390 Compression.
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Postmaster
Joined: Oct 2004
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From: Delisle/Vanscoy, Sk.
390 Compression.
Did the compression test on the 75 truck I bought. The right bank is at 123-124 and the left bank is 115-118. Why is one side that much lower. This engine has the bill of rebuild from Feb 2004.
It starts right up and runs smooth and has lots of snap. I will have to change the intake gasket since it leaks at the front.
Also saw today I was lucky when driving it back. The rubber breakaway on the steering colunm was nearly sheered off from its accident. Just one side was holding it together with a tear in it also. You can see the frame shifted that hard from the accident. The steering colunm and steering box did not line up. Wow.
Glad I got it home with out any problems. This guy is lucky too. He was still driving it like that. He could of had it finished tearing and have no steering.
It starts right up and runs smooth and has lots of snap. I will have to change the intake gasket since it leaks at the front.
Also saw today I was lucky when driving it back. The rubber breakaway on the steering colunm was nearly sheered off from its accident. Just one side was holding it together with a tear in it also. You can see the frame shifted that hard from the accident. The steering colunm and steering box did not line up. Wow.
Glad I got it home with out any problems. This guy is lucky too. He was still driving it like that. He could of had it finished tearing and have no steering.
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Joined: Dec 2003
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From: Saskatoon, Saskatchewan
The compression doesn`t sound bad, it is strange that one bank is some what lower than the other. It`s not that much different and shouldn`t cause a problem. It`s a good idea to change the gaskets and I also had the front and rear main seals replaced before installing my 390 last winter. Saves headaches later on.
The front and rear of the intake is prone to leaking, use a good gasket sealer in those two places to hold the gaskets in place as you reinstall the heavy intake. I ended up buying an Edelbrock light weight, hate those heavy cast iron ones that came stock.
Good thing you got home safely, that could have been bad. It`s always exciting driving a new purchase home, you never know what to expect. Lately I have mine towed or hauled home, too many of these kinds of surprises.
The front and rear of the intake is prone to leaking, use a good gasket sealer in those two places to hold the gaskets in place as you reinstall the heavy intake. I ended up buying an Edelbrock light weight, hate those heavy cast iron ones that came stock.
Good thing you got home safely, that could have been bad. It`s always exciting driving a new purchase home, you never know what to expect. Lately I have mine towed or hauled home, too many of these kinds of surprises.
Lead Driver
Joined: Jan 2006
Posts: 8,423
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From: Colonsay Sk. Canada
Those surprises is what keeps restoring old Fords interesting. you learn what all needs fixing, and after a long tow you kinda get attached to these rusty beasts. Where would we be if a person has never handled the unexpected thrill of a long tow in a rickity truck through a residental area where there are too many idiots.
If anyone needs someone to steer home a truck pulled by a rope, bar etc.
Give me a call, I'm always Ready, Willing, and Able.
Anything is childs play, since the cement truck.
No brakes, No steering wheel, No PROBLEM
If anyone needs someone to steer home a truck pulled by a rope, bar etc.
Give me a call, I'm always Ready, Willing, and Able.
Anything is childs play, since the cement truck.
No brakes, No steering wheel, No PROBLEM
Last edited by Snowking; Apr 26, 2006 at 10:22 AM.
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Joined: Jan 2008
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I assume you only did a dry test ?
Being within 10 % difference between cylinders is quite normal.
Some pieces of metal wear at different rates.
Which cylinders pulled the lowest compression ?
You have no need to be concerned
Being within 10 % difference between cylinders is quite normal.
Some pieces of metal wear at different rates.
Which cylinders pulled the lowest compression ?
You have no need to be concerned
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Postmaster
Joined: Oct 2004
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From: Delisle/Vanscoy, Sk.
Cyl 6 &7 were the lowest. At 118. The rest was 119 and 123 124.
The engine runs real good. Just curious why one side is 5 lbs different.
Good Idea Fom about the seals. While the motor is out I should do that. Then no worrys about that later.
It will be late June or July when I egt to it. Today moving vehicles around here. Moved 5 of them today, pumping tires up bolting on a tow bar or chains. Still got to move the 54 Plymouth here. I wish I could of sold it. But it is sitting where I plan on making my garden. Also getting ready for the delivery of the 300 trees I have to plant and water.
I hope to lose some weight with all this work. That would be a bonus.
The engine runs real good. Just curious why one side is 5 lbs different.
Good Idea Fom about the seals. While the motor is out I should do that. Then no worrys about that later.
It will be late June or July when I egt to it. Today moving vehicles around here. Moved 5 of them today, pumping tires up bolting on a tow bar or chains. Still got to move the 54 Plymouth here. I wish I could of sold it. But it is sitting where I plan on making my garden. Also getting ready for the delivery of the 300 trees I have to plant and water.
I hope to lose some weight with all this work. That would be a bonus.
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