Silicone(?) used to repair leaking head bolt - Page 2

jscap99 · 08-19-2008, 04:15 PM

what kind of silicone? where did you get it. thanks, John

jscap99 · 08-21-2008, 04:17 PM

What kind of silicone? I might try that first. Thanks, John

**den35** · 08-21-2008, 06:40 PM

Wonder if automotive RTV sealant(the stuff used on the ends of a car engine intake manifold) would work.It's made for heat and pressure.

bugman53 · 08-28-2008, 01:51 AM

better idea get a copper washer used in banjo bolts and brake lines and put it under the leaking bolt and that will seal that leak.

But really silcone to fix a head bolt. I not trying to insult anyone but that suff might old 5psi not 150 psi in a cylinder head. If its just a oil leak then thats different but a head bolt.

If is leaking compression then have the head surfaced. and get a good gasket and there will not be a leak. Its a flat head, not a OHC watercooled race motor(and yes i build race motors for a living)

But the copper washer would hold. My concern is hot gases geting past the fire ring in the head and causing the gasket to burn up.

If a head gasket ever leakes for a few seconds then the gasket is toast.

bugman53 · 08-28-2008, 02:00 AM

I just read that you have a new head. What kind of gasket are you running?

We will get her fixed for you.

a quick trick to make sure the head is flat. Take a peice of glass and lay some 400grit sand papper on it and move the head in figure 8 patterns and look at the smooth parts on the bottom of the head. you will quickly see if there are any low spots. you can do this for a wile and get the head pretty flat. It is possable that the new head has warped if the casting was not aged before maching.

jscap99 · 08-31-2008, 06:48 PM

It's a new gasket on there, not a new head. The gasket is OEM and copper. I also used some copper spray sealant. still leaks.

When I get to it I want to try truing up the head with sandpaper, although I don't have any plate glass. I also heard you can use a file to do this, but I don't want to ruin it.
I would like to get this head surfaced but don't know where to look to have it done. any ideas on getting the head surfaced?
I guess using silicone as a sealant is not a good idea?
-John

Rhovis · 08-31-2008, 09:41 PM

Why don't you just put a heli-coil in the block and be done with it and quit fooling around with band-aid gasket sealers

jscap99 · 09-01-2008, 04:45 PM

The bolt and threads appeared to be in good shape. I hear you about the sealers. The tecumseh book says not to use sealers. You just make sure the head is true and replace the gasket.

I'm going to take it apart soon. When I put it back I'm going to use a brass washer. I might want to get the head resurfaced but I don't want to spend that much. At a harbor freight near me they have the 6.5hp clone for $100.
John