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Rear Main Seal Kit Installation

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TimK

TimK

Jedi Knight
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I would like to share my experience with the aftermarket kit to add a seal to the rear main crankshaft.

I purchased the kit in 1996 from Norman Nock and received all the tools, items, and instructions needed with one exception. I offer this report to help anyone else who is contemplating this project.

I recently retired and finally had the time and inclination to attempt installation of this kit. I removed the transmission, modified the rear engine plate with a sawzall!, put in a new clutch (the old one had started slipping and had oil on it), replaced the bushings for the rear steady bracket (these had dissolved from the oil soaking them, and rear transmission mounts (one of them had completely dissolved in oil). After installing the kit (I ruined the garter spring by trying to stretch it over the crank flange rather than connecting it after putting it on behind the flange (this cost $40 to get a replacement (had to buy a new seal to get the garter spring). After I got the second spring it went together easily. I used the head of a nail and my thumb to coax the spring into the groove of the seal.

After I reinstalled everything and started the engine, I immediately had a major oil leak (one drip per second) and shut it down. <span style="font-style: italic"> It really hurts when trying to fix a problem you create a worse one</span> After removing the trans and back plate, I discovered that my attempt to use RTV sealant rather than get a new gasket between the rear face of engine block and the rear engine plate failed miserably and oil was leaking from the cam bearing opening. Yes, I was an idiot not to replace the gasket, but I thought the sealant would do the job. Yes, I don't have much experience doing this. I recommend this seal kit, but offer this lesson from my experience in case anyone like me tries this. If anyone wants to contact me before they do this job, I'd be happy to share more.
 
I to want to do this installiation but am waiting for retirement or at least closer to then. I think I will print this out and save it. Thank you for sharing the experience.
 
I noticed that Moss also sells a rear main seal. Is it different that the one Norman Nock sells and does anyone have any comments on which is the better seal? Thanks and have a good day!

John
 
Tim,

I'd like to offer advice on acquiring the "Right Stuff" sealant. It is named that way intentionally. It is made by Permatex, which if you google Permatex should take you to a site that answers all your questions.

MB had a sealing problem on the front cover seals on the inline engines for years and years. When I worked at a dealer MB changed the rtv sealant twice that I can recall before they finally started using the "Right Stuff". Front cover seals would leak, every two to three years. Until the "Right Stuff".

So acquire a dispenser of the "Right Stuff". Used to come in a tube and also comes in a "cheez-whiz" type dispenser. When you do use it, make sure you "waste" some of the remaining and leave an extension coming out of the tube/dispenser to pull off and access the remaining sealant in the tube/dispenser as it drives up quickly.

It replaces gaskets, works in oil, I recommend it. A lot of car manufacturers market it in their own packaging(under license from Permatex).
 
Tim,
Your timing is perfect.
I removed my transmission last week. (Yes I did guys). I took it to a Healey transmission specialist. We opened it up and he kept saying hum a lot. Dude, stop saying that. No problem he told me. Everything is fixable. Some wear, some things need replacement and some parts are missing. What?
He told me it will shift like butter when he's done. I will be very happy with it. Right on! I should have done this years ago.

Good time to fix another leak while the tranys out. I purchased the real seal kit, the one that Dennis Welsh makes, from the Nock's.

My mechanic is coming over to my house (what a great guy), for the cars up on jack stands, and we will install it this Friday.

I purchased the kit, a new gasket and the engine plate that the Nock's cut. (I'll be sending them mine. That's a big piece of metal to cut, correctly).

I'll print your experience and let him read it.
Again, thanks for the heads ups and sorry to hear of your extra work. We've all been there. Well... we, as in the guys who attempt to work on our cars. And good for us I say. That is part of owning a Healey.

Happy motoring!
Roger
 
Hi guys

I had a rear main seal kit fitted by the people that did my engine reconditioning and now i can't get my oil pressure above 18-20 psi, i'm just wondering if this wasn't fitted up right then this could be the route of my problem, would i even see an oil leak or would it run into the bell housing ?

Rob
 
The oil would run into the bell housing & be deflected by the flywheel so that it didn't get into the clutch. The small hole in the bottom with the cotter pin in it would allow drainage.

It would not affect oil pressure.
D
 
I forgot to mention that after reading other posts on the forum, I realized that maybe the rear main was not the source of oil on the clutch, but rather the input shaft seal in the bellhousing of the transmission. I replaced that while the transmission was out before putting everything back together. The info I got from the forum was that oil from the rear main does not end up on the clutch, but goes into the bottom of the bellhousing and out the little hole with the cotter pin. Oil from the transmission, however, has a straight shot at the clutch if it runs along the input shaft and gets spun out to the clutch. I'm still glad I did the rear main seal kit. It is well engineered including the drill guide bolt, the drill and the tap needed to thread the holes. I used 10mm bolts instead of 12mm bolts because I had trouble getting the 12's into the hole without removing the flywheel nuts which were a pain to get back in.
 
I've heard that a common leak problem post instalation is that the four holes are not drilled deep enough to go beyond the length of the screws, causing a poor seal against the block.
 
I bought the best drill bit and tap I could find before I did my rear main seal kit that I got from Norm. I added a piece of tape on the drill bit to mark the proper depth when drilling.

When installing the rubber seal with spring I was becoming frustrated trying to get the spring in until I used a scribe tool with a "L" shaped end on it. Once around the rubber and spring and I was done with it in less than a minute.

Be sure to put good gasket sealer on the papergasket when putting the rear engine plate back on especially in the camshaft area. I read someplace that the camshaft area is the source for about 75% of the rear engine leaks.

Use a lot of patience and are when doing this job and refrain from drinking until the "spring is in". I did mine with the engine installed in the car.
Patrick
 
I installed this kit, was fairly straightforward, though the crank needs machining and the back plate opened up a little, anyhow, I crimped the seal when putting it on, you have to be very sure you have it seated right when you tighten it down.
 
I've had 95% success with leaks by doing the following:

1) rear engine plate--masked off the area equivalent to the rear of the engine, sprayed with several thick coats of Permatex spray copper sealant.
2) seal--pinned the ends of the spring into the very ends of the rubber part of the seal that opens.(pix on web site) Sealed the mating surfaces of the seal, as well as the seal carrier and the backing plate of the carrier with Permatex Aviation Formagasket. Allowed to dry.
3) inserted the seal with the spring toward the engine
4) cleaned the rear surface of the rear main bearing 'block' with lacquer thinner, then liberally painted the surfaces with formagasket. Allowed to dry.
5) painted the area around the cam hole with formagasket, allowed to dry.

I have an aluminum sump so was able to do the following:
6) used bonded sealing washers on all the 1/4-28 bolts holding the sump on.

Have pix of this stuff at:
https://www.pbase.com/stevegerow/healey_tech/

One comment--The rear main bearing vertical joints seem to be where much of my oil is coming from--at some point will want to inject silicone or other sealant in there to really seal those holes.
 
Patrick - looks as if we both went through the same processes, I fitted the seal with the engine in the car, I bought new bits and taps, and I drilled in another 1mm due to the bottom plug tap not being flat but slightly rounded that sorted the depth of screw problem out. Again, we came up with similar ideas for the installation of the spring into the seal, I used a bent piece of coat hanger wire, but with a slight U shape on the end - not too deep but it held and fed the spring in effectively when the seal was turned around on the crank. It had taken me an evening and the next morning to figure that one out, but less than a minute to install once the tool was made. When a good plan comes together and all that.

Bob
 
tahoe healey said:
I've heard that a common leak problem post instalation is that the four holes are not drilled deep enough to go beyond the length of the screws, causing a poor seal against the block.
Click to expand...

I agree, I left out that part of my saga. The first time I bolted the kit on with the 12mm bolts it would not pull up tight against the block. I was reluctant to drill deeper and risk messing up the threads, so I used 10mm bolts instead and got a tight seal. I hope the loss of 2mm length will not materially weaken the connection. I measured the drill depth, but the tap provided had a tapered end so didn't get threads down to the bottom of the hole.
 
Bob Hughes said:
Patrick - looks as if we both went through the same processes, I fitted the seal with the engine in the car, I bought new bits and taps, and I drilled in another 1mm due to the bottom plug tap not being flat but slightly rounded that sorted the depth of screw problem out. Again, we came up with similar ideas for the installation of the spring into the seal, I used a bent piece of coat hanger wire, but with a slight U shape on the end - not too deep but it held and fed the spring in effectively when the seal was turned around on the crank. It had taken me an evening and the next morning to figure that one out, but less than a minute to install once the tool was made. When a good plan comes together and all that.

Bob
Click to expand...
And I'll drink a "job well done" toast to yours and my sucess...again. I flattened my taps end also. Cheap tools, innovated techinques!!
Patrick
 
We (MG-T group) have had what seems to be a 50% success rate with the seal kits... not the best result! There is no machining involved on the XPAG engine, but still drilling and tapping. Most have found no leak for a day or so, then a small one is always back.
My mechanic had an AH3000 in a while back and the machining on the crank(?) had made it unusable for rebuild (might have been a different kit)?
 
Here is the Rest of the Story:
I replaced the gasket between the engine and the rear engine plate and used Hylomar sealant. I reinstalled the transmission and started the engine. Same leak, but this time it leaked straight down on the floor. It turns out that the flexible oil line to the oil pressure gauge had cracked (probably when I jacked up the engine the first time I took out the transmission. The first time it had leaked onto the back of the engine plate so I just assumed the plate seal was leaking. I did get some good practice removing and installing the transmission. The second time was a lot easier and quicker than the first time. I have a replacement oil line on order and hope to get the car back on the road next week.
 
For tool usage in the future. A quick tool that helps isolate the source of the leak, for oil leaks, hydraulic fluid leaks.

Get a spray bottle of tinactin or other athletes foot powder.


I guess it doesn't really have to be for athlete's foot. But the Tinactin dries to a powder and if you clean the suspected area, spray with tinactin, let dry, fire it up and you can pinpoint the leak source a lot easier...
 
Another good technique utilizes a product that causes engine oil to fluoresce under black light. It lights-up your oil leaks very well (works best in the dark). I am fortunate in that I work on turbine engines on a daily basis, and turbine oil needs no additive to make it fluoresce under black light. It makes spotting the real source of oil leaks go from being iffy to being obvious, in many cases.
 
I used 10-32 SS Allen screws instead of the supplied metric screws--don't like having metric screws in oddball locations on my car. That said, I used 2 lockwashers on each screw to get it to seat tightly.

Side note: previously had mentioned I pinned the spring ends to the end of each side of the seal, then installed the seal facing inwards toward the engine--happy to report no visible leakage after several weeks of use.
 
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