[guarnibl]

So...

I think I've got possibly two issues with my stroker motor (302 2v). Not sure what compression ratio is... I think -around- 9 to 1. It was setup with Patriot stage 2 heads that were ported/polished with larger valving. Not sure about the cc dish but it was setup for a Kenne Bell... been a while but for whatever reason 25cc rings a bell (mahle forged pistons). Stage 2 blower cams (VT). Stock intake manifold / JLT cold air intake.

1) I'm burning around a quart of oil every 2500 miles. This is a tad higher than what my M3 burned so it has me wondering about the intake manifold or ring gap.

2) I smell a sweet smell from the exhaust and white smoke comes out of both exhaust pipes.. not a ton but enough to notice if you're looking for it or around the car for a while (outside of it).

We changed the oil about 1,000 miles ago and it was clear (essentially perfect). But again, was a quart low from the prior change.

The coolant level has dropped a bit, but not a ton.

I have a fluidyne radiator and 7 qt Moroso oil pan.

We're going to run a compression test.

No external leaks that we can find.

Does anyone know the proper compression per cylinder that my engine should have?

Thoughts in general? Thinking a minor head gasket leak ... doubt I have a warped head. No knocking or pinging, solid oil pressure, no over heating issues

[ytngt]

There are many variables when checking compression:
-Plugs in/out
-How long you crank
-Warm or cold
-Battery voltage
-Throttle open/closed

Then you have the engine variables:
-cams (and overlap)
-static CR

I would guess and say that over 140 psi would be good with those cams

[guarnibl]

Originally Posted by ytngt There are many variables when checking compression: -Plugs in/out -How long you crank -Warm or cold -Battery voltage -Throttle open/closed Then you have the engine variables: -cams (and overlap) -static CR I would guess and say that over 140 psi would be good with those cams

And the dish size?

I assume for 18-25cc pistons you're going to read a bit lower since my overall compression ratio is pretty low (8:5 to 9).

Would 135-180 with no more than 20% variance be about right?

[ytngt]

Just for reference:

I have a 281ci, 21cc dish, stock stroke, comp 278 cams (big duration cams)

It has always turned over by hand easily, so very low dynamic compression. Mostly from the cams, my static cr should be approx 9:1. Any way since new I have got anywhere from 90-160 psi. I learned that my compression test method made more difference than anything else.

Here is how I currently do a comp test, just as fyi:

-Leave plugs in
-Motor cold
-Battery on charger
-turn over for 7 sec (timed)
-Pull harness plug or fp fuse, you don't want spark or fuel

I like to get several readings on each cylinder. If one seems to be testing high or low, I will test even more to see if it is consistent.

Not that this is the correct or best way. Just what I do.

[guarnibl]

Perfect.

we'll run some tests tomorrow or next day hopefully all is good with the internals. Probably just a gasket going.

What's a good way to test if the rings are going bad? I have not had to do that before.

[ytngt]

If you want more information than a compression test, then try a leak down test.