My oil pressure is a little low and I suspected the oil pressure relief valve/regulator.
I fixed a piece of acrylic to the oil filter housing and pressurized the whole thing with an air compressor. A glove is fitted to the sump return hose to show when the valve opens. (The glove has a hole in it to prevent blow-up.)
Link to movie: https://youtu.be/_upJus7w4LY
The oil regulator does not seal internally, a lot of air passes the oil regulator this way.
As shown in the movie the regulator opens at 40 psi.
(Needle is between red 30 and 60 PSI mark or 2 and 4 BAR mark in black).
I think the pressure relief valve is ok according to this test.
But:
Wil the pressure relief valve act the same on hot oil.
The pressure relief valve does not seal in the oil filter house completely. Wil this influence the oil pressure?
On some engines, the OPRV is there to simply prevent a maximum design value that would risk blowing out the weakest link, typically the oil filter, and typically on cold startup. More sophisticated systems could use the OPRV to manage the oil pressure at a target value. My educated guess would be the former (limits max design pressure) as I canāt think that oil pressure needs to be managed at a certain value. Hopefully someone more educated on the XK engine will chime in.
From memory you can increase the spring pressure to up the OP slightly if you feel you need to but 40psi is IMHO adequate. Sometimes its beneficial to give the ball a bit of a tap to āseatā it to make sure that it is sealing as good as it can, also make sure the ball is free from any imperfections.
The valve is probably working OK. I would not trust the pressure gauge reading that low on the scale. Itās in the āmudā a technical termā¦ How many miles on the engine? It could be the bearings and/or oil pump are worn a bit. What oil weight are you running? If you are trusting readings from the stock electrical gauge then they could also be suspect. Try feeding the electrical sensor with air pressure and see how accurate it is. On mine, I calibrated the sensor and matching gauge at 40PSI. It was not so linear elsewhere.
I think the relief valve should open about 55 or 60 PSI.
My guess is that when the spring that keeps the valve closed is hot, it will open at a slightly lower psi - very slightly
When I last looked at the innards, it was not a sealing ball, but a plunger that sealed a hole. Mine had imperfections and was definitely leaking so I had a machine shop skim the plunger where it seats
I had low pressure for several years. It wasnāt the sender. Couldnāt really see any problem with either the plunger or the spring. Finally this spring simply ordered both new. Didnāt cost much. Oil pressure has been fine ever since
As far as I can see, @Hedde doesnāt tell us what year E-Type he has. There are two different models of pressure relief valve. The S1s and S2 up to engine numbers 7R.2297 and 7R.35582 used a multi-piece valve that fitted behind the spigot that leads to the sump. S2 engines beyond the above numbers used a single piece valve that screws into the base of the oil pressure housing separate from the spigot that goes to the sump. Whether this makes a haāporth of difference, I donāt know, but it would be good to know which version the OP has.
Hi David,
I forgot to mention. It is the S2 version, so a sealed relief valve that is not servicable.
ThatĀ“s the problem, the part is no longer available.
The former multi piece valveĀ“s are available as is the later XJ6 S3. Both do not fit my S2 filter house.
Regards,
Hedde
Thanks Hedde. You never mentioned what you meant byā¦
What do you consider to be low? It seems to me that if your pressure relief valve is not opening below 40psi it is not the source of any low oil pressure problems. By the way, I really liked your experimental set up - very innovative!
Thanks for your thoughts. My oil pressure is arround 30 when cold, I thought a little low. When hot it drops to almost zero on the dash meter. (I know I cant trust these.)
I hoped it was the oil relief valve. When I closed the oil to sump hose the oil pressure went up to 60 psi so this was my best bet. (Because I have two oil filter heads I started expirimenting to pinpoint the problem. Mayby I have to retry some of the expiriments. I have two e-types, exchanged engines, long story but 1 of them is now matching numbers. I canĀ“t recall what I did to which engine. Otherone is ok, have good oil pressure etc.)
The engine is refreshed with new bearings and the head is professionaly rebuild. I could not find any indications why something in the engine was totaly wrong. Next try wil be the oilpump.
Is it true the S2 oil pressure relief valve is now longer available. SNG does not have them, Rob Beere does not have a solution (asked them).
Has anybody succesfully opened and refurbished a S2 relief valve?
Regards,
Hedde
That certainly sounds like a pressure relief valve problem. Have you removed the valve from the oil filter head and inspected it? Debris can get caught in it and prevent it closing fully like this:
I have the latter sealed version of the bypass valve and when tested with air pressure opens up at 60 psi. I thought I saw a replacement available from Guy Broad in the UK?
I checked the site again and could not find it, it may be worth a try to email them?
Glenn
Hedde Iām not familiar with Ser II filter blocks - but Iām familiar with Ser I and a lot of XJ6 filter blocks with the spin on filter. If you look at the bewildering number of gaskets for the blocks that you get in a gasket set itās apparent there are a bewildering number of internal set ups for the blocks. Some are full flow some are partial flow for example all set up by the partitions in the blocks. My first reaction to reading about your problem was - have you installed the correct gasket between the block and the filter block. If you have leakage between the chambers you may have low oil pressure.
