3.1 RWD rebuild

[NAP1947]

I have spun 2 or 3 of the con rod bearings in my 92 Camaro 3.1, T5 combination (installed in a 73 MGB). Silly but gratifying when I did it.
I have found and purchased an NOS crank but am having trouble finding connecting rods, other than high performance.
I gather from reading here that all 3.1s and 2.8s share the same crank and con rods.
If this is true, I have access to an 04 Chev ? 3.1 and use the con rods in my engine (FWD to RWD) Could I also use the heads and SFI? Obviously the computer should work.
Any guidance or references would be greatly appreciated.
Norm

[geoffinbc]

Yup all rods are the same. No problem using them from another engine. They just need the standard rebuild treatment. The FWD heads will bolt up but compression will be very low on your iron head pistons so you may want convert the FWD motor for use in your MG. Its not too hard and you will get all the benefits of the newer generation block and heads.

[NAP1947]

Thanks BTY, If I used the FWD con rods and pistons, would I keep decent compression?
The reason I want to keep the original RWD block is the starter location, I just don't have room for the starter on the driver's side due to body and clutch and exhaust interference.

[3400-95-Modified]

Just drill and tap the block for the starter on the other side... its rather simple from what I've heard.

[NAP1947]

Does this mean there is a starter flange on the what would be the passenger side of the FWD block when installed in a RWD car?
My understanding was that there were 2 issues, one no flange and 2 a bell housing that would fit the FWD block with a starter pocket on the right side.
Please dispel my understanding.

[Superdave]

I think Betterthanyou was thinking backwards.. if you put the FWD aluminum heads on your 3.1 engine with the old flat top pistons compression will be very high. 11.4:1 or 10.72:1 depending on what head gaskets you use.


IIRC The FWD block only has enough meat on it to get the inner bolt drilled/tapped when installing the starter on the passenger side, the outer bolt will have to go into a fabricated bracket. The advantage is that the modern FWD blocks have a much better oiling system and are stronger. It won't just drop in though, you'll have to make some motor mounts and do a few other things like grind off the uppermost tab and swap over your RWD timing cover, flip the lower and upper intakes around, maybe do a little custom bracketry to get the accessories to fit (Marc at BCC probably has everything you need though).




Building a hybrid out of it, You won't be able to use the old distributor and your block isn't set up to use a 7x trigger so you'll need to either make one or pick one up from BCC here: http://www.britishcarconversions.com...category_id=28 It'll still take a little engineering to work but a few of us are using them with good results.

Just a little wiring to get the FWD DIS system installed and you'll have a mean little engine. you'll Probably pick up 30-40 HP



The crank in that "3100" will also work in your 3.1 block so if you want to just drop in the entire bottom end and have about 9.5:1 compression you can do that as well. In this case you may be able to get a machine shop to modify the block to accept a crankshaft sensor, they'll have to figure out if it's possible though. I can't recall anyone trying.


Good Luck!

[NAP1947]

First I have dished pistons in my 3.1. This engine was a replacement for the original Camaro which the owner had trouble with.
Could that explain why the pistons are dished and not flat?
So putting the newer 3.1 into the B is a lot of work and I may not have the skills to make all these changes.
SuperDave, you said just drop in the bottom end, do you man put the newer crank, rods and pistons into my old block?
Could I just keep the old heads and carb setup or could I use the new heads and carb, I have an edelbrock manifold and Holler 350 CFM on it now with an S-10 dizzy.

[Superdave]

the old intake manifold won't work with the new aluminum heads. They have a totally different design. So you'd have to use the whole aluminum top end. There aren't any carb manifolds for them other than custom built ones.

your pistons may have a slight dish but the FWD heads have a smaller combustion chamber so they dished the pistons more. (12cc vs 25cc).


If you're keeping the iron heads, stick with your 12cc pistons but yes, the 3100's crank and rods will work in there. The only difference is the 7x trigger ring on the crank is cut out vs being blank. It should have a "981" cast into it.

[NAP1947]

Thanks SuperDave.
If I can summarize, use the NOS or Chey crank with the Chevy con rods and pistons, for better efficiency and driveability use the aluminum heads and FI making sure I have the 7X? trigger ring crank. Use all of the Chev FI, reversing the intake manifold so the TB is at the front of the RWD. Use the Chev ECM and convert the fuel system to high pressure, which is probably another question when I get there.
If you see a problem with this plan please let me know.