The Complete Engine Sealant Thread...

[Alan L]

OK guys, just ploughed my way thru most of this. I cant help but laugh when I look at the motor I'm working on at moment. It is a friends 2.7 that finally leaked so much oil I was embarassed for him and offered to strip down. About to reassemble this w/end. But the Japanese have got you all beat. This car came via Japan.
There they seem to use just one sealant - some marine grade silcone (white).
You can dispense with the rest, just one large tube does all.
Crankcase halves (was going to take pic, camera flat), nose bearing, crank seals , rocker bushes, all gasket surfaces.
Apparently you just ladle it on with a spoon.
I bought a 930 in via Japan, and same story - same white gunk everywhere.
The 2.7 has about a pound of black RTV underneath to stop spot leaks, my 930 had red instead of black for spot leaks.
So, if you want monochrome, go for white.
If you like variety, red, white and black is available.
Life can be simple. If you are Japanese.
Regards
Alan

[JFairman]

lol...

[Alan L]

Does anyone here NOT use sealant on gasket surfaces. I rebuilt my SC from crank up 3-4 yrs ago. Followed Waynes recipie for sealing the case religiously.
But for all the gasket surfaces I used no sealant.
Just made sure they were true and clean. My Dad was an engineer and taught me that an oil proof gasket should be enough, unless there is an issue.
I know using the gunks is good insurance, and if was doing a shop job for a customer, I would not want it coming back for an oil leak.
But am I the only one not using sealant on gasket surfaces? If you do have to pull anything apart again, it is a quick and easy job. If I had to pull it for a leak, if I could not identify a cause, I'm sure I would use sealant.
My SC is still leak free.
Regards
Alan

[WERK I]

Originally Posted by Alan L

Does anyone here NOT use sealant on gasket surfaces. I rebuilt my SC from crank up 3-4 yrs ago. Followed Waynes recipie for sealing the case religiously.
But for all the gasket surfaces I used no sealant.
Just made sure they were true and clean. My Dad was an engineer and taught me that an oil proof gasket should be enough, unless there is an issue.
I know using the gunks is good insurance, and if was doing a shop job for a customer, I would not want it coming back for an oil leak.
But am I the only one not using sealant on gasket surfaces? If you do have to pull anything apart again, it is a quick and easy job. If I had to pull it for a leak, if I could not identify a cause, I'm sure I would use sealant.
My SC is still leak free.
Regards
Alan

I use a very thin film of Curil-T on the gasket surfaces. The gaskets come off very easy and you don't have the problem of cleanup of metal surfaces with paper residue.

[jimbauman]

I don't use any on valve covers and chain covers... Didn't use any on the chain housing gaskets either. No leaks.... Proper torque helps a lot - especially resisting the urge to give it that one extra twist.....

JB

[Alan L]

Originally Posted by jimbauman

I don't use any on valve covers and chain covers... Didn't use any on the chain housing gaskets either. No leaks.... Proper torque helps a lot - especially resisting the urge to give it that one extra twist.....

JB

WEll, that almost covers it (bad pun). That pretty well just leaves little gaskets like breather cover etc.
Alan

[jimbauman]

LOL! Ya true. I guess the point is, if your surfaces are clean and smooth, AND you assemble everything to spec, adding goop to your gaskets may complicate matters for you on disassembly.

I just this week popped the engine out (last time out was 2005) for some minor cleaning (lots of dirt, and a leaky pully seal and #8 bearing) and adjustments.



It was pretty clean except for one of the tensioner lines, and the seal/#8 area, and all the gaskets released nicely.

JB

[Henry Schmidt]

A quick note from the resident curmudgeon.

We would all like to believe that if we clean everything and make sure every surface is perfectly flat that the chances for oil leaks disappeared. It's a nice thought but in 1991 (the only time I could get accurate information, all factories hide these kinds of memos) the return from dyno test oil leak rate at the factory was 4%. That's 4% using all new parts. If 4% of the factory engines leak within the first 30 minutes using all new parts what are our chances of leaking using heat cycled parts. Our challenge is greater and requires a more aggressive plan of attack.
Just my humble opinion.

[jimbauman]

Henry - all factory stats aside, I think the careful backyard Porsche mechanic may take a little more time making sure things are "right" as opposed to the factory engine assember who is under productivity pressures AND has a factory fridge nearby stocked with plenty of fine German bier!

JB

[Henry Schmidt]

Originally Posted by jimbauman

Henry - all factory stats aside, I think the careful backyard Porsche mechanic may take a little more time making sure things are "right" as opposed to the factory engine assember who is under productivity pressures AND has a factory fridge nearby stocked with plenty of fine German bier!

JB

With all due respect.
Sorry but that's just non sense. There is nothing more important than experience when it comes to engine assembly. We have built hundreds of engines and that experience leads to a better product. To think that a back yard mechanic can come close to the consistent quality of a factory engine assembler in naive in the extreme.

[jimbauman]

Henry - with all due respect, you missed my point entirely! But, we're getting off-track here...
JB

[Henry Schmidt]

Originally Posted by jimbauman

Henry - with all due respect, you missed my point entirely! But, we're getting off-track here...
JB

Off track for sure but let's remember that each engine moves though the assembly line with an assemblers number attached. Too many assembly errors lead to very long unpaid vacations.

[CBRacerX]

Originally Posted by Henry Schmidt

Off track for sure but let's remember that each engine moves though the assembly line with an assemblers number attached. Too many assembly errors lead to very long unpaid vacations.

I saw an interesting special on Discovery Channel recently that focused on the Z06 Corvette. Much of the special was around building the car, and they spent a good bit of time on the engine assembly - which is done by one person who puts his name on the long block. It was fascinating, in part because the assembler had some incredible special tools at his disposal to make the assembly as "perfect" and repeatable as possible. This is all the gentleman does, and he was good at it. There is no way the occasional mechanic (and I put myself in this bucket despite having built about a dozen 911 engines and several 944) can do as clean a job as they do in the factory with all new everything.

This is not what I saw, but you see some of the assembly methods: http://www.youtube.com/watch?v=XdWTz_H0dUA

So, I used sealant on my gaskets!

[Alan L]

Jim,
I saw a thread recently where a leaky nose bearing was fixed with goop - by machining a tolerance fit piece, inserting goop in the gap and squeezing it somehow thru the cavity.
That is about as much as I understood of it. But if required, could probably find thread.
Regards
Alan

[jimbauman]

Thanks Alan - I saw that - and bookmarked it!

Successful #8 Bearing Oil Leak Fix

Jim

[Gregsgroup]

Ok, I'm the novice when it comes to these types of debates, but a simple question remains.

Any reason you won't use either 574 or Curil-T on all your gaskets? With all the time going into cleaning the case, the extra insurance makes sense to me. Nothing is worst then having a newly rebuilt engine run beautifully and drip on the garage floor, or on the exhaust.

IMO, sealants on gaskets is the way to go.

[alniki]

Originally Posted by jimbauman

There was another older thread that talked about Loctite 518 replacing 573/574 - something Warren had recommended. According to the 518 data sheet, as it ages, it increases its resistance to oil, whereas 573/574 decrease their resistance. Lap shear strength compares favorably too.
JB

Since I got to decide which to use or not using Loctite at all I read the data sheet and found that:
1. 518 loses half of its strength at a lower temperature than 574, 90 vs 120 degree Celsius, but retained a bit higher strength at 150 degree C or higher
2. 574 cures faster than 518 as ambient temperature increases and may leave less time to torque the bolts
3. heat aging looks similar for both after 400 hours
4. 574 has higher lap shear strength but lower compressive shear and tensile strength

So, your choice. But 518 will be easier to handle if you work in a hot environment.
BTW, John Walker seems to be using the Dirko with good results.

[911SCfanatic]

New sealant question (I think):
What sealant do I use between the metal-to-metal joint of the left chain box cover and camshaft collar (through which the cam extends on a '68 with cam driven air injection pump)? I was going to use CurilT...

[Carrerax]

Ok, I really hate to ask this but is the first page updated with the latest common ideas on what to use? I guess I can read all 10 pages but would prefer not to. I know that there are several schools of thought but I just want to do it right the first time. Thanks and sorry for the lazy stupid question.

[B D]

Originally Posted by Carrerax

Ok, I really hate to ask this but is the first page updated with the latest common ideas on what to use? I guess I can read all 10 pages but would prefer not to. I know that there are several schools of thought but I just want to do it right the first time. Thanks and sorry for the lazy stupid question.

Yes, the info on the first post is still good. One change is 1104 is now 1194. Also Yamabond (from Yamaha) and Threebond are the same and Curil-T and Hylomar Blue are just about the same, be careful Curil has several products.