Sealing the 4 chain case studs

[jag68]

Has anybody devised a successful method of sealing the four 5/16" downward studs that are at the front corners of the head and bolt it to the front of the block? I've tried sealant on both sides of the head gasket, wrapping the stud with gasket maker, copper and aluminum washers, and BSPP washers with the rubber do-nut, under the nuts, and eventually all leak. Will countersinking an O ring work?

[Series1 Stu]

Try using Dowty washers. They're designed for this kind of application.

Regards

[abowie]

We just use flat copper washer (annealed), a flat steel washer and tighten to approx 15 lbft (solid hand tight with a normal spanner). They don't seem to leak on our engines.

If you wanted to use an o ring it would be easier to make a slightly thicker washer and cut the groove on it, rather than trying to machine a groove on the timing cover.

[christopher storey]

What type of leak is it ? Oil - or water?

If water than there is something seriously wrong, probably a cracked or porous head

[Terry Sturgeon]

It's oil Chris - It drips from the bottom of the studs under the head where they go through the chain cover (front studs) and the crankcase (rear two)

[christopher storey]

Ah, that's a relief !

[rfs1957]

I think we're missing something here.

I can't remember whether the tops of these studs are "blind", or open to the oil in the timing chamber, but whether the oil is getting to the stud via a sideways leak through the head-gasket, or down the UNC section of the footing from an open upper end, no sealing washers under the nuts will stop oil finding its way down the UNF threads of the nut to form a drip, so the O-ring approach is a waste of time.

Beere uses gasket cement on any stud that is open at the other end (water-pump studs for example) for this very reason.

He also says that 99% of drips in the area of those studs is actually coming from higher up, from the cam-covers.

In my experience, on my engine, drips around the front are always in fact the accumulation of tiny weeps from the breather-cover, higher up, which I find very difficult to seal completely because of the multitude of egresses that are available, especially with regards the coil-bracket.

The latter really needs a Dowty washer on either side of it if these leaks are to be avoided.

I would wash off the whole area with brake-cleaner, spray athlete's foot powder on the critical surfaces, and then start the motor and watch ..................