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BJ8 rear main seal kit - is it necessary and worth the risk to install?

jjs64bj8

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About ready to install rebuilt engine into 64 BJ8 phase II restoration. I was not going to install the rear main seal kit but am having second thoughts before continuing. I have read through most most of the prior posts on the installation and have have a little concern about the risk and the ultimate reward.

SO is the seal really necessary? I have been told that if the car is never parked on a steep slope that should not have a problem and under normal driving conditions also no issues. Is this folk lore or is there some truth to this? The factory never install a seal so what keeps oil from not leaking with no added seal? Once completed the car will get very little use. It will not be a daily driver. So if seal is not installed what can we expect going forward - a clutch disk soaked in oil? If so after how long?

Opinions as I really do not want to do this unless there is a significant advantage.

Thanks

jjs64bj8
 

Jerry

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I think it is an advantage but I only saw the improvement when the new seal is put on properly. I found the best results putting it on with a sealant called "the right stuff". Comes in a can and works on any gasket, it sealed my oil pan so well, I could not get it off!

The drilling for the seal is pretty easy.

Jerry
 

BJ8Healeys

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Yes, I think it is well worth it. I had the rear seal kit installed in my BJ8 engine when I had it rebuilt in 1999. In 2002, I drove the car from North Carolina up to Maryland, and then across the country to Lake Tahoe for the Open Roads Healey International event. I left home with a fresh oil change, and did not have to add ANY oil all the way to Ely, Nevada. At that point, it was 3000 miles so I did another oil change. I drove it home again without having to add any oil. That certainly was less oil consumption than I had experienced before installation of the seal kit. After 80,000 miles on the engine rebuild, I still usually only add about half a quart or less between changes.
 
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We installed one in our BN2 and it still leaks. We were careful and installed per the instructions; however, it was recommended to drill another drain hole on the rear cap and we didn't do that. Plus, we seem to have a lot of pressure in the block and valve cover (it's possible the seal contributes to this). Compression is over 160psi over all four so I don't think blow-by is the problem.

I have a seal for my BJ8 and I'll be facing the same decision some day. Can tell you a couple things I do know: 1) my car leaks more on short, stop-and-go trips than over long highway trips (as measured by oil consumption). I think the 'reverse Archimedes screw' stock 'seal' is more effective at higher speeds, and 2) if you want to minimize oil leaks from the block install a PCV valve--no drilling required and it's reversible. When I installed a PCV my oil consumption went from ~1qt/800 miles to a quart over almost 2,000m.
 
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jjs64bj8

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To Bob_Spidell

I like the PCV valve idea but how and where is it installed? Could you provide a diagram as it might help others as well.

To all, when you say the oil consumption is less when the seal is installed, can I assume the new seal is stopping oil that has leaked past the rear stock seal arrangement. So if you do not have the rear seal then the oil is leaking into the bell housing and could get onto the clutch disk. Right?

More opinions and comments and experiences?

jjs64bj8
 
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Thousand words (got a kit from BCS):

100-0007_IMG.jpg

Note tiny screw to seal breather hole in oil filler cap and (not shown) gasket on dipstick.
 

BJ8Healeys

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To all, when you say the oil consumption is less when the seal is installed, can I assume the new seal is stopping oil that has leaked past the rear stock seal arrangement. So if you do not have the rear seal then the oil is leaking into the bell housing and could get onto the clutch disk. Right?

More opinions and comments and experiences?

jjs64bj8

The original design was an Archimedes screw machined into the crank that "winds" the oil back toward the engine when the crank is spinning. I guess this works reasonably well for 1950s technology, but probably also contributes to the Healey reputation as a "leaker". The seal kit is a modern solution to the problem of stopping leaks. It has a seal with a spring-loaded lip like wheel bearing seals. The Archimedes screw doesn't do much when the engine is stopped. I know I used to get oil drops on my garage floor under the rear of the engine before I installed the rear seal kit and I no longer do. I used much more oil before the seal kit was installed than I do now, but of course I installed the kit during an engine rebuild, too. I never had any problem with oil getting on the clutch, either before or after the kit.
 

Healey Nut

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if you install the regular seals and gaskets correctly and the crankshaft is not damaged in the seal area then the amount of leakage IMHO isn't worth the work to install the kit . I change the oil on my Healeys every season regardless of mileage . (Oil and filters are cheap) . I don't add any oil for the rest of the running season . My cars are not daily drivers but do go on long summer runs and weekends away . My cars have no modifications to fuel ignition or crankcase breathers , they are plain stock .
 

steveg

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I'm currently using a pcv valve setup (similar in concept to Bob's above) in conjunction with the rear seal kit.

Would advocate attention to detail in the seal kit install. Had very good success with Permatex Aviation Form-a-Gasket, painting the area between the seal and the block, between the rear bearing cap and rear plate, and between the cam gallery and rear plate.
See: https://www.pbase.com/stevegerow/image/97270433

In addition, the method of inserting the spring into the seal with straight pins was successful. See: https://www.pbase.com/stevegerow/image/91637854 and succeeding picture.
This allows you to mount the seal with the spring facing the engine.

I also swapped out the metric drill & tap for 5/32" drill and 10-32 tap to keep metric screws off the car.

Be very careful to put tape around the drill so you drill just the right amount and don't get any swarf into the block internals.
HealeyOilSpot.JPGResults, seven years later - small oil spot with car sitting for two months. Caveat: Toyota trans doesn't leak at all.
 

John Turney

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I did the rear seal and PCV valve and had no engine oil leakage in 14 years. (Transmission is another story.)

A couple of months ago, I removed the intake manifold looking for a vacuum leak and found that the tops of intake valves on #5 and # 6 cylinders had a lot of coke on them. Oil vapor would enter the vacuum port at the rear of the intake manifold from the PCV. That oil would collect on those two intake valves and cook. I've removed the PCV valve and went back to venting to the air cleaner. We'll see how the oil leakage goes.
 
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jjs64bj8

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Thanks for all the comments and opinions thus far. I am still on the fence as to install the kit or not, so other please weigh in on this. I really appreciate the response thus far.

For info the crank was in great shape, did not need grinding just a polish, so the rear section should be nice and clean with the new bearings. Thus I would hope the original style sealing arrangement would work as designed. Something to consider in my decision.

If this were a vote it appears that the majority of responders favor the seal installation!

Thanks

jjs64bj8
 

Keoke

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I think the oil seal is a required when the engine gets worn and the pumping action of the factory rear seal degrades. Installation was a little tricky but worked great. I have never had any success with the PCV Valve installation though.
 

CLEAH

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While the engine is out, it seems to make sense to add the items designed to improve weaknesses in the design of these engines. Same for when doing a full rebuild, it makes sense to do the oil gallery sleeves while the engine is apart.
 

Bob Hughes

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When I bought the car 14 years ago, I was leaving puddles of oil everywhere, the clutch started slipping so had to be renewed, Whilst everything was apart, I took the opportunity to install the aftermarket seal whist the engine was in the car. Following the instructions and using a drilling compound to help capture the swarf I found that the drilling and tapping was easy. What I found hard was installing the spring into the seal behind the fly wheel mounting flange. I spent hours getting nowhere, then the penny dropped. using 7 inch piece of coat hanger wire, I flattened one end for about 5mm and bent it around 90 degrees to form a short hook, the other end was formed into a handle, working from under the car, the rubber seal was installed into the aluminium housing (not bolted to the engine) the seal spring was pulled down and connected together, then using the hook and rotating the housing the spring was fed into the seal - less than a minute, then the seal unit was bolted onto the engine with some locktite - job done. The oil loss was greatly reduced but not absolutely free of drips.

Last year the engine was rebuilt and the rubber seal was replaced - much easier to attend to it at that stage than scrabbling around under the car. I still have a slight leak but that may be from another source as I missed a cork seal and used gasket goo instead, I may sort that out one day.

It is your call but it is definitely easier with the engine out and during the rebuild.

:cheers:

Bob
 

Superwrench

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OMG put a seal kit on before you install engine ! Like Steve said, It is 1950 technology that you can improve by about 90%. Either get the square one from Denis Welch or the round one from Ahspares and put it on. They have simple instructions and it will save a lot of headaches down the road !
 

Keoke

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Labyrinth seal as used by the factory is a very expensive type of shaft seal but is not optimum for an automotive engine. Add the updated seal kit.
 

steveg

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...[Snip]...found that the tops of intake valves on #5 and # 6 cylinders had a lot of coke on them. Oil vapor would enter the vacuum port at the rear of the intake manifold from the PCV. That oil would collect on those two intake valves and cook. ....

I was afraid of something like that and built this PCV setup to go into the balance pipe on my DMD manifold:
PCVsetup.JPG
 
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jjs64bj8

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Looks like you all have persuaded me to install the seal. Honestly I was not going to do this and at the last minute decided to post the question and you all have responded. Unless someone overnight says not to proceed with good reason then tomorrow morning it gets ordered. So what the heck, budget is already shot and another week of delay but in the end worth it. Now I need to practice a steady hand for the drilling.

Hope this also helps someone else make the same decision in the future.

THANKS

jjs64bj8
 

steveg

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Keoke, the Healey doesn't have a labyrinth seal. In the linked wikipedia article male discs on the shaft rotate inside matching female areas - any excess oil is slung off by the first disc or two. As far as I know there's nothing like this on the Healey engine.

My understanding is the Healey has a reverse archimedian screw in a bore. Like a meat grinder in reverse. The "threads" move in a reverse direction, in theory always pushing any oil overflow back toward the crankcase.

Perhaps Randy in his vast collection has a picture of this part of the crankshaft.
 
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