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chiliredDX
chiliredDX
8/24/09 2:32 p.m.

I am new to the forums, but not new to Grassroots Motorsports.

To start, I would like to do a project MGB/C GT hybrid swap, but do not want to go down the V8 road. Ideally, I would like to bring a MGC GT up to date with a modern I-6, such as the TVR speed six or Nissan RB platform. I have seen a few individuals squeeze a SR20 under the bonnet of a MGB, but have not seen anyone try to fit one of two examples above into the GT.

Granted, i know that this will take a lot of work and more coin than I probably care to think of at this juncture since this project is only in its infancy and probably will not see the light of day for at least a five or six years since the military is not the best place for these kind of projects.

What i am looking for so i can keep the dream alive until i have a). time b). enough money drop and c). car, engine, and all the fixin's, is specifications for a TVR speed six and or the some other inline six motors. I would prefer to keep the project purely British, but if anyone could point me to a site or other information source that would give me dimensions i.e. length, width, height, of the engine/transmission that would be a great help to start my search.

Thanks in advance.

BoxheadTim
BoxheadTim GRM+ Memberand New Reader
8/24/09 3:10 p.m.

I don't have the specs for the TVR speed six engine, but you do realise that these engines do have a bit of a reputation for self-destructing in a very expensive manner?

The original designer of the engine is offering a rebuild service that brings them up to his original design and I'm led to believe that these engines are OK...

Ian F
Ian F HalfDork
8/24/09 3:19 p.m.

The issue is space. Not saying it can't be done, but the chances are slim the car while have much of the original chassis remaining. While it doesn't sound like it would be so, modern I-6 engines are surprisingly wide once you add on all of the hanging bits. Most are pretty heavy, too...

There is a guy on BCF who rebuilt a TR6 with running gear from an E36 M3. It looked and ran great, but he basically had to rebuild the entire frame for the car.

Have you looked under the bonnet of a MGC recently? Even the OE version of the I-6 was a tight fit.

Tim Baxter
Tim Baxter Online Editor
8/24/09 3:29 p.m.

I think your best bet in terms of cost, availability, etc, is probably the BMW six... IF it will fit. The MG wants the engine upright, the BMW motor is canted... could be VERY snug. But that's what I'd go with. And since BMW bought some of the remnants of BL, it's sorta in the family.

Keith
Keith GRM+ Memberand SuperDork
8/24/09 3:44 p.m.

The obvious British inline 6 to me is the Jaguar one. I'd be amazed if this hadn't been done several times by now. Of course, it's more of a period swap than a modern one, but Jaguar did keep developing that engine for some time. Looks like the 4.0 version in the 90's was around 235 hp and 290 ft-lbs. That would be healthy in a C.

spitfirebill
spitfirebill Dork
8/24/09 3:51 p.m.
Keith wrote: The obvious British inline 6 to me is the Jaguar one. I'd be amazed if this hadn't been done several times by now. Of course, it's more of a period swap than a modern one, but Jaguar did keep developing that engine for some time. Looks like the 4.0 version in the 90's was around 235 hp and 290 ft-lbs. That would be healthy in a C.

If you can get one in a Spridget, you should be able to get one in a B.

Tim Baxter
Tim Baxter Online Editor
8/24/09 3:53 p.m.

Y'know, Keith may be onto something there. My first instinct is that the Jag six is insanely heavy and large, but then again, so is the Austin-derived 3 that's in the C anyway.

According to this (and if I found it on the internet it must be true) the AJ6 weighs in at 500-odd pounds: http://www.35pickup.com/mulligan/weight.txt

That would put it within spitting range, maybe even slightly lighter than the stock 3 liter. I'm betting the external dimensions aren't too far off, either. The AJ6 is canted 22 degrees, which is closer to upright than the BMW engine, too.

2002maniac
2002maniac Reader
8/24/09 3:55 p.m.

In reply to Keith:

Those Jag sixes weigh a ton. Other than that, sounds fun!

Tim Baxter
Tim Baxter Online Editor
8/24/09 4:06 p.m.

Yup, if my sources are correct, the Jag AJ6 is about 50 pounds lighter than the CGT six.

John Brown
John Brown GRM+ Memberand SuperDork
8/24/09 4:43 p.m.

Why not a Cosworth Sierra engine? They can be had out of Canada and the Ford 4 fits pretty well.

I like the Jag6 idea.

I like the BMW 6 idea, plus if you squint you can get a lineage (BMW makes MINI which is from England where they made MGs! Also in my logic all Dodges are Vipers and all VWs have Bugatti engines.)

Keith
Keith GRM+ Memberand SuperDork
8/24/09 5:01 p.m.

It would be interesting to list all the modern inline 6-cylinders. It's not as common a configuration as it used to be. By "modern", I guess we're talking 90's or newer based on my suggestion of the AJ6 I'm not going to use engine codes because I'm not cool enough to know them all

  • Jaguar
  • Nissan Skyline (RB, I think)
  • Toyota Supra
  • TVR (as mentioned, it's not one I would have remembered)
  • BMW (various, probably the most widespread)
  • Dodge Cummins
  • Ford Falcon
  • Jeep

Ummm...

Tim Baxter
Tim Baxter Online Editor
8/24/09 5:04 p.m.

Almost any four will fit. Inline sixes are tougher.

Sorting out the lineage...

MG and Austin were both part of BMC/BL, which is where the MGC got it's Austin engine.

Jaguar was also part of BMC/BL, so there's that family connection.

Jaguar and MG were eventually spun off, and BMW bought most of whatever was left of BL, which included Mini, but also Austin (and Triumph, for whatever that's worth). So there's that connection. In a sense, the MG would still be borrowing a motor from "Austin". Sort of.

walterj
walterj Dork
8/24/09 5:22 p.m.
Tim Baxter wrote: Almost any four will fit. Inline sixes are tougher. Sorting out the lineage... MG and Austin were both part of BMC/BL, which is where the MGC got it's Austin engine. Jaguar was also part of BMC/BL, so there's that family connection. Jaguar and MG were eventually spun off, and BMW bought most of whatever was left of BL, which included Mini, but also Austin (and Triumph, for whatever that's worth). So there's that connection. In a sense, the MG would still be borrowing a motor from "Austin". Sort of.

...and Kevin Bacon rode in an Austin...

NOHOME
NOHOME New Reader
8/24/09 6:16 p.m.

http://www.youtube.com/watch?v=aiMMzaW_Qs4

bunch of other supra mgb videos are also available. C cassis should make this an easy swap.

Pete

I can't believe I used the words "swap" and "easy" in the same sentence! Good luck.

Brust
Brust Reader
8/24/09 6:32 p.m.

Those Jag 6's are pretty too when the valve covers are polished. I think that's about as good as you're going to get with "British". For the "all in the family" thing, I'd stretch to the BMW. Also, there is strong rumor that Datsun copied the a-series to make their own A-series's (A12-A15), so you could conceivably maneuver that little Bacon game to the RB26 also. A-series was predecessor to the B-series, which was used in MGB's. Datsun became Nissan. Lots of inbreeding. Lots of first cousin stuff.

Shoot, I played the whole game with my Midget: Toyota 4age 20v descended from Toyota 4age stolen design from Ford Cosworth BDA used in Lotus product (Cortina, racing cars, Caterham) (here's where it gets a bit sketchy) lotus used k series in series 1 elise Mg used K-series in the MGF

Close enough

racer_ace
racer_ace New Reader
8/24/09 7:31 p.m.

In reply to Keith:

my $0.02

Volvo

GM Vortec (i.e. 4.2 in the Trailblazer)

chiliredDX
chiliredDX New Reader
8/25/09 12:31 a.m.

Thanks all for your input. I now have several new avenues to research which will keep me busy for a while.

I failed to mention last night when i wrote this thread that part of my inspiration for this build is the MGR. I do realize that pretty much all of the suspension will have to be looked at seriously. However, I do appreciate all the information.

As for the RB25 (Nissan Inline Six), it is the same width as the SR20 block. As mentioned before, I have seen pictures of this swap in a few B roadsters, so I am inclined to think that the RB would fit with the right modifications depending on what chassis I find for the build.

BoxheadTim
BoxheadTim GRM+ Memberand New Reader
8/25/09 12:36 a.m.

Don't forget there is also a Nissan RB20 (used in the R32 Skyline) which can be had with or without a Turbo (much like the RB25). Easily tunable and a little smoother IMHO than the RB25.

96DXCivic
96DXCivic Reader
8/25/09 12:51 a.m.

I have to be honest it seems a shame to cut up a MGC. They aren't that common. Why couldn't you get a normal MGB and put a six cylinder in it?

chiliredDX
chiliredDX New Reader
8/25/09 1:07 a.m.

thats probably the route i am going to go since BGTs are a little more common.

96DXCivic - what all have you done with your civic? I have a 92 which is my current project and has been for the past three years. I dont intend to hijack my own thread, so if you can PM me, i would appreciate it.

96DXCivic
96DXCivic Reader
8/25/09 1:25 a.m.

It is pretty much stock now. I am going to tighten the loose nut behind the wheel first.

oldsaw
oldsaw Reader
8/25/09 1:52 a.m.
96DXCivic wrote: It is pretty much stock now. I am going to tighten the loose nut behind the wheel first.

Once upon a time, an old magazine (Sports Car Graphic" featured an MGB roadster with a transplanted Ford 289 w/ four speed. The swap required some serious firewall mods, but the end result was a nice piece of work.

An SBF swap would make a really nice alternative to the more traditional Tiger!

Are SBF's bigger/smaller, and/or lighter/heavier than in-line sixes?

BoxheadTim
BoxheadTim GRM+ Memberand New Reader
8/25/09 3:38 a.m.

I wouldn't be surprised if an SBF is noticeably lighter than the MGC inline six, but that one was one heavy beast. The Rover (née Buick) V8 they put into the BGT V8 is lighter IIRC and an SBF is not that much heavier than the Rover engine.

Ian F
Ian F HalfDork
8/25/09 6:50 a.m.
Keith wrote: - Dodge Cummins

Hmm... looking at the engine in my truck... yeah... sure... if you want to put the driver in the back seat... and have you seen the transmission that goes behind a Cummins? It's freakin' HUGE...

Honestly though, I agree... if the car is a real MGC, then you really shouldn't chop it up...

aeronca65t
aeronca65t HalfDork
8/25/09 7:09 a.m.

Yeah, kind of a shame to chop up a good MGC.

But don't forget that the MGC has compeletly different (torsion-bar) front suspension to accomodate the big six. If you swap a big engine into and MGB, you may have to fiddle with more than just engine mounts (~my MGB~ ain't ~that~ roomy under the bonnet).

If a swap if desired, I would also look at the General Motors Vortec in-line, five cylinder engine. Comes in 3.5 or 3.7 L. All aluminum. Very light and very smart looking , modern twin cam. Often comes attached to a nice Aisin five-speed manual trans. ~Here's One~. They've built zillions of these here in the US, so should be cheap (at least in N. America....not sure where your are?)

If you had buckets of money, the best thing would be to put in one of those Australian-built ~Aluminum Healey Engines~.

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