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Oil pressure relief valve?
- Thread starter BOBBYR
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Randy Forbes
Yoda
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As seen bottom/center, below my home-made oil cooler adapter.abarth69 said:
OP
BOBBYR
Jedi Trainee
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Hi Guys,
Thanks for the quick response. Last night I pulled the starter out to clean up the drive and when removing the oil filter,I thought that cap was the valve.I'm going to shim the spring and see if I can't get about 10 lbs more of oil pressure.Again,thanks for yor help.
Bobby R
Thanks for the quick response. Last night I pulled the starter out to clean up the drive and when removing the oil filter,I thought that cap was the valve.I'm going to shim the spring and see if I can't get about 10 lbs more of oil pressure.Again,thanks for yor help.
Bobby R
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For whatever it's worth:
When I first got my BN2 with around 85,000 miles on the lower end, the oil pressure ran around 55 psi cold, 25 hot idle, & 45 hot run at 3,000 rpm.
I experimented with shimming the presure relief plunger spring .160". The pressures were the same, no change. Next I
added a .360" long spacer in place of the .160" spacer. The hot oil pressures went up to 40 at idle & 60 hot run at 3,000. I expected the hot run pressure to go up because of the additional spring pressure raising the pressure relief setting. What I didn't expect was the increase in idle pressure since 40 is well below the relief blow off setting of 60. Pressure now never goes below 40 at idle, or above 60
running. Of course idle pressure drops from 60 to 40 as the oil gets hot but It used to drop to 25.
I came to the conclusion that the regulator valve was leaking (bypassing) all of the time (not fully seating) & causing the low idle pressure. The additional spring pressure caused the regulator valve to fully seat & raised the idle pressure which was previously leaking through the non seating valve. The first try shim of .160" apparently
was not enough additional spring pressure to fully seat the valve.
It is possible that by checking for full valve seating & lapping the valve to it's seat that the low idle pressure would have been considerably higher without the spring change.
On my particular engine, a spring shim of more that .360" would result in the relief valve not uncovering the bypass port due to spring coil bind & complete blocking of the regulator, so .360" was the limit, but fortunately just the right amount.
It might be useful for you to experiment with the regulator valve seating & spring pressure.
Regards,
Dave
When I first got my BN2 with around 85,000 miles on the lower end, the oil pressure ran around 55 psi cold, 25 hot idle, & 45 hot run at 3,000 rpm.
I experimented with shimming the presure relief plunger spring .160". The pressures were the same, no change. Next I
added a .360" long spacer in place of the .160" spacer. The hot oil pressures went up to 40 at idle & 60 hot run at 3,000. I expected the hot run pressure to go up because of the additional spring pressure raising the pressure relief setting. What I didn't expect was the increase in idle pressure since 40 is well below the relief blow off setting of 60. Pressure now never goes below 40 at idle, or above 60
running. Of course idle pressure drops from 60 to 40 as the oil gets hot but It used to drop to 25.
I came to the conclusion that the regulator valve was leaking (bypassing) all of the time (not fully seating) & causing the low idle pressure. The additional spring pressure caused the regulator valve to fully seat & raised the idle pressure which was previously leaking through the non seating valve. The first try shim of .160" apparently
was not enough additional spring pressure to fully seat the valve.
It is possible that by checking for full valve seating & lapping the valve to it's seat that the low idle pressure would have been considerably higher without the spring change.
On my particular engine, a spring shim of more that .360" would result in the relief valve not uncovering the bypass port due to spring coil bind & complete blocking of the regulator, so .360" was the limit, but fortunately just the right amount.
It might be useful for you to experiment with the regulator valve seating & spring pressure.
Regards,
Dave
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I'm just glad there are only two major choices.
D
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gblawson
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Guest
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Too old to Rock and Roll, Too young to die!
chicken
Jedi Trainee
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Dave
On speaking with my local engineer he suggested that the end of the pressure relief valve should be rounded and not like the one i have which is tapered, i know where this relief valve came from (a company known to me for getting things wrong) so i am now suspecting that i have the wrong valve.
I have tried to attach a picture of my one to let you have a look (although this is my first attempt at pictures so it may well not appear !) if not do you have a picture of a correct one.
Rob
On speaking with my local engineer he suggested that the end of the pressure relief valve should be rounded and not like the one i have which is tapered, i know where this relief valve came from (a company known to me for getting things wrong) so i am now suspecting that i have the wrong valve.
I have tried to attach a picture of my one to let you have a look (although this is my first attempt at pictures so it may well not appear !) if not do you have a picture of a correct one.
Rob
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Rob,
See the attached pic. I can't tell for sure from your pic but you appear to have a six cylinder valve which is stepped, as you can see. If we indeed are discussing the BJ7, this would be the correct valve.
We are still not sure that this valve is completely seating. To check, coat the valve and the seat with layout dye, rotate the valve against the seat & examine both for a full circle marking that shows a complete seat all around.
Not easy to do this in that small hole but with good lighting & the valve on the end of a tightly fitting stick the valve can be rotated against it's seat.
Best,
D
See the attached pic. I can't tell for sure from your pic but you appear to have a six cylinder valve which is stepped, as you can see. If we indeed are discussing the BJ7, this would be the correct valve.
We are still not sure that this valve is completely seating. To check, coat the valve and the seat with layout dye, rotate the valve against the seat & examine both for a full circle marking that shows a complete seat all around.
Not easy to do this in that small hole but with good lighting & the valve on the end of a tightly fitting stick the valve can be rotated against it's seat.
Best,
D
Attachments
Bob_Spidell
Yoda
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OK, I give up ... where did y'all find a 0.360" (or, for that matter, a 9.144mm) shim suitable for use behind the oil relief valve spring?
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The first try of 0.160" was a convenient hex head bolt with shank that fit inside the spring to guide it & a head thickness of 0.160".
The second try was a piece of metal that I machined on my lathe. It had a short guide step which fit inside the spring & a larger diameter step of 0.360" long & diameter same as the outside of the spring. A step of more than 0.360" long caused spring coil bind before the plunger was adequately released. This on a BN2. See pic:
The six cylinder might require something other than 0.360" long. A bit of experimenting might be required. If you get the spacer too long, the spring will coil bind & the oil pressure will not be released & the pressure will go sky high. If the spring guide step is too long the same thing will happen. It just took a little trial & length adjusting.
As I mentioned, strangely, the shorter spacer did not increase the pressure enough to fully seat the valve but the longer spacer did. Don't know exactly what was going on in there.
D
The second try was a piece of metal that I machined on my lathe. It had a short guide step which fit inside the spring & a larger diameter step of 0.360" long & diameter same as the outside of the spring. A step of more than 0.360" long caused spring coil bind before the plunger was adequately released. This on a BN2. See pic:
The six cylinder might require something other than 0.360" long. A bit of experimenting might be required. If you get the spacer too long, the spring will coil bind & the oil pressure will not be released & the pressure will go sky high. If the spring guide step is too long the same thing will happen. It just took a little trial & length adjusting.
As I mentioned, strangely, the shorter spacer did not increase the pressure enough to fully seat the valve but the longer spacer did. Don't know exactly what was going on in there.
D
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chicken
Jedi Trainee
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Dave
Mine sort of looks like the 6 cylinder one although it is tapered all the way back from the stop end to the outside edge of the piston, i have ordered another one from my ususal supplier to see if there is a difference between them (i'm hoping initially there is and this may be my problem) if not i will check the seat and try the shimming.
Rob
Mine sort of looks like the 6 cylinder one although it is tapered all the way back from the stop end to the outside edge of the piston, i have ordered another one from my ususal supplier to see if there is a difference between them (i'm hoping initially there is and this may be my problem) if not i will check the seat and try the shimming.
Rob
Bob_Spidell
Yoda
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Thanks, Dave. I'll see what I can come up with, my BJ8 always has low pressure (at hot idle especially). Think this is typical for the later pumps.
Ed_K
Jedi Knight
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I had lower pressure than I liked on my 65 BJ8. I pulled it apart and found that the spring had compressed. The shop manual states it is supposed to be a specific length and mine was significantly shorter than specified. I stretched the spring to the correct length and reinstalled it, then pulled it back out and found it had collapsed back to the shorter length. I stretched it a 2nd time, this time to a longer length than specified and reinstalled it. I pulled it back out and found it had collapsed to the correct length as specified by the shop manual. It appears to me that the spring had lost it's original heat treating if it ever had any, and had developed a " memory " of sorts. It wanted to stay at the specified length but only after it was stretched further than it's original length and allowed to compress back. It also had another " memory " of sorts at the shorter than specified length probably from years of being compressed.
I ordered a replacement spring from one of our usual suppliers only to find that it also was shorter than specified by the shop manual. Unlike my original spring, the new one stayed put at the correct length after I stretched it out a little. I kept my original spring installed and my oil pressure is 60 lbs cold and 40 lbs hot at a fast idle. It was never that good either cold or hot before I stretched my original spring back to the correct length. If the pressure ever gets low again, I'll try the new spring first.
I ordered a replacement spring from one of our usual suppliers only to find that it also was shorter than specified by the shop manual. Unlike my original spring, the new one stayed put at the correct length after I stretched it out a little. I kept my original spring installed and my oil pressure is 60 lbs cold and 40 lbs hot at a fast idle. It was never that good either cold or hot before I stretched my original spring back to the correct length. If the pressure ever gets low again, I'll try the new spring first.
chicken
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Dave
Yes my car is a BJ7 and has the stepped valve. I tried shimming the valve and this did bring the pressure up a couple of lb/"2 to about 20, so nothing great and this was with a 9mm shim, i didn't like to go anymore but it may be worth a try, perhaps upto 12mm.
Is there a way of blanking of the return valve, i.e to stop oil returning past the pressure relief valve and down the drain holes as then i could quickly assertain if it is indeed the valve not seating which then may have to be reamed out.
Yes my car is a BJ7 and has the stepped valve. I tried shimming the valve and this did bring the pressure up a couple of lb/"2 to about 20, so nothing great and this was with a 9mm shim, i didn't like to go anymore but it may be worth a try, perhaps upto 12mm.
Is there a way of blanking of the return valve, i.e to stop oil returning past the pressure relief valve and down the drain holes as then i could quickly assertain if it is indeed the valve not seating which then may have to be reamed out.