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[cem_devecioglu]

its the main bearings on the crank that carry the pressure Mark, if they are worn the engine will have low oil pressure when hot,its possible to change them with the engine in the car , problem is knowing which size vxhall used when building the lump!! many had production tolerance problems and were resized at the factory!!
the only really difficult one is the gearbox end as access to the main bearing is not possible without dropping the gearbox although you can change the bottom half!!
it will probably run for years like it if its only on tickover its pressure is low, whats the pressure reading at 2.5k rpm?

 
 
 
ps: Omegatoy, referring to an old thread to what oil to use in manual gearbox, you were right (I finally realized why) EP 80 which I use was ok for summer but too thick for cold winter months..first 2 gears very hard when tempertures below 0 and car is cold.. so I will use sae 75w-90 next winter..

[Omegatoy]

its the main bearings on the crank that carry the pressure Mark, if they are worn the engine will have low oil pressure when hot,its possible to change them with the engine in the car , problem is knowing which size vxhall used when building the lump!! many had production tolerance problems and were resized at the factory!!
the only really difficult one is the gearbox end as access to the main bearing is not possible without dropping the gearbox although you can change the bottom half!!
it will probably run for years like it if its only on tickover its pressure is low, whats the pressure reading at 2.5k rpm?

More than 1k, its way up 50/60 psi, rising further with revs.

in that case my guess would be stuck or sticky relief valve in the pump!! but if it getting that high the lifters should be full of oil and not making any noise at all unless they are very dirty and sludged up!!

[TheBoy]

in that case my guess would be stuck or sticky relief valve in the pump!!

That was my suspicion...

[Omegatoy]

its the main bearings on the crank that carry the pressure Mark, if they are worn the engine will have low oil pressure when hot,its possible to change them with the engine in the car , problem is knowing which size vxhall used when building the lump!! many had production tolerance problems and were resized at the factory!!
the only really difficult one is the gearbox end as access to the main bearing is not possible without dropping the gearbox although you can change the bottom half!!
it will probably run for years like it if its only on tickover its pressure is low, whats the pressure reading at 2.5k rpm?

 
 
 
ps: Omegatoy, referring to an old thread to what oil to use in manual gearbox, you were right (I finally realized why) EP 80 which I use was ok for summer but too thick for cold winter months..first 2 gears very hard when tempertures below 0 and car is cold.. so I will use sae 75w-90 next winter..

good news Cem, straight 80 is very thick when cold, but the 75/90 is just right in the cold temps!!
glad you noticed a difference though or i could be accused of not knowing what im talking about lololol

[cem_devecioglu]

its the main bearings on the crank that carry the pressure Mark, if they are worn the engine will have low oil pressure when hot,its possible to change them with the engine in the car , problem is knowing which size vxhall used when building the lump!! many had production tolerance problems and were resized at the factory!!
the only really difficult one is the gearbox end as access to the main bearing is not possible without dropping the gearbox although you can change the bottom half!!
it will probably run for years like it if its only on tickover its pressure is low, whats the pressure reading at 2.5k rpm?

 
 
 
ps: Omegatoy, referring to an old thread to what oil to use in manual gearbox, you were right (I finally realized why) EP 80 which I use was ok for summer but too thick for cold winter months..first 2 gears very hard when tempertures below 0 and car is cold.. so I will use sae 75w-90 next winter..

good news Cem, straight 80 is very thick when cold, but the 75/90 is just right in the cold temps!!
glad you noticed a difference though or i could be accused of not knowing what im talking about lololol

I know your knowledge level.. and you were right..
 
 

[tunnie]

Yeah as TB says, pressure shoots up with any amount of revs. Topped out at around 80Psi near the red line.

It's drives fine day to day, only notice it of get out with engine running.

Just sounds awful

How long to strip down & replace the relief valve? (not me someone who knows what they are doing)

[VXL V6]

Yeah as TB says, pressure shoots up with any amount of revs. Topped out at around 80Psi near the red line.

It's drives fine day to day, only notice it of get out with engine running.

Just sounds awful

How long to strip down & replace the relief valve? (not me someone who knows what they are doing)

You don't, you run something in the oil that disolves the sticky crud that's attached to it... however, if I mention the words i'm likely to get shot down in flames for eternity!

[TheBoy]

Yeah as TB says, pressure shoots up with any amount of revs. Topped out at around 80Psi near the red line.

It's drives fine day to day, only notice it of get out with engine running.

Just sounds awful

How long to strip down & replace the relief valve? (not me someone who knows what they are doing)

You don't, you run something in the oil that disolves the sticky crud that's attached to it... however, if I mention the words i'm likely to get shot down in flames for eternity!

He has already tried a strong flush...

[tunnie]

Yeah, used some tecsol that Omegatoy gave me years ago, strong stuff. No effect.

[Omegatoy]

Yeah, used some tecsol that Omegatoy gave me years ago, strong stuff. No effect.

lol you said earlier oil now stays clean, but it wont disolve a lump of something other than lumpy oil,
my bet is the relief valve has a score in the bore and is sticking, flush wont solve that!! needs to be removed and ball and bore polished till it runs smooth again!!

[tunnie]

Yeah, used some tecsol that Omegatoy gave me years ago, strong stuff. No effect.

lol you said earlier oil now stays clean, but it wont disolve a lump of something other than lumpy oil,
my bet is the relief valve has a score in the bore and is sticking, flush wont solve that!! needs to be removed and ball and bore polished till it runs smooth again!!

Is that an offer? When you back in the UK?

[VXL V6]

Yeah as TB says, pressure shoots up with any amount of revs. Topped out at around 80Psi near the red line.

It's drives fine day to day, only notice it of get out with engine running.

Just sounds awful

How long to strip down & replace the relief valve? (not me someone who knows what they are doing)

You don't, you run something in the oil that disolves the sticky crud that's attached to it... however, if I mention the words i'm likely to get shot down in flames for eternity!

He has already tried a strong flush...

Ah sorry, must read the entire thread next time! 

[Kevin Wood]

Pressure relief valve is in a bore in the top of the oil pump covered by a plug that is easily accessible with the cam belt cover off, IIRC, so probably not a bad job to pull it out and debur the piston and bore.

Agreed, that sounds like the most likely problem. It's probably sticking slightly and not fully seating when the engine returns to idle. Although I'd expect much lower pressure at idle, that's dropping a little too much, IMHO.

VX specification is 1.5 BAR at idle (21 PSI) and I'd expect an engine in good condition to be well clear of the minimum.

[JamesV6CDX]

Confirm this can just be done with cambelt cover off?

Never done one, but if so, I'd be happy to have a look sometime Mark...

[tunnie]

Pressure relief valve is in a bore in the top of the oil pump covered by a plug that is easily accessible with the cam belt cover off, IIRC, so probably not a bad job to pull it out and debur the piston and bore.

Agreed, that sounds like the most likely problem. It's probably sticking slightly and not fully seating when the engine returns to idle. Although I'd expect much lower pressure at idle, that's dropping a little too much, IMHO.

VX specification is 1.5 BAR at idle (21 PSI) and I'd expect an engine in good condition to be well clear of the minimum.

Thanks Kevin, very interesting. It was a tad worrying seeing it drop to around 17 Psi, but as mentioned before, just any amount of revs pressure appears good.

If its just the belt cover off, then that sounds good. I had visions of a large strip down to access.

Confirm this can just be done with cambelt cover off?

Never done one, but if so, I'd be happy to have a look sometime Mark...

Thanks for the offer James, I've never done anything related to the oil pump before. Be a good excuse for a curry too?

Are we looking at just cambelt cover off? Belt stays on?