Another gasket sealing question

TT Oversteer · 01-18-2013, 07:19 PM

I've read the "ultimate engine sealing thread" and there are still some questions in my mind:

I bought the more expensive and better quality Wrightwood Racing gasket set which includes many gaskets that appear to be coated with a slippery grey graphite type material that comes off easily on my fingers when handled. Should these be installed dry? It seems that it would be unlikely that any type of sealant would adhere to this material.

Specifically with respect to the cam chain housing to case gasket and the chain housing covers to chain housings:

Wayne's book recommends these be installed dry

Henry Schmidt's instructions included with his sealant kit recommend a light coating of Loctite 574 on these gaskets.

But what about the graphite coated gaskets?

So many subtle nuances to these engines......

KTL · 01-21-2013, 06:51 AM

Yeah too much information can sometimes make things more difficult

The graphite gaskets can be installed dry no problem. I'm not a big fan of 574 on top of gaskets because it hardens and can make gasket removal a pain to clean up the next time disassembly is done. Often times people do this to help seal any imperfections on the sealing surfaces, which is perfectly understandable. I like to use a non hardening sealant like Curil T in that case.

lindy 911 · lindy 911's Garage

If you're building a race car, build it to take apart. If you're building a street car, build it to go another 100,000 miles before it comes apart again. Henry builds engines that don't come back out for a while so his recommendations are going to be for assemblies that will stay in the car for years. This makes the cleaning up of 574 not so much of a problem given the sealing benefits.

rctophobby · 01-23-2013, 12:42 AM

too much information is not good some times. RC Helicopter

BURN-BROS · 01-23-2013, 07:18 AM

Below is a photo of curil T on a camshaft gasket....

This has happened multiple times to engine builders who use Curil on paper gaskets...specifically on the cam plate gasket.

The Curil T does not allow the gasket to achieve a mechanical bond to the surface, relying only on pressure of the hardware. As a result, the gaskets can walk and leaks develop.

I use 574 on all gaskets with the exception of valve covers as they need to come off from time to time. No leaks and no gasket wandering.

TT Oversteer · 01-23-2013, 10:57 AM

I don't have a problem using Loctite 574 on the paper gaskets....just wondering if it will stick to the slippery graphite style of gasket.

BURN-BROS · 01-23-2013, 11:22 AM

Quote:

Originally Posted by TT Oversteer

I don't have a problem using Loctite 574 on the paper gaskets....just wondering if it will stick to the slippery graphite style of gasket.

Yes, it does a decent job on the chain box and cover gaskets.

KTL · 01-23-2013, 11:58 AM

Interesting to see the Curil T problem Aaron mentions.

I have installed the cam seals in the past with a sticky-like gasket sealant (Permatex copper) and recently have had mixed results. My most recent installation on the racecar had a leaky left (cyls 1-2-3) and I had to re-do it. Upon disassembly the gasket was off-center like Aaron's pic shows, causing a significant drip down the chain box & eventually onto the exhaust.

So since it looked like the gasket moved and got stuck during installation, I used Curil to allow the gasket a bit of slipperyness to seek it's desired position during install. Worked fine and no leaks. Granted this was a short duration gasket because I wasted the engine the next time I hit the track with it..... But a friend who's built several engines swears by his use of the Curil and strongly recommended I use it to avoid having another leak. So I guess results vary on the Curil.

I just get miffed by the 574 cleanup. Especially since the old tried and true Permatex gasket remover spray that used to work SO good at removing the cured 574 is now a low VOC formulation and sucks butt at removing 574. I resorted to Loctite Chisel spray recently and it works so-so. Not nearly as effective at removal as the old Permatex butt whooping spray.

Incidentally I chose to use Curil on one of the chain box gasket areas where it mates to the engine case. My heads in this instance were cut down so much that the bore in the chain box was not aligning well with the cam housing. So I used no gasket and just a light coat of Curil. Worked good. Could've used 574 there too.

What I certainly didn't want to use again was Permatex aviation gasket sealant. That brown sticky stuff doesn't do all that good in my experience. Although it does clean up pretty easy with brake or carb cleaner. Some have mentioned on the rebuild forum that it is their sealant of choice. I'm surprised because my use of it on cam tower sealing areas did not go well. Apparently the brown stuff needs to be used very sparingly because any excess starts to migrate when it gets hot. Not to mention I didn't think it did a very good job of sealing either.....

Just curious, are those center-oiled cams you pictured Aaron? I've not seen them before and cams i've worked on with the large retaining nut have been only "dimpled" in the center.

Thanks for sharing the experiences. Always good to add more info to the brain database......

BURN-BROS · 01-23-2013, 12:15 PM

Hi Kevin,

911/73 2.5 ST. Centerlubed with racing rockers/ lashcaps. The exception is Weber 46's are installed.

The gasket walking seems to be a recent phenomena... say the last five years. It has happened with factory as well as the green gaskets.

lindy 911 · lindy 911's Garage

My build did exactly as Arron describes, gasket moved when the three bolts were tightened using Curil-T.

A little off topic but if you're building a '78 or '79 SC check that there is a through-bolt hole chamfer on the 1-2-3 side of the case. If not, the o-rings will pinch and leak worse than the disheveled camshaft gasket. I have too much experience with this issue.