2.85 (2.9) Stroker with S50 Crank - it lives!

[RobE30]

This thread is great. I should be picking up a 100k M20 this weekend and it will be the base for my stroker build. Thanks for documenting your adventure with this.

[digger]

The solder method definitely sounds easier. I've used it on the exhaust side before, but where do you go in for the intake side?

Correct me if I'm wrong, but if I'm advancing the cam the intake clearance is the one I'm concerned with, exhaust clearance should increase with cam advance.

If its not too much trouble i'd be interested to see a pic of your tool Digger

sorry I dont have a pic the tool is long gone, I might see if I can mock something unbelievably ghetto up really quickly to illustrate though

Install a weak valve spring. You can then push down the valve with your finger. Rest the dial indicator tip on the retainer at 90 deg. to check clearance.

It’s a pita to remove the spring in situ without a special tool

[e30sh]

Install a weak valve spring. You can then push down the valve with your finger. Rest the dial indicator tip on the retainer at 90 deg. to check clearance.

[sert57]

The solder method definitely sounds easier. I've used it on the exhaust side before, but where do you go in for the intake side?

Correct me if I'm wrong, but if I'm advancing the cam the intake clearance is the one I'm concerned with, exhaust clearance should increase with cam advance.

If its not too much trouble i'd be interested to see a pic of your tool Digger

[ForcedFirebird]

I use solder after assembly, and clay during. Your idea sounds nifty, though, Digger. Sounds like it would be easy to use a dial indicator on such a setup too.

[digger]

What i did was rotate the piston to just after TDC (5-10*) on inlet stroke where min clearance is on inlet . i made a lever tool that gets bolted down using the rocker cover studs with a pivot and lever that allows you to slowly press down on the rocker near the eccentric. You can feel the hard point but you want a fair amount of leverage to have some finesse and not smack into the piston too hard. this doesn't check radial clearance but with stock pistons you should be fine where as aftermarket all bets are off

[sert57]

Yeah feel free to reach out! There are others who have way more experience, but I'll be happy to share the little I know.

I'm curious, for those of you who have used a cam gear. I have been wary of adjusting it because I didn't check P2V clearance when assembling at any point beyond 0 advance/retard. Are there any tips for messing with it without destroying the valves? I was thinking if I was careful I could adjust it and use a long piece of solder to check clearance each time, but this seems pretty tedious.

[bimmer_party]

Finally began tear down on the M20 for the build. I’ll probably be hitting you up over the next 6 months while I get it going. Thank you again, so much, for all the info!!

[sert57]

Yep! Leaving Friday morning from Marietta!

I'm thinking of meeting up with a group leaving from Chamblee area, but we will see if that happens or not.

[ATL_E30]

I need to see this ASAP! You going to The Vintage this weekend?

[zaq123]

I'm not sure truer words have been said on here lol




I decided to go with the 42mm kit - maybe in 2-3 years I'll do a "proper" head build with a 288 cam and porting and polishing, so it leaves that door open. Still ironing out the tune, but its gotten about 90 % of the way there. I'm also just running ramflow socks for the moment, I'll probably upgrade to an airbox around the end of this year.

I can't wait to get a proper dyno tune done and see what it puts down, but with the 272 and ramflows I'm not expecting anything out of this world. That being said, it does feel a bit faster, and it sounds incredible!

Good for you on the progress. My ITB 2.9 is sitting on the stand almost a year, waiting on the finished chassis and all


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[sert57]

It's slope covered in gear oil while you're getting blasted with a fire hose.

I'm not sure truer words have been said on here lol




I decided to go with the 42mm kit - maybe in 2-3 years I'll do a "proper" head build with a 288 cam and porting and polishing, so it leaves that door open. Still ironing out the tune, but its gotten about 90 % of the way there. I'm also just running ramflow socks for the moment, I'll probably upgrade to an airbox around the end of this year.

I can't wait to get a proper dyno tune done and see what it puts down, but with the 272 and ramflows I'm not expecting anything out of this world. That being said, it does feel a bit faster, and it sounds incredible!

[Kershaw]

It's slope covered in gear oil while you're getting blasted with a fire hose.

[digger]

It's a slippery slope

[sert57]

Glad to hear I could help someone out! After doing it all - fair warning - its pretty easy to go over budget. After Megasquirt and everything i was around 6k all in. you could probably do it for less depending on where you cut corners. If you have any questions feel free to PM me! The most ...interesting... part was grinding down the block for clearance.

I'm loving my engine still. I have around 8k miles on it and it has been running strong! Its done a few autocrosses and plenty of highway / around town driving. Right now I'm working on putting my wideband closer to the exhaust to help it heat up better, then I plan on re-tuning and doing another dyno on a dynojet. When that happens I'll post here.

I'm also playing with the idea of ITBs because of many reasons.