Experience/recommendations for sealing TR camcovers

One of my TR valve covers leaked, about a year ago. I used a "grey" silicone product........paste in a tube, on the gaskets......a little on each side. No leaks since. I believe I used a silicone on the square O-rings........yet, have been told that one should not use silicone on O-rings.

I am now doing a major service. I am trying a Permatex spray gasket sealer, for the gasket, and Hylomar for the internal square O-rings. I used the spray because it is a lot quicker, and appears more evenly laid down. I will not know the results untill I start up the car.

Where is it leaking from? I have found that cutting the gaskets properly is critical to a good seal.

BTW: Are you referring to the end cam covers, and NOT the valve covers? I have replaced the seals on the end cam covers, and am using Hylomar on the O-rings.

 

As you noted, the grey product, while being silicone, is NOT a slippery as the "regular" silicone........such as the blue.

The last service done on my car was by the Ferrari dealer. When I disassembled things EVERYTHING was covered with silicone.......a whitish, slippery product. Why else do we read about so many people have cover leaks???????????

BTW: The Hylomar is NOT a curing type product. It stays wet.

 

Steve..

I noticed when doing TR services that alot of techs use way to much sealer/RTV on the gasket edges. This I have noticed causes the gasket to "slip" as the cam cover is being tightened down. As the RTV gets older, oils seeping past the gasket will cause the RTV to be rendard useless and in the process producing a big leak.

When I do the gaskets, I lay the cam cover on the bench and carefuly cut the gasket to mach the cam cover. I then take the gaskets to the car and place them on the head and check for fit. If they need to be trimed futher then I do the enitre proccess over until they fit as good as they can.

I then make double and triple sure the surface of the head and cam cover are free from oil. Sometimes I even try to get as much oil out of the head as possiable by using shop rags to soak up the oil. I then apply a very samll amount of Locktight red 518 gasket sealer to the front corners and inbetween the cam seal o-rings. You don't need to use much at all. A very small amount will do just fine. I don't put anything on the o-rings. I then do the same to the cam cover . I place the gaskets on the head "dry" I only use a sealent at the front of the head no were else.

Torque the cover down as evenly as possiably using a criss cross pattern from the middel work you're way out. Once tight start the car and let irun until opertaing temp. shut car down and recheck the covers for tightness.

HTH

Tom

 

Tom: Interesting..... using dry gaskets. I heard this is OK only when the parts are new. Time, and use, are supposed to have a tendency of warping, even slightly, new products...........this is why, I have heard, is the reason most people use some sealant.

I respect your opinion, since YOU are the mechanic, and NOT I.

Then, can you explain to me why seasoned Ferrari mechanics use silicone, in this application? My previous major was done by a veteran Ferrari mechanic, at an authorized Ferrari dealership.

Thanks,

Hank

 

The reason that most Ferrari mechanics put silicone sealant on the o-ring to cam cover gasket joints, is because that is what Ferrari does at the factory.

The silicone sealants available at you local auto parts store are crap. While Loctite 518 is great for certain applications, I wouldn't recommend it in this instance. I have been using Threebond sealants for years, and have found them to be unequaled in their sealing capabilities. Both BMW and Ducati have switched to Threebond as their OEM sealant.

For the cam cover joints I use Threebond 1211, which is white in color.
See: http://www.threebond.co.jp/en/product/series/sealants/1200list.html
for specifications. Most good motorcycle shops will carry it. The only downside is that it has a very long cure time, at least 12 hours before the part can be put into use.

Brian Brown
Patrick Ottis Company

 

Silicone has become like a bandaid unfortunatly. Silicone allows for the mechanic to cut corners and not clean surfaces as well as they should be for proper sealing. Many techs put silicone as insurance to protect against leaks,but this can backfire if too much is used. Silicone is a very good sealer when used correctly but most mechanics uses way too much and end up causeing more pronplems then they solve.


Remember when usinging silicon at max a 1/8 beed is all that is nessasary. When you tighten everything down and see the the silicon squish out the sides you have used too much. As much silicon gets squeezed in the engine as you see being squeezed out side of it. This silicone with then start to break apart and fall off inside the head. In the area of the cam cover on the TR this can result in clogged oil drain holes thus causeing pooling of the oil,and of course causeing leaks among other things.

I have seen the effects of silicone being over used on and engine and it's not a pretty sight. The worst case is it falling into the oil sump and then being sucked back up by the oil pump and clogging the screen. I had a customers GM truck with low oil pressure. I dropped the oil pan to replace the oil pump..and saw strands of silicone hanging out of the pump pick up tube!! Very bad.

Silicone is a good tool but it must be used propperly.

Regarding using no sealant on the cam covers other then were I stated befor,e I have done this for years and never had a leak, wheather it be a Ferrari or a Ford. It would be very rare to have a warpped cam cover or head unless the engine was severly overheated at one time. The cam cover on any engine(besides and early 350 chev) are made of fairly heavy alumium. It would take alot of heat to warp one causing a gasket not to seal. if you have ever had an engine apart for the first time..notice the the manufacuter does not put sealent on gaskets (usually they only put sealent in an aera were 2 joints meet like a corner)...only glue to hold the gasket in place during manufacture. Even Ferrari does this. When you have a stubborn gasket that has never been changed and is really hard to remove it's mainly because it's stuck there due to age and heat cycles the engine goes through. It will harden an become very difficult to remove comming off in peices.

Tom

 

Good suggestion about the sealents. I'll have to check them out..but a 12hour cure time? I really don't(and my customers) have time for that in a busy shop.

As far as Ferrari using a sealent on the o-rings themselves..I have never seen it on a car that I did the first service on. And I have done quite a few first services on 348/355 cars. They do use the white colored sealer in the corners on the front and the rear of the cam covers though. The sealer does sometimes seem to be a fair ways up on the o-rings but almost never all the way around.

I have seen cars that were dealer serviced with this however. But I have also seen were dealers cut the o-rings and slip them around then then try to seal the split with silicone,to avoid removing the cam shafts on the 328/348 cars.

Tom

 

I just did the valve covers on my 328.
I used a little Hylomar where the gaskets met the O-rings and aroung the O-rings. When I tightened the valve cover down a little sealant ozzed out. After running the engine for about an hour an oil leak developed and I noticed a couple of the valve cover gaskets ozzed-out by the O-rings. It seems the Hylomar is pretty slippery.
I retightened the valve cover (several nuts loosened?) and there has been no more leaks.
If I have to remove the valve cover again, my thoughts might be to glue the gasket to the valve cover with contact cement and possibly put a light coat of a liquid gasket sealer on the other side of the gasket. I would also put a little Hylomar near where the O-rings meet the gasket.
The reason I would do this is to seal the gasket to the cover, prevent movement of the gasket, and to facilitate removal of the valve cover.
Mark

 

I have to assume there is no positive pressure in the valve covers. While what I have to say does not apply to your TR, it worked on my track car, a Porsche. I was leaking oil at the head gasket. Oil flows from the valve area down through the head then down the sides of the block. The head gasket is supposed to seal this - the oil return. Mind decided not to after 20K miles following my installation of an O-ringed head gasket for higher boost. Rather than replacing the head gasket, I smeared Hylomar into the crack between the head and block (after cleaning it up). It has not leaked in several weeks.

The acid test is next month at Road Atlanta.