• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR6 TR6 repower?

Share this page

3

35thbdaytr6

Senior Member
Offline
First time posting here, other marque forums have proven indispensible. The wife bought me an early 74 TR6 for my 35th back in July, and I have been playing with it ever since. It is a project, but other than the hole in the drivers floorboard (water leak, no salt here) it's very solid. It runs good, burns a little oil and leaks everything, but that's part of the charm. I'm a BMW Master Technician by trade, and this car is for my entertainment while the rest of the family is studying. I am sorting out the mechanicals right now, here is my problem. The car runs and drives great. The overdrive works, but everything on it leaks, smells, and will need to be overhauled. Question is, do I spend thousands rebuilding the Truimph driveline back to original with updates - hardened valve seats, electronic ignition, stuff like that, or make it speak in German. Thing is, I can put a 168hp, 2.5l BMW M20 inline six, Bosch Motronic engine with a 5 speed Getrag gearbox and a BMW limited slip 3.73 diff in the car - for free (I part out BMW's on the side). Actually, I could make money, since the engine, trans and J-type overdrive are all sound. I'd machine off all the BMW markings to throw off the non-experts. I can make it all look factory, and period correct, the power to weight ratio would be within 1/10th hp of my 98 M3. The body and frame are coming apart next winter, so I have a little while to decide. Should I sacrifice originality for driveability?
 
First of all, welcome to the forum!

Regarding question... originality versus performance, I'd say it's your car, so do whatever makes you happiest. However, if you want to know what would make *me* happiest, I'd like to see you keep it as original as possible. /ubbthreads/images/graemlins/wink.gif

Either way, good luck with the car. I'm sure you'll get lots of varying opinions in response to your inquiry.
 
Why don't you keep the original motor and put a slick fuel injection setup on it? Half the fun of these little cars is the "rawness", if that's a word. Installing fI would keep a lot of the personality of the car but update the reliability a bit.

But again, it's your car... have fun with it.

-Shannon
 
I'm not that much of a purist, especially with a car such as the TR-6. There were a lot of them made, so there will always be plenty of "originals" around. If it were a long door TR-2, then I would draw the line on originality. I have a TR-3 that is in the middle of a frame off resto that will get some updates such as rack and pinion steering and dual braking. I contemplated stuffing a small block Ford in there, but decided to just give the tractor engine some more grunt, and let it go at that.

It sounds like putting in the German goodies will be a piece of cake for you, and cost effective. I say go for it. If nothing else, it'll make for great conversation, accompanied by lots of smiles and, I sure some groans.
 
Welcome to our Triumph corner of the world. The leaks and smells are a characteristic of all things British, so your car is no different (unless the leaks are massive). I say go for the engine swap as what else will keep you occupied? The M20 engine you describe will not overpower the stock TR drivetrain, although I would carefully inspect/overhaul the diff mounts (a known weak design) and half-shafts/hubs as part of the swap. BTW--hardened valve seats are not really necessary for the typical driver and can interfere with exhaust valve cooling.

Have fun and keep us updated.
 
It's no secret that I value the original character of these cars and feel that is best preserved and enjoyed by keeping them as stock as possible. I have never found reliability of the original set-up to be a problem -- what they lack in modern German engineering they make up for in pre-war British simplicity.

That said -- it's your car to enjoy anyway you like.
 
Quite a dilemma!
The Triumph straight six is in some ways a wonderful engine, smooth, torquey, sounds great and simple to maintain; but it does have problems, long stroke limits revs, weak thrust bearings, fairly frequent maintenance.
I like the idea of repowering with another straight six of similar displacement, bringing it up to date rather than making an overpowered hotrod, and there is a sort of family connection through BMWs MINI ownership and other assets.
If you can do it so its reversable at a later date I think I'd do it!
Not everyone is going to like it, but that's always the case.
Simon.
 
I like originality but I also like things that go. How about a sort of compromise? Put the German stuff in but keep the original drive train and rebuild it as part of your tinkering-- that way you and/or next owner will have that option. I've had several mgb's and I often wondered what it would be like to have a modern 16 valve kicker in there with about 140-150 HP to play with.
 
The BMW Differential is going to be installed either way. It's a strong, quiet, light 3.73 limited slip unit. I have already had a machine shop make flanges so the TR axles will bolt up, and the TR mount weakness will be eliminated since I'm sectioning in the mount (a steel clamshell) from a BMW subframe directly to the TR. The BMW engine is 45 pounds lighter, and revs freely to 7000 rpm. The only thing holding me back is that I get a kick out of throwing the column mounted OD switch, and that sweet exhaust note. My wife wanted to get me a radio for the car - why? My dad does not even know if the stereo works in his Ferrari, heck, I find myself with the radio turned way down in my Power Stroke Excursion because I like to listen to the turbo.
 
I love a good restoration, but a bimmer powertrain would be cool. Since it's free (parts, that is) I would go for it. Like everyone has posted, it's your car, dude. /ubbthreads/images/graemlins/thumbsup.gif
 
Welcome aboard! It sounds like it could be a really nice conversion. I took my 1975 and installed a SBC, 700r4 tranny and a BMW 2.93 LSD in the rear. Drives beautifully and behaves quite nicely. The BMW diff seems very bulletproof with a couple hundred pounds torque applied.
I've always liked the concept of doing something new and interesting. I'd say go for it!
Please keep everyone posted as to your decision and progress!
all the best,
Jeff
 
[ QUOTE ]
.............bringing it up to date rather than making an overpowered hotrod......

[/ QUOTE ]

I didn't know there was such a thing as an overpowered hotrod...heh!

If one can carefully regulate throttle and clutch, then high horespower can be managed. Ofcourse, you won't be able to just dump the clutch and nail the throttle at a standstill cause you will just burn your tires off. The useful and, most importantly, fun thing about extremme power is having the same rate of acceleration in higher gears and at higher speeds that most cars have in low gear at low speeds.
 
Somewhat off-topic, but what about the Datsun/Nissan I6 Z engine as a swap? Better performance specs? It would be very ironic putting a Z engine in a TR as the Z's introduction played a big part in the demise of the TR series.
 
My roommate has a 280ZXT and my previous roommate had a 280Z so we've had the TR 2.5L next to the Datsun 2.8L. The 2.8 is WAY too big for the TVR's engine bay, and I don't think the TR had much longer in the bay than the TVR did. They're nice motors though, capable of ~450hp IIRC on the stock block & crank.
 
[ QUOTE ]
[ QUOTE ]
.............bringing it up to date rather than making an overpowered hotrod......

[/ QUOTE ]

I didn't know there was such a thing as an overpowered hotrod...heh!

If one can carefully regulate throttle and clutch, then high horespower can be managed. Ofcourse, you won't be able to just dump the clutch and nail the throttle at a standstill cause you will just burn your tires off. The useful and, most importantly, fun thing about extremme power is having the same rate of acceleration in higher gears and at higher speeds that most cars have in low gear at low speeds.

[/ QUOTE ]

Mr. TR7/8 TPI,
I like the way you think!!
Until you know what that's like to accelerate at the SAME rate to 100mph....(the 2nd/3rd gear shifts are amazing..)

Flipside is my beloved bride misses the sound and mannerism of the stock setup.

Hats off to BOTH innovators and purists.
/ubbthreads/images/graemlins/smile.gif
 
My vote is to build the 2.5 up to where it should have been back when. Start with the crank, lighten, nitride, balance.Lighten flywheel. Carrillo rods, forged pistons. Take 125thou off the head for 9.1 comp Get the cam dejour, do some moderate head work and see if it doesnt make 165hp at 6500rpm(with the right header and the Good Parts tri carb of course). The money spent, is money saved in classical car value.In the long run it will be much better to have the old lump right where it is, making happy Triump noises!!!!!
MD( mad dog)
 
The engine is 1/2 inch shorter and 45 pounds lighter.
 
Its from freakin Germany!!! dont go over to the darkside!!!!!!!!!! Take 10lbs of the flywheel, 5lbs off the crank, 2lbs rods/pistons, shorten the head 1/8th of an inch(godknowswhat that weighs) It will be close and MORE valuable in the long run.
MD(mad dog)
 
Mad dog you crack me up!
Not a bad suggestion, either, as the value of the car is preserved.
There are lots of things you can do to lighten the car; remove bumper overriders and heavy supporting brackets, replace steel brackets with aluminum, get lighter seats, smaller battery etc. Easy to get rid of 50lbs and improve weight distribution without cutting any metal.
All a question of what you want, I suppose.
Simon.
 
Back
Top