Compression low?

sganc4life_4 · #1 02-10-2006, 07:07 PM

120 110 110 110

thats my compression, its pretty even but I thought it was supposed to be at like 170-180?

E-Klips · #2 02-10-2006, 07:22 PM

Yes that is low. Do a wet test and see if the compression raises. Dump a cap full of oil down each cylinder and recheck your compression.

2g compression:

178psi is standard
133psi is the service limit

ez1286 · #3 02-10-2006, 07:36 PM

If it goes up it means you're rings are worn if it stays the same (or really close) it's either valve seats, head gasket, or warped head.

sganc4life_4 · #4 02-10-2006, 08:10 PM

Well I did a wet compression test too and the results were:
120 115 110 110

95_GSX · #5 02-10-2006, 08:30 PM

Well it just might be time for a rebuild.

But either way it looks like your pulling a head to see whats wrong.

ez1286 · #6 02-10-2006, 08:58 PM

Yeah, you're gonna need to do something soon, does the car still run?

sganc4life_4 · #7 02-10-2006, 09:03 PM

It will run once I replace the crank position sensor.

ez1286 · #8 02-10-2006, 09:19 PM

The compression in my talon was about that bad and it wouldn't run for shit. I think mine ranged from 95 to 140 though, and such a huge variance is worse than all of them being low.

scottsee · #9 02-10-2006, 10:23 PM

Wet tests are not effective on flat-top pistons. They are good to do on dome style pistons only. On flat-top pistons the oil just puddles giving a false higer reading becasue of the extra volume.

crunchymilk55 · #10 02-12-2006, 02:04 AM

yep if those readings are accurat, it's rebuild time

sganc4life_4 · #11 02-12-2006, 07:35 AM

Well, I have a lot on my plate right now, including an 8 hour drive to FL in the middle of march, would I be better off buying a new engine and just dropping it in and rebuilding a monster out of my old one, or just rebuild it?

sganc4life_4 · #12 02-12-2006, 02:26 PM

Or can i just take a built bottem end and a head from SBR and use my cams to build everything?

gthompson97 · #13 02-12-2006, 08:23 PM

it all depends on what your goals are for the car. if you want a monster, you'll need to build it up but you'll need more than just a built bottom end and a sbr head, you'll need gauges and loggers and what not. the quickest way to get it running is to get a different motor (used or new) and just swap them out. the cheapest route will be to re-build it yourself if you know how but it will take more time than just a complete swap. your car, your decision.

sganc4life_4 · #14 02-12-2006, 09:01 PM

Well, im thinking about ordering the stage 1 long block for now, then having my motor on the side slowly building it. Do I absolutely need the 2g conversion for it, its another 1400$

ez1286 · #15 02-12-2006, 09:55 PM

Quote:

Originally Posted by scottsee

Wet tests are not effective on flat-top pistons. They are good to do on dome style pistons only. On flat-top pistons the oil just puddles giving a false higer reading becasue of the extra volume.

Thats not really true considering the pistons are moving throwing the oil all over and coating the cylinder walls then getting to the rings.

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