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Hi, I'm looking for some advice. I'm working through jobs on the TR3A through lock down. Not a great deal to do at weekends. I took the propshaft off to change the seal on the diff, have found some grinding on one UJ so changing both so I don't end up doing the a year later. 

       I've been thinking about the rear Crank seal which has the usual smallish leak. Been like this for years and I'm not at a point I want to take the engine out for this. Although I plan to change the front crank seal and the engine mounts so would be part way there. The thought of removing it and taking the crank out just seems a step too far for things to fill the days in lock down. I'm a little confused and struggle to understand why the upgraded Karl Marx rear seal cannot be fitted with the crank still in and therefore the engine in situ with the gearbox removed. I'm thinking that taking the box out (which I've done before) is relatively easy. 

     Am I dreaming, do you really need to take the crank out to fit this and use the tool? It's not much of a leak so I can live with it if it really is an engine out job but would welcome experience. I have looked in the search facility which I seem to struggle with but I haven't found anything that confirms this cannot be done. 

Neil

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Hi Neil,

as you may appreciate everybody takes the crank out - probably.

I think the difficulty would be to remove the scroll clam shell TRapped between the crank and block.

If that comes out then the Christian Marx shell should fit reasonably easy(ish).

When the crank os not there then a mandrel is used to centre the shells and seal. 

With the crank in place then the mandrel can't be used -  but!!! the crank itself should be able to do this.

You would be doing this (if it is possible) upside down.

 

Roger

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Having recently fitted the MM seal while rebuilding my engine I can throw some light on this.

With the flywheel, & sump off you would have to remove the rear main bearing cap (the manual shows how to make a simple puller to do this) this also takes away half of the scroll seal. you would then have to undo the three bolts securing the other half of the seal to the block. Then you should be able to swing that half around the crank so that it can be removed downwards.   Replacing the new one is basically the reverse procedure, plus fitting the viton seal over the crank, & getting the spring into it's groove (fit that before the metalwork). Then fit the main bearing cap, pulling the two halves of the seal together, press the viton seal into place, & centralise the two halves (normally a mandrel is used to centralise the scroll on the crank, but you can't do that, but luckily the viton seal will probably do this quite well).

Tighten up the 6 bolts on the seal halves.

The bearing cap will then need to be sealed to the block using sealant soaked strips of felt, & then re-assemble flywheel etc.

Note sealant should be used on the inside flat surfaces of the new seal, & also on the edges where they meet.

Bob.

Edited by Lebro
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23 minutes ago, Lebro said:

Having recently fitted the MM seal while rebuilding my engine I can throw some light on this.

With the flywheel, & sump off you would have to remove the rear main bearing cap (the manual shows how to make a simple puller to do this) this also takes away half of the scroll seal. you would then have to undo the three bolts securing the other half of the seal to the block. Then you should be able to swing that half around the crank so that it can be removed downwards.   Replacing the new one is basically the reverse procedure, plus fitting the viton seal over the crank, & getting the spring into it's groove (fit that before the metalwork). Then fit the main bearing cap, pulling the two halves of the seal together, press the viton seal into place, & centralise the two halves (normally a mandrel is used to centralise the scroll on the crank, but you can't do that, but luckily the viton seal will probably do this quite well).

Tighten up the 6 bolts on the seal halves.

The bearing cap will then need to be sealed to the block using sealant soaked strips of felt, & then re-assemble flywheel etc.

Note sealant should be used on the inside flat surfaces of the new seal, & also on the edges where they meet.

Bob.

Check the length of the flywheel attaching bolts as they may protrude through the rear crank flange and touch the new seal.

  The MM instructions mention this.  

Peter W

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Good point.  Also I think doing my above procedure will not be easy.  The bolts holding the scroll seal on to the block will be hard to get a spanner onto, fitting the viton seal to the crank will be very tricky to do in situ.   You will have to take the gearbox out anyway, so why not remove engine & gearbox together, & do it off the car, where you can replace a few other items while you are at it - bearing shells piston rings etc.  Also to change the front crank seal means lifting the engine up so the pulley clears the central steering rod, then the bolt has to be undone, which could be very hard to do with the front apron in place. 

I would suggest  leave both jobs until you a happy to remove the whole lot, & do everything which needs doing.

Bob.

Edited by Lebro
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33 minutes ago, Lebro said:

Good point.  Also I think doing my above procedure will not be easy.  The bolts holding the scroll seal on to the block will be hard to get a spanner onto, fitting the viton seal to the crank will be very tricky to do in situ.   You will have to take the gearbox out anyway, so why not remove engine & gearbox together, & do it off the car, where you can replace a few other items while you are at it - bearing shells piston rings etc.  Also to change the front crank seal means lifting the engine up so the pulley clears the central steering rod, then the bolt has to be undone, which could be very hard to do with the front apron in place. 

I would suggest  leave both jobs until you a happy to remove the whole lot, & do everything which needs doing.

Bob.

+1

If the gearbox is out it may be worth the Australian ‘O’ ring trick.  Roger posted it here some while back.

Are you sure the oil leak at the back of the engine is not a shrunk rocker cover seal?

Peter W

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11 hours ago, NCS_TR3A said:

Thanks Roger, that makes total sense. And oops on the Karl Marx, comment. Different chap all together. :)

Neil

Hi Neil,

His seals are Red.  Christians are Blue

 

Roger

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17 minutes ago, BlueTR3A-5EKT said:

+1

If the gearbox is out it may be worth the Australian ‘O’ ring trick.  Roger posted it here some while back.

Are you sure the oil leak at the back of the engine is not a shrunk rocker cover seal?

Peter W

Or a leaky core plug behind the camshaft, or a leaky oil gallery plug, or a leaky front gearbox seal

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Hi Neil,

All good info above.  Bob explains clearly the vision I had in mind. It can be done but a great deal of effort.

As Pete states  check that the rocker cover seal is not leaking down the back of the head.

I normally take the engine AND gearbox out together. I find that the GB + OD are too awkward these days. Let the hoist take the strain.

 

The Australian fix for a leaky crank rear seal  http://www.tr-register.com.au/Files/technical/scrollseal.htm

you still need the GB OUT and the flywheel OFF - is it worth it.

With the GB out it may be worth looking at the gear selector rod 'O' rings - they tend to leak

One upgrade that has worked is to use 'Q' seals - they have a cross section like a four leaf clover

Or open out the counter bore where the 'O' rings live and fit a 3/4" lip seal

Also on the centre selector rod you will see a very small drill hole at the end where the gear stick locates. Fill this with epoxy glue - it is a leak source.

 

Roger

 

P1060823a.jpg

P1060824a.jpg

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The "Australian fix" (which I had not seen before) is clever, & would probably work. it does rightly explain that the scroll does need to be exactly centered on the crank to work, hence the need for a mandrel (or the shim method described).

I can vouch for the quality of the MM seal.  I filled my engine with oil before putting it back in the car in order to pump oil around the engine using a cordless drill on the oil pump shaft.  When I was replacing the engine /gearbox combo into the car, the assembly had to be tipped up at quite an angle to get it in. The oil inside would have been covering the rear of the crank completely, & yet no oil escaped, with just the scroll there would have been a flood of oil.

Bob.

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Why using the centering tool?

The reason for the tool is, to put the housing to its center with the ROTATING crank.

If you center to the standstill crank, then you automatically offset the housing about 0,025mm or more (or whatever your bearing clearance is).

This means, that it is likely possible, when the engine is running that the crank is grinding on the housing, damaging the scoll area (that's why the original seal construction of Triumph fails after rebuild) and forcing the lip seal to run offset for ages which rises the wear and tear.

The standard bearing clearance is 0,05mm on the mains, and worn out at about 0,07mm.

The clearance of the housing to crank is 0,1mm. This is enough to cover wear and crank flexing.....but only if these parts are INLINE and not offset.

That's why I recommend the centering tool, to do a proper work.

Check for PROTRUDING flywheel bolts. They will scramble the seal if protruding .

http://www.tr4-racing.de/download/splitseal.pdf

 

20210127_104923.thumb.jpg.076d8b0a37b8e66c7b96d32daea89997.jpg

Edited by MadMarx
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Well done Christian, thanks for adding this information.

Stuart.

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45 minutes ago, Lebro said:

The "Australian fix" (which I had not seen before) is clever, & would probably work.

Interesting idea but it is not sure, which parts are moving and which ones are standing still. If the O-rings starting rotating with the crank....I could imagine on high revs they are shifted away from their position by centrifugal force and might get scrambled somehow.

Edited by MadMarx
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Gents, 

       Thanks for the replies. I've no major issue taking off the front apron, done this before with no major consern. I'm slowly going around the car changing rubber parts as they have been in for 27 years. So engine mounts and gearbox mount are on the cards as well. The only thing that puts fear up me it taking the crank off a perfectly running engine for a small oil leak. I'm pretty sure it is the rear oils seal as I've been through this before. It's not a big leak and everything else seems dry. I've had the gearbox off before to look for leaks and at that time I deduced it was rear Crank so just put it all back together. 

       Given what I have (want) to do it feels like engine out would be the right thing to do. I just need to consider if I have the confidence to strip the bottom end of engine. At the end of the day its just nuts and bolts but it's just the confidence to do it. 

   I do have a spare engine so I can have a look at to determine the risk in me taking on this. Bob, your thread on your engine rebuild has both impressed but made me fear the work (even though this isn't a rebuild). It's truly and excellent thread. Christian, thanks for the explication, I now understand and accept if I take this on its a case of doing it the right way, no short cuts. 

  It feels like do it as part of the other changes or live with the leak, which I could do....... But I have lock down itchy feet. 

Thanks all, 

Neil

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6 hours ago, Lebro said:

Just do it !!

You would say that with your skills :)

I've done a lot on cars but I've never rebuilt an engine or gearbox. Swapped then, changed several head gaskets etc. But no Pistons out (OK I've done a few lawnmowers but they don't count). It's a scary leap.

Neil

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8 hours ago, Lebro said:

Or a leaky core plug behind the camshaft, or a leaky oil gallery plug, or a leaky front gearbox seal

Must admit whilst I've looked before I wasn't aware of the core plug behind the camshaft or the oil gallary plug. Can these be fixed with the engine in if these are part of the problem

Neil

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5 minutes ago, NCS_TR3A said:

You would say that with your skills :)

I've done a lot on cars but I've never rebuilt an engine or gearbox. Swapped then, changed several head gaskets etc. But no Pistons out (OK I've done a few lawnmowers but they don't count). It's a scary leap.

Neil

Gearbox out, from inside the car.

Mick Richards

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8 hours ago, RogerH said:

Hi Neil,

All good info above.  Bob explains clearly the vision I had in mind. It can be done but a great deal of effort.

As Pete states  check that the rocker cover seal is not leaking down the back of the head.

I normally take the engine AND gearbox out together. I find that the GB + OD are too awkward these days. Let the hoist take the strain.

 

The Australian fix for a leaky crank rear seal  http://www.tr-register.com.au/Files/technical/scrollseal.htm

you still need the GB OUT and the flywheel OFF - is it worth it.

With the GB out it may be worth looking at the gear selector rod 'O' rings - they tend to leak

One upgrade that has worked is to use 'Q' seals - they have a cross section like a four leaf clover

Or open out the counter bore where the 'O' rings live and fit a 3/4" lip seal

Also on the centre selector rod you will see a very small drill hole at the end where the gear stick locates. Fill this with epoxy glue - it is a leak source.

 

Roger

 

P1060823a.jpg

P1060824a.jpg

Roger, that's really interesting and I might give that a go with a view that if it doesn't work I can plan to take the engine out. The leak is really small and whilst I'd kind of like to have the experience of delving into the bottom end of an engine it kind of feels I have more to lose than gain. 

Neil

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3 minutes ago, Motorsport Mickey said:

Gearbox out, from inside the car.

Mick Richards

Yes, most my experience is on minis. Bare shell rebuilds, ended up with a metro turbo in having to cut bulkhead and reweld to get the turbo in. Changed the brakes along with it, and changed the diff to get it right for smaller road wheels. Felt fast but not in reality by modern standards. 

   I have had the gearbox out in the TR, I was probably 15 years younger when I did it. But I'm only 50 now and I have a helpful 22 year old who would be involved so I don't see it as a huge job to get the gearbox of on one these. 

Neil

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I have had the gearbox out in the TR, I was probably 15 years younger when I did it. But I'm only 50 now 

Lucky man, wait ‘til your 70 it only gets heavier!

I’m lucky to have helpful, younger, stronger neighbours.....

james

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"so I don't see it as a huge job to get the gearbox of on one these."

Aha...you fell into the trap. it's often getting the  b u g g e  r  back in that's the problem, lining up the splines witrh the clutch plate and being able to rotate the gearbox or overdrive drive flange in 4th gear to "fidget" the splines around whilst pushing it in with your feet normally does the job.

Mick Richards

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