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Rear main seal question.

RyanBez

Jedi Hopeful
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Where can I get one? Napa says they are obsolete and I can't seem to find it on the Moss website. Mine is leaking pretty bad and I need to replace it asap. Maybe I'm just not looking hard enough, so if someone has the Moss part # let me know!
 
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They are not obsolete. They never existed. The engine does not have a modern seal. It has a scroll on the crank to draw the oil back into the engine.
 
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However, Gerard does have a retrofit option. He'll probably be along shortly.
 

regularman

Yoda
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If its not leaking while it is running, I wouldn't worry about it. Its kind of normal for them to leak while parked after running because the oil is running back down into the motor and the scroll is no longer scrolling. Especially when the nose is pointed uphill. Certainly not worth pulling the motor over unless its leaking while running. I have seen several times people look under and see oil and think its the rear main when its the oil pressure gauge line leaking and blowing back in that area.
 
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Not sure about that part#. It may be the seal for the front timing chain cover.
 

regularman

Yoda
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BillW103 said:
Is all the crank cast venting working?
Good point. If there is not a vacuum on the crankcase then it will blow out like crazy. I forgot about that. I had that problem at first with my weber intake. I had to make a vacuum hole in the intake and connect to the breather.
 
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RyanBez

Jedi Hopeful
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Yeah, I guess I'm not too sure about the venting. I haven't gotten the engine running and just noticed a bunch of oil leaking when I put oil in the car.

How would I know if the crank venting it working?
 

Jim_Gruber

Yoda
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So Ryan are you working with a 948 first and foremost. Which engine as they were vented several different ways.
 
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RyanBez

Jedi Hopeful
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I have the 1098 engine. I wonder why Napa says that seal fits the 1098 engine...
 

jlaird

Great Pumpkin
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1098 and 1297 have a real seal on the timeing chain cover that looks like that,948 has a felt washer.

None of our engines have a real seal other than the scroll seal spoken to earlier.
 

Gerard

Luke Skywalker
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Trevor Jessie said:
However, Gerard does have a retrofit option. He'll probably be along shortly.

Thanks Trevor.

Ryan,

I do have rear seal conversions for 1098's, both 2" main and 1.75 inch main. If you are not sure which you have, you can give me the engine serial # if you know it. Sequence beginning 10CG is a 1.75 inch main, 10CC is a 2" main.

As previously mentioned, the A-series engines never had a lip seal, they have what is referred to as a scroll seal. This type of seal depends on correct tolerances and some engine vacuum to keep oil moving inward instead of outward. Unlike others that are available on the market, the seal I have makes use of the scroll seal design <span style="font-weight: bold">and</span> incorporates a lip seal as a backup system. No one else has this design for this type of kit. It can be used <span style="text-decoration: underline">with or without</span> the 5 speed conversion. It <span style="font-style: italic"><span style="font-weight: bold">is</span></span> a retrofit item, and you can see some of the components and explanation here:

https://gerardsgarage.com/Garage/Tech/5speedKit.htm

Feel free to contact me with any questions you have.
 

BlueMax

Jedi Warrior
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Ryan,

You can also find the backup rear seals at Moss Motors, British Victoria, and Mini Mania. In my opinion if you are not experience enough with installing them your time and money will be in vane. In most cases these engines are tired having blow-by with to much crankcase pressure. It’s like putting a band-aid on a six inch cut, it just doesn’t work. However if you are into originality and want to keep your engine original, then have the engine line hone with the rear eyebrow in place. This enables the proper clearance for the reverse scroll to function properly, but the engine needs low crankcase pressure for everything to work normally. With LBC’s its best to stay with distributors that specialize in this field. Trying to purchase parts from one of the chain box suppliers will send you down the wrong path and make you confused.
 
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RyanBez

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Thanks for all the help. So, basically what you are saying is that oil leaks are normal if the engine is tilted/on a hill?

Since I haven't got the engine started yet I won't know if there is an issue, I just got concerned when oil started leaking everywhere (I noticed when I hoisted it out of the car the other day).
 

Westfield_XI

Jedi Warrior
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RyanBez said:
Thanks for all the help. So, basically what you are saying is that oil leaks are normal if the engine is tilted/on a hill?

Since I haven't got the engine started yet I won't know if there is an issue, I just got concerned when oil started leaking everywhere (I noticed when I hoisted it out of the car the other day).

Was the transmission still attached when you pulled the engine? If so then much of the oil will run out the gearbox when the driveshaft coupler pulls out. This could be most of the oil you saw.
 

markberry

Jedi Trainee
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I tightened up the clearance of my rear main cap and crescent shaped cover using a procedure I got from Paul A. the process involves spreading JB weld on the surfaces of the cap and crescent that come in close contact with the crank, then reinstalling all the parts with a parting agent sprayed on the crank scroll so that the JB weld doesn't stick to it as well. The two components are removed and a perfect mold of the scroll is left in the now hardened JB weld. A dremel tool is used to remove the raised ridges from the scroll lines molded in the JB weld and the whole thing is re-torqued. Now you're left with a newly refreshed scroll area.
Worked great for me. Let me know if you would like me to send you the instructions.
Mark
 
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