Compression: here we go again!

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BigMike
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Compression: here we go again!

#1

Post by BigMike » Wed Sep 14, 2005 2:07 pm

I thought I had the bugs worked out of my '64, but after checking the ignition out, verifying good spark, etc, I've found something that has me really pissed off. (still only cough gag and puke) I took a compression test, it takes 3 or 4 kicks to get gauge up to 120lb. I thought maybe the hydraulic lifters were sticking or something. I dropped in a set of "mechanical adaptors" and set them to 0 lash like solids. No change. I hope that I didn't lose a top ring land on the pistons. (KB Hyper) I set the end gap correctly last year when I did the top end. Good clean oil, good pressure and no overheating. Heads were done by superior machine in Wisconsin. I have a feeling that I'm not going to be happy when I dig into it. I'm going to be losing my shop in the next month and need to find another, I really don't need to have the f-ing Pan apart or down right now...... Could a trashed cam (on the intake side) cause this? everything seemed to head south when I replaced the battery and a local guy used a light to set the timing. (I had set it up by eye with the mark on the flywheel and it seemed to be decent) So much for trying to get it exact.



rigidpanman
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Re: Compression: here we go again!

#2

Post by rigidpanman » Wed Sep 14, 2005 2:40 pm

i dont think 3 or 4 kicks is all that bad

BigMike
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Re: Compression: here we go again!

#3

Post by BigMike » Wed Sep 14, 2005 2:43 pm

3 or 4 kicks to get compression, not to start. SOB still won't start.

rigidpanman
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Re: Compression: here we go again!

#4

Post by rigidpanman » Wed Sep 14, 2005 3:19 pm

damn,that do suck.

dan

Re: Compression: here we go again!

#5

Post by dan » Thu Sep 15, 2005 5:34 am

I'm not sure 3-4 kicks is a problem. The motor only goes about 1 revolution when you kick it over, and you need two revolutions to go through a complete cycle to ensure the valves are closed for the compression gage to read.
If the cyclinders are within 10% of each other, thats good. I don't remamber what the cranking pressure should be, but don't think 120 is horrible.
I'd look for something simple, like the timing, plugs, carb, fuel level, etc. before pulling the cam, etc..

Cotten
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Re: Compression: here we go again!

#6

Post by Cotten » Thu Sep 15, 2005 12:35 pm

Some cams with overlap may never show full compression when kicked, but 120 sounds fine. They will start as low as 50 or 60!

If there are no noises, nothing serious is broken.

When all other variables are eliminated (vacuum leaks, valve adjustment, timing, etc.,), then look for causes of plug fouling. (A plug need not appear fouled to have serious resistance.)
A weak coil, resistor plug wires, corrosion within rubber boots, fuel additives, and even a poor groundstrap can hinder clean fire at the plugs. And of course, a fat carb adjustment will eventually 'insulate' electrodes after they have cooled.

Good luck!

BigMike
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Re: Compression: here we go again!

#7

Post by BigMike » Thu Sep 15, 2005 2:47 pm

<panic mode off> I'll go over everything once more.

BigMike
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Re: Compression: here we go again!

#8

Post by BigMike » Sat Sep 24, 2005 3:51 am

>sheepish look< sonofabitch! all the headbolts had worked loose, had about 10lbs. torque on every one of them. Cheap fix!

moral: when you hear the sound of hooves, don't assume that it's Zebras.

dj

Re: Compression: here we go again!

#9

Post by dj » Sat Sep 24, 2005 3:23 pm

"moral: when you hear the sound of hooves, don't assume that it's Zebras."

So much for horsepower there BigMike. Yea....easy fix! Good luck!

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