The Dark Side: V8, V6 & 4 Cylinder Engine Conversions and related radical modifications (brakes, transmission, suspension, drivetrain) for MGB, MGA, Midget and all other MG models. Purists beware!
I am looking into converting a 69 MGB to a v6 for a friend and I went to the local GM auto dismantler and they have 2.8, 3.1,3.4 and 3.8
I know that the kits use the 3.1 and 3.4 but why not a 3.8 ?
what blocks are the same dimensions ?
Brian
The 3.8 or 3800 as it is called is the different engine of the group. The other three are of the same family. One problem that I know of is that the modern 3800 is only a FWD engine. Others will post with better info.
Joe
Brian
As Joe mentioned, the 2.8, 3.1 & 3.4 are 60 degree v6's and are in the same family. The 3.8 and let's toss in the 4.3 are I believe 90 degree v6's based on the v8 but with two cylinders lopped off. On another post I had inquired why the 4.3 isn't a more popular conversion (stock approx. 200hp/270tq). Could be because width, parts, etc. Bill Guzman and Brian of BMC (and I'm sure others) seem to be the experts on this subject since they're knee deep in providing conversions, accessories and knowledge. Looking forward to their comments!
Tony
The 4.3 is a Chevy, derived from the SBC. The 3.8 (and 3800 with some differences) is a Buick, derived from the SBB and therefore very similar to the BOP/R engines but with the BOP bellhousing on the 3.8 and the small GM corp bellhousing on the 3800, otherwise the same two engines. So the 3.8 will accept all BOP transmissions including the 2004r and the 3800 will accept all small GM corp trannys including the small GM corp 700r4. The 2004r is generally considered the better performance transmission, but the 700r4 is available with computer controlled shifting, a major advantage, particularly if MegaSquirt is used for engine control. For manual transmissions, the correct bellhousing for either engine is plentiful.
The 4.3 is heavier and more difficult to fit.
Jim
Brian,
You might want to have a look at www.60degreev6.com. You'll find the information on all variations of this engine and then decide which one is most suitable for you.
And you could consider a FWD engine, it would be a bit lighter, but... your call.
The 60 degree engine is of coarse more narrow, which I think, is key feature for the MG engine compartment.
Still lot's of people have used V8's. have a look at the British V8 site and you'll see many variations.
Good luck,
Mike
A little advice I can give you. Don't go for the 4.3 like said larger engine. Also don't go with the older 3.8 rwd motor. I think from the 80's It has a front mounted oil pump that is where the crossmember is. Terry father car is the 4.3 and had major surgery on it. Terry is building the 3.8 motor and run across the other problem but he solved it. Not for the bashful. Terry's father car is here if want to look. http://www.britishv8.org/MG/JoeHutcherson.htm
4.3 is a chevrolet V6 and they come in different flavors. Early version of the 4.3 was uneven fire, 198... something, then they went even fire. The 4.3 is also well known for the Vortec intake after 88? they came with a roller cam later versions came with a balance shaft and there are no cams for this engine that are worth the time, well some of them could be good. Wiring kits for the FI are availalbe up to 95 due to the fly by wire throtle. Painless and few others out there.
The 3.8 FI came in the Camaros RWD after 1995, after 98 they all have the fly by wire throtle.
This engines are 90 degree and require a bit more work to fit in the B.
The 4.3 is very capable of developing 500 hp and about 400 lb of torque or more. This engine was used for Nascar cars.
High performance heads are availalbe from GM, pistons etc. rods are the same a the V8
Brodix also has two part # for the heads, one is for street the other for racing (no good for the street)
gm laso has the V8 style Vortec head for the 4.3
The 3.8 I have seen on Camaros can develop 400 safe hp. requires work on the intake.
Keep in mind that all FI air intakes were created for low mid torque.
The 4.3 responds very nicely to a 600 cfm carb and modified FI. But the Vortec set-up is nice and simple, it has a great air intake that really works and develops great torque.
The simplest of the swaps, yes, it's the 3.4 and you can have different intakes for the engine, carb, TBI, MPFI and SQFI. I would recomend using an aftermarket ECU driver.
My first choice was to convert a 3.1 FWD to RWD. In the process I purchased several parts in error. Yesterday I received a Camaro pressure plate, that I purchased because I though that the Cavalier pressure plate that I had originally purchased was incorrect for the 3.4. They are virtually the same.
So my advise is to try and get a complete engine/transmission. Which ever engine you prefer. This will give you a better starting point.
Everyone here is very helpfull, but when buying parts over the net, it's very easy to make mistakes, and difficult or impossible to return them.
Still it's a lot of fun.