Pressure relief valve in back of Block

[priobe]

Hello all,

I would like to know how many are running the 2nd pressure relief valve in the back of the block on the 427 Side oiler.

If not, what did you do to block it and why did you do this?

Also, do the repro's have this second valve iin th back of the block?

Thanks

[FWB]

i always kept them in. i don't see a reason to remove it.

[patrickt]

The argument for removing it is that the original Ford pumps had no built in pressure relief valve (so Ford put them in the SO block to help deal with oil pressure at high RPMs). Ask yourself, if that valve opens where does the oil spray? (right to the crankshaft) You might not want that, so many learned engine builders block off the relief valves and then simply calibrate the oil pump to provide the proper pressure (all newer pumps allow for that). FWIW, Gessford is on record over on www.fordfe.com as saying "He leaves it in, because that's the way Ford built them." On my 428, the decision was relatively easy....

[priobe]

Just curious,

What is your oil pressure at idle when hot (180 +) water / oil (170+)

[patrickt]

Originally Posted by priobe

Just curious,

What is your oil pressure at idle when hot (180 +) water / oil (170+)

High teens. Goes immediately up with any throttle and will get close to 60psi with high RPM. Rick L. will post that those numbers are not high enough, but they really are.

[Ron61]

Mine is around 20/25 lbs. when hot and runs about 50/55 when up to speed. It has been that way since it was new in 1969, so I don't worry about it.

Ron

[priobe]

what is your idle speed?

[patrickt]

Originally Posted by priobe

what is your idle speed?

About 850RPM. My clearances are .003 for the mains and .0028 for the rods, .060 restrictors up top. HV pump and Canton pan.

[priobe]

patrickt

you have PM

[patrickt]

Phil, here's the "low oil pressure" thread I was talking about. Note about half way down on the thread Barry writes about liking to see something in the upper teens at idle.
http://www.network54.com/Forum/74182...ions+please%21

[427Rook]

I too run high teens at idle, and jumps up the moment I add any RPM. Idle set to 850. And I did install the oil relief valve in the block.

[priobe]

Thank you Gents for your feedback

[Jac Mac]

Food for thought, If you were designing a relief valve from a 'Clean Sheet of Paper', would you:
A. Put it in the oil pump so that the relief is oil squirted back into the incoming oil and thereby create cavitation & air bubbles into the oil system along with having your oil pressure set/regulated a considerable distance away from the bearings.

B. Install it as close as possible to the bearings & relief flow is directed back into the pan or valley in such a manner that it doesnt create windage & any entrapped air can seperate.

[priobe]

I normally choose "C"

But would have to go with "A & B" based on the response that I have been getting from this thread.

J/k

I choose
"B" but what a PITA if it fails

[FFR428]

The repro blocks do not have the pressure relief valve. There's just a dummy plug (at least in my Genesis block) where they'd normally go on the oem sideoilers.

[elmariachi]

My fresh side oiler is idling at 20-22 psi hot and running 55-60 psi down the road.

[undy]

25 hot with 55 to 60 down the road..

[ERA Chas]

22PSI hot idle, 75PSI @ 6800 hot with Rotella 15-40.
I never noticed that the PR valve was causing drag on my crank...

[patrickt]

Originally Posted by ERA Chas

22PSI hot idle, 75PSI @ 6800 hot with Rotella 15-40.
I never noticed that the PR valve was causing drag on my crank...

What makes you think it's opening at all?

[ERA Chas]

Because it was originally shimmed to 100PSI by the machinist. I changed that fast while on the dyno. Would still prefer 65PSI but this is within a good margin.