Compression? What Does This Mean?

[Shane@DBPerformance]

There definately was some buildup on the pistons just from looking through the spark plug holes with a flashlight.

[rhino]

carbon buildup on the piston top leading to higher compression which the rings can't hold and there's excessive blowby.

what do the plugs look like and are they the correct heat range?

[Goat Blower]

Hit it with some MCCC.

[rhino]

mccc works great.....but that might only be a temporary solution

was this a problem before the mods?

what kind of mileage on the stock internals?

[SlowWhite]

Stock Bottom end (replaced at 71K miles ) now at around 112K. 99 Style Head installed recently now has around 28K miles on it.


I never had a logger before. And the last time I hit the dyno to do some tuning was back in 2001. (alot's changed since then, back then my motor only had 20Kish miles)


-brian

[Kracka]

Originally posted by SlowWhite@Jan 23 2004, 08:55 AM
Tried 2 different compression Testers: (8-15 turns of the motor)
1st one)
-192 across all 4

2nd one)
-189-192 across all 4

8-15 turns is a pretty big difference. Whenver I have done them I usually go about 5-6.

[CVD]

Yeah. Over the course of 15 revolutions I would think that some fuel would probably start to build up in the cylinder. I would try 4-6 cranks and/or hold the gas pedal on the floor when you turn the motor over.

[Kracka]

Have you been pulling the MPI fuse when doing the compression tests?

[A//// Guy]

That would prolly be a smart idea.

[Enes]

when i did my test, i pulled the fuse and full throtle, only cranked 4 times and i was getting in the 160 range..

All of the instructions i read anywhere said only 4 cranks.. and you will now that by looking at the Compression tester, the gauge will jump each time.. 4 jumps and you are done. read, write, done.
-E