Low oil pressure when hot

[boggie]

Hi All,

 

I have finally found a restoration car for my Dad. The first problem to solve is the oil pressure. the previous owner tells me that it is fine when cold but once the engine is warm it loses pressure. Anyone have any ideas please?

 

Thanks

[67_gt6]

Hi

 

Depends what he means. They all do that as the oil heats up, however once the oil is hot you should be getting about 15-20 PSI at 800RPM and 65-70 at 2000RPM+

 

If you aren't, it could be:

 

oil pressure relief valve stuck open, remove and clean

oil too thin, use correct viscocity oil

problem with oil pressure gauge, substitute known good to test

big end clearances too big - drop sump and replace

 

Andy

[TR 2100]

I have finally found a restoration car for my Dad. The first problem to solve is the oil pressure.

the previous owner tells me that it is fine when cold but once the engine is warm it loses pressure.

Anyone have any ideas please?

 

Hi boggie,

 

Sounds like my very first TR, a TR3. Bought after a quick blast, when of course

the oil pressure was OK.

 

If you get 50psi at 2000rpm hot, you don't have anything to worry about.

Don't expect 65-70 hot. But be warned, it takes a long time for the OIL to

get hot.

 

Finding the problem can be difficult. I rebuild the engine, checked out everything

on the oil filter relief valve and oil pump and I never did solve the problem before

some clown drive into the back of me a wrote off the car.

Only thing I had left to check was worn bushes on the rocker shaft - oh yes, and

camshaft bearings. I don't think they were replaced during the engine

rebuild.

 

AlanR

[boggie]

Thanks All,

 

I assume if the problem is anything serious such as big ends then the engine would be knocking? If it is the rocker bushes would it audiable? I am hoping the pressure relief is the problem as it is a relatively easy fix. How big a job is it to access?

[TR 2100]

I assume if the problem is anything serious such as big ends then the engine would be knocking?

If it is the rocker bushes would it audiable?

I am hoping the pressure relief is the problem as it is a relatively easy fix. How big a job is it to access?

 

No noises usually mean not a major problem as in a full rebuild being necessary,

though camshaft bearings can turn into almost the same.

Rocker bushes gone is one of the later items to check, and no, you wouldn't

necessarily hear anything as it's the rocker clearances on the valve that make

the noise.

 

You may get lucky and find it's the pressure relief valve, but this is always the

first thing owners check, often overtightening the relief spring as a means of

elimination. It's easy to access.

You may get lucky but don't get discouraged if it makes no difference - they

don't usually go wrong. Check that the ball is seated properly - a bit of swarf

jammed in the seating would certainly cause lower oil pressre.

 

You haven't told us just how 'low' your oil pressure is.

It would help us to know.

 

AlanR

[67_gt6]

Check that the ball is seated properly - a bit of swarf

jammed in the seating would certainly cause lower oil pressre.

 

Yes, in several thousand miles this is the only engine problem I have had. The symptom was that at 1500 - 2500 RPM when you would expect the oil pressure to wind up to its normal max, it didn't climb higher than about 40PSI. Idle was about 10PSI so not much lower than normal.

 

Refer to the manual as to how to remove, don't just leap in and start unscrewing.

 

Andy

Edited September 22, 2008 by 67_gt6

[angelfj]

Hi All,

 

I have finally found a restoration car for my Dad. The first problem to solve is the oil pressure. the previous owner tells me that it is fine when cold but once the engine is warm it loses pressure. Anyone have any ideas please?

 

Thanks

 

Question: What grade oil are you using? One possible solution would be to change to a multi-grade oil. For example here in the Northeastern USA, I use Valvolene, VR-1 , 20W-50. This oil is formulated to have cold viscosity of 20 weight and hot viscosity of 50 weight. If you are using a single weight, e.g. 30, 20W-50 would provide an improvement (unless your main bearings are very worn).

 

Good luck, fja

[G.Guiot]

Hi All,

 

I have finally found a restoration car for my Dad. The first problem to solve is the oil pressure. the previous owner tells me that it is fine when cold but once the engine is warm it loses pressure. Anyone have any ideas please?

 

Thanks

[G.Guiot]

Hi All,

 

I have finally found a restoration car for my Dad. The first problem to solve is the oil pressure. the previous owner tells me that it is fine when cold but once the engine is warm it loses pressure. Anyone have any ideas please?

 

Thanks

 

 

Hello, (soory for the previous ... empty answer)

If you don't mind a french answer ... before looking at yours rod bearings and/or oil pump , JUST check the connection of the pipe at the level of the oilo filter; a) is it a stud + nut (not a bolt) holding the pipe?

do you have the right size for the inner washer ? ... I just hasd the same problem on my newly restored TR3A...

Good luck

GG (www.trmenvotre.com)

[RogerH]

Hi Boggie,

another area - look at the oil pump. if it is the original then thevanes may be worn allowing oil to slip by. Replacement not too bad.

 

Roger

[boggie]

I just spoke to the chap and he tells me that when hot the oil pressure is 20psi at idle and 30 to 40 psi at over 2000rpm. He took it to Revington who looked at it and said they thought the engine was getting tired, they gave it a service and thicker oil which helped a little. Revington suspect the bottom end as there was a slight big end knock. So it sounds like an engine rebuild is on the cards which is a pain but I guess they are not a complex engine and with the engine out I can refurbish the engine bay easily.

 

Are there any recommendations for engine reconditioning at a reasonable price or perhaps parts so we can do it ourselves?

 

Many thanks.

[Bald Rick]

Are there any recommendations for engine reconditioning at a reasonable price or perhaps parts so we can do it ourselves?

 

Many thanks.

 

Hi Boggie

 

There are many specialists that sell parts to enable you to DIY the re-build. Moss, TRGB, TR Shop & Rimmer Bros are just four that you can easily find by doing a Google search. They will all sell you the parts. Some will do exchange engines and some will give advice. No doubt fellow forum members will be able to suggest many others.

 

If you are going to DIY buy a good workshop manual. There are a number available through the Register. Hope this helps

 

Tony

[Menno van Rij]

Are there any recommendations for engine reconditioning at a reasonable price or perhaps parts so we can do it ourselves?

 

There's just one recommendation I can give you: the Roger Williams' book 'How To Restore Triumph TR2, 3 & 3A' is an absolute must! It covers all major aspects of rebuilding your TR. Then there's the Register's membership too. Imho you can't do without it.

 

Menno

[boggie]

Just bought the book - thanks for the tip! Does it cover engine rebuilds in similar detail to the Haynes series of manuals? Would it be worth me getting both?

 

Going by the oil pressures the seller has told me, do you guys think it unwise to drive the car 150 miles, gently along a motorway?

 

Thanks

[TR 2100]

Going by the oil pressures the seller has told me, do you guys think it unwise to

drive the car 150 miles, gently along a motorway?

 

Should be OK. When TR engines start to rattle, it means you can

expect to have to do a rebuild in 50,000 miles or so.

 

As with any 'new' car, take it easy to begin with, but TR engines

are very robust.

 

AlanR

[BrianC]

...when hot the oil pressure is 20psi at idle and 30 to 40 psi at over 2000rpm.

...Revington suspect the bottom end as there was a slight big end knock.

...Are there any recommendations for engine reconditioning at a reasonable price or perhaps parts so we can do it ourselves?

Doesn't sound too bad so I'd be inclined to drive it (but not too hard) and see what other problems manifest themselves.

 

You might even get away with just dropping the sump and putting in new big-end shells. Whatever you do, use good quality oil and you could get a year or two out of it before you need to rebuild. This would give you time to acquire a spare engine to rebuild whilst still enjoying the car before the price of petrol forces us off the road.

 

If you don't fancy rebuilding the engine yourself, I can recommend TRGB for a good engine rebuild to whatever spec you want. Not the cheapest, nor the most expensive, but you will get a thorough job done. (Usual disclaimers)

[88V8]

Just bought the book - thanks for the tip! Does it cover engine rebuilds in similar detail to the Haynes series of manuals? Would it be worth me getting both?

 

Going by the oil pressures the seller has told me, do you guys think it unwise to drive the car 150 miles, gently along a motorway?

 

Buy all possible books and read them. Books are cheap, knowledge is priceless.

 

Yes, gently, meaning 3,000 revs or less and not making the engine slog or using much throttle.

 

And when starting from cold, crank the engine for a bit without choke, so the oil gets around before it starts. That will save a period of damaging oil-less rattling on startup.

 

If the bottom end is rattling I'd do as BrianC suggests, take the sump off as soon as you get home and spend a few quid to change the shells and perhaps the oil pump. Watch you get the right size shells, it might already have been reground. With new shells you may get another 10,000 miles without needing to touch it, and then if money is tight you might even string it out with another set of shells. But without new shells the crank will knock oval and you'll definitely be in for a regrind.

 

Ivor

[Dave Herrod]

Now you guys are getting me worried!

 

My hot oil pressure has been 20psi at idle and 40 psi at 2-2500 rpm for ages and I certainly don't limit it to 3000rpm. I have just assumed that the engine is worn and, as Alan says, will need a rebuild sometime in the increasingly near future.

 

Dave

[TR 2100]

Now you guys are getting me worried!

 

My hot oil pressure has been 20psi at idle and 40 psi at 2-2500 rpm for ages and I certainly don't limit it to 3000rpm. I have just assumed that the engine is worn and, as Alan says, will need a rebuild sometime in the increasingly near future.

 

Dave

 

Hi Dave,

 

40psi at 2-2500rpm when hot (and remember, it does take quite a few miles to

get the oil hot) isn't much to worry about.

It's not quite as high as it would be when newly rebuilt but really not too much to

worry about for some time yet.

And if the pressure increases nicely up to 4-5000rpm, then enjoy.

 

Maybe new shells before too long? Not a big job.

 

AlanR

[BrianC]

Now you guys are getting me worried!

 

My hot oil pressure has been 20psi at idle and 40 psi at 2-2500 rpm for ages and I certainly don't limit it to 3000rpm. I have just assumed that the engine is worn and, as Alan says, will need a rebuild sometime in the increasingly near future.

 

Dave

Don't panic Dave

The engine in my current TR3A had similar oil pressure to yours and I got about 15-20,000 miles hard driving out of it before the crankshaft broke

 

Early on in my ownership, I had to make an economic decision between rebuilding or replacing the bottom end or upgrading to Stage 3. Guess which option won? I never regretted it as I had so much fun for a few years whilst I was still young and foolish enough to drive it within an inch of its life (and probably mine too to be honest). Now it's been rebuilt and I'm still enjoying it, albeit as an older and much more responsible driver (Are you reading this Lynda?).

 

I don't believe the crankshaft failure was due to the low oil pressure so much as a totally knackered bottom end by then, so this shouldn't affect you or 'boggie'. My only regret is that the damage done by driving it home with the broken crank wrecked my SAH head.

Edited September 23, 2008 by BrianC

[boggie]

Thanks for all the input chaps! What a wonderful resource this forum is! :-)

 

I feel a road trip coming on! So, assuming I go and collect the car, jump on the motorway and keep the revs around 3000 - 4000 (how slow is that going to be without overdrive?) for 150 miles it sounds like I should be ok. I will of course keep a close eye on the oil pressure but if it keeps getting lower as the engine gets hotter, at what pressure do I stop and call the breakdown cover?

 

Many thanks!

[Don Elliott]

3000 RPM = 60 MPH

4000 RPM = 80 MPH

[88V8]

at what pressure do I stop and call the Breakdown cover?

It's not so much the pressure that would bother me, as has been said, 30-40psi isn't so bad and at 70mph it probably won't drop off very much, what would bother me is the comment that there is some big-end knock.

So I'd be listening carefully as you drive.

 

I ignored a tapping big end on a 46 Wolseley many years ago and ruined the engine.

 

Ivor

Edited September 23, 2008 by 88V8