3.8 Series 1 - specific : Removing The Sump And Changing the Sump-To-Seal-Carrier Seal ?

[ralphr1780]

Would anyone have a new one of either of the seal types to hand, the all-rubber or the cork/rubber, and could measure the thickness ?

I have 2 new in my gasket pile: one Jaguar original, and one in a Payen set.
The Jaguar original is made of softer more flexible rubber and looks a bit greyish compared to the Payen one, but they both show the same thicknesses: 5.70mm on the edges, 4.30mm in the center.
Hope this helps!

[rfs1957]

Thanks Ralph.

Rob Beere says they use the C36499 indifferently for both 3.8 and 4.2.





The gap is a pretty consistent 5mm around the whole periphery, both by metrology - taking into account a 0.75mm thickness of the Cometic sump side-gaskets - and by the use of Plasticine, which you can only judge to about 0.1mm, but useful nevertheless.





Beere says, however, that they use Loctite 5660



https://www.henkel-adhesives.com/uk/en/ ... 56601.html

which I had assumed was just a grey version of what I've always used, and had used during my first attempt, the black Loctite 5910



https://www.henkel-adhesives.com/fr/en/ ... 59100.html

HOWEVER if you read the small print, the 5910 is "suitable for gaps of up to 1mm" and has a Shore hardness of 30, whereas the 5660 says "for applications requiring the sealing of large gaps" and a Shore hardness of 45-75.

Our sump seal application should not require the sealing of large gaps, BUT I'm going to gamble that the 5660 is tougher than the 5910 and will therefore build up The New Deal using the former.

At least then Rob can't say I used the wrong stuff

[rfs1957]

Okay, I got some new genuine JLR seals, and they measure up exactly like Ralph's did.



Definitely not of uniform thickness, and given that my measurements on the 3.8 sump show a pretty perfectly even 5.00mm everywhere, the 4.30mm at the base is definitely inadequate per se.

Hence the advice given by Dick Maury, confirming Jaguar's distinction, to use this one on the 4.2, and the cork/rubber on the 3.8 ?

Which conflicts with the Rob Beere judgement - BUT they use with that the pretty robust Loctite 5660.

What follows is probably a complete waste of time, but I REALLY didn't want to have to do this again ......





So I knocked up a really tough bit of 12mm MDF to act as a "fake-sump", filled the seal-carrier groove with Loctite, and clamped the C36499 in place overnight - having put the sump gaskets into place, complete with dabs of sealant, and held them up with pipe-sleeves slid over some 5/16 UNF studs.





Then the next morning I removed the "mould", applied Loctite to both the seal's outside and the sump's scoop, and closed it all back up.

Dave aka 44DHR's idea of adding long dowels to help guidance was a boon - I added six in all, three pairs, and found it worked best with longish ones nearer the front, maybe 2", dropping to maybe 1" in the middle, since the sump is best offered up tilted upwards at the rear upon approach ; on my car at least (different bell-housing ?) you have to get the rear of the sump into a somewhat tighter gap, getting it past the crank etc, before you can raise it into place.



I tried the Loctite 5660 with a test-lump on the bench and can confirm that it results in a much stiffer compound than you would expect from one's usual RTV.

The excess that oozed out from the rear looked convincing, and I just hope nobody will judge me too harshly when the engine next gets opened up if they see any excesses within - but at least with stuff this rigid it is NOT going to break off and block oil-ways !

Fingers crossed ; I've other stuff to do, so it may be a few weeks before I give it the acid-test.

[mgcjag]

Hi Rory..that's why I linked you to Dick,s comments..the rubber strip is tapered to fit a 4.2......the cork for a 3.8.
Your obviously carefull with sealant....others may not be.
Steve

[rfs1957]

If it's good enough for Rob Beere, who builds engines by the dozen, it's good enough for me.