L-48 Compression test results..OK?
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
L-48 Compression test results..OK?
In preperation for some top end work I did a compression test today on my 73' L-48 to make sure the lower end was ok
Warmed it up to 190*
Pulled all the plugs (I have the burns on my hands to prove it)
All cylinders came in at 155# +/- 3 pounds
I think this tells me that the lower end is in good shape?
Am I correct in assuming this?
Any comments are appreciated
Thanks
Bob
Warmed it up to 190*
Pulled all the plugs (I have the burns on my hands to prove it)
All cylinders came in at 155# +/- 3 pounds
I think this tells me that the lower end is in good shape?
Am I correct in assuming this?
Any comments are appreciated
Thanks
Bob
Last edited by Bob Onit; Aug 25, 2006 at 02:33 AM.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Did you tie the throttle wide open? If they are all within 3 psi thats excellent. If you did not test with the throttle open, its about 10-15psi less then what it will be if you test it wide open. I would say you are in good shape!
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by ajrothm
Did you tie the throttle wide open? If they are all within 3 psi thats excellent. If you did not test with the throttle open, its about 10-15psi less then what it will be if you test it wide open. I would say you are in good shape!
Used a long tight spring and just to be safe I tied the choke open too
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I would say its good to go. I don't remember what the service range is but...it is a low compression motor so you are probably right in line. The last old one I tested was a 406" pontiac, it was around 175psi with the throttle closed, I never tested it open but it was about a 10.5-1 motor.
On my bike, if I test with the throttle closed it only makes about 115-120psi, with the throttle open, its 130-135psi. Its around a 8.8-1 motor now since I lowered the compression.
When you put fresh heads on it, the compression will probably come up more...unless your new cam bleeds off some.
Mod away.
On my bike, if I test with the throttle closed it only makes about 115-120psi, with the throttle open, its 130-135psi. Its around a 8.8-1 motor now since I lowered the compression.
When you put fresh heads on it, the compression will probably come up more...unless your new cam bleeds off some.
Mod away.
