Updated oil pump relief spring

[Chip-mk1]

I don't think they are designed to run exactly a certain amount of oil pressure , otherwise they wouldn't need a pressure relief valve , personally I think they will run more pressure , and is capped on the valve , we'll soon see

sorry my reply to this I somehow posted in a thread about starting trackdays by mistake:


The valve is an excess pressure relief valve, designed to open when there is an excess of oil pressure to allow the pressure not to increase anymore.

If its opening at 3 bar, there is a fault with it in the first place IMHO

 

[ian-speedy]

yes your right , and that pressure is what Renault have decided is right for the use , ie , a standard car , that doesn't mean the pump is as you say made exactly to only run that pressure , each engine will have different requirements as no two engines will leakdown the same I bet , so the pump makes more pressure than needed and the relief valve bleeds off the excess , but by shimming the pump WILL increase the oil pressure in this engine.

Where has 3 bar come from ? my car was 3.8 hot when running right , which I have been told is about standard oil pressure.

I wonder how much pressure the standard pump would make if it didn't bleed off any excess

 

[Chip-mk1]

yes your right , and that pressure is what Renault have decided is right for the use , ie , a standard car , that doesn't mean the pump is as you say made exactly to only run that pressure , each engine will have different requirements as no two engines will leakdown the same I bet , so the pump makes more pressure than needed and the relief valve bleeds off the excess , but by shimming the pump WILL increase the oil pressure in this engine.

Where has 3 bar come from ? my car was 3.8 hot when running right , which I have been told is about standard oil pressure.

I wonder how much pressure the standard pump would make if it didn't bleed off any excess

The pump itself doesnt make pressure as such it makes flow, and then the differential between this flow and what the engine haemorages is what determines the pressure, and im sure that with cold oil and no relief valve opening that flow would be resulting in 200psi plus on cold oil, so the pump is no doubt "capable of making" 200+ psi

BUT when the relief valve spring is already holding it shut like I expect it to be at only 3 bar of pressure (the 3 bar mentioned was in the first post) I dont believe that holding it more firmly will result in a significant change in pressure as such a tiny amount is going to be going past it anyway (even when shut if you want to get really detailed about it some oil will still seep past but its a very small amount in most cases)

 

[ian-speedy]

Yes I know how a pump works , basically on the similar lines of a turbo , a turbo moves air and if it can't move all the air it builds up pressure and the wastegate bleeds off the excess , same as an oil pump , I mean oil mover , lol , see if I prove you wrong then when I mess about with shims on mine :rasp:

 

[Chip-mk1]

Yes I know how a pump works , basically on the similar lines of a turbo , a turbo moves air and if it can't move all the air it builds up pressure and the wastegate bleeds off the excess , same as an oil pump , I mean oil mover , lol , see if I prove you wrong then when I mess about with shims on mine :rasp:

And much like a turbo wastegate, if you are already at far less pressure than its set for (so its shut) and are running out of airflow to make more, than putting a stronger spring in the gate wont help.

I really hope you prove me wrong too as I would love it if the oil pressure problems when hot on these engines could be solved by a simple shim in the pump!

 

[ian-speedy]

ok lets forget about 3 bar for the Minute then as they run more pressure than that , speaking to various people they all say the pressure mine was running , 3.8 is about normal , so my pump must have been making more than that to hold it , if not the pressure would have dropped with revs , even a 1000 revs , which it didn't , it was dropping at about 2k revs , but you would expect that , so if its making max pressure to open the relief valve at say 3k revs , then it will be making considerably more at 7k revs , but is being bled off , so if you shim it up to make the spring stronger then it can only make more oil pressure.

​I realise you will get some leakage in the pump , and especially on the valve , as it has no seal

 

[Chip-mk1]

ok lets forget about 3 bar for the Minute then as they run more pressure than that , speaking to various people they all say the pressure mine was running , 3.8 is about normal , so my pump must have been making more than that to hold it , if not the pressure would have dropped with revs , even a 1000 revs , which it didn't , it was dropping at about 2k revs , but you would expect that , so if its making max pressure to open the relief valve at say 3k revs , then it will be making considerably more at 7k revs , but is being bled off , so if you shim it up to make the spring stronger then it can only make more oil pressure.

​I realise you will get some leakage in the pump , and especially on the valve , as it has no seal

Well it certainly wont make less, so no harm in trying it for your application.

Maybe the very high cold pressure isnt a sign of the spring being strong enough but a sign that the relief valve is too small and cant flow enough away even when open, seems unlikely to me but would certainly be great if your shims prove that to be the case (ie that it achieves the holy grail of more hot pressure and no more cold pressure!)

 

[ian-speedy]

And much like a turbo wastegate, if you are already at far less pressure than its set for (so its shut) and are running out of airflow to make more, than putting a stronger spring in the gate wont help.

I really hope you prove me wrong too as I would love it if the oil pressure problems when hot on these engines could be solved by a simple shim in the pump!

yes but no turbo runs with the wastegate shut all the time , you will get turbo's running out of puff on boosted cars on standard turbo's , my GTR is 600 hp and to go to 750 I need new turbo's lol , but they will produce more boost midrange than needed so is bled off , so putting a stonger spring even on a standard turbo would produce more pressure low down , I agree it would be pointless higher up the revs as it won't produce enough boost to open the wastegate

 

[ian-speedy]

Well it certainly wont make less, so no harm in trying it for your application.

Maybe the very high cold pressure isnt a sign of the spring being strong enough but a sign that the relief valve is too small and cant flow enough away even when open, seems unlikely to me but would certainly be great if your shims prove that to be the case (ie that it achieves the holy grail of more hot pressure and no more cold pressure!)

Surely you can control the difference in hot and cold pressure with a better choice of oil , if its getting too thin when hot making a big difference in pressure , then a thicker oil would reduce that gap considerably , tbh , I don't see a big difference between hot and cold temps in mine , maybe half a bar

 

[Chip-mk1]

yes but no turbo runs with the wastegate shut all the time , you will get turbo's running out of puff on boosted cars on standard turbo's , my GTR is 600 hp and to go to 750 I need new turbo's lol , but they will produce more boost midrange than needed so is bled off , so putting a stonger spring even on a standard turbo would produce more pressure low down , I agree it would be pointless higher up the revs as it won't produce enough boost to open the wastegate

Indeed, once the wastegate is shut, thats it no more power available, same thing with the oil pressure relief valve, and at the OP's 3 bar, I am confident its shut so a stronger spring wont help him (he has some other issue) but hopefully in your case it will prove that the valve opens at least than the pressure you have currently, especially as in your case you dont have the additional flow through the dephasor that most of us have if you are on non VVT cams.

 

[Chip-mk1]

Surely you can control the difference in hot and cold pressure with a better choice of oil , if its getting too thin when hot making a big difference in pressure , then a thicker oil would reduce that gap considerably , tbh , I don't see a big difference between hot and cold temps in mine , maybe half a bar

Yes I agree, I tend to run 10W50 or 10W60 oil for this reason.

 

[EVOgone]

Shimming the pump up hot oil pressure on mine from 4 to 6 bar hot. Cold idle did increase but 6 bar cold idle and the car was always warmed up before use so no issue. I don't see any reason why it wouldn't work. Even the remaultsport manuals say the gp A spring give 1-1.5 bar oil pressure increase.

 

[EVOgone]

Oil was always millers 10/40

 

[ian-speedy]

Shimming the pump up hot oil pressure on mine from 4 to 6 bar hot. Cold idle did increase but 6 bar cold idle and the car was always warmed up before use so no issue. I don't see any reason why it wouldn't work. Even the remaultsport manuals say the gp A spring give 1-1.5 bar oil pressure increase.

Did you just change the spring on yours , or did you shim it up , if you shimmed it , what thickness did you fit to get to 6 bar ?

​Cheers Ian

 

[EVOgone]

I will let you know early next week when the pumps off.

 

[Chip-mk1]

Shimming the pump up hot oil pressure on mine from 4 to 6 bar hot. Cold idle did increase but 6 bar cold idle and the car was always warmed up before use so no issue. I don't see any reason why it wouldn't work. Even the remaultsport manuals say the gp A spring give 1-1.5 bar oil pressure increase.

Sounds very promising then

 

[hissingsid]

What happened to this, did the shim make a difference or not ?

 

[Laine_16v]

I shimmed my F7 pump years ago, it worked well. From memory i used 4 x M5 washers inside the metal cup that sits on the reataining "R" clip. Cant remember the exact readings but it was a healthy boost.

 

[hissingsid]

So I have shimmed the spring with 2 washers, fresh pump, and a 4mm restrictor in the oil way to the head, tick over oil pressure when warm is now 25psi (was 16psi) and above 6000 rpm the oil pressure is no 80psi (was 45psi) so I feel more confident, It may of been my old pump, but I have never seen these figures as high.

 

[Chip-mk1]

Sounds like your old pump had a problem to only make those numbers. I've seen standard pumps making roughly what you are getting now, although without temperature and viscosity info it's utterly pointless comparing my results to yours etc.

 

[EVOgone]

Mine was from France and has a modified Spring and shows same has Hissingsids with Millers 10/40. Cold oil pressure was quite high and needed to warm up before use as the oil pressure would get to 100psi.

 

[hissingsid]

I'm using 5/40 total oil. same here with the cold pressure having to be careful not to get 100 psi when cold.