1969 MGB GT thinking about engine swap

[azn_iMack]

i'm thinking abuot dropping in an SR20DET engine (nissan silvia engines as well as other nissans). i was thinking about dropping in a v8 but they're going to consume gas too quickly and i figure why not use a smaller engine with more displacement? tell me what you think.

[dejoux]

Ive never heard of that done, its going to be a huge hassle.

Particularly electrically because EVERYTHING will be different.

I assume itll fit but its definately not going to drop straight in, youll end up spending alot of money and hacking the car around that much it wont be possible to change it back.

Any reason why you'd want to do this?

It would be easier in a 73+ car as they changed the inner guards so there will be more room.

[DWF Engineering]

I'd use a small-block Ford; believe it or not, an H.O. 302 is actually weighs less ,with alloy heads, than the BMC engine. It should fit with little (if any) cutting of the unit body. The hood clearance may be a problem. The stock rear axel will hold up if you keep near stock tires and engine. You should be able to find a shop locally that can narrow a Ford axel if you want to go faster. My dad had an A with a 305 hp 289, automatic, and Ford axel. It pulled mid 11s on the little skinny stock tires. The mpg stayed about 20-25. With a later 225 hp EFI 302 you should expect more mpg. Remeber that you'll be lighter so it'll actually take less power to roll down the road at X speed, you'll just have more power on tap. A Mustang GT driven lightly can get between 25 and 30 mpg so I don't see why the MG would be worse with 600-1000 lbs in weight savings.

A small block GM will also work but you'll have problems with distributor/fire wall interference resulting in the need to cut some sheet metal out. The GM is also heavier. Even with the Ford you'll need to notch the front crossmember. If you want a 2.0 turbo the Toyota 3S-GTE is a tougher engine than the SR20DET. Both are available in RWD configurations. The 302 is tough to beat though, with turbo options up to 1,700 bhp! (not for the stock MG unit body)

Also, a turbo BMC engine should be able to make 180-200 bhp and would be very unique and in my opinion, very classy.

[azn_iMack]

thanks for the input. i haven't used this in so long. well, i'm at school now and that's 300 miles away from home, and from my car. it's been pretty scary driving that car actually. the brakes are pretty crap, and i've bled them twice already. no power anything. and since it's more than 30 years old, everything is rusting. i'm not sure if i really want to keep it around.

if i decide to keep it, i'll probably not really work on it too much until after college because of all the money.

-Julius

[Layla's Keeper]

If you're going to put in the work to swap an engine into an MGB, then make life easier on yourself and do what the factory did in 1974, and again in 1992; use a Rover 3.5L/Buick 215ci V8. Beyond being 35lbs lighter than the 1800cc OHV MG engine, the Rover 3.5L has excellent off-idle torque and is a ready supply piece. Your options for them are as varied as locating original GM pieces (as I have dwelling between the fenderwells of a 1961 Oldsmobile F85 sedan), to importing them at surprisingly low cost from English junkyards (easily as cheap as the SR20DET idea you spoke of).

Being small displacement (for a V8) the Rover actually does not eat gas as you'd assume. Though the head work to wring proper power out of them can get tricky (long obsolete parallel valves are the problem here) it's a very worthwhile undertaking. With thoughtful tuning, Rover 3.5's and their later 4.0L brethern (breathing under the snouts of Morgans and TVR's, no less) can churn out well in excess of 350-400hp NA. And remember, that's in an engine 35lbs lighter than the factory 1800cc OHV four and it IS a factory swap.

As soon as I acquire the aforementioned Olds F85, I'll be performing this swap to turn my dear Layla (a Royale Blue 1970 MGB GT) into a slayer of modern performance machinery. I'd think that you'd be quite interested in doing the same.