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Re: [Fot] Viton Rear Seal ?s

To: "'Rich'" <>, "'Steve Yott'" <>, <>, "'Jim Gray'" <>
Subject: Re: [Fot] Viton Rear Seal ?s
From: "MadMarx" <>
Date: Mon, 1 Dec 2014 22:51:10 +0100
References: <SNT407-EAS153EF3244D927419BFFE27FC67D0@phx.gbl>
Thread-index: AdANrHanS/wnj34fSoSGzVgK9keKvAAA7vcg
Hi Rich,

as long there is a gap all is fine. Seems that the cranks do have some
variations of flange thickness.

The only way to enlarge the gap is to put the seal flat on sanding paper and
grind off the rubber to the steel arches.

The side to grind is the side in the housing.

But as long there is a gap that should not be needed.

There are two limits to respect:

1.    That the lip is not touching the scroll on the crank

2.    The rear side of the seal doesnbt interfere with the cranks flange

All within this range is okay.



Von: Rich []
Gesendet: Montag, 1. Dezember 2014 22:20
An: MadMarx; 'Steve Yott';; Jim Gray
Betreff: RE: [Fot] Viton Rear Seal ?s


Tried using wedged shaped shims this time, let it set up for 24 hours and it
is a little better but nowhere near 1/16" gap between the seal and crank

In fact it is  less than 1 mm, measuring about .033" using a feeler gauge.

Looking at how the seal sits in the housing, I can tell that it is fully
seated.  I just don't see how to make the gap any larger aside from tinkering
with crank end float, which can only net a very small amount.

I suppose, as long as this seal stays where it is, doesn't back out, things
will work out.

What do you think?




From: MadMarx
Sent: 11/30/2014 4:55 AM
To: 'Steve Yott'; 'Rich';
Subject: AW: [Fot] Viton Rear Seal ?s

Hi Rick,

the gap between the seal and the flange is designed to have a minimum
distance of 1mm (=0.4"). In most cases you have a little more distance.
This 1mm is the safety to deal with crank movement when depressing the

Please make sure that the flywheel bolts don't protrude through the flange.

It is important to use a good sealer, like silicone.
I had on my race a seal slipping out and was then scrambled by the crank
flange. Since then I recommended to use silicone to hold the seal in place.
Back pressure in the block can force it out after a while if no sealer is
Maybe only an issue on race cars and not so much on road cars.


-----UrsprC<ngliche Nachricht-----
Von: Fot [] Im Auftrag von Steve Yott
Gesendet: Sonntag, 30. November 2014 03:45
An: 'Rich';
Betreff: Re: [Fot] Viton Rear Seal ?s

I have installed a number of these and feel that if you are measuring only
.020" that the seal may have crept during the install process.  This is easy
to have happen since there is a lot going on during the setting of the
crank.  First question would be, did you machine your own aluminum scroll
seal for the Marx seal or did you purchase the kit?  I know that the parts
provided in the kit are machined properly and that machining your own can
give inconsistent results.  I machine my own since I built a fixture to hold
the seal halves on the mill before the kit was available.

What I do after getting the crankshaft in place and the bearing caps
installed is take two medium screw drivers and work the seal gently into the
scroll shell.  When I feel it is fully seated I leave it alone until the
sealer/glue sets a little so the seal does not creep out.  I normally end up
with about a 1/16" between the crank flange and the face of the seal.

Now the most important part is to make sure that your flywheel bolts will
have shredded the seals by using too long of a bolt.  Measure this twice to
ensure the bolts end up at the proper length.

It is a great seal setup and works far better than  the standard scroll or
Rover lip seal type of process.  The best of both worlds!

Steve Yott

-----Original Message-----
From: Fot [] On Behalf Of Rich
Sent: Saturday, November 29, 2014 5:16 PM
Subject: [Fot] Viton Rear Seal ?s

For those who have done this before, what clearance do you end up with
between the seal and the crank flange?

I'm getting around .020" which seems too little to me?


Rich Rock




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