Roadster or not for a V8 conversion

Have you had a look at

There is a board there for V8 and V8 conversions.

Cheers

Thanks Ian,

I have been poring over it, the relevant bit says that Rover though the 'roadster shell was not strong enough', but that in truth it didn't happen for political reasons.

I suppose the point is about whether the non V8 roadster shell is identical to the factory V8 roadster shell.

I was hoping some had experience of converting a roadster to a V8.

As it happens, I started a V-8 conversion with the Buick 215CID and a Muncie

4 speed in 1986. After moving to another town, I sold it to another guy who finished the project. Due to having the engine out for some work, and his garage catching fire, melting the 215 block, he acquired a Rover 3.9L.

The car puts out upwards of 270 hp (not dynoed, just a guesstimate), and will out accelerate a big block Pontiac Trans Am from a rolling 40 mph. Below that, any "serious" acceleration breaks the back end free. He reports several 360 degree spinouts on heavy acceleration from start, so he's had to be very careful.

All in all, I'd say you're likely to be safe; the rear end will break away before twisitng the shell any.

BTW, the rubber bumper engine bay was DESIGNED to accept the Rover V-8!

Another BTW: I've just agreed to buy the beast back!

I've got a Roadster with a 3.9, it's not a problem for the shell. But the conversion is easier if you use a rubber bumper shell as opposed to a Chrome bumper shell. Colin................

Whats the difference in the two shells???? and why is it easier???

rm

The bulkhead position was moved when the V8's were produced to give more space in the engine bay. The same modifications were made to the non-V8 rubber bumper cars as it only made sense to make the one variant of body shell - that's why there's more legroom in the chrome bumper B's/BGT's.

Thanks I have only seen one rubber bumper model under the bonnet the V8's haven't looked that closely. Will next time I find one.

can sleep in my '62 B. :)

rm

Thanks Colin, thats reassuring. I have the SD1 (engine and box are coming out next week) but I'm taking my time finding the MG. I knew about the March 76 shell change. Suits me down to the ground - the later rubber bumper ones are the least desirable and therefore cheaper!

Did you do your conversion yourself ?

IIRC, not just the firewall (bulkhead); the wheel wells were also reshaped to allow the headers to fit.

And the RB cross member allows more room for the crankshaft pulley, the steering column is shorter and the pinion shaft is longer so the universal joint is set back behind the rear exhaust header.

Ian F

Sorry for the late reply, convert the car myself? well no. After weighing up the pro's and con's I decided it would be quicker and maybe cheaper (for me) to buy a ready done job and just tidy it up a bit.

If yours was a rubber bumper - can you see the engine mounts - and in particular which one is drivers side and which one is passengers side? They are not symetrical - the engine facing plate is towards one end of the mount, does it go towards to front or back of the car?

When I was doing this conversion, I used stock Buick pads, and had my brother make new mounts and weld them in the engine bay after removing the stock mounts. I may have some pictures but not sure; this was 15+ years ago.

I don't think I'm going to be much help here, my mounts are not the stock ones. Mine have been moved to the inside of the chassis leg, as opposed to the normal position of being on top. They are round rubber blocks with non of the plates that you mention.

I guess it would boil down to just how hot you plan to twiddle the engine to. Those old alloy 8s were only around 150 bhp as used in the orig. form, so shouldn't be much of a problem even in the roadster. The same engine is however capable of being tuned to very nearly double that output, and if you intend to go that hot it would make sense to put it in the considerably stiffer GT package.

I've had a number of roadsters over the years, from ' 65 to a ' 72, and currently have a ' 70 B-GT. The GT is much more rigid with far fewer rattles, no scuttle shake, and less flex in hard corners. It's quieter of course and all 'round it just feels far more solid. Makes sense, since the tin lid closes off the big hole in the middle left by the roadsters' tent.

To me, much of the MGBs' charm is that even a relatively inexpert driver can push it close to it's limits without it actually biting him or her. Handling is anything but precise, but it is predictable and about as forgiving as it gets. That's fine with a motor which produces a modest 95 hp. ( on a good day), and even when tuned to produce up to say 120.

The Rover/Buick 8 pushes it up over 150 in a very mild state of tune, and would make the car into a pleasant little tourer, but once you start playing with the engine to make it produce real grunt, you'd have to spend a lot of money to upgrade that suspension to handle the power well.

There isn't really a lot of sense in building something which has a hard time putting all it's power to the ground. A chap down the road from here has been building a Lotus 7 clone for the last ten years or so. He has shoved a hopped-up 5 litre Ford Mustang motor into that flyweight chassis, but so far hasn't had it fired up. I keep encouraging him to get it finished so that I will be able to buy the wreckage from the grieving widow at a reasonable price, then repair it and stick in a more suitable motor.

I've been told the Ford 2.3 liter 4 banger is also a good place to start, as there are plenty of options to warm it up, and the Buick/Olds/Pontiac blocks are getting hard to find (much less the 3.9l Rover that's in my B).