[TR] Gasket sealant for sump

DAVID MASSEY dave1massey at cs.com
Sun Mar 29 06:33:22 MDT 2020

 I have seen applications of RTV go bad.  One was when it was used in place of a proper gasket for the fuel sender on my TR3.  When it was clamped down RTV icicles oozed out into the tank.   One problem is that  I know of  no RTV that is rated for exposure to gasoline but the other problem is there was an RTV-cicle that softened, broke loose and found its way into the fuel system blocking the flow of fuel resulting in a tow home.  This scenario in an engine crankcase is scary.  Creating a lubrication blockage can result in bearing failure.
None-the-less, I use the Blue stuff on waterpumps and other cooling system parts as just about any RTV has no issues with water.  But I use a trick I once read many years ago where I loosely assemble the parts taking up any slack but leaving the bolts or nuts snug but not tight so as to not force the sealant to flow.  Then I wait 15 - 30 minutes to allow the RTV to start to set.  Once it is partially set it will not flow and the part can be torqued down without fear of RTV-cicles.
If you are going to use Ultra Gray, which looks like an excellent choice for this application, I recommend this technique.
 But I prefer to use Form-A-Gasket #2 on one side of the gasket to more or less permanently adhere it to once surface and , like Tim, Hylomar on the other surface to allow for easy removal down the line.

-----Original Message-----
From: Alex & Janet Thomson <aljlthomson at charter.net>
To: 'Dean Mericas' <dmericas at gmail.com>; triumphs <triumphs at autox.team.net>
Sent: Sun, Mar 29, 2020 5:56 am
Subject: Re: [TR] Gasket sealant for sump

I have used Permatex Ultra Black on a number of occasions and have had good luck. Disassembly of items cemented together with this product can be challenging, though. Maybe I should try the "ultra-gray". I find things work best if you can insert a couple of studs into the larger half of whatever is being assembled so that the attached item goes on straight, without any sideways movement. I have found that large gaskets for tractor transmission castings have gotten really expensive ($50 plus) and then sometimes they either come damaged from shipping, crack & break when being installed, or holes don't line up properly for bolts. As a result, I tend to use the "gasket-in-a-tube" approach more than ever. Sometimes I find it challenging to decide what product to buy - there are so many.

Alex Thomson

-----Original Message-----
From: Triumphs [mailto:triumphs-bounces at autox.team.net] On Behalf Of Dean Mericas
Sent: Saturday, March 28, 2020 8:23 PM
To: triumphs at autox.team.net
Subject: [TR] Gasket sealant for sump

I’m resealing the engine and transmission on my TR4 after 20 years of reliable service. 

Today I had a massive failure installing the sump gasket using Hylotyte Red100 sealant. It seems to have weakened the gasket to the point that it tore around several bolt holes as I torqued the bolts. 

Plan B is to thoroughly clean the mating surfaces and use Permatex Ultra Gray, which I’ve generally had good luck with on my Alfa Romeos. 

Before I do that, I wanted to see if any of you can recommend other sealants for this purpose. I only want to do it one more time. 


1965 TR-4
Sent from my iPad
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/triumphs/attachments/20200329/d08ef546/attachment.htm>

More information about the Triumphs mailing list