Labor Day Putting down your wrenches or time for
MORE wrenching? 
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| | | | Joined: Nov 2005 Posts: 123 Shop Shark | | Shop Shark Joined: Nov 2005 Posts: 123 | I got a 1956 235 engine to replace my 1950 216. I followed the list of starting an engine that has sat for a while. The engine fired right up and started pumping oil to the rockers only ran it for about 30 seconds. Decided to do a compression test. The results are as follows
#1 cyl. 130 lbs
#2 cyl. 150 lbs
#3 cyl. 160 lbs
#4c. 150 lbs
#5 c. 160 lbs
#6 cyl. 145lbs
How do these numbers seem to be? Okay to put it in the truck? | | | | | Joined: Apr 2005 Posts: 7,440 Bolter | | Bolter Joined: Apr 2005 Posts: 7,440 | 30 lb differential between high and low? A bit suspect. The engine experts will be along shortly.ðŸ›
Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
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| | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | The 'while' sitting probably has to do with the disparity, pot some water in it and warm it up for a while. Se how it improves.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | They are all so high that I would lose no sleep over the differential.
If you have a running truck, if you have not changed the oil/filter, do it.
I'm a shade tree mechanic - set the timing and carburetor mixture to maximum vacuum using a vacuum gauge at the wiper-vacuum port on the intake manifold. Adjust the idle speed at a slow/smooth idle (or, 350-500 RPM, if you have tachometer).
Then, go for a long drive.
Then, check the compression again.
Then, report back here.
Maybe, then, congratulations from all will be in order.
| | | | | Joined: Feb 2004 Posts: 29,742 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,742 | I wouldn't be concerned with a difference that small, especially on an engine that's been out of service for a long time. Once you get it tuned well and put an hour of more of running time on it, the differences in compression will probably even out a little. A small error in valve adjustment or slightly sticky piston rings can account for more of a difference than you've got right now.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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