Compression test fail

Topic: Compression test fail (Read 1838 times) previous topic - next topic

Compression test fail

October 04, 2010, 02:21:12 PM

Well, I was hoping to be excited about good readings so I could just smack my heads on and go on down the road. Not so fast buddy.

First six cylinders were 145-150, Seventh 45... Uh, lets try that again...45. Well, Im replacing the heads anyway, so cmon, bad valve. Pour a little oil in...155-160. AAAAHHHHHHH!!!

Ive never pulled a piston with the block in the car. If you've done it, would you do it again, or just pull the engine? If I pull, I may just buy a complete Exploder engine. I already have P heads/intake, etc., but a complete engine seems to be going for 4-500 around here. Then I could run a small cam without sweating ptv too bad.

Compression test fail

Reply #1 – October 04, 2010, 02:41:05 PM

Pulling a piston wouldn't be to bad, But getting the oil pan off is the tough part.

Compression test fail

Reply #2 – October 04, 2010, 04:02:28 PM

it's a real pain to get the pan off, but to make it a whole lot easier, lift the motor enough to drop the pan so you can get the oil pump off.. it also helps to loosen the trans mount and slide it as far forward as possible so you can get a bit more clearance on your bellhousing/firewall. it's definitely a c

Compression test fail

Reply #3 – October 04, 2010, 05:24:44 PM

If you have the means, just pull the engine up and out.

3 hours of unbolting most everything to drop the pan, or 3 hours of unbolting completely everything and lifting engine...

I'd rather pull the engine, than fight with 2 inches or so of room to finagle an oil pan in..lol

Good luck though

Compression test fail

Reply #4 – October 04, 2010, 08:56:20 PM

I could have the motor and tranny out in about 1 hour. I doubt I could do an oil pan in less then 2 hours without it leaking, and your talking about pulling a piston. pull the whole block. If its anything more then a head gasket, pull the block.

Compression test fail

Reply #5 – October 07, 2010, 01:13:00 AM

it can be done,, just get that motor up as high as it will go till the bell housing hits the transmission tunnel then block that friggin thing up.

i would remove the motor mount pin (long horizontal bolt) then add wood blocks between the underside of the mount and the frame of the car.

drop the pan and prepare for a tech support call into gumby as you discover your human defect is the lack of another bodily joint between your elbow and your wrist.

Honestly, it can be done and if i were you, thats the way i would do it if my budget only allowed me to repair the one piston.

verify its its not a valve seat by doing the following
-remove both rocker arms
-add air to the cylinder using a bike pump that transitions to a fitting that fits the spark plug hole
-you cant use the compression tester hose because it has a one way check valve and will not allow you to see presure is holding.
-add air like say 20 or 30 psi and watch the needle
-if presure stays put at a certain psi, then you eliminated your rings and your head gasket.
-if the pressure drops then listen out at the trottle body
-if you hear air, then its the intake valve
-listen at the exhaust manifold by using a wooden dowel
-if you hear air then its the exhaust valve
-If you year no air at either spot, but you do at the pcv then its a HG.
-if you see air bubbles in the radiator or hear air bubble noise in the lower radiator hose then its still a HG but you should've been smoking white out the tail pipe.

there is another options such as cracked head but these are just the basics.

Compression test fail

Reply #6 – October 09, 2010, 10:27:03 PM

Quote from: Haystack;338049

I could have the motor and tranny out in about 1 hour.

With a jack, jackstands, impact, and a hoist? I'd think it'd take me by myself still some 3-4 hours to get it all out. Wish I knew how to get it out that fast - the accessories and radiator need to come out separately if you want the clearance for the transmission stuck to the back, iirc.

Compression test fail

Reply #7 – October 09, 2010, 10:37:05 PM

yeah, i had to pull my accessories and rad off/out to get my motor and trans out when i did my tbird.. only took me an hour all by myself.. but then again, i just cut my harness at the firewall lol

Compression test fail

Reply #8 – October 10, 2010, 04:05:22 AM

I just pull the power steering and A/C brackets off, with them connected, and leave them in the engine bay. The alt can stay on, but its quicker to take it off, same with the smog pump. The radiator is two bolts and two hoses, plus tranny cooler lines. Takes just a couple of minutes, and keeps you from messing it up when you pull it. The fan needs to come out too. Pull the driveshaft, radiator, and lossen some bolts and wires. There always seems to be a bolt or two that I miss, and I usually pull the exhaust off the day before I start, so 2 to 3 hours is probably more accurate. I almost never use air tools of any kind, unless I am pulling the crank/harmonic balancer off.