Small leak from head gasket.

rob needs · Post by **rob needs** » Sun Apr 08, 2007 7:44 pm

I put Hylomar around the edge of the crankcase,and around the edge of the gasket.Then torqued up to 38.5ft lb.I then left it for a couple of days,when i checked it there was a bead of water along the gasket at the bottom.Cant see any coming from the studs.

I think the copper to the crankcase is sealed, but what about when the water gets past this to the fibre side of the gasket.Do you think i should put sealent on this side too?

Bryan Walker · Post by **Bryan Walker** » Sun Apr 08, 2007 10:21 pm

Hi Rob,
Instructions for gasket installation below, (These are the instructions Neil Moore from the JCC Spares ltd supplies). Note that the cylinder liner hight is .006-.008 not .008-.012 as per instruction book, this is due to the gasket materal used today dose not compress as much as the old asbestos type used by jowett in the 50's.
Also note you do need to re torque the heads.

Bryan

FITTING INSTRUCTIONS FOR JAV/JUP HEAD GASKETS

Piston Bore 72.5mm to 75.0mm

1/ Set Liner heights above block 0.006" to 0.008" Use Assorted thickness Copper Shims ONLY to Achieve this.

2/ Smear Thinly Loctite Master Gasket, Silicon Rubber( or similar) to the edge of the gasket and block to assist in sealing water.
(Not on Liner to Head Seal area)

3/ Fit 'O' Ring around stud feeding oil to rockers - push into gasket.

4/ Tighten heads to 37.5 pounds/foot torque.
Say 20x3 times, 30 x2 times 37.5 x2 times.

5/ Run Engine up to 75 degC water Temp.
Leave 15-20 Min's and re torque to 37.5 pounds/foot

6/ Reset tappets.

Jowett Spares (NZ) 2003

Post by **Forumadmin** » Mon Apr 09, 2007 9:51 am

Also read Mike Allfrey's Tech Notes in JowettGallery!

rob needs · Post by **rob needs** » Tue Apr 10, 2007 8:35 pm

I refitted the gasket to the instructions and still it leaked.It defintely looks like its coming from the fibre side of the head gasket.If i fit a gasket which has copper on both sides,could i smear sealant on both sides,because i reccon this could do the trick.

Or would it be ok to put sealant on the fibre side of the head gasket.Would it stick?Rot?

TedAllen · Post by **TedAllen** » Tue Apr 10, 2007 11:13 pm

Hi Rob,
I used the club's gaskets some time ago but I never felt confident about them. For some years now I have used the copper, 'asbestos' copper ones with no problems. I got mine from Bill Lock and they weren't much more expensive.
An old tip, given to me by Roy Braddock many years ago was to paint both sides of the copper with yacht varnish and let it dry before fitting.
It seemed to work but does anybody have any ideas on this procedure ?
Ted

Keith Clements · Post by **Keith Clements** » Wed Apr 11, 2007 7:58 pm

Interesting I have dismatled a number of engines with what looked like varnish there. I thought it was some sort of head gasket sealant. There was one which was brown. I use Blue Hylomar.