Resealing cylinders

[jlex]

I'll be installing new heads on my '70 SP 1600 in a couple of weeks & in addition to installing new push rod tube gaskets (to eliminate oil leaks) I want to re-seal the cylinders.
I've read posts where people are saying not to use the paper gaskets on the cylinder base; just to go with the Permatex red hi-temp silicone sealer.
What's the consensus here? Throw the gaskets away & just use the Permatex? Or use both?
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jlex.
'70 std. "Elsie"
'88 Carrera

[tabbottuf]

You took the question right out of my mouth. I am currently building a 1776 and have ran across a couple of articles and references that have suggested that the paper gaskets are inferior. I am sort of on the fence on this one bcause in previous builds I have used the paper gaskets with a light coat of permatex aviation gasket (the brown stuff that is used on case halves) brushed onto both sides of the paper gasket. Don't know if its right or wrong but I haven't had a problem yet. Would be interesting to see some more input on this one. Maybe Johnnypan can jump in on this.

Tracy

[jlex]

Hey, I'm just looking for something that will prevent any oil leaks after I'm done... I was going to use the paper gasket + the Permatex aviation sealer just as you had done, but have since read differently.
The proof is in the pudding... tell me how the prior build held up to oil leaks... how long ago were they done & is there any leaking at all?
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jlex.
'70 std. "Elsie"
'88 Carrera

[Cadaver]

your question is not possible to answer
here is why....

are the jugs ,new, yes, so the flanges are perfect.
was the case decked or does it look 40 years old and like crap.

see?
there are other factors,, did the new case severs shorten the deck margins?
photos. work.

i can say this , never use RTV, RTV is dimensionally unstable.
and as SUCH, never use dimensionally unstable substances in the TORQUE path
this is rule one in Aircooled air craft shops.
ask them.
makes sense right..
but you will find lots of folks that have the magic finger the can lay it down
so fine that the RTV goes to zero clearance and is stable.
GOOD FOR THEM. (can you and do you want to find out? with leaks)

My retired VW pro mech said.
"the gaskets are not to be used, they like to creep in time and you loose head torque" That is a quote.
best practice
both surfaces milled flat , perfect.
and a good stable sealant that is
very thin
is compatible with oil (not balling up. etc)
non compressible. (goes to stable at full head torque)
and comes off at rebuild time (RTV lost that)
ok at 230F case temps, long term. (air craft rated. yes? its not a GM water car at all.)
(mine, how happy am i when this crap gets inside my case,?)


I use 3H aircraft sealant (H- size jug) (old school best )
but VW recommends this.

Curil ( said to be the best by most top builders, new school. )
not sure what K number is best for VW.... not me...

seen in HOTVW builders books and other articles all the time.

not saying I KNOW, saying this is my long research before i did mine.
just that...

YMMV, (your motor my vary)
_________________
for sale now.
in Samba classifieds....1968 T1.

[tabbottuf]

My oldest build is a stock 1600 in my 72 SB convertible completed about 6 years ago with zero leaks at the cylinders. My newest is 1641 finished a couple of years ago and no leaks either.

Tracy

[tabbottuf]

I have been considering using Curil (instead of permatex) on my current build. Read alot about it. If price is indicative of quality, then Curil should be the best stuff available (it is expensive). I believe that aircooled.net sells it on their site.

Tracy

[tabbottuf]

I agree with candymustang's statement about the possibility of compressability issues with the paper gasket but I am one of those diehards that pull the engine to re-torque the heads (all eight studs or none). Some supposedly just re-torque the ones under the rockers. Either I have been lucky or what I have done in the past works ok(at least so far). Not saying that its right or wrong. Also, all of the paper gaskets that I have used have been soooo thin that i am not sure that there is enough compressability to cause any problems as long as the heads are torqued properly.

Tracy

[jlex]

Wait a minute... if I had done an engine 6 years ago using the gasket & permatex aviation and it hasn't leaked since, I'd stick to what works...
I mean, why try something else if you have a winner already?
I just need a couple more people to chime in on no leaks for years using permatex before I decide to go that route instead of using something else...I'm halfway thinking that those who use hi temp RTV without a gasket are those who don't have a gasket to use in the first place so they're essentially making a gasket up out of silicone.... right?
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jlex.
'70 std. "Elsie"
'88 Carrera

[Cadaver]

yes , you do have that best and right. periodic pulls and re-torques.
for sure... I'm sure the aircraft guys do that.
and is logged. (stud 1, par, stud 2 spun 1 full turn to hit spec....hummm)
they track everything. just in case. in some cases all parts have serial numbers
and the part is tracked on all engines. total life history. ( really works too)

what do you think like every 15k or 30k?

fun story on serial numbers.....
i was in Boston Logan AP.
my plane silent and loading. plane to right , me in middle right side of silent.
the other plane spooling up. and BANG, the front compressor blade
flew through the wing and fuel like a water fall on the ground < I'm OMG.

I jumped up and yelled STU ! we have a FUEL LEAK TO THE STARBOARD
she said WHAT? I said, ON THE AIR CRAFT TO THE RIGHT. see peeps and wets pants...
the Pilot overheard me and piped " DEBARK NOW, do not panic."

No bad happened, good thing on the ground, no hope in the air.. zero.

turns out that serialized blade was decommissioned due to cracks.
ON another air craft, (shame...)
dang. NTSB. kicks some butts.....

ever land with no landing gear.? don't ask. frost happens...

have a friend that has been in 3 aircraft crashes (a master mech)
1 in Vietnam (in a sh|thook ,shot down. )
2 in commercial air craft here, (he never flies today , 3 strikes and all that)
1 in Oregon, one in San Diego.
People laugh and call him names mr no fly, until the truth leaks out....
SSDD.
_________________
for sale now.
in Samba classifieds....1968 T1.

[Willhelm]

I went through all the gaskets and a heavy cleaning in the fall of 2010. I used the paper gaskets (which are indeed thin) and aviation sealant. No leaks. I actually had to re-inspect my work and check for mis-oriented pistons and in the process partially tore a paper gasket. I re-applied aviation sealant to the open surfaces and torqued everything down. No problems. I park this in a garage constantly and still have no "pee" marks from anything. Take it for what it's worth I'm not a guru or anything. This is the second year of fair weather driving.

First line from Wikipedia:
"A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. Gaskets allow "less-than-perfect" mating surfaces on machine parts where they can fill irregularities."
http://en.wikipedia.org/wiki/Gasket