Jump to content

Recommended Posts

Last year we went to the Triumph National Rally in the Clare Valley in South Australia. Before we went I had noticed some oil mist on the back of the car. I initially thought that it was a leaking gearbox seal, but a Triumph Specialist (TS) thought that it was leaking pushrod tubes. I had the tubes resealed as well as new seals in the gearbox.

 

On the first day of the trip we noticed LARGE amounts of oil on the bottom of the car. It took a litre to top it up. In the course of the 3000km trip, it used/ejected 6 litres of oil. It all appeared to be coming out of the dipstick hole. On our return, TS diagnosed worn liners (after 25,000 miles...?) and put in new pistons and liners. Thinking all was now well, I thoroughly cleaned the underneath of the car, and took it 25 miles to another mechanic to fit the Goodparts roller rockers. He called me shortly after to come and have a look at the oil that it had dropped on the floor of his immaculate workshop. It is spewing oil out again!!

 

The car has 87mm liners, a cam with about 280 duration, HS6 SUs and a standard exhaust manifold. We have tried both the standard PCV valve and a Japanese one. Both appear to have plenty of vacuum. It has a TR6 boosted master cylinder with a seperate pipe off the balance tube.

 

The problem appears to be excessive pressure in the sump. The mechanic and I are at our wits end. We have done a leakdown test and all cylinders are fine.

 

Any and all suggestions would be greatly appreciated.

Link to post
Share on other sites

From what you say the general condition of the engine should now be fine.

 

The "worn" pistons and liners are at bit of a puzzle at 25,000 miles ! Especially given that these Pistons can have as much as a 5 thou difference between piston and liner and still run ok ! In fact that's about where many of the TRs with large power outputs will be, the extra clearance being necessary to reduce drag.

How has the Triumph specialist arrived at his " worn" diagnosis ? What has he seen that made him come to that ? What oil are you using ? Mineral or synthetic ? How do you drive the car ? Is it used robustly within it's torque range 3000-4000 revs in top gear and loaded ? Or do you easy foot it at 50mph in top overdrive trickling it along ? The engine has had a leak down test, what compressions are coming out of the cylinders ? Has he tried a " wet" compression test with oil added ? If so what was the results ? Better if so how much ?

The excessive crankcase pressure has to come from cylinder blow bye, if the PCV valve is ok and the engine is good it will handle it, if the engine is breathing the PCV valve will get swamped but why should the engine breathe if the piston to liner clearances are good with new rings in a freshly honed liner ?

 

See what information you can give us, there 's some answers we just need to define the correct one.

 

Mick Richards

Link to post
Share on other sites

What rocker cover and oil filler cap do you have? Is the cap the correct vented one?

 

What if you run a pipe off the rocker cover direct to atmosphere, thus removing the PCV from the installation - does that help with oil spew from the dip

stick? I am no fan of the PCV and would dump it in favour of a vent pipe that I pointed at the rusty bits of chassis or into a vented catch tank - Bid coke bottle without lid.

 

Peter W

 

PS What oil is in the engine?

I used to use cheap supermarket 20/50 and it went out the exhaust pipe at 1000 mile a pint (good consumption for a Jaguar but not a TR)

Swapped to Millers Classic 20/60 and now no top up needed between yearly services.

 

Could you upload photos of the engine in situ? and the length of your engine oil dip stick - are you overfilling?

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

I reckon a garage ought to check compressions before

diagnosing (and replacing) "worn pistons and liners".

As for a leaking pushrod tubes - hard to believe a savvy

specialist (or any mechanic) would attribute such an

extensive oil leak to the pushrod tubes.

 

+1 for PeterW's suggestion to check oil sump level and

RogerH's idea to bypass the PCV.

 

TR 4-pots do generate a bit of pressure in the sump but

nothing of the scale you are experiencing.

 

AlanR

Link to post
Share on other sites

I like simple solutions and always try them first. I never thought that after having taken off the rocker cover dozens of times that I would make the simple mistake of catching the carb side cover on the edge of a head stud. I did (I guess my eyesight to blame). It only caught the edge of the stud by a few mm but it lifted the base of the cover so little it was not noticeable, It was certainly noticeable when I lost a quart of oil in 25 miles!

Maybe not the problem in this case but severe symptoms are often caused by simple faults.

 

Simon

Link to post
Share on other sites

There are more tricky points to see: I suspected the rear crank seal for all the oil appearing at the end of the block. But the little screw at the rear of the cylinder head (its closing the oil channel to the rockers) was leaking. Almost impossible to see the oil running down the back of the black block......

 

Is there any more specific information, where the oil appears? Cleaning the block as fas as possible and then waiting for the oil helps.....

 

Johannes

Link to post
Share on other sites

In order to eliminate the possibility of the PCV or its tubing causing pressurisation within the engine, disconnect from the rocker cover and use a length of rubber hose (the type used to feed coolant to the heater will suffice), take it over the top of the rocker cover and drop it down the left side of the engine, past the fuel pump, so that it ends near the bottom of the sump.

Better to discharge of the left side, away from the heat of the exhaust manifold, and taking the hose over the top of the rocker cover avoids small droplets being blown out, as might occur if the tube didn't rise upwards.

If the idea of discharging to the road offends you, connect the hose to a catch tank.

Don't forget to seal the hole into the inlet manifold!

Ian Cornish

Link to post
Share on other sites

Thank you all for your comments and suggestions. In no particular order:-

 

The engine had a ring gap of .052" at the top of the stroke and about .040" at the bottom when he measured it. How this much wear had occurred remains a mystery. The car has never been driven without air cleaners. I first noticed some oil residue on the boot of the car at about 20,000 miles which led me to think that the gearbox was leaking. He diagnosed the pushrod tubes and said that the gearbox was fine. The major leak started AFTER he had done the tubes. He has been racing and servicing TRs for about 30 years.

 

It has a TriumphTune alloy rocker cover to clear the roller rockers. There is no restriction in the pipe off the cover or in the rubber hoses to and from the PCV valve. It has the Land Rover type rear oil seal conversion. If only the Mad Max Viton seal had been around 20 years ago........

 

It showed 160 in the leak down test after the new liners and pistons and held that pressure. When we first noticed the leak, I blocked off the PCV valve (which was new) and ran a piece of heater hose from the rocker cover to atmosphere. It made little difference. TSOA South Australia donated 5 litres of Penrite oil to me at dinner one night to get us home. Like Hansel and Gretel, you could follow us home. The car has done most of its' miles on long trips e.g. Melbourne to Queensland and back and across the Nullarbor to Perth. So cruising at 60-70mph. It has not been raced.

 

I am hoping that the problem may be the dipstick as suggested by Malcolm. Off to get a new seal today. I shall report back!

Link to post
Share on other sites

Hi hope you find the problem and it's easily fixed.

I have driven round OZ and crossed the Nullabor (in a 1973 ford falcon in '89/90) so it's clear you have the cooling system working perfectly.

 

Have you tried cleaning every thing e.g. Pressure wash then powdering everything (liberal covering of talcum powder or similar) and then doing a short run to create the leak to see where the oil runs from.

Really difficult to trace as you know as oil ends up dripping from lowest point ????

Best of luck

H

Link to post
Share on other sites

I took the car to the brake shop where I had the TR6 booster and master cylinder refurbished many years ago to see if I had a leak in the booster which might be reducing the vacuum. The booster was fine but he put his vacuum gauge on the pipe from the manifold and it was showing about 6Hg at idle. He said that it should be 20-25Hg to give proper performance at the booster. He blamed the overlap on the reground cam and said that I would be better off with a standard cam. I doubt that I can get a fourth regrind out of the cam!

 

Does anyone have a figure on manifold vacuum? I drove the car home 25 miles and parked it in the garage. I had a brief look last night and there is an oil stain on the concrete under the clutch housing. It looks like it could be the rear main. Should I simply ship it to the UK and part it out????

Link to post
Share on other sites

Was the 6Hg measured with your PCV inlet to the manifold blocked off??

Personally, I would not run 2 vacuum sources from the inlet manifold on a TR engine.

Worst case scenario, fit an electric vacuum pump, which I am doing with one of my V8 cars with an overlap cam, just to obtain optimum power boosted braking

Or, "simply ship your car to me"...lol.

Link to post
Share on other sites

Another one of our Australian members Tony Milward who doesnt post anymore had a similar problem with his 6 that had a wild cam and he ran an Alternator with a vacuum pump fitted to the rear of it. Not sure what car it came off but Im sure a Google search will find it.Rear oil seal does sound favourite for a leak.

Stuart.

Edited by stuart
Link to post
Share on other sites

Sadly Tom, the Land Rover seal conversion that I fitted all those years ago meant that the scroll was machined off the crank so I cannot fit the Mad Marx seal. Not about to spring for a new crank at this stage of life.

Link to post
Share on other sites

At the time the Land Rover conversion was being touted around there was some confusion about the exact size to machine the crank to and there were then problems with leakage shortly after, I have also seen leakage from in front of the seal housing, between it and the block..

Stuart.

Link to post
Share on other sites

It would seem that the land rover rear seal conversion was not a long lasting success.

IMHO...Best option is to pull the engine and redo the LR seal, perhaps with modifications to its design and also crankcase breathing.....or another crankshaft with improved seal design..

Stick with it Barie, as yours is a very nice car......and it's only money that is required...lol.

Link to post
Share on other sites

At the time the Land Rover conversion was being touted around there was some confusion about the exact size to machine the crank to and there were then problems with leakage shortly after, I have also seen leakage from in front of the seal housing, between it and the block..

Stuart.

+1

Mine poured out until I had the seal land resized.

Peter W

Link to post
Share on other sites

Barie ~

 

You can still fit the 'Mad Marx' seal as it does not need the original scroll seal.

 

Tom.

No Tom you cant as the crank is machined down in the are where the Marx seal sits. Im afraid once the LandRover seal mod has been done then its irreversible.

Stuart.

Link to post
Share on other sites

Hi Stuart,

this will get your grey cells scrambled.

To recover a machined crank for the Landy seal.

machine and fit a pair of shells that are tight(ish) on the crank that has the correct OD but without the scroll and then fit the Chris Marx seal.

The sk=hells can be bonded to the crank with screws into the joints of the two halves.

 

I hope you v=can visualise that. - basically like a con rod big end but a good fit so it does not spin

 

Roger

PS - how many do you want.

Edited by RogerH
Link to post
Share on other sites

Roger,

 

Take a tablet and go lie down.

 

The split line of the shells would be a favourite fail point with the constant hot/cold expansion contraction which would lift an edge ( I don't think it would be all that thick ?) about a 1/10th of a thou which would then carry out machining on the Landy seal = oil on drive, I think you are pulling our plonkers.

You'd need to get a slip over sleeve finished in one dia but you have the flange flywheel abutment (lovely word) in the way at the end of the crank to prevent it going on.

Might be easier just to inspect the seal and see if it's failing now because of 20 years of wear (not too bad) or it may have worn a groove into the crankshaft surface, cure fit another seal but with it spaced away by 2 or 3 mm from the shoulder so the seal material seats upon virgin crank material.

 

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.