Crazy high oil pressure on today's cars?

[Bonnewagon]

So this is normal. OK, I won't worry about it unless it causes leaks from the gauge or copper tubing line. Actually I remember now reading something about some oil pumps being able to produce very high pressures but that the built-in bypass/regulators limit that. It would explain why the 60 psi pump I put in my 301 only shows 40 psi no matter what the conditions. The regulator limits it at 40 psi. As for low pressures, I once opened a Pontiac 400 and pumped solvent through the oil system to flush out crud. Just using a hand held drill and a distributor shaft as a priming tool I watched the solvent spurt out the lifter feed holes like gangbusters. The oil gauge I had monitering this would barely move. So even though the pressure was low- it flowed a huge volume.

 

[pontiacgp]

I guess the new car's oil filter is designed differently than the SBC. The SBC oil filter bypass would allow some of the oil to bypass the filter with the oil pressure of the new engines. I wouldn't like to have any unfiltered oil lubricating the engine all the time

 

[Bonnewagon]

Steve- it is totally different. I can only compare it to a BMW 323i that I had worked on. There is a filter receptical built into the engine block. A cartridge type filter is inserted into the receptical and a cover with an "O" ring seal is screwed on top. It looks to be very capable of high pressures. Maintenance is a breeze. According to the factory manual there is a bypass/regulator somewhere.

 

[olds307 and 403]

Yup I'm there every weekend sometimes twice...and when they open evenings in the summer I'm there alot more. I've gotten to know Shaun pretty good. If there's ever anything you need give me a holler I'd be glad to pull it for you.

I guess the new car's oil filter is designed differently than the SBC. The SBC oil filter bypass would allow some of the oil to bypass the filter with the oil pressure of the new engines. I wouldn't like to have any unfiltered oil lubricating the engine all the time

The Olds V8 is the same way, some put a thread in plug in the bypass. I know one guy found a piece of nylon timing gear jammed in there, permanently bypassing! The Engineer's no doubt thought unfiltered oil is better than no oil.

 

[81cutlass]

My l67 in my firebird before I cammed and really got into doing stuff to it (just a pulley at the time) ate the front main for some unkown reason. I think it was poor metalurgy on the crank. The front main on the crank was like .060" out of round and it wore a third down quite a bit in the crank.

Bearings were a touch wore on that main but the rest of the rods and crank were mint. It was October and I didn't have anything else to drive. It made like 10psi at cruise and 0 at hot idle. Drove like 1000+ miles on it. Took it apart later that spring and just threw a new crank and bearings in it.

Motors aren't picky by any means.

 

[Bonnewagon]

My cousin just informed me his wife's Turbo Shadow ran 90 psi cold and 75 psi hot way back then. Something about overhead cam motors needing massive oiling because the cam rides on the aluminum head's base metal? I would have figured some sort of sacrificial bearing insert so as not to waste the entire head should a cam wipe the journals. I mean I've spun plenty of bearings in my old Pontiacs and always got away with just changing the babbits.

 

[lilbowtie]

Most oil filter bypasses are set up to start bypassing after an 18psi differential pressure is seen between pressure in and out. I've done a lot of cold start testing and oil @ 20 -30 deg below zero is like thick honey at best. Trying to get it through the filter is tuff and I want that by-pass there not to starve it. In my race cars I always install a non bypass filter adaptor for the break-in and the first day of running. After that the bypass goes back in mainly because I run alcohol and water and filters don't get along. I see a 3 to 5 psi drop at idle after 30-40 passes and it's time to change the filter. The bypass is there as a safety and as long as your up on your maintenance your probably not bypassing till you hit an extreme condition and it's not like that oil hasn't filtered.