The Stovebolt Site Forums The Shop Area Engine Shop oil pressure 235 engine

My oil pressure on my 3100 with a 235 engine maintains itself around 27lbs while driving, when shifting gears or idling it drops around 12-14 lbs. Is that normal or is there an issue somewhere?

And yes I do have the proper amount of oil in the engine.

s'OK, maybe even better than usual, nothing wrong

Bill

What year 235 engine?

Hey while we're talking oil pressure in 235's, mine is a '55 fresh rebuild, I was reading 45psi when cruising and around 25 on a idle. This is with an after market S&W guages. Just last week after putting 500 miles on it, it pegs the oil guage at 60. I've obviously checked the oil and everything looks fine, did I loose a sending unit? I drops to 0 when I shut it down.

Try a different gauge first.
It is possible, but unlikely, the relief valve is stuck.

1953

the old timers rule of thumb was you need 10 lbs of oil pressure for every 1,000 rpm. Since you're likely running 8-900 rpm at idle, 8-10 pounds would probably be considered normal for idle. Don't know what "today's" recommendations are, that was just something I heard as a kid.

1953 oil pressure specifications are:

14 psi at 2000 RPM for all (low pressure lubrication system) engines, except Powerglide equipped cars
"Specialized four-way method of engine lubrication: direct pressure, metered pressure, pressure stream and splash [cylinder walls and pistons]"

45 psi for 235s in Powerglide equipped cars (high pressure lubrication systems)
"Full-pressure lubrication: oil from main bearings flows through drilled passages in the crankshaft to the rod bearings. The cylinder walls and pistons are sprayed by oil metered through a hole in the connecting rod journal boss."


Does your 235 have hydraulic lifters (Powerglide engine), or mechanical lifters (manual car or truck engine)?

What is the engine ID that is pressed into the block to the rear of where the distributor goes into the block?

on my 235 new rebuild motor going down the road ( auto power glide ) its 40 or better and when hot ( 80) or so it drops to 10 to 15 just as soon as you touch the gas it jumps to 35 to 40 ,, i was told that was normal

just saying

I'd like to see Pre '68 Dave's comment on that.

Should a rebuilt 1958 235 engine display the oil pressure behavior described by lilrobo?

i am running 10w 30 oil after it runs for a while it sounds like water draining back down lol i know there is oil up top anyway ,, it only take 3 to 5 lbs to make the light go off , i am thinking about hooking the light back up so i dont keep looking it lol

Most 235's I have seen in good shape have 30-35 max when warm and half that at idle.
If it is going much above that when warm I would suspect the relief valve in the pump is hanging up.

Dave, my new rebuild(still running break in oil) keeps my gauge pegged at 30. When I can afford it I want to go to the Jim Carter rebuilt gauge cluster with the increased oil pressure gauge and the higher temp gauge but for now should I be concerned about the higher pressure?

Are you saying even at an idle it is pegged? That could be a problem.
If it is only when revved up that you peg the gauge then do problem.
I have never seen or heard of any problem with running the 30 lb gauge pegged.
If you want to know what the actual max pressure your engine is putting out you can hook up a temporary mechanical gauge.

I'm taking the truck to my builder tomorrow to be timed so I'll bring the oil pressure issue up. My builder knows his stuff...Dragmaster was really big in the 50's and 60's and they did all our marine engines when I worked the boatyard in the 70's. Dode has been around the block a few times(and down the strip many, many times).

I have a 216 converted to full pressure, with a 54 235 oil pump, I get around 32 psi while running, and about 23 psi idling.