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| | | Joined: Oct 2012 Posts: 85 Shop Shark | | Shop Shark Joined: Oct 2012 Posts: 85 | I've got a 235 engine that came with a powerglide transmission. The engine was removed and installed in a 50 truck with a manual transmission. Engine runs well however I have notice something perculiar about the oil pressure and not certain if it's normal.
When the engine is cold the oil pressure maintains itsels around 28 as it gets warmer say 1/2 hour drive it drops around 20 in high gear and hold around 14 at idle.
When the engine keeps running say for an hour the pressure drops to 15 in high gear and around 8 or 9 at idle.
Is that normal for the oil pressure to drop as the engine gets hotter?
Dan
Last edited by DJRoy; 07/13/2013 2:17 PM.
| | | | | Joined: Feb 2007 Posts: 434 Shop Shark | | Shop Shark Joined: Feb 2007 Posts: 434 | Yes. The oil gets thinner.
Most engines you want 10psi per 1000 RPM.
What weight oil is in it?
R-Bo
1959 Apache 1/2 ton Big Window, Short bed Fleetside (under reconstruction)
1966 GMC 305V6 in the family
| | | | | Joined: Oct 2012 Posts: 85 Shop Shark | | Shop Shark Joined: Oct 2012 Posts: 85 | synthetic SAE5W-20
Last edited by DJRoy; 07/13/2013 9:42 PM.
| | | | | Joined: Mar 2007 Posts: 863 Shop Shark | | Shop Shark Joined: Mar 2007 Posts: 863 | too thin.....
SAE 30, 15w40, 10w30....is better, | | | | | Joined: Mar 2008 Posts: 1,775 'Bolter | | 'Bolter Joined: Mar 2008 Posts: 1,775 | I would go for 15w40 or 10w40, maybe even 20w50, and leave the synthetic stuff alone. | | | | | Joined: Jan 2013 Posts: 603 Shop Shark | | Shop Shark Joined: Jan 2013 Posts: 603 | Yep, try the 20w50. Or if you do not have hydraulic lifters, try just straight 40w non detergent. All the old 2 cyl. John Deeres manual says use 30w ND. That's the cheepo stuff, bet you will see a rise in oil pressure.
I don't know what the original manual says to use in the 1950's cars and trucks.
Like the old tractors manuals even say use 30w ND in the Hydraulic system. But people want to switch to all these modern oils and eventually have problems with foaming, ect.
Remember STP?
57 GMC LCF 370 55 John Deere 40-W 59 John Deere 430-W 2000 GMC 4x4 56 John Deere 420-W Pix on Photobucket | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | These engines do not have the tight tolerances of a modern engine, a higher viscosity oil would be better as the others have mentioned. Any of the grades mentioned will be fine, though I will disagree with running non detergent, and running synthetic oil will not hurt anything as long as the grade is correct.
Bill Burmeister
| | | | | Joined: Jun 2008 Posts: 145 Wrench Fetcher | | Wrench Fetcher Joined: Jun 2008 Posts: 145 | I ran a 15w40 diesel oil in my 235 , though there is some debate on here about using a diesel oil . You can still get a oil additive from GM dealers to bump the zinc level up or at least you could a couple of years ago.
Last edited by Hydra1/2ton; 07/15/2013 10:28 PM.
| | | | | Joined: Mar 2008 Posts: 1,775 'Bolter | | 'Bolter Joined: Mar 2008 Posts: 1,775 | I had a Dodge van with a well worn 318. I had all kinds of issues, oil pressure, up and down, foaming. Switched to 20-50 Havoline and problems solved. Held pressure around 60psi, hot or cold. No foaming. She was a little hard starting in winter, but always did.
My dad runs farm stock tractor pulls. He had a fleet of old gasser Olivers. He runs 15-40 Rotella in all of them. BTW-He's been a New Holland and White mechanic for over 40 years.
The stovebolts are built just like old tractor motors too. | | |
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