Increasing compression - Milling?

[nando]

yeah, I don't think I have a pic of mine, but it was definitely not that smooth. it had a specific swirl pattern on it actually, like a brake disk.

[Chuckcruzin1986]

Worrying about the flywheel being to smooth

don't forget to turn a step for the pressure plate :D

and turn the back side down (the big chunky part), you can get it to 12-13lbs. Basically it's exactly what a 323i flywheel is.

Should I roughen it up a little? The finish is very smooth.

Chuck

[Curt Hayes]

the big chunky part on the back. you can turn it down nearly to the ring gear. I had mine done in bellingham by a small shop.

Sweet. Good to know. thanks!

[nando]

the big chunky part on the back. you can turn it down nearly to the ring gear. I had mine done in bellingham by a small shop.

[Curt Hayes]

don't forget to turn a step for the pressure plate :D

and turn the back side down (the big chunky part), you can get it to 12-13lbs. Basically it's exactly what a 323i flywheel is.

Hey, nando, any diagrams of what to turn down on the flywheel. Replaced my clutch a while back and have lots of vibration now. Thinking that Action Auto may have effed the flywheel grinding so probably going to need to pull the tranny and flywheel anyhow. Got a m/c shop recommendation?

[nando]

don't forget to turn a step for the pressure plate :D

and turn the back side down (the big chunky part), you can get it to 12-13lbs. Basically it's exactly what a 323i flywheel is.

[Chuckcruzin1986]

Grinding the flywheel

It was in real bad shape. We have to mill away where the Pressure plate bolts on to the wheel.

Chuck

[Chuckcruzin1986]

Ground the top of the block today

Ground about .003" off the top of the block :)

Chuck

[nando]

Do a mock up with a used crushed head gasket to check piston to valve clearance. 0.020 is about the most you hear about on budget strokers and even that's close with the stock cam.

.020" piston/valve clearance? that's way too little, you need 1.5mm minimum.

[Chuckcruzin1986]

Major machining

Do a mock up with a used crushed head gasket to check piston to valve clearance. 0.020 is about the most you hear about on budget strokers and even that's close with the stock cam.

I did some major machining and did check everything with clay. I checked a used gasket compared to a new one. The used one was only .001" thinner!!

Chuck

[Chuckcruzin1986]

Milling the combustion chamber?

so hows this going? won't milling you comb chambers negate the compression gain?

When you mill the head, there is an area that will be hit by the piston. The area is fairly small (I did not cut the main bowl).

the truth is, I did kind of get lost on this: .050 off the head, .003 off the block, cleared the pistons where the valves would have hit, milled the outside edge of the piston and mill the area of the head where the piston would have hit. Soooooooo, I really don't know my exact compression ratio , BUT, I am sure I have increased it quit a bit.

Chuck

[e30ne21]

Do a mock up with a used crushed head gasket to check piston to valve clearance. 0.020 is about the most you hear about on budget strokers and even that's close with the stock cam.

[bear]

so hows this going? won't milling you comb chambers negate the compression gain?

[Chuckcruzin1986]

Timing?

sorry I am a little late, but milling the head for compression is less than ideal as it removes contact area for the head gasket. I suggest upgrading the head gasket/studs and make sure your timing is spot on through all RPMS.

My race car had a milled head for compression and the timing was off, we went through 3 head gaskets before we found the problem with timing in the chip.

Going from 8.5 - 1 to approx 10 - 1 will require engine management to be safe and squeeze max power. I will also be timing the camshaft. I have also ground the rockers. See image and video. We will see :-D

Video of rockers being ground: http://www.youtube.com/watch?v=WAgalIMddns

[Chuckcruzin1986]

I am just doing it.

Looks good, but I cannot comment to the orginal question

I am keeping my fingers crossed. One problem is that it is hard to measure the amount that the piston protruds into the combustion chamber........therefore, measuring the exact compression ratio is tough so i am just making an educated guess.

Chuck