Bimmerheads reground cams?

[ForcedFirebird]

Yeah, he PM'd me asking for a cracked head. That's when I remembered the head I already cut up a while back (jogged my memory for this post... https://www.r3vlimited.com/board/sho...50#post4844750

Had the cold saw out recently and trimmed those up, chopped off a couple cyls for cuting pockets, then cut another intake and exhaust port down the center.

As far as using the head bold holes, they are all symmetrical.

[So Live]

Not a bad night in the garage:






After a little clean up:


Got 4 of 6 done last night after machining the stop and then figuring out the process. Should be done cutting reliefs tonight and have new p2v numbers. Hopefully my educated guess for how much to take off is close enough...

Cheers,

[zaq123]

Not a bad night in the garage:






After a little clean up:


Got 4 of 6 done last night after machining the stop and then figuring out the process. Should be done cutting reliefs tonight and have new p2v numbers. Hopefully my educated guess for how much to take off is close enough...

Cheers,

Pretty cool setup

Sent from my VS985 4G using Tapatalk

[ForcedFirebird]

Very clever. Might have to steal something like that for the flow bench valve opening fixture. Right now have a piece of aluminum that bolts across the valve cover studs and has a set screw to slide shims under for quick testing at per-determined valve lifts. Something like you made would make a lot more room to put the shims in.

[Kershaw]

[ThatOneEuroE30]

Thats bloody brilliant

[ForcedFirebird]

Thats bloody brilliant

Very high-tech compared to most of us low life's that use an old head. :(

lol

[ThatOneEuroE30]

Very high-tech compared to most of us low life's that use an old head. :(

lol

Pretty much lol

[So Live]

haha thanks guys. Just doin what I can to get it done as well as I can.

Got the reliefs cut and p2v clearances checked. Smallest clearance is about .085” at +/-6 degrees of cam adjustment.

I’m happy haha.

[ForcedFirebird]

FWIW .057" and .073" are accurate numbers for a high effort 2.8l m20.

[digger]

for reference here is some data to help

head bolts are pitched at 91mm in crank axis and 88mm transverse

[So Live]

Nice diagram Doug, thanks for posting! I was looking for that a while ago. Makes sense with the valve position relative to the centerline. My exhaust side tool was closer to the stud. Had to use set screws instead of cap screws on the stop to clear.

John, what do you mean by accurate? Accurate measurement from an engine that works? Mine won’t be “high effort” but it is a bottom end with unknown miles so I’m more comfortable with it a little looser. There are a lot of mixed opinions on p2v but most people say .060” is the minimum. The only concensus I’ve found is that bigger clearances are safer haha. Either way, interesting to see some numbers that actually work on these motors. Funny that sometimes info like that is tough to find...

[ForcedFirebird]

Those are just the clearances I had on a build with no issues. Just confirming you have plenty. :)

[digger]

Catcams recommend 1mm. The important thing is good valve springs and cam grind if you dare go that close

[DesertBMW]

Problem is that my head has been decked and my p2v clearances are way too tight on the intake side with everything at “zero”.

Why are you putting in $325 camshaft in a thrashed cylinder head that had to be 'decked'? There is thicker head gasket that compensates for decking, unless it is decked too much and ruined.