#1-#8 cylinders zero compression. WTF

Dark_5.0 · 09-18-2003, 09:12 AM

Ok my block is good for sure.

My Canfield heads were pulled off of a car that was running 12's and were working fine.

Here is the problem, I finally got my valve trane geometry correct and set the stud mount roller rockers, and I decided that I should go ahead and do a compression test.

I got "0" compression on all 8 cylinders. The motor turns over weird instead of a err...err.err sound the motor spin really fast and effortless like the heads are not even on it. WTF!!

If I totaly remove the rockers I barely get any compression at all.

Right now I dont have my upper intake on and when I crank the engine I can feel air blowing out of the lower intake ports.

This is weird.

billheis · 09-18-2003, 09:42 AM

Sounds like the valves are staying open. Iknow you said you went checking geometry, but maybe the lifters were collapsed and when you spun it over the oil pumped them back up or something. Your not going to get very much comp. with rockers off. It has to draw and exhust all air throught the plug hole

Dark_5.0 · 09-18-2003, 10:16 AM

I tried resetting the rockers on the #1 cylinder and still got 0 compression.

This sux,

Dark_5.0 · 09-18-2003, 10:45 AM

Last night as I was messing with the rockers my friend changed out my starter solenoid that mounts on the drivers side by the battery.

Is it possible to reverse the polarity of the starter. I guess I will check that when I get off work.

Jeff Chambers · 09-18-2003, 11:38 AM

Don't think its possible to reverse the polarity; the starter is internally grounded. Sounds to me like you've got bent intake valves if you're getting blow-by back into the lower intake runners. What was the compression on the rest of the cylinders?

If you've got the rockers completely off, you won't get any compression since the intake valve won't open to let any flow into the cylinder. See if you can borrow a leak-down tester from someone. Or even just hook your airhose to the spark plug hole, then back off both rockers all the way. If you've got blow-by into the intake or exhaust with the rockers all the way off, then you've got bent valves or a messed up valve job.

Dark_5.0 · 09-18-2003, 11:54 AM

I am getting "0" compression on all 8 cylinders. I pulled these heads off of a car that ran 12's the day before I removed the heads from the car.

This is so phucking irritating. I might go and see if I can buy my worked over E7's back.

richd · 09-18-2003, 12:09 PM

If I'm not mistaken the starter is grounded to the block so that should be alright. Could the pos + neg wires be reversed on the battery? Does everything else (electrical) work like the radio, guages? Power windows?

Is the engine rotating in the correct direction (clockwise from the front of the car)?

Only other thing I can think of is you are over tightening the rockers but it sounds like you've checked that.

Verify the + side of the battery with a voltmeter and trace it through the solenoid to the starter (among other things). Make sure it goes from battery to solenoid, solenoid to starter. Also make sure the - side of battery is connected to the block somewhere. Maybe something got switched and you're actually applying +12 to the block and ground to the starter.

The motor should spin fast because (I think) you don't have any of the plugs in. Without a spark plug or a comp tester there's nothing to maintain compression.

Post some pictures of the wiring and starter if you have or can get a digital camera.

Good luck,

Rich D.

Dark_5.0 · 09-18-2003, 01:14 PM

I went home during lunch and checked it out and yep I over tightened the rockers.

was 180 on #1 and #2 I will check the rest when I get home.

Thats what I get for working on the car at 2am.

yoshi351w · 09-20-2003, 02:55 PM

If you overtightend the rockers then you probably bent pushrods. I am confused. The only way you wouldnt be getting compression is if your rockers are so tight that your valves are staying open. Good luck and let us know what the turnout is.

Dark_5.0 · 09-22-2003, 10:37 AM

After I got the rockers figured out I completed putting the engine back together and it runs great. My compression #'s varied from 180-188. Pretty good Huh!!!!!

Time to put in my new rear end and go get some track times.

Thanks for the replies,

09-18-2003, 10:16 AM	#3
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I tried resetting the rockers on the #1 cylinder and still got 0 compression. This sux, __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

09-18-2003, 10:45 AM	#4
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Last night as I was messing with the rockers my friend changed out my starter solenoid that mounts on the drivers side by the battery. Is it possible to reverse the polarity of the starter. I guess I will check that when I get off work. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

09-18-2003, 11:38 AM	#5
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	Don't think its possible to reverse the polarity; the starter is internally grounded. Sounds to me like you've got bent intake valves if you're getting blow-by back into the lower intake runners. What was the compression on the rest of the cylinders? If you've got the rockers completely off, you won't get any compression since the intake valve won't open to let any flow into the cylinder. See if you can borrow a leak-down tester from someone. Or even just hook your airhose to the spark plug hole, then back off both rockers all the way. If you've got blow-by into the intake or exhaust with the rockers all the way off, then you've got bent valves or a messed up valve job. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

09-18-2003, 11:54 AM	#6
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I am getting "0" compression on all 8 cylinders. I pulled these heads off of a car that ran 12's the day before I removed the heads from the car. This is so phucking irritating. I might go and see if I can buy my worked over E7's back. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

09-20-2003, 02:55 PM	#9
yoshi351w Registered Member Join Date: Aug 2003 Location: s. fl Posts: 23	If you overtightend the rockers then you probably bent pushrods. I am confused. The only way you wouldnt be getting compression is if your rockers are so tight that your valves are staying open. Good luck and let us know what the turnout is. __________________ 351w powered 86 gt with a reverse manual c4. Lots more but whos counting.

09-18-2003, 09:12 AM	#1
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	#1-#8 cylinders zero compression. WTF Ok my block is good for sure. My Canfield heads were pulled off of a car that was running 12's and were working fine. Here is the problem, I finally got my valve trane geometry correct and set the stud mount roller rockers, and I decided that I should go ahead and do a compression test. I got "0" compression on all 8 cylinders. The motor turns over weird instead of a err...err.err sound the motor spin really fast and effortless like the heads are not even on it. WTF!! If I totaly remove the rockers I barely get any compression at all. Right now I dont have my upper intake on and when I crank the engine I can feel air blowing out of the lower intake ports. This is weird. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

09-18-2003, 09:42 AM	#2
billheis Registered Member Join Date: May 2001 Location: Fernandina Beach, FL 32034 Posts: 178	Sounds like the valves are staying open. Iknow you said you went checking geometry, but maybe the lifters were collapsed and when you spun it over the oil pumped them back up or something. Your not going to get very much comp. with rockers off. It has to draw and exhust all air throught the plug hole __________________ Bill Heiser 90 Convertable 5.0 LX, ported E7s w/ THumper valve job, TFS street, FR 65mm TB, B cam w/1.7 cobra rockers, kirban AFPR, Mac CAI, Mac Headers, off road h, 3 chamber flows, Crane ign. box, 3:73s, Art Carr AOD & 2600 converter

09-18-2003, 12:09 PM	#7
richd Registered Member Join Date: Jul 2001 Location: Edison, NJ, USA Posts: 125	If I'm not mistaken the starter is grounded to the block so that should be alright. Could the pos + neg wires be reversed on the battery? Does everything else (electrical) work like the radio, guages? Power windows? Is the engine rotating in the correct direction (clockwise from the front of the car)? Only other thing I can think of is you are over tightening the rockers but it sounds like you've checked that. Verify the + side of the battery with a voltmeter and trace it through the solenoid to the starter (among other things). Make sure it goes from battery to solenoid, solenoid to starter. Also make sure the - side of battery is connected to the block somewhere. Maybe something got switched and you're actually applying +12 to the block and ground to the starter. The motor should spin fast because (I think) you don't have any of the plugs in. Without a spark plug or a comp tester there's nothing to maintain compression. Post some pictures of the wiring and starter if you have or can get a digital camera. Good luck, Rich D.

09-18-2003, 01:14 PM	#8
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I went home during lunch and checked it out and yep I over tightened the rockers. was 180 on #1 and #2 I will check the rest when I get home. Thats what I get for working on the car at 2am. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

09-22-2003, 10:37 AM	#10
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	After I got the rockers figured out I completed putting the engine back together and it runs great. My compression #'s varied from 180-188. Pretty good Huh!!!!! Time to put in my new rear end and go get some track times. Thanks for the replies, __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

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