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#1 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() 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.
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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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#2 |
Registered Member
Join Date: May 2001
Location: Fernandina Beach, FL 32034
Posts: 178
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![]() 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
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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 |
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#3 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() I tried resetting the rockers on the #1 cylinder and still got 0 compression.
This sux,
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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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#4 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() 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.
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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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#5 |
Moderator
Join Date: Aug 2000
Location: Milan, OH
Posts: 2,699
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![]() 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.
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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!" |
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#6 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() 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.
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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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#7 |
Registered Member
Join Date: Jul 2001
Location: Edison, NJ, USA
Posts: 125
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![]() 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. |
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#8 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() 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.
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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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#9 |
Registered Member
Join Date: Aug 2003
Location: s. fl
Posts: 23
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![]() 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.
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351w powered 86 gt with a reverse manual c4. Lots more but whos counting. |
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#10 |
Registered Member
Join Date: Apr 2001
Location: Staging lane
Posts: 4,337
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![]() 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,
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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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