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Oil Leak from somewhere behind the timing cover plate


dellyend1
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Hi All, 

My recently acquired MkIII has had an engine re-build in the very recent past (before my purchase) and prior to me buying I checked and checked for Oil seepage and was clean. A couple of slightly spirited drives by me since and I have a very noticeable oil leak from somewhere above the sump where the sump meets the block and timing chain cover. I've been reading quite a lot on an American forum as to causes and I am just wondering , am I opening up a pandara's box if I take off the cover to investigate and what is the point of no return ? I'm fine with taking things off, new gaskets, re-sealing but new oil seals extraction and replacement and any notion of knocking a timing chain out of place and re-setting is beyond me and best I use a knowledgeable TR mechanic . 

If the latter, does anyone know of a knowledgeable / reputable TR specialist (on GT6s) within a hour or so of Oxford .

 

With Thanks

 

Jeremy

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Ok... first work out which it is. Clean the oil off and then see where it's coming from; a very small area between the bottom of the timing cover and the sump, but if it's coming from the front edge of the sump it's easier to sort than from behind the timing cover. Oil from the sump can either be a bent front sump edge, maybe just requiring straightening or even just a new gasket; if the bolts have been overtightened it could be the sealing block along the front edge; again easy enough to replace and you can buy steel versions that won't strip or warp like the original alloy.

If it's coming from behind the timing cover it's probably a crank oil seal; not a difficult job to replace but yes you will upset the timing. There are ways of marking the chain and the cam etc so that the chain can be replaced afterwards in exactly the same position, so you don't have to worry about resetting the timing, but first make sure that's what you need to do. 

 

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a useful tip for leak finding is clean of the leak , use brake cleaner , in aerosol or 5 litre  cans   very useful degreaser clean to use

then give the zone a good puff of talk or french chalk  the leak will show as a trace thro ' the talc    might even smell nice !!!

the one big problem with the main bearing bridge is use of long set screws that bottom out and strip the alloy bridge , its quite common 

you can change a timing cover oil seal wont upset any cam timing , read the manual to see how to get the tensioner back over the chain when replacing the cover

the seal is just a tap in fit  , always try to buy a metal cased oil seal  the plastic repro ones dont always stay put  its a shallow cover  pressing and they fall out 

when you re insert the pulley 

do not gorilla the sump bolts a good nip is all thats needed note the clues about theres a number of long and short bolts on sump and timing cover 

short less of a problem but fit a long where a short goes and they bottom out and can strip or not clamp anything 

https://www.canleyclassics.com/?catalogue=triumph-gt6-mkiii&diagram=triumph-gt6-mkiii-camshaft-timing-details-distributor-pedestal

https://www.canleyclassics.com/?catalogue=triumph-gt6-mkiii&diagram=triumph-gt6-mkiii-plates-sump-rear-oil-seal-dipstick-lifting-eyes

Pete

 

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Jeremy

There is an alloy sealing block under the timing chain cover. The bottom timing chain screws/bolts and two sump bolts go into it. As it's alloy and 40 years old the threads can strip. If bolts or screws won't tighten the threads are stripped and will leak oil. Steel replacements are available from the club shop. Not too bad of a job to replace, I have had to do both my spitfire and 2500 recently. Cured the leak in that area.

If the sump bolts at the front won't tighten that's the problem

hope this helps

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+1 for sulzerman. Obviously gravity plays a part in where you might see a leak, especially along seams but it was the sealing bar for me and it is a common problem if original alloy. I did mine with the engine out so can’t comment on ease of doing in situ! Good luck!

Adrian

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Thanks All for the advice and guidance , have just done the baby talc technique and pic attached. I guess it is radiator out and then careful dismantle of fan etc to get to the point of being to pull off cover. I have a Haynes manual arriving mid week so won’t do anything until I’ve read through and done more google research . If anyone could send me the link to the steel upgrade piece that would be great.

just curious about the circle on the lower left that looks like it has oil in it , is this meant to have a bolt in it ? 
 

cheers 

ADB9033D-B2D4-4F34-A766-7073A0157356.jpeg

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Hi Jeremy

 

I'm assuming MK3 GT6 given your reference to TR6 (GT6) specialist. My car was in a lot worst state than that (I think the rust prevention system (leak) was turned up too high!!), the before picture interestingly shows my bolt heads in the two inner holes and not the outer two. You can see the inner two bolts anchor into the sealing bar (the shiny bar in the third photo (engine bottom to right). I changed the chain and the sprockets, you can see the sprocket teeth are pointed and asymetrical showing wear in the second picture. I'm no mechanic and the GT6 was the first car I've taken apart other than the odd brake piston, but provided you're careful and mark everything, you might surprise yourself, I certainly patted myself on the back when I did it, and when you get lost there's always someone here who can help. I was very nervous that things might turn and throw everyting off but it needs more than a feather touch to move them.

I used a bent nail to retain the tensioner when the cover went back on.

I'd suggest you grab the workshop manual as well. 

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2 hours ago, Adrian said:

Hi Jeremy

 

I'm assuming MK3 GT6 given your reference to TR6 (GT6) specialist. My car was in a lot worst state than that (I think the rust prevention system (leak) was turned up too high!!), the before picture interestingly shows my bolt heads in the two inner holes and not the outer two. You can see the inner two bolts anchor into the sealing bar (the shiny bar in the third photo (engine bottom to right). I changed the chain and the sprockets, you can see the sprocket teeth are pointed and asymetrical showing wear in the second picture. I'm no mechanic and the GT6 was the first car I've taken apart other than the odd brake piston, but provided you're careful and mark everything, you might surprise yourself, I certainly patted myself on the back when I did it, and when you get lost there's always someone here who can help. I was very nervous that things might turn and throw everyting off but it needs more than a feather touch to move them.

I used a bent nail to retain the tensioner when the cover went back on.

I'd suggest you grab the workshop manual as well. 

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Adrian, thank you ever so much for the pics and encouragement, pics speak a thousand words and can really helpful. Cheers 

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3 hours ago, dellyend1 said:

Thanks All for the advice and guidance , have just done the baby talc technique and pic attached. I guess it is radiator out and then careful dismantle of fan etc to get to the point of being to pull off cover. I have a Haynes manual arriving mid week so won’t do anything until I’ve read through and done more google research . If anyone could send me the link to the steel upgrade piece that would be great.

just curious about the circle on the lower left that looks like it has oil in it , is this meant to have a bolt in it ? 
 

On our cars its worth checking the tightness of all bolts regularly. I dont know if its down to the heating and cooling effect or vibration or poor spring washers but on my car I can always find loose ones which obviously doesnt help sealing.

Those empty holes should have bolts in - I believe the early bridge pieces only had one forward facing tapped hole and the later ones 3 (as can be seen in Adrians steel replacement). Your front plate looks like it should be used with the later type so you need to see if your bridge has the corresponding holes and in useable condition...

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looking at your talc test you may just need a light re nip of the bolts ,, no gorilla hands  just a nice feely nip 

the seal does not seem to be leaking  

the hole may just be full of leaked oil but test the hole has a thread , and fit a setscrew if it has with some sealer on the threads 

the mix of how many fixings is the hang ups of the model evolution , its not disaster 

steel sealing block from club shop    put   "block " in the search box or you wont ever find it 

you must be a member and logged in to the main site to get the members discount 

this is non members price https://shop.tssc.org.uk/product/front-engine-sealing-block

the alloy block provining it has the correct hole layout is fine providing its not been gorilla hands or long bolts fitted .

you cant wreck the steel replacement and yes it must have the wooden packers to seal the sides 

but a re nip  is worth a test to save a lot of unnecessary work  always do the easy as a first option 

Pete

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The torque for sump bolts is 8-10 lb ft according to the manual,  but even that can be too much for the threads in the alloy sealing block.  A good quality gasket with the bolts nipped up little more than finger tight will suffice. 

Also consider whether the gasket between front engine plate and block may be leaking, hard to distinguish from a problem with the sealing block. Again, this join needs a good quality gasket plus sealant,  Reinzosil or Three Bond 1215 work well. Traditional gasket jointing compounds don't always work for this join,  something I learned the hard way! 

Nigel

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Not to mention that over tightening of the bolts can lead to distortion of the sealing face. Might be more a sump thing but check face of cover for trueness with a straight edge, if you end up removing.

Thats interesting Nigel I had some wellseal but thought it looked a bit too runny so used my remaining golden hermatite. It would be useful if somewhere on the site we could list good consumables for certain applications!

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Jeremy

I understand that there are two versions of the alloy bridge piece. The later version has the two additional inner holes.

My 1969 GT6 came with the original bridge, but I managed to procure one of the later ones (from Mike Papworth if IRRC) and drilled the front engine plate to suit, so I now use all the possible fixings. Photo attached.

Hylomar Blue is generally my sealant of choice. Care is needed with the tightening as others have said.

I dare say the club's steel version will solve most problems if you choose to follow that route.

Ian

 

 

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38 minutes ago, Ian Foster said:

Jeremy

I understand that there are two versions of the alloy bridge piece. The later version has the two additional inner holes.

My 1969 GT6 came with the original bridge, but I managed to procure one of the later ones (from Mike Papworth if IRRC) and drilled the front engine plate to suit, so I now use all the possible fixings. Photo attached.

Hylomar Blue is generally my sealant of choice. Care is needed with the tightening as others have said.

I dare say the club's steel version will solve most problems if you choose to follow that route.

Ian

 

 

DSC_7975.JPG

I bought a steel version from Jigsaw (now sadly gone) and it has the extra threaded holes Ian describes. The Club Shop version also has these holes:

https://shop.tssc.org.uk/search?search_api_views_fulltext=sealing+block

Nigel

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Jeremy

A further thought.

If your front engine plate has the inner holes, then it is possible that you have the matching (later) bridge installed and a gasket without the holes has been fitted. (do gasket sets include both flavours?)

It might be worth trying to penetrate the gasket to confirm. Might save you a lot of effort and negate an unnecessary purchase.

Ian

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15 hours ago, Colin Lindsay said:

Still selling them on eBay, but incredibly high postage rates.

If you contact Mark directly (e-maul can found in the eBay listing) he can work with you on shipping...

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Thank you all for the support and guidance and as an update / closure : 

1. Have tightened up all bolts and swapped a couple for new that were a bit ropey

2. Tried piercing the gasket where the two bolt holes on the cover plate are and it is solid so assume I have a later timing cover and older alloy block

I think it will be a case of living with it for the summer ( as just got the car) and when winter approaches I will attempt to install the new steel block and new gaskets. Hoping that it is not the gasket behind the timing plate. 

Many Thanks once again.

 

Jeremy 

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If it is just the thread stripped in the alloy block you can always Helicoil it. I got the kit for £25 of eBay and it has worked a treat. It saves having drain the oil and drop the sump.

Mark

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