Rebuild questions.

Post Sat Sep 12, 2009 1:22 am

I've decided to rebuild the M20 in my 325 touring around the e36 crank. My question is, what else can I do to improve things further while the engine is in bits?
Can I lighten the rods for example, or gas flow the head? Any other suggestions?
Any tips/advice would be greatly appreciated.

Post Sat Sep 12, 2009 11:22 am

Lightweight flywheel is a good mod, Z3 1.9 gear selector if you havent got one.

Post Sat Sep 12, 2009 11:46 am

willnz wrote:You are probably only limited by cost.

I would start by getting the bottom end balanced. (crank, rods, flywheel, crank pulley etc)
Consider knife edging the crank as you will save rotational mass.
Lighten/treat the rods or fit steel ones.
Fit forged pistons. If you are considering forced injection, get the right pistons now.
Gas flow head, fit bigger valves, fit decent cam and vernier pulley.
Dry sump?
etc

You're absolutely right about the budget mate, so I'll be more specific.
I want to rebuild using the 2.8 crank and a "fast road" cam. Forced induction is definitely not an option, nor is dry sumping purely due to the cost involved. I don't want to fit new pistons unless I have to (or if it's silly not to) and I'd like to lighten and balance everything I can. I believe you balance the crank/rods/pistons/crank pulley as a set, and I'm unsure about the effectiveness of knife edging against the cost involved. In terms of camshaft I'd be looking for something around 270-276 degrees or so, nothing wilder, then I'd need to make the visit to Mr. Ant for a remap. Are there any threads in here relating to rebuilding the M20, as with some basic searching I couldn't find any.

stonesie wrote:Lightweight flywheel is a good mod, Z3 1.9 gear selector if you havent got one.

Definitely gonna want a lightened flywheel mate, and as my linkage is extremely worn I think I may as well go for the short shift route.

Post Sat Sep 12, 2009 11:57 am

You have not searched very far!
Stonsie's thread relating to his 2.8 build will help you lots.

Post Sat Sep 12, 2009 12:20 pm

daimlerman wrote:You have not searched very far!
Stonsie's thread relating to his 2.8 build will help you lots.

Yeah mate I'm reading that one, but I thought there would've been a sticky relating to rebuilding the standard M20 with any tips/tricks to be done along the way.

Question for you.
After a rebuild including the 2.8 crank, the engine will need a remap right? But, as you'll be running it in due to new rings/shells how is that possible? Surely part of the remap procedure involves revving the spheres off it?