View single post by Esprit2
 Posted: 03-11-2006 12:39 am
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 572
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 There is a special tool for centering the front seal during installation (and another for the rear seal).   It takes all the guess work out of centering the seal and ensures a dry seal.   I highly recommend using one.   Ask your favorite parts supplier if they have a J-H/ Lotus tool rental program.   If not,  Jeff at JAE does rentals (?  it might be tied to buying the part from JAE...  I'm not sure ?).

Without the tool,  be really anal retentive about getting the seal centered accurately.   I've used a long-jaw vernier caliper to measure the gap between the housing ID and the crank journal OD.   Measure top & bottom and left & right,  tweaking the housing position until the dimensions are equal.

I've also used plug gauges (drill bit shanks).   Measure the housing ID and crank journal OD,  subtract,  divide the difference by two.   Buy three drill bits (or actual plug gauges) that diameter and place them at 120 degree intervals around the journal so they also pick up the housings OD.   Hold everything while you tighten the bolts with your third hand.

Boy,  that seal centering tool takes all the time and frustration out of installing the seal.

The original front seal has a 67.71mm OD.   I don't know if they've in short supply now,  or if the Lotus prices just got way high;  but most independent Lotus/ J-H parts suppliers are now selling a non-Lotus seal that is very similar but with a 68.00mm OD.   It's an SOB (!) to get into the front housing.   I've ruined more seals than I've managed to get in properly.    Considering my success ratio and the expense of replacing damaged seals,  I don't see the value of an economically priced alternate seal.   If you can find an original Lotus seal,  buy it.

The diameter difference may not sound like much,  but when you start with a negative fit,  going tighter by  0.29mm (0.0116")  is a lot tighter !

Original seal  =  51.81mm ID,    67.71mm OD,    7.92mm Thickness

Tim Engel  (Lotus Owners Oftha North)