Sealants www (Why, Which, Where)

[RichardL]

HDhikaru,

In looking at your photo, there is one thing that has not been mentioned, but should. The red silicone gasket sealer as shown in the photo should not be used anywhere where it comes in contact with circulating oil. It breaks down in the oil and bits of the sealer try to circulate in the engine, with very likely clogging of critical oilways, such as, inside the crankshaft. I use old-fashioned #2 Permatex, which is non-hardening. Here is the link:

http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_sealants/auto_Permatex_Form-A-Gasket_No_2_Sealant.htm

I believe you are in Japan, and I don't know the Japanese equivalent. I do use silicone on the gasket between the primary case and the crankcase, as there is no real chance of it getting into the oil supply.

I am thinking that our fellow A7/10 owners will soon report in to share their thoughts on this, which, I believe, will be in agreement. Otherwise, they will tell me I am loaded with the proverbial...

Richard

[HDhikaru]

thanks guys!!

Richard, I agreed with you.
personally,  I normally do not use silicon gasket.
this is previous owners job.
but I used it on head cylinder gasket
because  it leaks sometime but
after  1-200 km  trip,  still see some leak......

any good idea to stop it or just leave if not bad ??

Shin

[groily]

I hesitate to open my metaphorical mouth after last imbecility (and thanks for your restorative words Richard!)! But re gasket sealants, I do use blue silicon in small quantities for pretty much anything that's likely to leak, especially the primary chaincase and the rocker box gaskets. But for the cylinder head itself, just a smear of grease is best. And definitely not something that should go anywhere near an oil drilling or pipe!
Many say Hylomar is the best stuff - haven't seen any here in France, but it's what Rolls Royce allegedly used and it does a very good job. I never use  Red Hermetite - messy and hard to clean off surfaces when they have been apart. I just use whatever the auto-parts shop has for sale . . .

[RichardL]

I am sure we are off on a new topic. Perhaps our administrator will rearrange these posts to make better sense for transportation historians 500 years from now. (Oh, what an optimist I am!)

Regarding head gaskets, let's remember to mention the annealing process for solid copper gaskets discussed at length in this forum. (Search : "anneal" in box on the upper right.)

Of course, the manufacturers of silicone sealants (Permatex is one of them) say that their products are resistant to petrolium products, and perhaps they are (or at least, some of them). My own experience has been to find bits of silicone floating or laying about where they should not be. Maybe it was the technique of the previous mechanic at fault and the sealant is innocent. However, it is the finding of the floating bits, and warnings I've read elsewhere on the web, that now make me leery of silicone.

I went to the Hylomar website (not having heard of them) and found that they make several different types of silicone sealant, among other types. (Groily, are you referring to a specific product?) Interestingly, they do not mention resistance to petroleum products but do recommend silicone for such uses. They also have a product called "Universal Blue" (for, which they DO mention resistance to petroleum products) which sounds something like the Permatex #2 I've described. I would have to say that the Permatex is also messy and must be removed chemically or with a razor. When it comes to getting it off the hands, a little mineral spirits does it.

Shin, as you can tell, there are going to be contradicting opinions on this topic (oh, that's, a first). I am not the most expert commentator here. It happens that Permatex is the sealant of my early years playing with cars and I've stayed with it for most of the time since then. Call it nostalgia. My A10 engine did not stay together long enough after the last rebuild to do a real evaluation of the effectiveness of the seals over time. I have a lot of respect for the experience of Groily and the other the folks on this forum and will be interested to hear more opinion on this, if they don't mind doing "Gasket Sealer 101". 

End-o'-Blabber

Richard

[a10 gf]

Richard wrote: I am sure we are off on a new topic. Perhaps our administrator will rearrange these posts to make better sense for transportation historians 500 years from now

Done, with a hopefully new good topic title.
Content was from http://www.a7a10.net/forum/index.php?topic=497.msg2637;topicseen#msg2637

e.

[a10 gf]

One very good sealant: nicely mating undamaged surfaces and correct cross tightening for large parts and covers.

Loctite 243 (blue) for petrol tap threads (I use it on some carb parts as well), takes care of any leaks and eases correct postitoning without crushing fibre gaskets or damaging threads. The 243 keeps things very well together, but with the possibilty for unscrewing afterwards.

e.

[BSA_54A10]

I have always used Stag on the fuel taps as it is soluable in alcohol so it is easy to clean off but insoluable in petrol up to 10% ethanol. Never thought of  locktite but I might give it a go as I have  a lot of it hanging around the place.
As for the rest well I am another Hylomar & grease man.
Hylomar between the gasket & cover, wheel bearing grease between the gasket & case.
Hylomar cleans off with metho & grease with turps.

[dpaddock]

Permatex Hylomar (25249) and its successor Permatex Ultra (85409) are both good sealants and dressings for gaskets and flanges. I prefer the latter.