Anyone had any experiences with Crossflow heads on MGBs?

[Sebring67]

Hi,

looking at getting some more power out of my MGB (currently stage 2 head, DCOE45, balanced, etc.) and considering my options. I've driven a V8 and wasn't impressed and not keen on a modern engine, so I'm guessing crossflow head and twin webers are my only option.

So has anyone had any experiences with Crossflow heads and would care to comment? Or do you have any other possibilities (aside from the V8 or modern engine)?

Thanks in advance

[mgtony]

Something like this:


http://cgi.ebay.co.uk/MGB-engine-1860cc-Stage-2-Cr...

[alfa pint]

My old B was pushing out 105 bhp at the wheels, but on a normal freeflow head (K+Ns, stage 2 cam, full freeflow exhaust and manifold, bigger SUs etc). Looked at the crossflow, but seemed very expensive for the modest increase in power.

There's a few threads on this forum about alternative engines. Not sure what it was that you didn't like about the V8, because I loved the one I drove. But there are things like K series, Zetec on bike carbs, Mitsubishi V6s etc going in that engine bay. Suspect it helps if you have a rubber bumper cross member to provide extra clearance.

I know someone who added a turbo from a metro turbo to a B and turned the boost up. The extra torque wrecked the overdrive box in 3rd. I've also seen a B with a supercharger fitted, but it didn't idle well at all and struggled to start well. From vague memory, it was putting out about 130 odd bhp, but again cost well over a grand.

I tried to budget £5k for a V8 conversion, but reckon something like a zetec would provide 3/4 of the performance for about half the price (no need to adapt inner wings for exhaust outlets, exhaust cheaper, engine cheaper, no need to replace prop shaft etc)

[Sebring67]

Cheers Alfa,

What I didn't like about the V8 was the laziness of the revs. I love the free-revving of a modified B engine and driving the V8 didn't feel like an MGB anymore - it was more like driving a fast saloon, and that's what put me off and I guess that's what puts me off a modern engine too.

When I got the car it was heavily modified. I had a load of work done on a rolling road and it was kicking out 115bhp at the wheels, but had a lot of issues (long story), short of it is I got it rebuilt last year by Baldyne Engineering at Biggin Hill and ended up with a disappointing fairly standard engine and a host of problems (as you can imagine I was very disappointed to say the least).

One slight spanner in the works limiting my options is my car's a mk 1 with the 3-synchro gb and at this stage I'm not looking at replacing the 'box at the moment.

So the plan is still crossflow head bolted on my bottom end (18V engine with mk 1 backplate) with a new cam (270 maybe?) with twin webers. Since the issues (fingers crossed) have been ironed out, it's just the head and associated bits (webers, manifolds, linkages, heater control, etc) and the cam that's needed which will be alot cheaper than a new plant. MSX crossflow heads are currently on ebay for £850 (inc delivery).

[alfa pint]

Did see a 3 bearing Mk1 MG B at a show in Plymouth a few years back with a full freeflow exhaust and a pair of weber dcoe 45s - 145 bhp on a rolling road, so ~ 130 at the wheels. Still on normal head, just one that had been gas flowed / ported.

Keep us updated!

[Chilliman]

Don't let driving one V8 put you off, they are usually serious fun to drive, and they can all be very different. The RV8 engine also comes in a host of varieties, varying capacities, induction systems, and states of tune, and can be extremely 'revvable' Typical conversion for a B is the 3.9 with an LT77 or T5 gearbox. States of tune for the V8 vary immensely, and to a great extent are constrained only by your pocket and whether you want to retain your original bonnet line. Ive carried out paper exercises on conversion (I also currently have a '72 roadster which I was considering converting), and assuming you were to correctly address all aspects of stuffing a V8 into a B(not a personal comment)then the cheapest route by a long long way is to buy a car that's already been done. V8 roadsters for sale aren't uncommon, and if you find one thats been done with all the right 'bits' It'll be seriously cheaper than doing it yourself (and you get to drive it sooner )

Apologies to the OP for not addressing his original question regarding crossflow heads, got a bit carried away with the V8 thing

Edited by Chilliman on Tuesday 8th March 11:42