Compression test
Thread Starter
Pro
Joined: Nov 2011
Posts: 517
Likes: 20
From: Scroggins Tx
Compression test
I bought this 75 last November and only ran it to get it on and off the trailer. The radiator and valve covers were leaking bad. The motor is not original and shows to be a CE and casting shows an 80-85 4 bolt truck motor. PO knew nothing about he motor.
No 1 - 195 2 - 210
3 - 190 4 - 180
5 - 200 6 - 205
7 - 210 8 - 210
I plan to keep the motor stock as I care nothing about smoking tires and I want as much vacuum as possible.
I have read where the compression readings should be within 5 or 10 percent of each other. Should I be concerned with these readings?
Thanks, Dave.
Oh, and these were taken with no intake or exhaust manifolds and all plugs removed.
No 1 - 195 2 - 210
3 - 190 4 - 180
5 - 200 6 - 205
7 - 210 8 - 210
I plan to keep the motor stock as I care nothing about smoking tires and I want as much vacuum as possible.
I have read where the compression readings should be within 5 or 10 percent of each other. Should I be concerned with these readings?
Thanks, Dave.
Oh, and these were taken with no intake or exhaust manifolds and all plugs removed.
Last edited by oledave60; Feb 25, 2012 at 10:37 AM. Reason: more info
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
I bought this 75 last November and only ran it to get it on and off the trailer. The radiator and valve covers were leaking bad. The motor is not original and shows to be a CE and casting shows an 80-85 4 bolt truck motor. PO knew nothing about he motor.
No 1 - 195 2 - 210
3 - 190 4 - 180
5 - 200 6 - 205
7 - 210 8 - 210
I plan to keep the motor stock as I care nothing about smoking tires and I want as much vacuum as possible.
I have read where the compression readings should be within 5 or 10 percent of each other. Should I be concerned with these readings?
Thanks, Dave.
Oh, and these were taken with no intake or exhaust manifolds and all plugs removed.
No 1 - 195 2 - 210
3 - 190 4 - 180
5 - 200 6 - 205
7 - 210 8 - 210
I plan to keep the motor stock as I care nothing about smoking tires and I want as much vacuum as possible.
I have read where the compression readings should be within 5 or 10 percent of each other. Should I be concerned with these readings?
Thanks, Dave.
Oh, and these were taken with no intake or exhaust manifolds and all plugs removed.
Thread Starter
Pro
Joined: Nov 2011
Posts: 517
Likes: 20
From: Scroggins Tx
I know how to do the leak down test, just don't have the tool. As I already have the body off I am going to pull the motor and tear it down, If I don't I will always be wondering whats in it. I will at least replace the bearings, rings, valve seals and gaskets.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
That compression is great!
Why do you want to rebuild a motor with good compression??? This make no sense unless u have big performance plans and i read u don't. Unless u have experience rebuilding the entire motor then more likey than not u will make a major mistake after spending dollars in the thousands.
If u are restoring the frame and body u will want an engine u know runs and not have to deal with engine problems while getting the whole car reliable for driving again.
IMHO u should just replace the vlv cover seals, front crank seal through the timing cover, rear main seal (includes oil pan gasket and timing cover gaskets). That old motor is great for ferrying the car while u sort the rest of the car out and its probly hard to break a truck motor. But if u do it will be much less of a loss. Rebuilding just a top end can become a nightmare of overlooked problems - just read this forum for a few days/weeks.
I suggest u focus on the body and frame which will include the rest of drivetrain too - plenty to worry about there in itself.
Good luck,
cardo
If u are restoring the frame and body u will want an engine u know runs and not have to deal with engine problems while getting the whole car reliable for driving again.
IMHO u should just replace the vlv cover seals, front crank seal through the timing cover, rear main seal (includes oil pan gasket and timing cover gaskets). That old motor is great for ferrying the car while u sort the rest of the car out and its probly hard to break a truck motor. But if u do it will be much less of a loss. Rebuilding just a top end can become a nightmare of overlooked problems - just read this forum for a few days/weeks.
I suggest u focus on the body and frame which will include the rest of drivetrain too - plenty to worry about there in itself.
Good luck,
cardo
Last edited by cardo0; Feb 25, 2012 at 02:42 PM. Reason: typos
