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Nigel Triumph

Timing Cover Oil Seal

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1 hour ago, ntc said:

Hairline crack in the cover as I said seen many abused.

I'm inclined to agree, though time will tell.

No time to do any more this week. Next week I will put another cover on from an engine that ran well without leaking.

Nigel

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Time for an update.

I've just fitted another new oil seal (the fourth time now, is this a record?). It is still leaking and I've almost run out of ideas. Here's what I've done so far in addition to changing the oil seal:

- Fitted a new sleeve to the crank nose.

- Fitted a new oil thrower, dished side towards the cover, away from the timing chain.

- Checked and corrected the alignment of the timing cover with the crank. It's within 1 thou.

- Checked ovality and run-out on the crank sleeve with a DTI. Maximum run-out is 0.0008", less than 1 thou.

- Swapped timing cover with one from an engine that didn't leak.

- Fitted the oil seal with sealant around its periphery.

- Checked the crank and sleeve for oil seepage. There doesn't appear to be any oil coming between crank and sleeve but I've added a smear of sealant anyway.

The latest oil seal is genuine Payen and it still leaks. The seal, the sleeve on which it runs and the timing cover which locates the seal have all been changed but it still leaks. I've never known anything like this and am starting to doubt my mechanical ability. I cannot see that there is anything wrong with the seal and its associated components.

I wonder if it's possible that multiple seals have leaked because there's too much oil inside the timing cover when the engine is running. There could be either too much oil feeding into the timing case, or an impediment preventing the oil flowing back into the sump as readily as it should.

Any thoughts welcome please.

Nigel

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Hi Nigel,

you must be getting {%^%>$<# by now.

The oil return is through the large hole in the front engine plate (for the crank shaft), then trough the gap between the steel front engine plate and the front bearing cap, then on both sided of the bearing cap back to the sump. I can send you pics of mine if you pm me your mail address.

If the return path is restricted or even plugged, I can imagine the timing chain and sprocket start pumping oil, not sure if this would cause leakage, an oil seal can withstand some pressure (but not much).

Are you sure that the leakage comes from the seal, not from somewhere else?

Did you note a drop in oil pressure, that would indicate a higher flow (possibly to the front cover)?

is the seal installed perpendicular to the shaft? Mine wanted to pop-out initially during installation, so I glued it in with Hylomar on the bench first. Maybe not relevant for you.

These are all long shots, but since the issue is so persistent, worth checking.

Good luck,

Waldi

 

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Can you give us picture please of where you see the leak, it may well help in suggestions?

John

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Hello Nigel

Not really an engineering fix but in the past I have stopped leaks on a BMW mini one power steering system with Wynn's power steering stop leak, and also stopped leaks on the TR using their engine stop leak fluid. Don't really know how this stuff works except that it has done the job.

I await replies from our engineering fraternity now about how this is really a bodge. The 'bodge' on the mini was a few years ago and it is still not leaking power steering fluid. The TR leaks less but I would be worried if it didn't leak somewhere. You shouldn't have black 'stuff' coming off the seal with a new seal.

I use 20:50 classic car oil. Years ago in France a friend of mine was running low on oil and we put some thinner oil in (only stuff we could get where we were) and it dropped the oil pressure and seeped out everywhere. I also had a similar problem in France in an Austin Allegro. The top up oil was too thin and ended up on the clutch. It took a couple of hundred miles to burn it off.

Hope you get it sorted soon

Keith

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Thank you for the continued input.

Waldi is right, I'm getting more than a little fed up with this leak. I fear I'm one more failed oil seal from a meltdown of Basil Fawlty proportions:

Seriously though...

I'm certain the leak is coming from this oil seal because the oil dribbles down the timing cover from behind the front pulley. I'm convinced it's not the sealing block or the sump. As far as I can tell the oil seal is perpendicular to the crank, each one has been pressed fully into its recess in the cover and hasn't moved until I levered it out to fit the next one. The oil pressure is exactly as expected, about 55psi when hot at 2,000rpm falling to 20-25psi at tickover. There are no strange fluctuations in oil pressure.

I was using an SAE30 monograde running in oil but after the first 250 miles I changed it to classic 20W50.

I know these stop-leak compounds can work on old engines by plasticising hardened oil seals but I really don't want to start adding such magic potions to a brand new engine.

The engine has an alloy front plate and a stainless sealing block below No1 main bearing and this is the area where oil must return from the timing case to the sump. I've attached a couple of photos taken during the build which are cropped to show some detail. The shape of the sealing block seems correct, with two cut-outs to allow oil return. The hole in the front plate around the crank sprocket is correct. The one thing I've noticed from these pictures is that the front plate gasket protrudes behind the engine plate, creating a small weir that could impede oil flow. It's a small point but I'm clutching at straws now. Another sign this gasket wasn't 100% correct is that two bolt holes were missing and had to be added.

Any thoughts please?

Nigel

PS: I met a Practical Classics colleague at a car show yesterday evening. He is having exactly the same trouble with the front oil seal on his recently rebuilt MGB. It helps to know I'm not the only one!

T2500 Sealing Block.JPG

T2500 Front Plate.JPG

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20 hours ago, Nigel Triumph said:

Time for an update.

I've just fitted another new oil seal (the fourth time now, is this a record?). It is still leaking and I've almost run out of ideas. Here's what I've done so far in addition to changing the oil seal:

- Fitted a new sleeve to the crank nose.

- Fitted a new oil thrower, dished side towards the cover, away from the timing chain.

- Checked and corrected the alignment of the timing cover with the crank. It's within 1 thou.

- Checked ovality and run-out on the crank sleeve with a DTI. Maximum run-out is 0.0008", less than 1 thou.

- Swapped timing cover with one from an engine that didn't leak.

- Fitted the oil seal with sealant around its periphery.

- Checked the crank and sleeve for oil seepage. There doesn't appear to be any oil coming between crank and sleeve but I've added a smear of sealant anyway.

The latest oil seal is genuine Payen and it still leaks. The seal, the sleeve on which it runs and the timing cover which locates the seal have all been changed but it still leaks. I've never known anything like this and am starting to doubt my mechanical ability. I cannot see that there is anything wrong with the seal and its associated components.

I wonder if it's possible that multiple seals have leaked because there's too much oil inside the timing cover when the engine is running. There could be either too much oil feeding into the timing case, or an impediment preventing the oil flowing back into the sump as readily as it should.

Any thoughts welcome please.

Nigel

AARRRRRRRGH !!!

Nigel as you are aware I am having exactly and I mean exactly the same trouble. The oil is leaking in the same place, dribbling down behind the pulley. My next oil seal will be my 3rd and before I start I was hoping for some resolution to surface. I Feel your pain, boy do I feal your pain.

Paul

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Is it possible to pressurise the oil system with the engine not running and the various cogs and pulleys removed so you

can see more clearly the hole in the cover where the seal is hiding. ???

On a rebuild of a 4A engine a few years back I had oil spouting out everywhere. The front and rear plugs for the oil gallery were undone without my knowledge.

 Roger

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A few thoughts, could it be the spot weld that holds on the bracket for the chain tensioner on the cover,  and are there also some spot welds on the cover next to where the seal sits and allowing oil running down to the bottom, the seal looks to be square with the sleeve from the contact polish mark in your photo above.

If you have the cover off with the seal in, put the sleeve back into the cover, and then fill the cover with some thinners, mount the cover high up so you can see underneath the seal area, that should show a wetness somewhere perhaps?

It would be nice to have a photo of the actual leak from both sides of the pulley before you take it off again. The seal may need to bed in a few miles weeps a bit then dries up.

Where are getting the seals from, is it worth getting one from a seal supplier take your cover and the sleeve for them to get the right dimensions, don't take your seals for comparison. 

How tight are you doing the pulley nut that relies on sealing the sleeve to the pulley.

John

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Hi Nigel,

John’s idea above to buy an oil seal from an industrial supplier is a good one. Ask for a double lip seal, not a single lip. Although your problem is not caused by this, it keeps dirt out so extends life.

Take the cover and sleeve with you.

Sealant: I used hylomar on the sleeve ID, especially at the key, not too much off course as it will end up in your sump. I also put some hylomar on the oil seal OD before installing, because the bore in the cover was a bit tapered. And before fitting the cover to the front engine plate, I put a smear of hylomar in the gap between seal OD and cover, as a secondary (stationary) seal. All in attempt to achieve a dry engine.

Front engine plate:

Did you compare the old and new SS front engine plate to see if they match, dimensionally. Probably not the cause, but better to compare them when you have the cover off.

The oil should be able to flow back it appears from your pics, but good to double check if the returns are not blocked by sealant or the gasket.

Can you ask a near by fellow for a cold eye review, often a 2nd pair of trained eyes helps with diagnosis.

Many of us have been in similar moods before (I have). You will resolve it in the end.

Waldi

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Thank you for your empathy and further ideas.

The latest seal isn't leaking as badly as the previous two, so I'm inclined to drive the car more and wipe up the mess as required, until I can muster the enthusiasm to strip out the timing cover again. Who knows, perhaps the seal will bed in and dry up.

Roger, I like your idea of pressurising the oil system. I could take out the distributor drive and spin the oil pump with an electric drill. I've made a tool for this to prime new engines but it's only possible to get very limited pressure as without the distributor drive gear in place, lots of oil comes straight up the shaft from the oil pump. Perhaps it would be better to take the plugs out, remove the front pulley and spin the engine on the starter to build pressure. I could get 20-25psi that way and as it's a form of dynamic test, I should be able to see exactly where the oil is coming out. Then repeat with the timing cover removed to see how oil is entering the timing case (messy of course!).

John, I will get photos from either side and post here. It's not via the rivets for the spring tensioner, and anyway, the second timing cover came from another engine that I had running in the car until 2 weeks ago, which was leak-free. The seals have come from different suppliers, as follows (but protecting the names of the innocent):

- First seal, from trusted Triumph parts supplier; this only weeped a bit, wish I'd left it alone.

- Second and third seals from another major Triumph parts supplier; these both leaked worse than seal no1.

- The present seal is genuine Payen from a seal and bearing specialist on eBay; this weeps, similar to seal no1.

Mark Field at Jigsaw has a double lip seal but they're currently out of stock. If the leak doesn't stop through some divine bedding in process, I will fit one of his double lip jobs. I'm setting the torque wrench to 95ft lbs for the pulley bolt, WSM says 90-100ft lbs.

Waldi, as above if there has to be a next time, I will try a double lip seal. As for a second pair of eyes, I will probably take the car over the the Practical Classics workshop and ask my colleagues on the magazine to have a look. I didn't compare the two front plates by laying one on top of the other but the new one fitted as expected. Next time I have the timing cover off, I will measure and take photos. I will also trim back that 1-2mm of gasket that could get in the way of returning oil.

Meanwhile, I'm just going to drive it some more.

Nigel

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Hello Nigel again

Couple of thoughts. If the oil is leaking out behind the pulley then only a couple of places it can get out. It could get out between the pulley shaft and lip seal or alternatively between the seal and the timing chain cover. Is it possible to take the timing cover off. Leave the seal in place and insert the sleeve, lay it flat and fill it as far as possible with thin oil as John suggests above. Alternatively (unlikely) is the oil seeping out between the sleeve and the shaft?

Another possible - when you fit the timing cover and the seal is a tight fit on the sleeve, could there be a hairline crack in the cover that only opens up when you fit the cover to the car (i.e. around where the seal fits into the cover.) Only way to check this would be with the cover off the car, leave seal in place, insert the sleeve and use a magnifying lens to look for a hairline crack in the cover around the seal. 

Another possible - when you press the clutch pedal does the mainshaft move forwards. I seem to remember one of our group having this problem on his 6 but shouldn't happen if you have rebuilt engine.

Can't think it is the seals themselves because you will soon have exhausted the UK supply. Surely they can't all be bad.

Keith

 

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A quick update, as I've been quiet on this thread for over a month.

In fact, after four oil seal replacements (including the first when building the engine), I needed a break before enthusiasm returned and I could face trying again. The Jigsaw double lip seal mentioned above was out of stock and so I ended up having a conversation with Chris Witor, who supplied most of the components for the engine rebuild earlier this year. Chris knows the big Triumph saloons better than anyone and so he knows 'our' engines well.

Chris says the timing cover oil seal often causes repeated leaks and he offers a leather-lipped seal, which he finds is more 'forgiving' and usually works where other timing cover seals have failed. The leather seal sounds like a better solution than the double lip to me. I thought the ideal of double lipped seals was to use the outer lip to exclude dust from the inner sealing lip, increasing longevity, rather than so seal where a conventional seal has failed. I'm going to fit one of his leather seals next week, and hope to arrive at the Stratford weekend behind the wheel of an oil-tight GT6. More news next week.

Nigel

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On 7/4/2019 at 9:56 AM, Nigel Triumph said:

Thank you for the continued input.

Waldi is right, I'm getting more than a little fed up with this leak. I fear I'm one more failed oil seal from a meltdown of Basil Fawlty proportions:

Seriously though...

I'm certain the leak is coming from this oil seal because the oil dribbles down the timing cover from behind the front pulley. I'm convinced it's not the sealing block or the sump. As far as I can tell the oil seal is perpendicular to the crank, each one has been pressed fully into its recess in the cover and hasn't moved until I levered it out to fit the next one. The oil pressure is exactly as expected, about 55psi when hot at 2,000rpm falling to 20-25psi at tickover. There are no strange fluctuations in oil pressure.

I was using an SAE30 monograde running in oil but after the first 250 miles I changed it to classic 20W50.

I know these stop-leak compounds can work on old engines by plasticising hardened oil seals but I really don't want to start adding such magic potions to a brand new engine.

The engine has an alloy front plate and a stainless sealing block below No1 main bearing and this is the area where oil must return from the timing case to the sump. I've attached a couple of photos taken during the build which are cropped to show some detail. The shape of the sealing block seems correct, with two cut-outs to allow oil return. The hole in the front plate around the crank sprocket is correct. The one thing I've noticed from these pictures is that the front plate gasket protrudes behind the engine plate, creating a small weir that could impede oil flow. It's a small point but I'm clutching at straws now. Another sign this gasket wasn't 100% correct is that two bolt holes were missing and had to be added.

Any thoughts please?

Nigel

PS: I met a Practical Classics colleague at a car show yesterday evening. He is having exactly the same trouble with the front oil seal on his recently rebuilt MGB. It helps to know I'm not the only one!

T2500 Sealing Block.JPG

T2500 Front Plate.JPG

Did the front crank oil seal thrower get fitted?  Pt No 119390

Must be there for some reason.

Peter W

link  http://www.leacyclassics.com/119390.html

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Hi Neil,

The front engine plate is an alloy version and the sealing block on main bearing no.1 is a stainless job, both from Mark at Jigsaw.

Peter,

Yes, I fitted the oil thrower and it's the right way round, concave side towards the front.

 

All other ideas gratefully received. My ambition, almost my life plan now, is to get to Stratford without dripping oil!

 

Nigel

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Time for more news...

I've been back in the garage for another - hopefully final - attempt to replace the timing cover oil seal on my 2.5 litre GT6 engine. A question raised more than once in this thread was: 'is the oil seal really leaking, or could it be coming from somewhere else nearby'. As I stripped out the fan then the crank pulley, I looked carefully for oil. There was none to be found inside the pulley or emerging between the sleeve and the crank nose. I found oil on the outside of the seal, contaminated with black which is probably rubber worn from the lip of the last oil seal. The tip of the small screwdriver in the attached photo shows where the oil was emerging.

I removed the timing cover, pulled out the old seal and fitted one of Chris Witor's leather lipped seals:

https://www.chriswitor.com/proddetail.php?prod=UKC110L

 Unlike modern seals, the steel periphery of the leather seal is not rubber coated, so for good measure, I put a thin smear of silicone in the timing cover recess before fitting the oil seal. After reassembly the engine was run up to operating temperature at about 1,500rpm in the garage yesterday afternoon. No leaks.

This morning I've been out and covered about 20 miles, getting up to 4,000 rpm a few times. The engine remained oil tight!

I can hardly express how good it feels to finally get this pain in the ar$e problem sorted. It only took five oil seal replacements including the one I fitted when first building the engine.

Chris Witor's advice that the timing cover seal can be problematic, and the leather seal usually works, was spot on. For Paul and anyone else battling this problem, I can thoroughly recommend the leather seal. Maybe a bit pricey at £22.50, but I would gladly have paid double to avoid the pain of multiple replacements... Come to think of it, I already spent more on conventional seals that didn't work.

Finally, thank you to all who have posted advice and encouragement here. I hope to see you at Stratford over the weekend.

Nigel

Timing Cover Oil Leak.JPG

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Could it be that the seal wasn't concentric with the crank?

There's no scope for significant adjustment but if you have a different front engine plate it may be that it's attachent points to the block are not perfect or the attachement points for the timing cover may also not be perfectly aligned compounding things enough to mean the seal doesn't work properly.

 

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Hi Ian,

Yes, I soaked the seal in engine oil for about 20 hours before fitting.

Hi Andy,

I had wondered about the seal being off-centre too. On the second attempt to fix the leak, I measured the gap between the crank sleeve and timing cover aperture and found the cover was about 4 thou off centre from the crank. By filing the dowel holes slightly I trued it up to within 1 thou, but it still leaked.

I'm going with Chris Witor's explanation, that on some engines stopping the timing cover seal from leaking is just plain difficult. I know there must be an engineering reason for this, but the seal was as near as dammit concentric with the crank sleeve, and a DTI showed the crank sleeve was true. In the end, I'm just glad it's fixed, even if I never got to the root cause of the multiple seal failures.

Nigel

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Congratulations with this result Nigel.

Like you say, they must be a reason, but you sorted it!

Cheers,

Waldi

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