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Panhead compression

Started by Mr. Torque, February 25, 2017, 01:47:43 AM

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Mr. Torque

Can anyone tell me what the cranking compression should be on a 74ci Pan kick start OEM stock camshaft?

HogMike

Quote from: Mr. Torque on February 25, 2017, 01:47:43 AM
Can anyone tell me what the cranking compression should be on a 74ci Pan kick start OEM stock camshaft?

7.5 to 1
8 to 1
up through 1957
Later years I think boosted that up a bit, I'd have to check my files.
What year are you talking about? Bone stock?
:nix:
HOGMIKE
SoCal

Mr. Torque

 :chop:what I'm asking is what the compression test should read. I get 80psi.on the front cylinder and 75psi.on the rear. That seems low to me, but I can't seam to find anywhere what the cranking compression should be.

Mr. Torque

1958 74 ci it is supposed to be stock.

58Tin

I have always understood about 100 psi for a stock well running pan is good. Anyway looking in the service manual I do not find anything-but the Clymer Manual has 90psi as your target.

Mr. Torque

Thank you, appreciate the help. I'm going to leak it down and see where it's blowing by.

58Tin

Last spring I couldn't get my tired old pan started without a marathon of kicking-comp test had numbers half of yours. Good luck to you.

HogMike

Quote from: Mr. Torque on February 26, 2017, 10:06:54 AM
:chop:what I'm asking is what the compression test should read. I get 80psi.on the front cylinder and 75psi.on the rear. That seems low to me, but I can't seam to find anywhere what the cranking compression should be.

I have my '65 on a battery tender and since it's raining this morning, thought I'd check cranking pressure on that pan. Good thing too, found the rear spark plug loose!  :banghead:
Hope this helps.
:missed:
HOGMIKE
SoCal

Ohio HD

Yeah, 80 psi is a bit low. Hogmike shows what should be healthy.

kd

That is cranking with an electric start though. Kicking it is a whole other world if you aren't aggressive enough.
KD