Oil pressure

[sasquatch]

Took my '49 2R15 out for a drive yesterday morning (it's second one) and had a bit of a scare. On the way home, I noticed the oil pressure gage was down to about 5 PSI. My speed was around 35 and the outside air temperature was 90, the hottest it's been since the rebuild. The temperature gage, which has never gone over 170, was past the 170 mark, maybe 180 or 190. I'm using Shell Rotella T 15W40 oil and it's less than half a quart from being full. The radiator is full of 50-50 antifreeze. I let it sit for about three hours and restarted it The oil pressure was 15 at normal idle speed and 40 at a fast idle and the temperature gage was below 170, maybe 130 or so. Did the engine get hot and thin out the oil or did the oil pressure drop causing excess heat in the engine? When the air temperature was only getting up to the high 70s I could keep the oil pressure up in a safe range, even idling. Is it time for new gears in the oil pump? Maybe the oil thins out when it gets hot and the pump has a bit too much clearance? Or could this be a problem with the oil pressure relief valve sticking? (It was new when the engine was rebuilt in January.) The engine is the original Champ.

Rick
Kingman, AZ

"Leroy"

[skyway]

Good looking truck! My vote is for excessive ambient heat thinning out the oil.

If it were mine, and barring any bad noises, I think I'd do a little watchful waiting, and see if the situation repeats itself. Try drives in the cool of the early morning as well as the worst of the heat, etc.

Another couple of things to consider. Components in that fresh rebuild may still be a bit snug which can cause heat. Maybe an oil change to look for scraps/filings from the new bearings is in order? That oil pump is pretty easily accessable. Shop manual will have both specs and procedure;you'd be inspecting both gears AND for wear on the inner side of the cover plate. Finally, and I hate to mention it, but were cam bearings and/or lifters part of your rebuild? Worn ones will lower oil pressure.

Good luck.

[jackb]

......that pressure is low. I say low due to the fact its a rebuild. I'll bet you didn't use oversized lifters ??? That's probably where the pressure is....Look into pressure restrictors through the "search" function on this forum.....Not oil filter restrictors.....I'm assuming small flat head 6

[sasquatch]

Tried it this morning with the temp in the mid 70's. Started out at 40+ PSI and kept going lower the warmer the engine got. Got down to about 5 PSI again at slow engine speeds but would go to around 20 with higher speeds. The water temperature got up to 180 or so. The machinist who did the engine said the cam bearings and lifters were good. I have an oil flow restricter in the rear oil galley hole. I'm not an engine expert but if the cam bearings or lifters had too much clearance wouldn't the oil pressure be low even with cold oil? By the way, I don't see any specs on the oil pump clearances in my 2R shop manual.

Rick
Kingman, AZ

"Leroy"

[GTtim]

What weight oil are you using?

Tim K.
'64 R2 GT Hawk

[skyway]

"By the way, I don't see any specs on the oil pump clearances in my 2R shop manual."

Ouch,sorry if I mis-spoke! I'm not at home, but I beleive that the big '59-'64 automobile manual, which covers both flat and overhead Champion motors, contains such info. Something about inserting a feeler guage between gears and housing to see if they bind, and also checking how deep in the housing the gears sit, and finally if the gears have cut into the cover plate?

Also, maybe something has let go inside your engine. If I read your initial post correctly, on your first drive with temperatures in the high 70's all was well. Then trouble on the hot second drive, and now, with temps in the low 70's, the trouble repeats itself? Could be time drain and sift the motor oil.

I'll try to get a look at my '59-'64 book tonight.

[Mike Van Veghten]

That sounds like classic, excessive internal clearances.

Mike

[sasquatch]

Tim, oil is 15W40. Skyway, let me elaborate on the history a little bit. When I got the engine, etc. back in the truck I started it. Oil pressure was around 70 cold at first. Ran it in the garage long enough to get the bugs out then drove it around the yard then around the block a time or two. Still holding good pressure but not more than 60 cold. Drove it to the DMV Monday (it's first road trip) to get license and title. Pressure was OK. Wednesday drove it to NAPA and back, maybe five miles, and that's when the pressure went down to 5 on the way home. So I guess it's been slowly going downhill since the rebuild.

Rick
Kingman, AZ

"Leroy"

[Bud]

I would suspect that you have one or more main or rod bearings failing if the pressure was good when you first started the engine and the pressure has dropped in a short time. It is possible that for some reason the oil pressure relief valve is sticking, I would check that first. Do not stretch the relief valve spring to increase the oil pressure. I use 15w-40 Chevron Delo 400 in my Stude engines and in several of my friends engines both six and eight with good results. Bud

[sasquatch]

Sometimes, the simplest things cause problems. I pulled the oil pressure relief valve out and compared it to the original parts that I had kept. The new spring was two turns shorter than the original spring! With the old spring back in I have oil pressure. Thanks for everybody's help.


Rick
Kingman, AZ

"Leroy"

[skyway]

Outstanding!

[nvonada]

And that is why we should never throw old parts away. I am glad that worked out for you.

_______________

http://stude.vonadatech.com

[sasquatch]

Now, what I'd like to know is why a shorter than original spring was included in that kit? Is it the correct spring for a different year Champ engine, even though the box was marked for my '49? The new piston/valve was identical to my old one so how could that shorter spring be expected to work? Am I the only person who has these weird problems?

Rick
Kingman, AZ

"Leroy"

[Bud]

You're dealing with replacement parts for a truck that was built almost 60 years ago. This is not an uncommon problem when buying replacement parts for old cars and the newer ones for that matter. I recently had a problem with a brake hose on the rear of a 48 Commander that had the wrong size end crimped on it. Fortunately I had another hose on the shelf with the correct fitting on it. I try to match the old part with the replacement part whenever possible. Bud

[52 Ragtop]

Well, at least it didn't have 2 valves in it! Right Bud!! LOL