TR4 oil relief valve again

[MKTR]

Hi all,

I have searched the forum and not found the answer to my issue. 

Whilst investigating a slight leak around my spin on oil filter I decided to check the relief valve operation. It has been fine for many years but now the pressure just keeps rising with revs and does not find the relief spot. When I back the valve screw off the pressure does drop but still does not find its maximum to relieve.  Any thoughts before I disassemble the whole lot?

Some have suggested replacing spring and ball anyway in case of wear.

Many thanks 

Mark

[Waldi]

What is the maximum pressure on the gauge now, cold and hot?

When you are convinced it is the pressure control valve, check for signs of sticking: after removal of the cap, move the plunger in and out and feel if there is any sticking. Also, turn it by hand. 

If the pressure was responding ok, there is likely no extra ring inserted under the spring in an attempt to raise the pressure.

My new valve-plunger (TR6) was sticking, so I lapped it to remove any high points in bore and on plunger. I did this by hand, using an aluminium polish, nothing special.

The valve is there for a purpose, it limits the oil pressure. A too high pressure can damage the pump and oil seals, so your leakage may well be related to this.

Waldi

[MKTR]

Thanks Waldi - I think the TR6 has a different valve type, though the concept of stick parts may be something for me to look into.

Mark

[BlueTR3A-5EKT]

Probably going to be the spring jammed over against the inside of the adjuster.  
Odd as they usuallly jam open.

Unscrew the entire thing and strip and inspect on the bench.

 

[MKTR]

Hi Peter,

Used lunchtime to strip the reflief valve:

• No debris found
• Ball bearing seems fine and not scored 
• The spring is straight and intact but has some worn areas on the edge

All cleaned and returned to car.  Idles around 45lb and I can get 70lb at 2000 revs but it still keeps rising with more revs.  I will try again to re-adjust, but perhaps a new spring is needed?

Do I also need to check items 4 and 5 in the manual or are they left alone?

 

Mark

[BlueTR3A-5EKT]

5 minutes ago, MKTR said:

Hi Peter,

Used lunchtime to strip the reflief valve:

• No debris found
• Ball bearing seems fine and not scored 
• The spring is straight and intact but has some worn areas on the edge

All cleaned and returned to car.  Idles around 45lb and I can get 70lb at 2000 revs but it still keeps rising with more revs.  I will try again to re-adjust, but perhaps a new spring is needed?

Do I also need to check items 4 and 5 in the manual or are they left alone?

 

Mark

Items 4-5 are the blocked filter bypass valve.  Only comes into play if the filter element is blocked so should not do anything to your oil pressure if the filter is ok.

New spring and ball sound like a good move.   Just to eliminate them.

When you say pressure rises after 2000 rpm how high does it rise to at 3k then 4k rpm.?

[MKTR]

1 hour ago, BlueTR3A-5EKT said:

Items 4-5 are the blocked filter bypass valve.  Only comes into play if the filter element is blocked so should not do anything to your oil pressure if the filter is ok.

New spring and ball sound like a good move.   Just to eliminate them.

When you say pressure rises after 2000 rpm how high does it rise to at 3k then 4k rpm.?

I got to 85lb at 3500 revs then stopped pushing it.

[RobH]

4 minutes ago, MKTR said:

I got to 85lb at 3500 revs then stopped pushing it.

Was the oil fully up to working temperature? 

[BlueTR3A-5EKT]

14 minutes ago, RobH said:

Was the oil fully up to working temperature? 

What oil is being used?.

Is the spin on oil filter element the correct one?

[MKTR]

46 minutes ago, BlueTR3A-5EKT said:

What oil is being used?.

Is the spin on oil filter element the correct one?

Hi Peter,

I am told that the operating temperature is a red herring as the valve should operate at a set pressure regardless of hot or cold.

Halfords classic oil used for many years and spin on correct as per previous forum discussions.

All seemd to be working OK a few months ago with the same set up and I have not done any work to impact on the oil system.  Just annoying me now, so Have ordered new spring and ball bearing to see what happens.

Mark

[BlueTR3A-5EKT]

My car's oil pressure drops the hotter the engine gets. This is using Motul or Millers or Penrite 20/50 weight oil.

Up to 90 psi at 3500 rpm when just started and the engine is not up to temp on the water ie stone cold

Then drops to

Between 65-70 at 3500 when good and hot after a fast motorway run on a hot summers day.  60ish at 2000

[monty]

1 hour ago, RobH said:

Was the oil fully up to working temperature? 

Mine starts @ around 80/85 when cold but quickly settles to around 70/75 once engine is warmed up with a tickover pressure of around 20. Always thought that the 20 to 70 are the kind of figures to be aimed for. Different oils have never really made the figures change much.

[BlueTR3A-5EKT]

33 minutes ago, monty said:

Mine starts @ around 80/85 when cold but quickly settles to around 70/75 once engine is warmed up with a tickover pressure of around 20. Always thought that the 20 to 70 are the kind of figures to be aimed for. Different oils have never really made the figures change much.

The removal of my oil cooler did change the hot oil pressure.   Down by upto 10 psi when the engine was  toasty hot.   Think Motorway run on hot day then parked on M25 for 1/2 hr.

[John Mellor]

Driving the 4 across central Spain got 30 psi on tick over and 70 above 1000 rpm. Ambient temp in high 30s

[MKTR]

Thank you to everyone that has contributed.

I am not concerned about the oil pressure I can achieve hot or cold, or tick over or fast speed (I don't think) but I am worried that the pressure does not stablise/relieve once it has reached the maximum set at 2000-2500 revs as per the manual.

Logic is leading me to consider that the ball bearing is not rising smothly enough to reach the point where oil can bypass it in the housing. New parts will hopefully rule that out soon.

Regards,

Mark

[BlueTR3A-5EKT]

2 hours ago, MKTR said:

Thank you to everyone that has contributed.

I am not concerned about the oil pressure I can achieve hot or cold, or tick over or fast speed (I don't think) but I am worried that the pressure does not stablise/relieve once it has reached the maximum set at 2000-2500 revs as per the manual.

Logic is leading me to consider that the ball bearing is not rising smothly enough to reach the point where oil can bypass it in the housing. New parts will hopefully rule that out soon.

Regards,

Mark

Thoroughly clean the inside of the housing that the ball goes in.

[Ian Vincent]

I recently replaced my ball and spring prior to a long drive across Europe (in some exceedingly warm weather) and I had plenty of time to ‘enjoy’ the behaviour of the oil pressure gauge.  When starting in the morning with everything cold, the oil pressure would rise to about 55 and stay there irrespective of revs, then as the engine warmed up the oil pressure would rise to about 70 at 2000 rpm and up to 90 at about 2500/3000 rpm.  As the oil started to get thoroughly warmed up the pressure would drop back and after say an hour of running on the autobahn the pressure at 2500/3000 would be about 60 psi but then if I let the revs drop to 2000 the pressure would rise to about 70.  At idle (700rpm) it would be about 20 psi.

my assumption was that at 2000 rpm the pressure relief valve was closed but that once it cracked open to relieve the pressure the resulting ‘gap’ allowed too much oil through to maintain the pressure at 70.

The oil pump is a NOS barrel inside my original pump body with the tolerance on the end face adjusted by rubbing down on a flat plate.

And while I had the sump off, I replaced the B/E shells and checked the tolerances with plastigage, they were well within the WSM figures.

I should add that when I replaced the spring, I noted the wear along the outer edges of the old one and inserted a length of 1/4 rod inside the new one to stop it buckling.

My car is a TR3a but that shouldn’t matter to this discussion.

Rgds Ian

Edited August 10, 2024 by Ian Vincent

[Ralph Whitaker]

4 minutes ago, Ian Vincent said:

I recently replaced my ball and spring prior to a long drive across Europe (in some exceedingly warm weather) and I had plenty of time to ‘enjoy’ the behaviour of the oil pressure gauge.  When starting in the morning with everything cold, the oil pressure would rise to about 55 and stay there irrespective of revs, then as the engine warmed up the oil pressure would rise to about 70 at 2000 rpm and up to 90 at about 2500/3000 rpm.  As the oil started to get thoroughly warmed up the pressure would drop back and after say an hour of running on the autobahn the pressure at 2500/3000 would be about 60 psi but then if I let the revs drop to 2000 the pressure would rise to about 70.  At idle (700rpm) it would be about 20 psi.

my assumption was that at 2000 rpm the pressure relief valve was closed but that once it cracked open to relieve the pressure the resulting ‘gap’ allowed too much oil through to maintain the pressure at 70.

The oil pump is a NOS barrel inside my original pump body with the tolerance on the end face adjusted by rubbing down on a flat plate.

And while I had the sump off, I replaced the B/E shells and checked the tolerances with plastigage, they were well within the WSM figures.

I should add that when I replaced the spring, I noted the wear along the outer edges of the old one and inserted a length of 1/4 rod inside the new one to stop it buckling.

My car is a TR3a but that shouldn’t matter to this discussion.

Rgds Ian

Mine does that, I have noticed that at certain revs the pressure drops to about 55psi, but as the revs drop it will go back up to 70, and like you I decided it was probably when the pressure relief valve opened that the pressure drops. Could this be a sign of wear in the valve or spring.

Unlike you, my gauge registers 70/75  from cold even at idle, but as the oil heats up it eventually drops to 20 psi at idle.

Ralph

[MKTR]

This is an interesting conversation, with such varied oill pressures and factors affecting things.

I have replaced the ball and the spring today and cannot see any great difference whether hot or cold. Initially idling at 45-50lb and up to 75 at 2500 revs, which seems lovely to say oil pump and bearings are working fine.  Drops a bit when fully warmed up but not by much.

Have I got the wrong end of the stick from the manual - I am expecting that, with my current setting, any revs over 2500 still max out at 75lb because the pressure relief valve should kick in. Am I wrong?  If not what else can I check that would stop the pressure relief?

Mark

[Lebro]

The relief valve is a crude device, it won't "lock" the pressure at a fixed value, It can only partialy control it. The standard setting when warm is 70PSI at 2000 RPM, but pressure will increase above that when revs are raised, just not nearly as much as if the PRV was not there.

Bob

[Tr4aJim]

Mark, have you also checked the accuracy of the oil pressure gauge? A while back I found that the gauge on my 4A was reading about 5lbs low.

Jim 

[MKTR]

On 8/13/2024 at 5:28 PM, Lebro said:

The relief valve is a crude device, it won't "lock" the pressure at a fixed value, It can only partialy control it. The standard setting when warm is 70PSI at 2000 RPM, but pressure will increase above that when revs are raised, just not nearly as much as if the PRV was not there.

Bob

Thanks Bob

That makes sense now.  Just a shame that this is not refelcted in the manuals.  I had assumed that the set spring/ball setting would only allow a certain oil pressure and no more - never assume hey.

I think all is OK as it is working as expected as I get the required levels at 2000 RPM.  Time will tell.

Mark