Fixing oil leaks on a four pot TR engine and gearbox

[Ian Vincent]

So hopefully I’ve fixed the sump but now I’m looking at the other oil leaks from my TR3a.

I have a leak from the gearbox that is gradually getting worse, I think it’s the rear oil seal (but there is also a weep from the joint around the o/drive), and I also have a small leak from the back of the engine that I think is the rear crankshaft seal.  The latter is probably a result of my not having enough tension on the spring when I installed the LR lip seal (the crank had already been ground to 63.5mm).

so my question is…..if I remove the gearbox over the winter, (I have a gearbox crane to that shouldn’t be a problem) and take that to someone knows how - e.g. Pete Cox - is it possible to replace the crankshaft rear seal with the engine in situ?

The alternative is I leave well alone and accept having to periodically clean my drive and garage floor.

Rgds Ian

[harlequin]

Ian

The 2 favourite sources for a gearbox leak is the selector rod seals and the speedo drive oil seal, both can be renewed without removing the gearbox and cost pennies.

It is worth changing them out and seeing if it reduces your leaks before doing the heavy jobs

George 

[BlueTR3A-5EKT]

16 minutes ago, Ian Vincent said:

So hopefully I’ve fixed the sump but now I’m looking at the other oil leaks from my TR3a.

I have a leak from the gearbox that is gradually getting worse, I think it’s the rear oil seal (but there is also a weep from the joint around the o/drive), and I also have a small leak from the back of the engine that I think is the rear crankshaft seal.  The latter is probably a result of my not having enough tension on the spring when I installed the LR lip seal (the crank had already been ground to 63.5mm).

so my question is…..if I remove the gearbox over the winter, (I have a gearbox crane to that shouldn’t be a problem) and take that to someone knows how - e.g. Pete Cox - is it possible to replace the crankshaft rear seal with the engine in situ?

The alternative is I leave well alone and accept having to periodically clean my drive and garage floor.

Rgds Ian

if it has an original simple 2 half aluminium scroll seal then……Engine rear oil seal could be replaced in situ The challenge will be getting the new one concentric with the crank.   It must not touch the crank once installed or it fails to seal.    Doing the job on the floor would be a real tease.   On a ramp it would be a lot easier.   Are you sure it is the rear seal leaking?    It could be a couple of other things.    
The cam shaft rear core plug?  

The felt seals down each side of the rear main bearing cap?  

Rear of the rocker cover gasket?

 

I had an issue that I thought was rear crank seal and confirmed it by running the engine with the flywheel removed.   You will need a starting handle to get the engine going as there is no flywheel for the electric starter to work on.

I could see the oil dribbling out of the oil seal when the engine was running.

 

 

 

 

[Ian Vincent]

12 minutes ago, harlequin said:

Ian

The 2 favourite sources for a gearbox leak is the selector rod seals and the speedo drive oil seal, both can be renewed without removing the gearbox and cost pennies.

It is worth changing them out and seeing if it reduces your leaks before doing the heavy jobs

George 

Thanks, rod seals have already been sorted so I’ll take a look at the Speedo drive seal when I’ve got a moment.

Rgds Ian

[Ian Vincent]

1 minute ago, BlueTR3A-5EKT said:

if it has an original simple 2 half aluminium scroll seal then……Engine rear oil seal could be replaced in situ The challenge will be getting the new one concentric with the crank.   It must not touch the crank once installed or it fails to seal.    Doing the job on the floor would be a real tease.   On a ramp it would be a lot easier.   Are you sure it is the rear seal leaking?    It could be a couple of other things.    
The cam shaft rear core plug?  

The felt seals down each side of the rear main bearing cap?  

Rear of the rocker cover gasket?

 

I had an issue that I thought was rear crank seal and confirmed it by running the engine with the flywheel removed.   You will need a starting handle to get the engine going as there is no flywheel for the electric starter to work on.

I could see the oil dribbling out of the oil seal when the engine was running.

 

 

 

 

It doesn’t have the scroll seal Pete, it has the LR lip seal.  I can remove the gearbox without too much difficulty but to remove the engine I would need to borrow an engine crane and it’s a whole lot more of a task.

if, and I repeat if, I decide to remove the gearbox it should be pretty straightforward to remove the flywheel and replace the lip seal assuming it’s possible and do it properly this time.  Hence my question.

Rgds Ian

 

[BlueTR3A-5EKT]

11 minutes ago, Ian Vincent said:

It doesn’t have the scroll seal Pete, it has the LR lip seal.  I can remove the gearbox without too much difficulty but to remove the engine I would need to borrow an engine crane and it’s a whole lot more of a task.

if, and I repeat if, I decide to remove the gearbox it should be pretty straightforward to remove the flywheel and replace the lip seal assuming it’s possible and do it properly this time.  Hence my question.

Rgds Ian

 

 You can probably fiddle it.

   The seal has to be wrapped round the rear area and inserted into a groove in the seal housing

Do not forget to get the spring to the revised length to ensure it grips sufficiently.   It is in the Tony Drew’s engine build techniques.

quote

http://www.tonydrews.com/uncle_jacks_engine_building_tips.htm#Crank

 

Crank

      1.     If you are going to install the aftermarket rear seal, have the seal surface of the crank turned to 2.525 – whatever the current instructions may say. These seals are leaky and they need all the help they can get. The lip tension is too low. Therefore, measure the length of the spring and alter it to be exactly 8”  long.

[Ian Vincent]

20 minutes ago, BlueTR3A-5EKT said:

Crank

      1.     If you are going to install the aftermarket rear seal, have the seal surface of the crank turned to 2.525 – whatever the current instructions may say. These seals are leaky and they need all the help they can get. The lip tension is too low. Therefore, measure the length of the spring and alter it to be exactly 8”  long.

It’s too late for that Peter, my crank has already been turned down to 2.5” (63.5mm), in line with the instructions that came with the original seal and repeated in Neil Revington’s instruction sheet for his version of the seal.  When I rebuilt my engine, I bought a replacement seal from Revington and the lip was quite stiff, so much so that the seal wouldn’t completely close around the machined area of the crank.  I foolishly assumed that the seal would close up when it was forced into the aluminium housing, and didn’t shorten the spring to make that happen.  The very slight leak I’m seeing from the back of the engine suggests otherwise.  And incidentally, it isn’t the back end of the camshaft leaking as that was sealed with JB weld.

Rgds Ian

[BlueTR3A-5EKT]

1 hour ago, Ian Vincent said:

It’s too late for that Peter, my crank has already been turned down to 2.5” (63.5mm), in line with the instructions that came with the original seal and repeated in Neil Revington’s instruction sheet for his version of the seal.  When I rebuilt my engine, I bought a replacement seal from Revington and the lip was quite stiff, so much so that the seal wouldn’t completely close around the machined area of the crank.  I foolishly assumed that the seal would close up when it was forced into the aluminium housing, and didn’t shorten the spring to make that happen.  The very slight leak I’m seeing from the back of the engine suggests otherwise.  And incidentally, it isn’t the back end of the camshaft leaking as that was sealed with JB weld.

Rgds Ian

I did an engine a short while back with this lip seal already fitted and took a 1/4” off the spring of the new seal to get it to the 8” length.   I installed a new seal and polished the crank sealing area.   That crank was already machined to 2.5” and the engine was and still is running leak free.

[Z320]

Hi Ian,

having a pit I have easy excess down under the car, this is what I do since a decade (?):

from time to time I renew a wrap made from kitchen paper, fitted between oil pan and gearbox.

The number of sheets is suitable to slide the wrap in but solid enough to hold it in position by the 2 lower bolts and nuts of the gear box.

Ciao, Marco 

 

[Ian Vincent]

8 hours ago, Z320 said:

Hi Ian,

having a pit I have easy excess down under the car, this is what I do since a decade (?):

from time to time I renew a wrap made from kitchen paper, fitted between oil pan and gearbox.

The number of sheets is suitable to slide the wrap in but solid enough to hold it in position by the 2 lower bolts and nuts of the gear box.

Ciao, Marco 

 

That sounds like a very un-German way of solving the problem Marco , and I can say that because my wife was half German (on her mum's side) and if something had to fixed - usually by me - it had to be done properly.

Rgds Ian

[Z320]

I have two hearts….

[Waldi]

Well done Marco,

it appears you have properly integrated in the British car engineering club.
You can now apply for certification.

Waldi

[Z320]

1 hour ago, Waldi said:

Well done Marco,

it appears you have properly integrated in the British car engineering club.
You can now apply for certification.

Waldi

A dream is coming true for me,

just a few days before my 60th birthday.

I'm really deeply moved....

[Pontious]

On 11/6/2024 at 6:48 AM, Z320 said:

Hi Ian,

having a pit I have easy excess down under the car, this is what I do since a decade (?):

from time to time I renew a wrap made from kitchen paper, fitted between oil pan and gearbox.

The number of sheets is suitable to slide the wrap in but solid enough to hold it in position by the 2 lower bolts and nuts of the gear box.

Ciao, Marco 

 

Works for me too!

[Bfg]

21 hours ago, Waldi said:

Well done Marco,

it appears you have properly integrated in the British car engineering club.
You can now apply for certification.

Waldi

[Ian Vincent]

On 11/6/2024 at 6:48 AM, Z320 said:

Hi Ian,

having a pit I have easy excess down under the car, this is what I do since a decade (?):

from time to time I renew a wrap made from kitchen paper, fitted between oil pan and gearbox.

The number of sheets is suitable to slide the wrap in but solid enough to hold it in position by the 2 lower bolts and nuts of the gear box.

Ciao, Marco 

 

When you are next down there, any chance of a photo please Marco?

Rgds Ian

Edited November 7 by Ian Vincent

[Z320]

no mystery,

that perhaps 10 sheets, slacky rolled

 

[Ian Vincent]

Brilliant. I love it. That’s definitely a ‘Bodge’. 

Thks Ian

[RobH]

That's not a bodge ---- THIS is a bodge:

[Hamish]

There is always one that doesn’t quite line up ! 
 

 

 

[roy53]

Or in this case one that dose

[BlueTR3A-5EKT]

And one from  the fairy tradesman 

[Z320]

Back to the question,

(in my opinion) I don’t dismantle a good and working engine only because of some drops of oil from the crankshaft.

If this has to be done because of another reason I will fit the Christian Marx oil seal.

Until this I have other projects.