S54 schrick- build and timing issues.

[eacmen]

Confirmed problem- timing is OK, problem was with surfaced engine block and head. Now will try to find adequate head gasket and maybe will machine pistons for deeper valve counterbores. If someone has measured piston to valve clearence in schrick 288/280 12.5 lift cams- will be appreciate for info.

Not trying to second guess you here, but how did you verify the timing was okay?

My thinking is that if the problem was just the head gasket then you should have felt the valve contact the piston when rotating the engine by hand after setting timing since timing is set with the cams fully retarded.

[BMWfanz]

Not clear to me bent valve due to wrong timing or head clearance.

Reason was head clearance

[BMWfanz]

Not trying to second guess you here, but how did you verify the timing was okay?

My thinking is that if the problem was just the head gasket then you should have felt the valve contact the piston when rotating the engine by hand after setting timing since timing is set with the cams fully retarded.

I don't know why it was not sensible to me, maybe cause last timing procedure was with spark plugs on place and slight concact was misunderstood with compression effect- I don't know.

[sapote]

Reason was head clearance

How was the timing verified to be correct?

[BMWfanz]

How was the timing verified to be correct?

Plugged OEM tool to activate vanos, then used oem tools to check cams position.

[eacmen]

Plugged OEM tool to activate vanos, then used oem tools to check cams position.

Activation of vanos is not involved in checking engine timing. I don't think it hurts but i would still be putting a wrench on the cams to make sure they are fully retarded.

[sapote]

Plugged OEM tool to activate vanos, then used oem tools to check cams position.

Which needs a compressed air source? Wow, so the Indi shop has this tool?

[George Hill]

Most BMW specialty shops will have this. Its just a banjo fitting with an air chuck fitting and then a switch block that opens the solenoids. Its some money but not the end of the world.

[sapote]

Most BMW specialty shops will have this. Its just a banjo fitting with an air chuck fitting and then a switch block that opens the solenoids. Its some money but not the end of the world.

Understand.

For me, the sure way to check the timing is to be sure that the vanos pistons are touching the front caps. So either using compressed air with the official tool to push the pistons forward, or my cheap way: remove the caps off, turn the cams CCW until pistons protrude out of the holes 1mm, then install and tighten the cap bolts. This ensures that the pistons are precisely at their timing position.

[BMWfanz]

Update: 3d-scanned my JE pistons for checking possibility of machining valve counterbores- there is no way to do it. So my basis question is current configure of my build. Now i have no information about basic clearence between valve and piston on non-machined engine or engine with JE pistons. I dont want to buy thicker gasket to unnown thickness and drop compression ratio. So maybe someone has some notes on builded engines- i have no confidence if i buy only gasket thicker on machined compenstation height- will it be enough for my setup or not.

[BMWfanz]

Update: working on custom JE Pistons for my setup. Has anyone ordered custom pistons for high lift 14mm cams? Maybe someone advice manufacturer

[sapote]

Update: 3d-scanned my JE pistons for checking possibility of machining valve counterbores- there is no way to do it. So my basis question is current configure of my build. Now i have no information about basic clearence between valve and piston on non-machined engine or engine with JE pistons. I dont want to buy thicker gasket to unnown thickness and drop compression ratio. So maybe someone has some notes on builded engines- i have no confidence if i buy only gasket thicker on machined compenstation height- will it be enough for my setup or not.

The sure way but a long way: add a 2mn of clay or solder lead on the piston valve pocket, install the head and torque head bolts, set timing and hand crank couple turns, remove head and check clay or lead.

[BMWfanz]

The sure way but a long way: add a 2mn of clay or solder lead on the piston valve pocket, install the head and torque head bolts, set timing and hand crank couple turns, remove head and check clay or lead.

Definitely will check it this way after receive my custom pistons, thank you for advice

[BMWfanz]

Ended my rebuild with new CP pistons. Pistons was ordered in LangRacing- 87.5 mms, custom releif: +2 mm exhaust, +1.5mm intake. Done Exhaust channels porting, now seems like need a bit tune. For additional installed sport damper with innertion (Better edition of ATI damper). Will post results soon, now on engine run-in for at least 1000 km.