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| | | | Joined: Sep 2013 Posts: 36 New Guy | | New Guy Joined: Sep 2013 Posts: 36 | Can anyone tell me what the cranking pressure should be for a 1950 GMC 228 motor please. I've just done a compression test and they all came out around 100psi on a cold motor.
cheers | | | | | Joined: Jun 2011 Posts: 1,901 Shop Shark | | Shop Shark Joined: Jun 2011 Posts: 1,901 | My 1958 motors manual says 130@ "cranking speed" for 248 to 270 for most years it lists...
Sound like your in the game to me...
Give me ambiguity
or give me something else
| | | | | Joined: Sep 2013 Posts: 36 New Guy | | New Guy Joined: Sep 2013 Posts: 36 | That's low. I'd of thought 150-170psi | | | | | Joined: Nov 2006 Posts: 2,544 Shop Shark | | Shop Shark Joined: Nov 2006 Posts: 2,544 | You may want to add some oil to the cylinders and retest and see if the numbers change. The good news is that your cylinders are all real close to each other so I would not be to worried about the actual number. | | | | | Joined: Apr 2010 Posts: 244 'Bolter | | 'Bolter Joined: Apr 2010 Posts: 244 | Compression specs, I believe, usually assume a fully warmed motor, all spark plugs removed, and throttle held wide open. | | | | | Joined: Sep 2013 Posts: 36 New Guy | | New Guy Joined: Sep 2013 Posts: 36 | You may want to add some oil to the cylinders and retest and see if the numbers change. The good news is that your cylinders are all real close to each other so I would not be to worried about the actual number. Yeah, I was pleased to see the pressures were very close. So I don't think I have much to worry about. It was more to see how the motor was fairing. I've yet to do a test when hot, or a leak down. Compression specs, I believe, usually assume a fully warmed motor, all spark plugs removed, and throttle held wide open. In the pipeline just haven't got round to it yet. Cheers | | | | | Joined: Sep 2013 Posts: 36 New Guy | | New Guy Joined: Sep 2013 Posts: 36 | Doh!!!
my mate came round last night for the compression tester. I'd not been wearing my glasses when I did the test, so didn't see the gauge too well.
Sooo it turns out it was reading 10bar not 100psi. lol
So more like 145-150psi per cylinder.... happy days.
Still need to find out why is burning sooooo much oil though?? | | | | | Joined: Feb 2004 Posts: 29,760 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,760 | Check the exhaust valve guide clearance- - - -lots of oil can go down the exhaust pipe without ever being noticed as fouled spark plugs or smoke. If it doesn't get into the combustion chamber and get burned, the characteristic blue smoke doesn't always become apparent.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2013 Posts: 36 New Guy | | New Guy Joined: Sep 2013 Posts: 36 | I think you might be onto something there, as on startup it always coughs out a load of soot. I might take the head off and get the guides replaced | | |
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