Crank rear oil seal

DaveEFI · Post by **DaveEFI** » Mon Dec 20, 2010 1:01 pm

In the SD1 BL workshop manual, it mentions the rear crank seal mustn't be touched with the fingers when fitting. It looks like any other seal to me. Any ideas why?

minorv8 · Post by **minorv8** » Tue Dec 21, 2010 5:52 am

Worried about dirt perhaps ?

DaveEFI · Post by **DaveEFI** » Tue Dec 21, 2010 9:38 am

minorv8 wrote:Worried about dirt perhaps ?

In the operating theatre that is my workshop?

softdash3.9 · Post by **softdash3.9** » Tue Dec 21, 2010 9:55 am

I've always touched mine when installing

DaveEFI · Post by **DaveEFI** » Tue Dec 21, 2010 10:10 am

softdash3.9 wrote:I've always touched mine when installing

It came up on another group and I'm just curious as usual.

Things like headlight bulbs (halogen) aren't meant to be touched with the fingers as natural oils from those can cause the quartz envelope to fail (allegedly).

But the crank seal will have sump oil thrown at it.

unstable load · Post by **unstable load** » Thu Dec 23, 2010 1:01 pm

I would have thought it would be so that the natural oily secretions of your skin don't contaminate the rubbing surface of the crank because your skin will cause corrosion.
It makes no sense that you should not touch the seal, though, it should read the metal, IMO.

I know on some of the helicopter bits I work on that you need cotton gloves to handle things like masts when fitting them to transmissions, specifically because of the damage that your skin will cause on contact with the steel.

bigaldart · Post by **bigaldart** » Fri Dec 24, 2010 6:50 pm

Makes no sense to me, any lip seal should be lubricated really, I have always given them a very light smear of oil before installing. Easy way to do that is with a finger, never had one leak on me if properly installed.

Alan

mgbv8 · Post by **mgbv8** » Fri Dec 24, 2010 8:48 pm

bigaldart wrote:Makes no sense to me, any lip seal should be lubricated really, I have always given them a very light smear of oil before installing. Easy way to do that is with a finger, never had one leak on me if properly installed.

Alan

Same here Al !!

I've never had one leak and I put my greasy paws all over them ??

kiwi303 · Post by **kiwi303** » Fri Dec 24, 2010 10:52 pm

Maybe that's because your paws are greasy? A nice insulating layer of hydrogenated dinosaur fat between your mitts and the seal?

ian.stewart · Post by **ian.stewart** » Sat Dec 25, 2010 12:09 am

I wonder if its its made from a toxic material, or has a toxic coating

DEVONMAN · Post by **DEVONMAN** » Sat Dec 25, 2010 10:09 am

My take on this one is that the outside of the seal should be dry and clean when fitting so that it is firmly grabbed by the bearing cap. Any oil /grease on the outside of the seal may cause the seal to move over a period of time. Naturally the cap and block should also be dry but not the running lip.

Can't say I have been strict on this one in the past and have never had a problem.
Regards Denis

ged · Post by **ged** » Sat Dec 25, 2010 11:08 am

I'm as guilty as everyone else. I've always oiled the journal & seal lip & had no problems but after a quick google I found this.

Read Installation Procedure about halfway down.

http://www.enginebuildermag.com/Article ... _seal.aspx

Don't know if it's relevant in our case so I'll carry on using oil on assembly.

Regards Ged