Bad compression but high speed?

growweirdstuf · #1 01-21-2007, 02:11 AM

I'm trying to figure out whether my engine has bad compression. Is it possible to have bad compression but still be able to drive a high speeds? I can start the engine, do 1-2 high speed passes, then the engine cuts out. Then it refuses to start back up. Can this be because of bad compression? Thanks.

SVTcobra04 · #2 01-21-2007, 02:41 AM

Sounds like your running lean and over heating or some other tuning related problem.

josh222 · #3 01-21-2007, 10:16 AM

If your motor has little compression what could be happening is your motor warms up, internals expand and theres just not enough compression to run after that.

SVTcobra04 · #4 01-21-2007, 11:45 AM

^^ thats sounds more likely.....

bigmike216 · #5 01-21-2007, 01:59 PM

Can you turn the engine over with one finger?

seanmanibog · #6 01-21-2007, 02:08 PM

^^^ Adding to that, Can you turn the engine over with one finger quite easily?

growweirdstuf · #7 01-21-2007, 04:49 PM

I can turn the engine over fairly easily with one finger. I have another engine that runs good, but that turns over almost as easily. I can't open up the engine and check because the person I got it from, he installed an aftermarket head and that thing is on tight, i can't unscrew it. I'm definitely not overheating, the engine never even gets near 200 degrees. It dies instantly, not like it's bogging down or anything. I sealed the engine with rtv silicone thinking it might be an airleak, but that didn't help. Oh yeah, installed a brand new glow plug too.

GHETTOTEACHER · #8 01-21-2007, 06:22 PM

Time for a new piston and sleave. That is typical when that happens. It's going to get worse if you don't change the P/S or have the sleave pinched.

Jayboy · #9 01-21-2007, 06:37 PM

just wondering, but i cant turn the engine over with one finger...is this good?

GHETTOTEACHER · #10 01-21-2007, 08:16 PM

Jayboy, your motor is good.

growweirdstuf · #11 01-22-2007, 12:33 PM

Well, I pulled the engine and removed the parts that can be reused. Since the cooling head won't come off, I have a nice looking paperweight now.

GHETTOTEACHER · #12 01-22-2007, 12:48 PM

Heat the motor up and then try to loosen the screws from the block. Use a heat gun or a hair dryer to heat the motor block. Just be careful when you handle the engine after heating. The heat will expand the metal and the screws will loosen up.