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Joined: Dec 2013
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Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Dec 2013
Posts: 89 |
I recently got my '25 Chevy truck running after being in a barn for over 50 years. I ended up doing a complete engine rebuild. A new cam, lifters, valves, valve guides, and springs were installed. It runs quiet, Oil pressure is 2-4 lbs. at idle and am happy with the rebuild. Last year I met someone who brought a 1925 Chevy to a cruise in that I was attending and we talked. He told me that the lifters must turn a quarter turn when the engine is running. I observed the lifters in my Chevy while it was running and none of them were turning. My questions are is this normal and is 2-4 lbs OK for oil pressure.
1925 Chevrolet Utility Express PU
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
They should turn, however not necessary for them to turn an exact amount. Perhaps the lifters were not ground correctly. Depends where they were purchased.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Oct 2003
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ChatMaster - 750
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ChatMaster - 750
Joined: Oct 2003
Posts: 814 Likes: 1 |
My lifters turn on my '25. That is caused by the way the lifter sits on the cam lobe. If it doesn't then you may have a worn cam lobe and or lifter .You may also have sludge built up between the lifter and engine block. 2-4 PSI is normal with a warm engine. Remember, your engine is splash lubed. You need constant flow of oil; not pressure.Also use a light oil. 10W30 or 5W30 work fine.Heavy oils don't splash well and before you know it you will be rebuilding the engine again.
Steve
'25 Superior "K", '79 Corvette , '72 Corvette LT-1 & 1965 Corvette Coupe
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Joined: Dec 2013
Posts: 89
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Dec 2013
Posts: 89 |
Lifters and cam are new from Billy Possum. Engine block was hot tanked so there's no sludge buildup. I'm using 10w-30 oil. The cam was pre-lubed with engine break-in grease before installation.
1925 Chevrolet Utility Express PU
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Joined: Oct 2011
Posts: 140
Shade Tree Mechanic
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Shade Tree Mechanic
Joined: Oct 2011
Posts: 140 |
It is normal for lifters to turn and quite normal if they don't. The turning is due to some small misalignment (wear or machining tolerance) between the lifter face and the cam lobe. On some engines, you may see some turn and others don't, quite normal too. Take no notice, it doesn't mean anything that will affect the life of your engine.
Pre '28 engines had lifters that were smaller than the width of the lobe and were quite prone to cutting into the cam. '28 lifters were the same width as the cam lobe, about 3/4" if I recall correctly. This was probably felt necessary by the factory because of the increased cam-to-lifter load due to the new off-set rockers.
Regards
Al
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Joined: Dec 2013
Posts: 89
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Dec 2013
Posts: 89 |
1925 Chevrolet Utility Express PU
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