I'm about ready to give up here....

Is it a Buick thing or what because 11psi of presure at idle to me sound REAL LOW. I've never own a Buick powered car so its a honest question.

 

More is always better (to a point) but 11psi at hot idle in gear is fine as long as it jumps as soon as you touch the gas pedal. Rule of thumb is at least 10 psi per 1000 rpm

 

I had the pick up tube come loose from the block on my engine started losing pressure little by little it got worse. When I pulled the pan the rope seal was also suck to the pick up!

 

I really think if you are in the warmer part of Texas a straight weight is the way to go those older motors need slick ums in them . 40W even 50W is good

I am pretty sure they did not have multi grades back then.{please correct me if I am wrong}

If you pull the pan to check the pick up tube a lot of people weld the tube to the pump to prevent it from falling out on every type of motor.

If you pull the pan plastic gage the mains & rods while you are there.

good luck.


SR66 :TU:

 

Hi all,

I just cut the filter open. I did not find anything that looked like metal or bearing material, not even any sludge. I bought a new Delco PF24, and 5 qts. of Rotella 15w-40. I'm gonna flush out the relief valve hole tomorrow and put back together, and change the oil. I'll take her out for a spin for about 40 minutes and see if the problem occurs again. If it does, I guess i'll be pulling the pan.


Harry

 

SR66,

I thought straight weight oil would cause the lifters to build up on deceleration....I seem to remember seeing this happen to a car awhile back that had straight 20w oil.


Harry

 

I run straight 40 in my boat engine!!!

 

"straight" weight oils won't give you any trouble if you always run a narrow range of operating temps like those seen in the southern climates.

Multiviscosity oils that we usually run these days are the way to go for the north, especially with the Buicks needing low, cold start pressures to help keep the distributor/cam gears and cam bearings alive.

Devon

 

SSR66, They had multi-grades in the mid 50s and possibily before. I remember when I was a kid my father going to a Texaco station to get the oil changed in his 1950 Ford and they had 10W30. He would not use this new fangle oil, he went for 30W30 non-detergent. ( a sludge creator if ever there was one). There was plenty of multi-grade in the 60s and 70s.
Jim N.

 

I've always ran 10W30 Mobil 1 in my race car. Ran one engine 650+ passes on the same bearings. But, the way I race may not be a hard on oil temperature as street driving.
Jim N.

 

Jim, I run Mobil1 10W-30 as well in my Wildcat, mostly street driven. It's been great for years. Low cold pressure, great hot pressure at any RPM.

Devon

 

Hi all,


Just an update on the situation. I put the relief valve back and put 15w-40 Rotella in the car with a new filter. Started her up and 0 oil pressure. So on a long shot, it took the oil pump apart, inspected for debris (didn't find any), packed it full of petroleum jelly and fired her up.....now I was back at 65lbs of oil pressure cold. Let the engine heat up (179degrees), back to 11lbs hot at idle, in gear. Took the car out, put some gas in it, aired up the front tires and took it back home, all was good. Still had 11lbs at idle,a and 25lbs at 2000 rpm and 40lbs at 3000 rpm, temp was about 185 degrees.

So I let the car sit for about 45 minutes, and decided to go get something to eat since I'm here alone tonight. Run out to the McDonalds, get my food everything is good. Start the car up, and get on the access road to the highway. I decided to punch it when the light turned green, everything looked good (and damn it went like hell), plenty of oil pressure at 4000 rpm (45lbs), get on the highway. Run about 1/2 mile to my exit. Turn off onto my street and the psi drops to 8lbs, made it to 4 houses away from mine and the pressure drops to 0lbs again.


I would love to get everyones ideas on this, as it is the strangest damn thing I have ever seen..... It seems the pump is losing the prime to me, but I can't figure out why, unless under hard acceleration the pickup is sucking air in....


Harry

 

I wouldn't think the pump would be capable of sucking the pan dry, but maybe?

How big of a gap is there between the bottom inside of your oil pan and the pick up? It could be to wide of a gap giving good psi at first due to the depth of the oil but once alot of that oil has been circulated throughout the engine the oil isnt deep enough in the pan for the pickup to properly suck it in.

Just throwing out idea.

 

I just got to thinking, maybe you have a severe oil drain back issue? Possibly something plugging/blocking a drain back hole somewhere/

 

Brian,

I don't think it's sucking the pan dry. That would take alot. The pan and pickup tube are not bent. My 'guess' is that the pickup tube has a 'leak' and is sucking air in under hard acceleration, if it's not that then the only other alternative (in my opinion, is the bottom end of the engine is tired, It is a stock '75 455, and had never been apart. It was supposed to be a 'low mileage engine').

So when are the engine elves coming to my house to fix the oil pressure problems, so I can get up in the morning and it will all be fine................:Brow:


Harry

 

I've been watching this thread, and my opinion for what it's worth is that the oil returns on the heads are plugged up with sludge and the oil is all getting pumped up to the top and can't drain back down to the pan fast enough, causing the pump to lose it's prime. If you let the car sit for at least 1/2 hour after this happens, and the pressure comes back that might comfirm this. Have you tried cleaning them out with a piece of wire and blowing some compressed air through the passages? You had indicated the engine was never rebuilt. You'd be surprised at the gunk that settles down into that area over time. :idea2:

 

I was thinking that sludge or debris in the bottom of the pan might be clogging the pickup tube.

 

Well for sure its NOT oiling Properly.

Weather its not going up or returning to the oil pan.

Time for exploratory surgery.

If you start it & it runs fine then drive it & it goes to hell quick check the dip stick.if its empty then the oil is up top


Valve covers are the easiest to check 1st


Drop the pan look for the pick up tube in the pan or clogged with sludge

Might as well check the mains & rods .

You could have something clogging a journal.

IMHO its time to start wrenching:rant:



SR66