Thread: Blowby

Originally Posted by Blknight.aus

dont forget to check the back of the bottom half of the rear main seal housing for the mod hole thats the oil leak back to the sump. it stops your rear main from having to hold back main oil pressure and puts it back to plain old splash oil only.

Originally Posted by Dougal

Got any more info on this Dave?

Land Rover 4BD1's mount the seal in the flywheel housing, where the truck engine has a separate seal housing, so there may be some difference in small details like drain holes.

i have one of those BYG 2767 seals, but haven't fitted it yet. May pull the seal housing and fit the new seal later in the week so will check it out further then.

BTW the seal is branded CR, which stands for Chicago Rawhide (a large seal manufacturer bought out by SKF). But going by the label it was probably manufactured in Japan.

rough as gutsly....

the mod is about a 3mm hole drilled at about a 40 degree downwards angle through the base of the seal mount more towards the front of the engine than where the traditional seal sits.

I'll see if I cant dig up the EMEI.

would it make a difrence if you have the winged or truck sump ?

Dougal
When you had the speedi-sleeve fitted, did you size it according to the seal ID or the crank OD??
When sleeving, you need to ensure the crank has a relief machined to take the sleeve leaving it with the original seal run diameter. If you use a sleeve that just goes over the original seal face, it will stretch the seal and put higher face load on it causing it to wear, not to forget that it makes the lip edge sit at a different angle on the crank.

Originally Posted by LOVEMYRANGIE

Dougal
When you had the speedi-sleeve fitted, did you size it according to the seal ID or the crank OD??
When sleeving, you need to ensure the crank has a relief machined to take the sleeve leaving it with the original seal run diameter. If you use a sleeve that just goes over the original seal face, it will stretch the seal and put higher face load on it causing it to wear, not to forget that it makes the lip edge sit at a different angle on the crank.

The seal is ontop of the crank surface, increasing the diameter by about 2/3 of a millimetre.
It's not seal wear as even new seals weep. Tightening the energising spring helps a little but doesn't cure the problem.

Originally Posted by Dougal

The seal is ontop of the crank surface, increasing the diameter by about 2/3 of a millimetre.
It's not seal wear as even new seals weep. Tightening the energising spring helps a little but doesn't cure the problem.

It wont cure it because the extra diameter makes the seal lips expand away from each other causing it to flatten out, even with such a small increase in diameter.
Either that or you just have a crap seal.
I dont have all my info on hand now as I have left SMS Diesel and moved to R. Moore & Sons Diesel Engineers, but I will see if I can find out any differences for you. Give me a couple of days.

Cheers

Andrew.

Not a commercial banner here, but this job is FAR more interesting! Have a look at the website gallery and see what I get to play with now!! Check out the Waukesha!

R.Moore & Sons - Diesel Engineers

Originally Posted by LOVEMYRANGIE

Either that or you just have a crap seal.

That's my suspicion. I'll throw in a better one next time I have the engine out and see how it goes.
I had a short holiday with no seal leaking, that was between the time I fitted my new crank main bearings and the time I flogged it hard up that mountain pass.

Originally Posted by LOVEMYRANGIE

I dont have all my info on hand now as I have left SMS Diesel and moved to R. Moore & Sons Diesel Engineers, but I will see if I can find out any differences for you. Give me a couple of days.

Cheers

Andrew.

Not a commercial banner here, but this job is FAR more interesting! Have a look at the website gallery and see what I get to play with now!! Check out the Waukesha!

R.Moore & Sons - Diesel Engineers

That's a nice 1500hp dyno you have there.

Originally Posted by Dougal

That's my suspicion. I'll throw in a better one next time I have the engine out and see how it goes.
I had a short holiday with no seal leaking, that was between the time I fitted my new crank main bearings and the time I flogged it hard up that mountain pass.



That's a nice 1500hp dyno you have there.

Mmmmmmm isnt it!!! Wonder if I can clock it with the Rangie........ not!!!!
You should have heard the K50 we had on it today with no exhaust at full note!!!

Ok, your seal, did some checking. Two dimensions based on year.
Up to 1984 - dimensions 135x100x10
'84 on - 135x100x15.

At SMS we never carried the early seal and AFAIR the later seal was not a supercession because of a carrier change/difference.
Check to see you havent had a 10mm seal put in place if it originally had 15mm one. Other than that, i would really be checking crank dia and making sure its 100mm exactly.
And OEM for the seal should be Ishikawa, but NOK would be as good if not better.

Cheers

Andrew.