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Triumph TR6 - Oil Pump?

You Canadian guys might be shut in due to the cold, but even down here, at least one TR6 is stuck in the garage as well.

I have had absolutely no trouble with oil pressure until now, always around or above the center of the guage. I just changed the oil, and while I was at it, I put on a spin on adapter. When I went to restart, the oil pressure was zip. I shut down immediately, and tried cranking (with the coil wire off) without the filter, and ultimately without the adapter...just the hole on the side of the block (I thought/hoped maybe the guage or the line might be the problem). With the engine cranking, I got no oil being pumped. Also tried with the old filter cannister, still no pressure.

This seems to be simply a failed oil pump, but have any of you ever heard of the failure being triggered by an oil change? And do they typically fail completely? Also curious if that regulator valve between the pump and the filter has a reputation for problems and should be checked first.

Any other diagnostics to recommend? Any advice appreciated.

Mark H

Mark - There have been catastrophic oil pressure failures reported in the UK, in some of my previous tech articles and also in the archives here. The pump pressure and flow suddenly stops. The newer pumps don't have the cross pin to secure the 4-lobe part to the pump shaft. They now use "knurling" and if this itty-bitty interference begins to slip, the pump shaft will still turn but the bottom end and of the rotor won't.

In the meantime, pull the plugs to reduce resistance, then remove the distributor cap and spin the engine. Check if your rotor is turning. If it is, that means your cam is turning and it is also turning the oil pump shaft.

So the problem may be down inside. This means pulling the sump (oil pan), then the oil intake filter and the pump housing to check the pump parts and to see if your pump has the pin or not. If not, then the knurling may be slipping. Hence no pressure all of a sudden ! better at home than a 100 miles from home as others have reported.

Let us know what you find.

Don Elliot, 1958 TR3A
Don Elliott

I just finished pulling the plugs and spun the engine. The distributor rotor does indeed spin.

I am not sure if I understand what this means. I am reading your comment as this being a confirmation that at least the shaft is turning, and the next step is to drop the sump and see if the bottom end of the shaft has this worn knurling situation where it connects to the oil pump.

Is that the right interpretation? It sounds like a reasonable next step and of course a fun Saturday on my back.

Mark H


Did you prefill filter when you replaced it? Short of Don's suggestion. You might try priming the pump get some oil down into it from whatever hole is open and filling the filter. I am not sure of this but if you had that whole system dry for a while changing things over the pump may not be able to get its prime due to wear.

Hope it helps
B Brayford

Well guys, the problem is semi-solved. Last night I spun the engine a while longer and loss of prime is apparently the culprit. There's one hurdle left though. Once the pressure returned, I then replaced the cannister with the spin-on filter and the oil pressure was reduced to about 25 psi during cranking (still didn't start it with pressure that low). I originally found pressure with the cannister to be 50 psi, which is about 20 pounds light for this engine when cold, but I switched to 10W 40 for the winter/short trips, which I hope accounts for that drop (wishful thinking?) But 25 psi definitely warrants attention.

I saw on the VTR website noted in our archives, that a change in oil filter to one with a pressure release had solved at least one guy's problems. So its off to the auto parts store over lunch hour, and hopefully that's the solution to my pressure problem as well.

Also, in looking at the Fram website, they talk about losing prime ocassionally during an oil change, along with a method for priming. Wish I caught that yesterday.

Thanks for the help so far. Keeping my fingers cross that I'm a filter away from decent pressure.

Mark H

Mark - If you get at least 20 to 30 psi at idle with the engine hot and then get at least 40 psi at 1500 to 3000 rpm on acceleration with the engine hot, you have enough pressure. On my TR3A, after my restoration, the by-pass valve was not correctly adjusted. I was getting 90 psi cold and 70 psi hot. I reduced it to 70 psi cold and got 50 psi hot at 3000 rpm. Ive ground the crank once and changed bearing inserts twice in over 70,000 since 1990 (my restoration) and still get 20 psi hot at idle and 40 psi hot at 3000 rpm in the summer. It's been colder up here recently and 2 weeks ago on a 500 mile trip, I got 60 psi hot because the ambient temperature was about 36 to 40 deg. F. I have run Castrol 20W50 for the last 3 years altough I ran with Castrol 10W30 previously.

Don Elliott, Original Owner, 1958 TR3A
80,350 miles from 1958 to 1990
Over 70,000 miles since 1990
Don Elliott

Home stretch.....
I put on the GT3600 (sounds like a Binford 2000 on Home Improvements), and with a primed oil pump, the car is back in business (back to 70 PSI cold)....almost. But thanks for the advice to get to this point.

What's left is a leak in the spin-on filter adapter. I got this adapter from the PO with no instructions, and the placement is obvious. Its the same model Roadster Factory has in the catalog.

The leak is the outer seal and it seems to be something others must have encountered. Did any of you have to double up the gasket to make the seal work? Is two enough? I have so much oil on the floor already, I figured I'd ask to avoid another puddle.

Thanks again,
Mark H

Hi Mark

Did you lubricate the filter seal with oil prior to installing. The filter should fit up hand tight plus 1/4 turn. Removing and replacing dry or even wet may damage seal.

You have to take off again so grab a new filter fill and wipe oil around seal and fit up. Check the surface were the seal hits though just in case. That should get you going.

B Brayford

Mark - If the PO left the spin-on filter case with you, may-be he bought it from Roadster Factory. They have a phone number you can phone to ask technical questions at certain times of the week about products they sold you or the previous owner. You could ask them to send you the papers that you are missing. Or they could fax them to you.

Don Elliott, 1958 TR3A
Don Elliott

I did put oil on the Fram filter before spinning it on. That's not where the leak is happening. Its the gasket in the groove on the block, where the cannister used to go and now the adapter goes in the groove instead.

A few months ago when I had some work done at the shop, the guy said the center o-ring was preventing a tight seal on the outer seal. Either needed a thinner o-ring (I doubt they can be smaller), or a thicker one for the groove in the block.

I have a few of the outer rings from the PO, that may have come from the kit, but it was all loose in a box without instructions.

I tried TRF earlier today, and their tech line didn't answer, and its a Monday-Friday line. The last couple of times I called, wait time was pretty long so they must be pretty busy.

I'll try to add another tomorrow, worst case is I'll get a little more on the floor and have to wait for Monday to call TRF. The leak is very obvious, so it will be easy enough to know if the extra thickness works or not.

Mark H

Hey Mark

Sorry I misunderstood.

I don't think the original side filter housing used an O ring more of a jar ring? An O ring will not seal in a square housing. My 72 is square I believe but not sure. I have a block original setup sitting in shop and will look tommorow.

If your garage has a problem figuring that out when they can see it, I wonder. Most have a full stock of seals and rings. If that is the case I would suggest a new shop maybe?

B Brayford

My thinking is ,there is an ols seal still in the grove from an old oil change. The groove is deep and it is easy to miss that old seal. Try digging (lightly) with sharp point to see if thereis one in there. They get crusty and very hard when they get old.
Don K.

Final installment guys.

I cleaned out the groove and installed once more. Also got TRF to confirm the seal is the same as the cannister filter would use. No luck. Still leaked.

I checked the local auto parts store, and incredibly, they had the stock cannister filter cartridge. Ran to town, picked it up and installed it. Not a drop, pressure back up, and got to ride around for the afternoon.

It leads me to think the adapter is somehow flawed, but that's now an issue for the next oil change...maybe. The cartridge approach was really not bad enough to motivate me to go thru this again anytime soon.

Thanks as always for the suggestions and the moral support.
Mark H

Mark-Don't give up on the oil filter adapter. I think there was several sizes of O rings for different applications. Perhaps someone who is changing their oil could check for the proper size.


Since I worked this out today I figured I would post anyway.

Using dial Gauge but going to closest inch rather than thou. very few thou. diff.

The center machined surface is 1/16 higher than outside machined surface. The outside machined groove is 1/8 wide by 3/16 deep square corner. The original england filter with square 1/8 by 1/8 square sealing ring new.

Using crush on existing non leaking filter I have 1/8 down in groove ring in, using a pin center on dial gauge eyeball center of line original filter cover sits.

I beleive if your center surface has a 1/16 O-ring or as you described too small? I don't have a spin on nor have seen one. Your outside has to be able to go in groove 1/4 inch deeper than center. Part going into groove from outside ,machined surface.

If that is true and the outside is 1/4 or greater the problem is the center O-ring is not large enough to allow full sealing of outer ring in groove before bottoming on machined flats of center ring. No rocking action. Once center bottoms your outside sealing is probably toast

Your original oil filter has an absorption type seal very thin spring loaded to keep everything square and allow the cannister to line up and seal with lots of tolerance.

I am trying to describe this as best I can. Simply if your center o-ring is too small and allows the metal to meet no rocking your outer sealing area will not seal full circle.

Clear as mud. Best I can do.

If you decide to continue let me know.

B Brayford

I agree with Bill. You don't mention the make of the spin-on fitting you have, but Moss in the UK and several other suppliers sell one made by Mocal.
Mocal kits come with TWO central O-rings, of different thicknesses, and a piece of Blu-Tack. You are instructed to trial assemble the fitting with one of the O-rings and the BluTack between it and the block face. If the BluTack is crushed to zero thickness, you have the correct O-ring.
I suspect you were given the fitting with the too thick O-ring.

On priming oil pumps, packing with Vaseline is good! It doesn't fall out while you assemble the rest of the engine, and dissolves easily in oil, unlike grease. I've had a new oil pump refuse to self-prime. Removing the oil pressure relief valve, and pouring oil down the hole filled the pump. After the valve was rapidly replaced, oil pressure appeared without delay.


Sounds like you have opposite theories (too thick, too thin), but a common culprit being the inner ring. The leak was consistently on the rear side of the adapter, which makes me think Bill may be on to something, that the adapter is hitting metal to matal before the adapter can 'balance' itself out and get a good seal all around.

In any case, I have a new filter and fresh oil to last thru whatever bits of driving the winter allows. That should give me time to recharge my patience and try again with the springtime oil change. I'm saving this thread, and plan to talk to TRF (I found the box, and its definitely theirs) about gaskets and replacement installation instructions.


Mark H

This thread was discussed between 17/10/2002 and 21/10/2002

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