Assembly Lube or just plain oil?

[Shuboxchevy]

So I'm installing my new rod with new bearing insert... and it I was wondering if I need to use any special assembly lube w/moly or anything like that. I was planning on just lubing it up real well with some VR1 SAE 30 and priming the oil pump before initial startup.

Should I pick up some assembly lube? Or am I ok with the SAE 30? THANKS!

Also, side question... It is possible to adjust the pressure on an oil pump? My pump meets the min requirements, but barely and was wondering if there was any way to up the pressure.

[veno]

I have always used moly disulfide assembly lube....

Oil pressure is affected buy a couple of clearances. bearing, main and rod, as well as rod side clearance... also lifter clearance play a factor...

as far a upping the pressure... the bottom of the oil pumphas a long hump cast into it... there is a roll pin that retains a spring .. the spring holds a pressure on the machined piece of steel. that steel is the bypass valve..

now to increase pressure... remove the roll pin. install a thin washer against the spring. push it back in and reinsert the roll pin. only use a thin washer.. as a little bit of additional pressure is all thats needed to increase the pressure by 20 to 30 pounds per square inch gage.

[Shuboxchevy]

I have always used moly disulfide assembly lube....

Oil pressure is affected buy a couple of clearances. bearing, main and rod, as well as rod side clearance... also lifter clearance play a factor...

as far a upping the pressure... the bottom of the oil pumphas a long hump cast into it... there is a roll pin that retains a spring .. the spring holds a pressure on the machined piece of steel. that steel is the bypass valve..

now to increase pressure... remove the roll pin. install a thin washer against the spring. push it back in and reinsert the roll pin. only use a thin washer.. as a little bit of additional pressure is all thats needed to increase the pressure by 20 to 30 pounds per square inch gage.

Thanks Veno... That's what I suspected with the oil pump. I wonder how thin a washer I really need....

[Paul Wright]

Shimming the spring is not a good idea. Simply replace the spring with a higher pressure spring.

[veno]

Shimming the spring is not a good idea. .

ok paul... I'm gonna bite.... Why?

[Shuboxchevy]

ok paul... I'm gonna bite.... Why?

I've been doing some thinking about this.... and looking for some more info without much luck.

Tell me if this is correct thinking, please... The oil pump is a positive displacement pump and the spring hold pressure on the relief valve to set a max pressure. So, the relief valve is just about always closed and opens only when max pressure has been reached at some high engine speed.

That being said, I'm having a hard time figuring out how changing that spring or shimming it would raise the pressure at low engine speeds when the relief valve is not bypassing oil anyway.

[veno]

even at idle the bypass is opening... when I started a new engine some 5 years ago. the pressure by pass valve had stuck closed... with just 1000 rpm the oil filter gasket pushed out sparying oil every where and scaring the bejesers out of me:rolleyes:... the pressure gage pegged the 100 psi gage... the pressure was so forceful that the needle spun a complete 360 degree and hit the zero peg. the result was the gage with no pressure on it at all registered 60lbs..... so you see..... at 1000 rpm I had at least 160psi....

[Shuboxchevy]

even at idle the bypass is opening... when I started a new engine some 5 years ago. the pressure by pass valve had stuck closed... with just 1000 rpm the oil filter gasket pushed out sparying oil every where and scaring the bejesers out of me:rolleyes:... the pressure gage pegged the 100 psi gage... the pressure was so forceful that the needle spun a complete 360 degree and hit the zero peg. the result was the gage with no pressure on it at all registered 60lbs..... so you see..... at 1000 rpm I had at least 160psi....

Thats some good oil pressure!! :eek:

Ok, makes more sense now. Its not a "relief valve" so to say, but a "regulating bypass valve".

Waiting for Paul to weigh in on why not to shim it. I shimmed the fuel pressure regulator on my Diesel Pickup to up the fuel pressure a tad, so I imagine this is the same or similar deal. I've looked for just the spring without luck so far.

[veno]

melling has the spring... check with summit or jegs.. its a common item

[Paul Wright]

ok paul... I'm gonna bite.... Why?

The reason is it's hard to select the correct shim for any desired pressure and even harder to correct a mistake. It's also risky as it might cause problems with the smooth operation of the piston. I knew a guy who shimmed the spring on a brand new Corvette (thinking more pressure would make the car run longer) and promptly blew the oil filter off. Made a big mess and starved the engine for oil until he noticed it.

Shimming an old, fatigued spring won't restore the spring rate. It's a temporay and shaky fix.
If the price difference between a shim and a $5 spring is a deal breaker maybe it's time to find a cheaper hobby.

(Note: I'm at CRC at Fort Benning and only get 30 minutes on the terminals when available. Might be delays in the future for responses)

[veno]

kinda figured it like that.... more so I precieve it changes the dynamics of the spring rate... when I did do it.. I used a .0625 shim... now I just buy the correct pump for the clearance. thanks for the reply...

Good luck in the Army! :eek:

[The Big Al]

Also, side question... It is possible to adjust the pressure on an oil pump? My pump meets the min requirements, but barely and was wondering if there was any way to up the pressure.



Summit part# 122170 65-70psi

Summit Part# 122171 80-90psi

Mr. Gasket Part# 26

[Shuboxchevy]

(Note: I'm at CRC at Fort Benning and only get 30 minutes on the terminals when available. Might be delays in the future for responses)

Fort Benning! Been there a few times for the intercollegiate pistol nationals. I wanted one of those tank crossing road signs so bad.

[Shuboxchevy]

Summit part# 122170 65-70psi

Summit Part# 122171 80-90psi

Mr. Gasket Part# 26

Awesome info. Thanks.

So can anybody see any reason NOT to do this (the spring). Its not a high revving engine, but I only get about 50 - 55 psi at about 5000 rpm which just barely meets the 10 psi for every 1000 rpm rule of thumb. Idles at about 25 psi. The pan is off so now is the time to do it if I am, but it would be a lot of work to change it back if it ended up blowing out all my seals or something crazy like that.

[The Big Al]

Awesome info. Thanks.

So can anybody see any reason NOT to do this (the spring). Its not a high revving engine, but I only get about 50 - 55 psi at about 5000 rpm which just barely meets the 10 psi for every 1000 rpm rule of thumb. Idles at about 25 psi. The pan is off so now is the time to do it if I am, but it would be a lot of work to change it back if it ended up blowing out all my seals or something crazy like that.

No issues with change.

And now is the time.

Al

[Paul Wright]

Awesome info. Thanks.

So can anybody see any reason NOT to do this (the spring). Its not a high revving engine, but I only get about 50 - 55 psi at about 5000 rpm which just barely meets the 10 psi for every 1000 rpm rule of thumb. Idles at about 25 psi. The pan is off so now is the time to do it if I am, but it would be a lot of work to change it back if it ended up blowing out all my seals or something crazy like that.


Smokey Yunick's "10 psi rule" is often taken out of context and about 25 years out of date. Ignore it and anybody that quotes it like it's important.

[mikeorwan]

Smokey Yunick's "10 psi rule" is often taken out of context and about 25 years out of date. Ignore it and anybody that quotes it like it's important.

Hey Paul, can you or someone else elaborate on Yunicks 10 psi rule?

This was the first I heard of it.

[veno]

Smokey said for every 1000 RPM 10psi was needed....so at 10,000 rpm what kind of pressure do you think you will have?


but I only get about 50 - 55 psi at about 5000 rpm

This is fine... IMO.. with the 25psi at Idle some would envy you again IMO...


MY 385, hot has 20psi IDLE and 60 psi @ 7300.... running 5 years... a street car.... not a strip car..

[Shuboxchevy]

Thanks for all the input. Interesting thread. I actually talked to a tech rep the other day at Melling and had a nice conversation. He didn't recommend changing the spring as he says there may be small differences between manufacturers and models of oil pumps (specifically in the design of the bypass valve) may make changing springs unpredictable.

Haven't completely decided what I'm going to do, if anything, but its all good information to consider.