Help! Resealing/building M20B25 for Turbo. Bottom end advice needed.

[77320i]

So I'm planning on resealing the lower end of my M20B25 and putting on a rebuilt head with a split profile cam and HD Rockers. When I originally pulled the head off the condition of the cylinder walls were great with good honing marks. I put diff oil on the cylinder walls and let it sit while I researched the turbo.

A year later I've finally bought the turbo kit and am looking to put it together but the walls have a little corrosion on them now. I don't mind rebuilding it if I HAVE to but I'd rather not spend the money.

Are these walls ok?

[Cabriolet]

get it re-honed. new rings and bearings. u are there already. what's another $200?

[77320i]

Was quoted like $1500 for the bottom end rebuild and the bearings and rings were like $500 or so for just the parts if I remember correctly.

[Cabriolet]

i have now rebuilt 13 M20s. changing the bearings and hone and new rings is a night and day difference.
honing should cost you about $150
rings are about $180
bearings are about $300.
new connecting rod bolts are about $60
be a man and build it yourself.
if you are this far in, you will notice the difference. esp since you plan to turbo.

[Liquidity]

That will wipe off with some wd40

[redlightpete]

Maybe start by checking valve clearances with your new cam. That might necessitate touching the bottom end anyway.

[ak-]

$1500 for a bottom end rebuild wat.

[77320i]

Head is all brand new so no need to worry about that. I guess I should just refresh the bottom end too.

[whodwho]

He is saying to check your valve to piston clearance, depending on the cam you may need to deepen the valve pockets.

[77320i]

Ahh. It's a well known cam without really much lift, just a little different timing. 280/274 split profile with 415 lift so it should be good for the stock pistons on a stock motor.

[77320i]

Thanks for the advice everyone. I think I'm going to take on this project since I got the prices back from the machine shop and they are pretty decent.

Clean & Check - $125
Hone - $60
Resurface - $60 (If needed)
O-Ring - $200

With new bearings and new rings it should run me about $900-$1000 if I rebuild it myself which will save me about $300 in assembly fees and a couple hundred in parts markup.

Should I get OEM rings and bearings directly from BMW or are there better quality ones out there that will stand up to the punishment of the turbo better?