2500 M, but it is much much wider (due to cam drives) than a SBF (small block Ford).

[img]www.kellymoss.com/Images/928GTR1.jpg[/img]

Dogsharks

[yellabelly]

DO NOT DO IT !!!

Was the car built with a V8? was it designed for a V8?
if you want an old car with a V8 buy a vette or a mustang or any one of the multitude of old American muscle cars. Why ruin a perfectly good old British car which had a perfectly good engine? Do you claim to know better than the original designer of the 2500M or are you more interested in power than heritage?
The attached article was from the August 1991 Classic and Sportscar it is sacrilege what some people will do.
Think again

[joospeed]

DO IT!!

whilstever there's other unmolested 2500Ms around why not modify your own motor car? .. make sense to me .. I love to see people playing with an inherently flawed design to make it better .. go for it

[2 sheds]

The current editor of Sprint Magazine, Tony Connor has IIRC an M series with a Rover V8, sound like a great idea to me.
Tim

[simpo two]

I think Dogsharks was looking for mechanical advice, not moral guidance.

[keirangrogan]

yellabelly said:

DO NOT DO IT !!! Was the car built with a V8? was it designed for a V8? if you want an old car with a V8 buy a vette or a mustang or any one of the multitude of old American muscle cars. Why ruin a perfectly good old British car which had a perfectly good engine? Do you claim to know better than the original designer of the 2500M or are you more interested in power than heritage

With an attitude like Jack Griffith would never have blessed us with the original 60's Griffith, The AC Cobra would still be an AC Ace with a puny engine. People have been mating British Chassis' with American V8 Muscle for over 35 years, the Rover V8 engine was originally an American unit, get your facts straight before trying to publicly humiliate people.



Try to get hold of back issues of sprint from the Club Office, There have been a couple of articles in the past 18 months about people carrying out this conversion.

>> Edited by keirangrogan on Saturday 4th October 14:17

[yellabelly]

keirangrogan said:

yellabelly said: DO NOT DO IT !!! Was the car built with a V8? was it designed for a V8? if you want an old car with a V8 buy a vette or a mustang or any one of the multitude of old American muscle cars. Why ruin a perfectly good old British car which had a perfectly good engine? Do you claim to know better than the original designer of the 2500M or are you more interested in power than heritage With an attitude like Jack Griffith would never have blessed us with the original 60's Griffith, The AC Cobra would still be an AC Ace with a puny engine. People have been mating British Chassis' with American V8 Muscle for over 35 years, the Rover V8 engine was originally an American unit, get your facts straight before trying to publicly humiliate people. Try to get hold of back issues of sprint from the Club Office, There have been a couple of articles in the past 18 months about people carrying out this conversion. >> Edited by keirangrogan on Saturday 4th October 14:17

Oh! right! the fact that the origins of the Griffiths and the Cobra were based on current vehicles at that time rather than modifying a 30 year old car, this is what we call progress. What earth shattering, ground breaking, revolutionary design are we going to see coming into production with this little mod? None, zip, nil, nul, zero!!

All we get is a hackneyed "stick a big engine in and mod the running gear to suit" and to what purpose?

Maybe there are sufficient of the M series about that we would not miss one more but is that what you want to happen, a slow erosion of the marque?

As for the patronising comment about the origins of the Rover V8, that really is a pathetic.
Yes we have seen a number of installations of the Rover V8, some were well executed like the V8 S, the late Griff, Chimaera, RV8 etc all based on a current production or new design.
Some will have been absolute pig's ears that thankfully have been long since forgotten.

Would you consider attempting the retrofit of a V8 into your S3? unlikely! how about a cossie V6? that seems like a good project but as we know it has been done, with difficulty and only because it is a closely related engine and it falls within the potential next steps of the model having been done in the racing S.

I, like you have the right to express my views and opinions and for them to be agreed with or challenged, a public humiliation of a newbie it most certainly was not.

Maybe you will also have the good grace to add a smiley when you post.

[richard sails]

I have three M series cars, two have Rover V8 engines, one of these was a TVR factory conversion back in 1975.

All I can say is that the Rover V8 works very well as it is a very light engine and does not affect the cars handling at all, if anything the V8's handle better than my 3000M V6.

I don't know what the effect would be of adding a heavy engine to the car but certainly a lightweight V8 is a big improvment and the increased drivability makes the car better to drive.

[simpo two]

yellabelly said:

As for the patronising comment about the origins of the Rover V8, that really is a pathetic.

Patronising? I'd say that it was a simple fact and expressed as such. Chill out man, are we fighting among ourselves or trying to help someone with a question here? If someone wants to modify their TVR that's their business, and if we disagree we can at least have the courtesy to turn the other cheek rather than row about it. Life's hard enough without bitching for pleasure, dammit!

[joolzb]

Have to say I agree with yella on this, it does seem a shame to change this classic. Couldn't you choose a Porsche or somein to do it to? Mind you it's a free world I spose, so do whatever you have to

[yellabelly]

richard sails said:

I have three M series cars, two have Rover V8 engines, one of these was a TVR factory conversion back in 1975. All I can say is that the Rover V8 works very well as it is a very light engine and does not affect the cars handling at all, if anything the V8's handle better than my 3000M V6. I don't know what the effect would be of adding a heavy engine to the car but certainly a lightweight V8 is a big improvment and the increased drivability makes the car better to drive.

Richard, as the owner of two 3500Ms, your comments are welcomed and appreciated, however as you state one of the cars was a factory conversion, in 1975, using the ubiquitous Rover V8 at a time when the car was still current.

My comments were against turning the 2500M into a another form of cobra repro, as dogsharks states "the ENTIRE drivetrain will need a LOT of attention, as it will essentially be a 427 Cobra in TVR clothing."

He also states "Any comments are welcome. If I'm nuts, tell me so. If someone out there has done this, lemme hear from you."

At least he amongst our bretheren is willing to accept differing views.

[rv8500]

JUST DO IT Sounds like my kind of car, classic style and proper power. Good luck

[2 sheds]

Dogsharks said:

Any comments are welcome. If I'm nuts, tell me so. "dogsharks"

You are obviously nuts, but thats a good thing, I find it strange that people get so passionate about all this, for me there is a certain amount of humour from sticking overpowered engines in old cars , I've done it , if you do it, do it BIG, its your money and i wish you good luck.
Tim

[joospeed]

here's another suggestion .. as you're obviously a competent DIYer , why not make your own chassis to take the bespoke engine / drivetrain and then take a mould off your 2500M to make a copy body? you get the 2500M shape which is what you're after plus you get up to date mechanicals, best of both worlds?

[yellabelly]

Julian, good suggestion

[dogsharks]

Well I guess I asked for it, eh?

Some good comments guys, thanks. Don't worry about me, I don't have tender toes. I remember seeing the first V8 powered "Tuscan" that had the 2500-M body style. It was at Penn State University in the early 1970's I think. Anyway, I remember hearing it before I saw it. Since I have a M car with "adequate" room for a SBF, I thought I would convert the M to Tuscan status, after all, the rear end has bolt holes for the 4-shocks used on the Tuscan, heh heh, and SBF motors are pretty reasonable. I guess the 427 would be total insanity, but I've always wanted to build a Cobra replica too, so you can kind of get the drift here. Since I'm a charter member of two antique and classic boating organizatiions, I can identify with the purists who want to keep the cars original too.

My feelings about the TR-6 engined cars is mixed. I think it was out of convenience and cost that the 6 motor was chosen. TVR chose whatever they could get their hands on, including the SBF, so what's the harm going with a SBF???

Anyway, I'm hunting information, and will make the decision at some later time, after feasting on the info and thinking a lot.

Thanks again for the comments,

regards, dogsharks, Nashville

[yellabelly]

dogsharks,

Good luck with the project whichever way you decide to go, keep us posted.

[dogsharks]

The TR-6 motor is a great sounding motor, and in fact, the one I have has a polished and ported head, Kastner Cam (for you guys in UK, Cas Kastner was the US director in charge of competition for Triumph cars), Weber carbs, and a few other tweaks, and it ran strong. I would guess it had somewhere around 165 horsepower or so.

Only problem is, I'm driving a 2.3 liter 1989 Volvo sedan with a 4-cyl normally aspirated motor that has more power from the factory (the 16-v). My 4-cylinder 3.0 liter Porsche 944 S2 Cabriolet has 208 horsepower, so the pushrod 2.5 in the TVR isn't really all that stressed, or is it?? The Porsche motors are all built for running hard, and the TR can be made to scoot, but even when hot rodded, it's not all that quick. Yes, I did out drag a Corvette onto the interstate one day, and left it a spec in the rear view mirror, but nowdays even the Japanese econo-boxes come with gobs of power and unless I do something, I'll find a Honda blowing by me and we can't have that.

I see they're making aluminum cylinder heads now for the MGB and big Healey, do they make anything for the TR-6 motor like that??? How about a big bore kit, how far can they be bored (I have a spare block).

The 944 4-cylinder motor has been supercharged up to 600-hp for road racing, so I'm also wondering if anyone has supercharged an injected TR motor. Just considering all the options. I'm old enough to know better, and have the cash now to do it right. 25 years ago I was driving it to work every day, got married with it 20 years ago, and it's been "pickled" for ten years now and I want to get it back on the road, with some additional power. Like I say, the V8 option is still there, but it won't be a cobbled job, if I go that route it will be very well done.

Anyone else out there wire OD switches to all the detents on top of the TR-6 overdrive transmission????? Works great in 2, 3, and 4th.

regards, dogsharks "AKA" "P"

[joospeed]

as far as I know the S6 triumph can only go to 2.7 litres .. triumphtune do a kit, but the crank is the weak point, they can twist easily even in relatively mild tune. I love the triumph engine but a high revving high HP motor it ain't!!
V8 the way to go