• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

Rear crank seal oil leak BN2

swiss

Freshman Member
Offline
Hi, I have a freshly rebuilt BN2 engine which has been fitted with a rear oil seal on the crankshaft.

After a hard drive, the oil seems to collect somewhere in the bell housing, and when I slow down or stop, a ton of oil comes out quickly, making a thick slippery spot about a foot in diameter! I estimate 200 miles per quart. Not good numbers for a freshly rebuilt engine. There is always real mess anywhere it stops, along with an ugly dotted line from the road to the parking space. Leaking occurs mostly after high speed running and climbing hills. Short trips under 5 miles or so leave small spots.

This engine has been rebuilt by a "Healey specialist" who currently cannot tell me what the problem is. will remove gearbox soon to analyse the problem

Does anyone have experience with these seals?
Does anyone have instructions how this should be fitted to the 4 cylinder engine?
What modifications are needed to the crankshaft?
what to look out for when inspecting?
 

kkaa

Jedi Hopeful
Offline
Sounds like your sure its oil and not gearbox fluid? Is your pressure ok?

I also installed the same unit from ah spares, but he has to make sure its not installed backwards, meaning the spring thats around the rubber ring has to be on the inside, closer to the block. Sounds like if he is a healey specialist, this would be a silly thought, but if backwards, oil everywhere.

Also, the rear main seal, it is two plugs. Hope he added them. There the width of a number 2 pencil, and could certainly pour oil if missing.

Im sure more people with a lot more experience will chime in, and really hope its an easy fix...

Hi, I have a freshly rebuilt BN2 engine which has been fitted with a rear oil seal on the crankshaft.

After a hard drive, the oil seems to collect somewhere in the bell housing, and when I slow down or stop, a ton of oil comes out quickly, making a thick slippery spot about a foot in diameter! I estimate 200 miles per quart. Not good numbers for a freshly rebuilt engine. There is always real mess anywhere it stops, along with an ugly dotted line from the road to the parking space. Leaking occurs mostly after high speed running and climbing hills. Short trips under 5 miles or so leave small spots.

This engine has been rebuilt by a "Healey specialist" who currently cannot tell me what the problem is. will remove gearbox soon to analyse the problem

Does anyone have experience with these seals?
Does anyone have instructions how this should be fitted to the 4 cylinder engine?
What modifications are needed to the crankshaft?
what to look out for when inspecting?
 
OP
S

swiss

Freshman Member
Offline
Oil pressure 50ish when cold and lower when hot. this is the AH Spares kit as well. It must be engine oil rather than gearbox oil because the gearbox does not need topping-up on every run. "Silly thoughts" are also welcome.
 

HEALEYJAG

Jedi Warrior
Offline
Had my 100 rebuilt too, just finishing 500 mile break-in, no smoke no leaks. I gave my rebuilder the awsome article in the AH club mag about the various modifications he had to do to the kit to get it to work properly.... so far so good.. Boy..you must be frustrated!!!!

Pete
 

TonyR

Senior Member
Offline
I have fitted the same kit, it should be sealed in place with a large amount of silicon. It worked for me.
Do not be disheartened, it can easilly be fixed,

Tony
 

Healey 100

Jedi Warrior
Offline
My Healey 100 leaked vigorously from the same area after a rebuild -- it leaked quite a bit before the rebuild, but after was even worse. I did not fit the aftermarket seal because I didn't want to modify my crankshaft. Several attempts to correct the problem were not effective, including resealing the bearing housing cork plugs, checking the gearbox front cover and redoing the rear plate/engine gasket. ( all you Healey folks know how difficult each of these repairs are). What finally corrected the problem still seems amazing to me: I removed that 5/16 drain tube that drains oil from the rear bearing gallery into the oil pan. It made an enormous difference. This tube is just too small to drain the oil fast enough and it eventually overfills the gallery and leaks out the crankshaft -- with or without a seal. I strongly recommend you remove the tube. It costs nothing to leave it out and it made a big difference on my 100. I can't see what value the tube offers. I have several vintage engines with similar rear main drains and no tube. That is what made me decide to try leaving it off. I have driven the car 5 or 6K miles since with no problems and very small rear seal oil leaks.
 
5

57_BN4

Guest
Guest
Offline
Hi Swiss,

If your engine guy pulled the brass oil gallery plugs for the rebuild and then reinstalled new ones, it is possible that they weren't filed flat afterwards which will result in the rear plate sitting away from the block by the corresponding amount. This would allow oil to leak out of the camshaft bearing. Even with no uprated seal fitted they didn't leak that much so something other than the new seal isn't right.

Oil is coming out when you slow down because the flywheel is acting like a fan and blowing it up around the inside of the bellhousing. I'd suggest don't drive the car any more because you'll get oil on the clutch.

Andy.
 
OP
S

swiss

Freshman Member
Offline
Hi Swiss,

If your engine guy pulled the brass oil gallery plugs for the rebuild and then reinstalled new ones, it is possible that they weren't filed flat afterwards which will result in the rear plate sitting away from the block by the corresponding amount. This would allow oil to leak out of the camshaft bearing. Even with no uprated seal fitted they didn't leak that much so something other than the new seal isn't right.

Oil is coming out when you slow down because the flywheel is acting like a fan and blowing it up around the inside of the bellhousing. I'd suggest don't drive the car any more because you'll get oil on the clutch.

Andy.

I think the clutch is still dry, and I'm not driving at the moment. I will check on the brass oil gallery plugs
 

TimK

Jedi Knight
Silver
Country flag
Offline
Hi Swiss,

If your engine guy pulled the brass oil gallery plugs for the rebuild and then reinstalled new ones, it is possible that they weren't filed flat afterwards which will result in the rear plate sitting away from the block by the corresponding amount. This would allow oil to leak out of the camshaft bearing. Even with no uprated seal fitted they didn't leak that much so something other than the new seal isn't right.

Oil is coming out when you slow down because the flywheel is acting like a fan and blowing it up around the inside of the bellhousing. I'd suggest don't drive the car any more because you'll get oil on the clutch.

Andy.
With all due respect, wouldn't a leak from the camshaft bearing flow down on the other side of the engine plate, not into the bellhousing?

Another thought would be the modification to the engine plate. I did my 6-cylinder and used a sawzall to modify the engine plate, not sure what mods needed on the 4-cylinder engine. But if the plate needed modification to fit the new seal, it may have been cut out too large.
 
OP
S

swiss

Freshman Member
Offline
My Healey 100 leaked vigorously from the same area after a rebuild -- it leaked quite a bit before the rebuild, but after was even worse. I did not fit the aftermarket seal because I didn't want to modify my crankshaft. Several attempts to correct the problem were not effective, including resealing the bearing housing cork plugs, checking the gearbox front cover and redoing the rear plate/engine gasket. ( all you Healey folks know how difficult each of these repairs are). What finally corrected the problem still seems amazing to me: I removed that 5/16 drain tube that drains oil from the rear bearing gallery into the oil pan. It made an enormous difference. This tube is just too small to drain the oil fast enough and it eventually overfills the gallery and leaks out the crankshaft -- with or without a seal. I strongly recommend you remove the tube. It costs nothing to leave it out and it made a big difference on my 100. I can't see what value the tube offers. I have several vintage engines with similar rear main drains and no tube. That is what made me decide to try leaving it off. I have driven the car 5 or 6K miles since with no problems and very small rear seal oil leaks.

Hi, do you mean the tube on the right in this picture? There is also an extra oil hole which has been drilled to increase the flow. It also has a metal plate welded as a flap in front of the second hole in order to prevent oil going up the hole in a wave when accelerating. That seems sensible to me
P1000487.jpg
 
Last edited:
OP
S

swiss

Freshman Member
Offline
had my 100 rebuilt too, just finishing 500 mile break-in, no smoke no leaks. I gave my rebuilder the awsome article in the ah club mag about the various modifications he had to do to the kit to get it to work properly.... So far so good.. Boy..you must be frustrated!!!!

Pete
really frustrated!!!!
 

Healey 100

Jedi Warrior
Offline
Swiss:Yes, the tube in question is pictured in your post. Note the small diameter inside that tube, it cannot pass enough oil to keep the oil gallery from filling. The end of this tube is submerged in the oil pan. Just unthread it from the bearing support and leave it off! It does not prevent oil from passing out from acceleration. If the oil level comes up that high during acceleration, it will still pass out with our without the tube in place. When you take the tube off, be sure to check the hole. Make sure there is no debris (such as blobs of gasket sealant or chunks of old gasket) in the hole. Once removed, the amount of oil than can be drained from the rear main oil overflow area will be greatly increased. It certainly worked on my car. Try it, you have little to lose.
 

Healey 100

Jedi Warrior
Offline
Swiss: My Healey does not have that extra hole with the steel flap that yours has. I suspect this is was an modification intended to increase the drainage flow, though it is not clear the hole pictured could end in the oil gallery -- that gallery is to the rear of the main bearing surface, back near the crank rear flange.
 

kkaa

Jedi Hopeful
Offline
Swiss, you may also want to consider since the plates off, buy the aluminum one form AH spares. It was a couple hundred dollars, but saves weight 30lbs or so and very easy to grind out the material needed for the seal to fit properly.
 
5

57_BN4

Guest
Guest
Offline
Been thinking about this discussion for the last couple of days. Ford and others used a very similar design in their engines of the era but instead of the scroll there is a piece of graphite impregnated rope stuffed into a radial slot in the cap/block and there is no drain tube attached to the bearing cap. They rarely leak more than a drip now n then if installed correctly.

2011-12-13_164105_38_cadillac_rear_main_cutaway.gif


I wonder how much of the leaking of the factory setup is entirely due to the tube. Imagine each time the car accelerates and the oil surges to the back of the sump, as the level rises up it traps air inside the tube which must be expelled somewhere to compensate and the only way out is past the scroll.

Think I'll experiment with removing the tube in due course as despite having a seal kit installed I'm still getting a drop on shutdown.

Andy.
 
OP
S

swiss

Freshman Member
Offline
Just took the seal out. The Healey restoration company which has put in the conversion kit has been completely careless in mounting the seal conversion. The crank is machined perfectly, but the seal is not mounted centrally on the crankshaft, meaning there is a gap between the crank and the lower side of the seal. Oil pours through when accelerating, comes out of the bell housing. Case closed.
Meantime on a freshly revised engine, I must replace the clutch plate after 500 Miles
I would have expected more from a Healey workshop. Never again.....
 

pan

Jedi Warrior
Country flag
Offline
It had to be something like that. This is often the cause of oil leaks at the front of the crankshaft as well. The timing cover should not be tightened until the crankshaft pulley is fitted and rotated to centralise it.
Is the clutch disc salvageable? If you haven't done too many miles it might be OK.
 
Last edited:
5

57_BN4

Guest
Guest
Offline
I'm curious to know how adding a seal kit- even a badly fitted one- can increase the amount of oil coming out. Surely a seal kit will still be at least as good as the original scroll? Or does something require modification on the 4 cylinder that eliminates the scroll seal function?

I'll be running the BN2 engine in a few more weeks and have removed the drain pipe from the rear main cap. It has no seal kit (still has original pistons, never been apart). Will be interesting to see how much oil comes out.

Andy.
 
Country flag
Offline
... Or does something require modification on the 4 cylinder that eliminates the scroll seal function?
Andy.

The 100 crank has to have the scroll machined off to install the seal kit. I think the flywheel mounting flange has to be re-radiused as well, but don't recall for sure. The 6-cyls don't need machining (but the bellhousing mounting plate still has to be modified).
 
Similar threads
Thread starter Title Forum Replies Date
R Dennis Welch Rear Crank seal conversion - Gap in back plate Austin Healey 19
T TR4/4A Oil drain hole from rear crank seal/rear main cap Triumph 3
MadMarx TR 3/4 rear crank Viton seal kit Triumph 6
rjc157 moss rear crank oil seal Austin Healey 4
steveg Fun with rear crank seal spring. Austin Healey 12
A Clutch Replacement + Rear Crank Oil Seal Replace? Austin Healey 8
B Rear Crank Seal Conversion Problem Triumph 4
B Torqueing the head, to cure a rear crank leak? Triumph 12
Healey Nut Rear Wiring Routing Austin Healey 2
R TR6 Rear suspension droop restraint Triumph 0
E GT6 Triumph GT6 MKIII rear hatch springs Triumph 2
drooartz Rebuilding rear axle Spridgets 10
S TR2/3/3A rear main seal is leaking Triumph 13
J TR2/3/3A TR3 Rear seat Triumph 11
T crankshaft (rear) bearing leak Spridgets 2
G For Sale: Triumph TR2, TR3, TR3A, TR3B Factory Steel Hardtop, New Rear window, Partial Bracket Set Triumph Classifieds 2
C TR4/4A Advice for grafting TR6 frame front to TR4A frame rear Triumph 14
5 TR2/3/3A Seized rear brakes Triumph 9
fpstude TR4/4A Replacing Rear Flexible Brake Hoses on TR4A w/ IRS Triumph 11
M TR2/3/3A Difficulty Adjusting Tr3A Rear Brakes Triumph 12
chicken BJ7 Rear Number Plate Mounting Austin Healey 3
Healey Nut Rear Wheel Cylinder Mounting Austin Healey 4
S Rear Wing Fit Austin Healey 4
chicken BJ7 Rear Quarter Panels Austin Healey 3
M For sale rear wings Tr6 Triumph Classifieds 3
Healey Nut BT7 Rear Suspension Austin Healey 15
FlyingCat Wanted 1980 Spitfire Rear Bumper Triumph Classifieds 2
M Have a pair of tr6 rear wings Triumph Classifieds 0
D MGB Rear Suspension Damper Link Arm MG 2
S Rear End Noises Spridgets 11
Jeepster Rear Brakes Adjustment Austin Healey 6
M Wanted TR6 Rear Bumper impact Brackets Triumph Classifieds 0
M TR2/3/3A Speedy Sleeve Repair Sleeves for Rear Axle Pinion and Half Shafts Triumph 1
E TR6 74 TR6 - Rear and windshield frame color Triumph 2
M TR2/3/3A Re-Assembling Rear Axle Outer Bearing and Hub Triumph 1
M TR2/3/3A Rear Axle Bearing Grease Triumph 5
8 BJ7 Rear rail trim Austin Healey 0
roscoe Rear end crown and pinion gear swap. 4.11:1 to 3.54:1 [long read] Austin Healey 12
L TR6 Rear Brakes Shoe Repair and Install Triumph 2
G Rear Brake Adjustment Austin Healey 30
Got_All_4 TR5/TR250 Trying to figure out rear transmission mount with a J type tranny Triumph 9
vette MGB Rear Fender Dog Leg Patch Panel MG 3
Martinld123 My left rear wheel is locking up Austin Healey 16
R TR2/3/3A Girling Rear Brakes Triumph 9
J TR6 Differential / Rear Axle Triumph 1
G Noisy Rear Hubs Austin Healey 6
Lotuswins Wanted TR4 H6 rear carb body Triumph Classifieds 4
K For Sale TR3 rear rebound brackets Triumph Classifieds 0
Tr3aguy TR2/3/3A Rear Axle Rebuild Triumph 3
PAUL161 MGB Early B Banjo Rear Gears MG 2

Similar threads

Top