Jag V12 - Vic or Fran, ideas?
- Thread starter Ron Earp
- Start date
Ron, you will remember an earlier post re: XJ13 and I made this comment:
"Hey Ron. Re: V12 availability. best motor to have is the '71-81 European motor as they have typically 10.1 cr and the "flathead" cylinder head design can develop extra horsepower 500 and above with absolutely no problems. The best one out of that range is the mid 1980 production. This was the basis for the 6 litre TWR developed motor in the race cars. After that (1982 onwards, the "HE") they enlarged the chambers to encourage mid range fuel economy and you are limited to about 400hp with these. But, they are cheap."
It would seem the "flathead" design is best, but i am unsure of what they shipped to the US with the tougher emissions etc. Hope this helps in some way.
"Hey Ron. Re: V12 availability. best motor to have is the '71-81 European motor as they have typically 10.1 cr and the "flathead" cylinder head design can develop extra horsepower 500 and above with absolutely no problems. The best one out of that range is the mid 1980 production. This was the basis for the 6 litre TWR developed motor in the race cars. After that (1982 onwards, the "HE") they enlarged the chambers to encourage mid range fuel economy and you are limited to about 400hp with these. But, they are cheap."
It would seem the "flathead" design is best, but i am unsure of what they shipped to the US with the tougher emissions etc. Hope this helps in some way.
Ron Earp
Admin
I remember, but we didn't get Euro spec stuff - things were very different back in the emission days over here. So, I need to pick from the best of these available and I don't know much about them. The induction doesn't matter since it'll get replaced with webers, but I don't want to pick a motor with inheriently bad heads or block. Thanks again, R
I built several Cobra replicas with Jag V12 Injected and with weber carbs. NOT my favourite engine by a long shot, very heavy, very long, not all that powerfull and VERY thirsty, lovely bit of design engineering otherwise. Given the size and weight of the unit, stick to V8 anytime ! Frank
Just a long shot Ron, a pal of mine in the UK is heavily involved in Historic racing, and he is assisting in the preparation of a Bob Tullius Jaguar with a V12. I know he is in contact with the original race team (Group 44) back in the States, so I have emailed him to see if he can help in some way? The other guy heavily into the Group 44 program back then I believe was Joe Huffaker who is still active of course with Huffaker Engineering. If these 2 don't know about US style Jag motors , then I don't know who does. We'll wait and see.
Ron Earp
Admin
I just talked to Joe and crew a few months ago about the Jensen Healey race car I'm putting together, they campaigned one and won with the in production even in 1995 - 20 years after it won the first time. Good group and I'll check with them. Ian, that doesn't sound good on the bellhousings and could be trouble, I need to check into that! And Frank, a V8 in a XJ13??????? Shame on you! ;-) Keith if you find something out let me know, I'll contact Joe, thanks,
Ron
Ron
Ron, if you really want to build a V12 into a XJ13, GET GOOD PERSONAL INSURANCE
Not to vear off thread....but I read last night the XJ220 is powered by a turbo V-6....what a letdown !
MikeD
MikeD
Mike,
Yeah, but it's a 200MPH V6! /ubbthreads/images/graemlins/cool.gif
How are your projects coming along???
Bill
Yeah, but it's a 200MPH V6! /ubbthreads/images/graemlins/cool.gif
How are your projects coming along???
Bill
I've got it the back of my mind somewhere (it's pretty dark in there so bear with me), that this V6 started off life as the naturally aspirated DOHC item that powered the now defunct but still active in rallycross MG Metro 6R4 Group B rally car. If so, it's one mother of a motor and sounds glorious in atmo form.
This is the first V12 offered in the E-type and although they "improved" the engine over the next few years, these improvements were mainly for improved fuel economy and emissions. Stock comp ratio should be 9:1 and the good news is that it will have the desirable flat head design which will facilitate power improvements. 90mm bore and 70mm stroke give 272 hp @5850 stock with early F.I. There doesn't seem to be a fundamental difference between Euro and US versions on this first model year the V12 was offered in the series III E type. Should also have ally block.
Ron Earp
Admin
Looks like it makes sense to get a late model since adapters are readily available to G50 boxes for 1979 and up blocks. That being said, I found a nice 6.0L 1994 block locally for only around $1000 - very nice and these have forged cranks and other internals unlike some other produciton versions. I'll try and get it and let you folks know.
Ron
Ron
Hi Ron! Finally tracked down my man and he agrees that the 6 litre is the way to go and it's found in the XJS. He also says that Cosworth still makes special pistons to increase the cr and overcome the low compression issues. It will also go out beyond 7 litres up to 7.4 litres with stroked crank and overbore. This is what TWR were doing. I have found a man in the UK who bought TWR stock when they closed the race program and currently builds V12 motors for Historic Group C cars (Jags) including 2 Le Mans winners, plus he has a shop full of spare race bits for these motors. He has a wealth of knowledge and I'm sure could answer any of your questions re: this motor. I'll PM you separately with his name, phone number and email.
Cheers
Cheers
Ooops. Something I forgot to mention. Apparently one of the major problems they all had with this engine under race conditions was the wet sump. A special sump was fabricated by Broadspeed but constant oil starvation problems caused many of the early blow ups. It is highly recommended to use a dry sump set up!
Denis Bedford
Denis Bedford
Ron Here is one I prepared earlier