351 C Low Oil Pressure?????

tchrome · #1 (**permalink**) 03-30-2008, 02:02 PM

if anyone out there has some experience with the 351 cleveland , please let me know. i thought that i read some where that they had an oil problem. i can't remember if it was pressure or distribution to a certain part of the engine. i am all of a sudden after installing an oil cooler system. (mocal) loosing oil pressure after the engine heats up. i start out with 65-70 lbs. cold, but drop to 10 lbs idling and maybe 20-25 at running speeds. aside from bad main bearings, can anyone come up with some possibilities? thanks for any help or suggestions you can give. you can also email me at tchrome@aol.com.

thanks ,
tony

blykins · #2 (**permalink**) 03-30-2008, 03:01 PM

Well my first thought is that if it just started after an oil cooler system was installed, then you should look there first.

DAVID GAGNARD · #3 (**permalink**) 03-30-2008, 05:21 PM

What Brent said!!!!!!!!!!!

Just how much oil pressure are you losing????????
Oil pressure cold and oil pressure with your oil at 180 degrees or so are going to be two different animals.....Cold, I run about 60 psi, after about 170 degrees or more of oil temp, my idle pressure is about 35 psi, at speeds it goes to 55 psi.........oil temp does make a big difference also......

My motor is not a Cleveland, but a 331 Stroker.......with the oil cooler I lose roughly 10psi of oil pressure across the board...I have a good size cooler and 12AN lines.......

I'm basing this on the oil pressure of the motor on the dyno with only an oil filter and the pressure once installed in the car with the oil cooler.....
BTW; my cooler with the big 12AN lines and a large oil filter add almost 3 quarts to the total capacity.............

David

mpanten · #4 (**permalink**) 03-30-2008, 06:24 PM

I have heard from many people that have taken off the oil cooler that they gain about 10 psi so that makes sense. If you are still running 45 psi at normal operating temp I wouldn't worry to much. I think a lot of people get to wrapped up with the oil preassure. Mine has run at about 40 psi at normal operating temperature for years with no problems.

tchrome · #5 (**permalink**) 03-31-2008, 05:52 AM

Quote:

Originally Posted by DAVID GAGNARD

What Brent said!!!!!!!!!!!

Just how much oil pressure are you losing????????
Oil pressure cold and oil pressure with your oil at 180 degrees or so are going to be two different animals.....Cold, I run about 60 psi, after about 170 degrees or more of oil temp, my idle pressure is about 35 psi, at speeds it goes to 55 psi.........oil temp does make a big difference also......

My motor is not a Cleveland, but a 331 Stroker.......with the oil cooler I lose roughly 10psi of oil pressure across the board...I have a good size cooler and 12AN lines.......

I'm basing this on the oil pressure of the motor on the dyno with only an oil filter and the pressure once installed in the car with the oil cooler.....
BTW; my cooler with the big 12AN lines and a large oil filter add almost 3 quarts to the total capacity.............

David

i start up cold at about 65 to 70 lbs. i am running 6 qts of 20x50 castrol gtx oil. after hitting 180 degrees to 190 degrees i am idling at 10lbs. and running 55 mph at 25 lbs. i just installed all new auto meter electronic gauges. previously i had stewart warner old mechanical gauges. i had been having and overheating problem when i first bought the car about a year and a half ago. so i was always looking at the gauges and i don't remember the oil pressure being that low before the cooler was added. i will install a mechanical gauge again and see what i get. i just don't think it should be that low, even with a cooler on it. i have a big block 96 chevy in a 68 elcamino that runs at 70 lbs at 190 degrees. idles at 65 lbs. and even if i was a qt low on oil, i don't think it would effect the pressure that badly. thanks for your input. it is good to know that the cooler would have effected the pressure. thanks again

tony

mpanten · #6 (**permalink**) 03-31-2008, 06:52 AM

I guess I should have read more carefully, I thought it dropped 10lbs not runs at 10lbs. I would not be comfortable at 10lbs.

DAVID GAGNARD · #7 (**permalink**) 03-31-2008, 10:49 AM

Tony;

I don't know a whole lot about Cleveland engines, but 10 psi at idle and 25 psi at speed sounds way too low to me on any engine......

I have used at least four different brand oils and weights as well as synthetic oil and my oil pressure did not vary more than 5 psi from the different oils....I presently use Mobil 1 15/50........

I would install an oil pressure gauge that you know works well or you have tested and check the oil pressure before doing anything else.....then go from there........

David

cobrabobby · #8 (**permalink**) 03-31-2008, 12:21 PM

check 351Cleveland.net site. Oiling system priorities on
this 335 series engine is controversial but when done
right works well. Probably type of filter used, (not Fram),
crap from remote install in pump pickup screen, or previously
mentioned inaccurate guage, or main bearing clearances too
big. Good luck.
Bob

Rick Yeager · #9 (**permalink**) 04-03-2008, 01:50 PM

I have the same problem with mine and sadly suspect it is the main bearings. If it were the remote or the oil pick up, would the pressures be down all the time of just go down when the engine is warm?
Rick