Gasket Sealers:  An Overview

By: Mike Cecchini


Part I

As with many things in life.........the pendulum of technology swings from one extreme to the other before settling down to a reasonable balance between the two.

 For many years, many of us used the "old brown paper bag" trick of making a gasket for things that did and didn't have gaskets.   We used a thin smear of wheel bearing grease on both sides of the paper to help the paper conform to the surfaces and to help separate the parts if we should ever pass that way again.

Some of the more notable products that served us well were Gasga-sinch, hard and soft   permatex, aviation permatex, Hylomar, Silicone, Hi-temp Silicone, RTV Silicone and many I'm sure to have forgotten.  All either applied to specific situations or attempted to cover the many of our needs and that of the internal combustion engine.

Many work well but have definite drawbacks and side effects.  I will avoid the many abuses of such sealants such as over application (too much, too thick) as we Americans are often been accused.  The overwhelming thought among us: "if a little is good..........more is better" can have catastrophic results in oil passageways.

 I will "ass-u-me" that all of you read the instructions of everything you use before use.  I'm amazed at the little tips, hints and specific comments the maker wants you to remember, now that you have bought his product and he'd like his product to succeed in your hands.  I know this sounds a bit amateurish and we're all "pros" and don't need to read instructions anymore.  But a quick glance at the instructions to review, only takes a moment and has certainly saved me from many mistakes.  It's like picking up the Locktite bottle, it's shaken every time it's picked up........every time.   So it's an ingrained rule.....................I just do it.

The latest to come along and being used by many notable engine builders is Germany's   Wacker--Elastosil #E41.  It's a transparent RTV-1 Silicone that is for "sealing, bonding, and coating".  It is moisture curing, permanently   flexible and reists aging and UV resistant.  Hmmmm...............sound like it's able to leap tall buildings in a single bound.

I've seen it in use and it sure smells, looks, feels, tastes (?) like the same Silicone RTV that we've been using for many years.  I'm sure a chemist can tell the difference, but I sure can't.   So, it makes me wonder why I need to spend the $8-$10 for a 90ml (about 3 oz.) tube from Germany when the Permatex RTV silicone gasket maker from local hardware store costs $3.


Part II

There is an opposite side of the coin that many of us fail to acknowledge or just don't really give a damn.  In this rush, rush, rush world we have created for ourselves, where speed is God Almighty and preparation and caution seem to take an eternal back seat to our workmanship (sorry for being cynical),  there is little regard for the poor soul that has to come behind us and remove the sealed cover, clean up the mess, and prepare the surface for another "bonding" to guarantee a seal.

The very last thing the professional mechanic wants to see and the customer can easily call to attention to.........is the dreaded LEAK.
Engine noises can be "explained" but leaks are the kiss of death and are to be prevented/avoided........at ALL costs.  A simple leak can render the worlds best mechanical work.........worthless.   Not to mention that it needs to be done all over again.  What a waste of time.  And time my friends is what we all live by.   It is our enemy............to be beaten, taken advantage of, but rarely conquered.

So..............the mechanic seeks a material that will serve HIS needs best.  He seeks a sealant that will "weld" the cases together, "bond" the covers to the flanges and generally "seal" potential leak areas.   Sometimes I think they'd like to weld the cases and covers on the engine.

The last 4V engine (926 155 hp) I bought from a west coast racer had some sort of silicone sealant used throughout out the engine.  I just shook my head when I attempted to remove the simplest of covers........the rocker cover.   After 20 mins of frustration and exercising all the restraint I could muster........the envitable mallet came into play.  I broke a screw hole edge and managed to remove the cover.    Oh yea..........a magnesium cover ($#%*).  I learned from that first cover and managed to apply excessive pressure on the remaining covers without incident.   I can still remember thinking.  "My God man........what where you trying to hold back..........the North Sea??".  Sure didn't leak....... but what overkill.

I was sure that the cam end covers would never come off.  And I was convinced that a missing gasket provided the clearances needed for the cam ends to clear the covers. The insides of the covers had swirling gouges indicating lost clearances.     "No......that's the way we do it now" said one of the best Ducati engine builders east of the Mississippi.   Annnnnnnnnnnnk (buzzer sound)...............wrong answer.   That application of the "do everything"......."seal everything".........."bond everything" material is not what I think is really needed and I submit.............serious over-kill.

I asked "how do you get the side covers off with that stuff ??" Oh........that's easy.  you take the side cover puller and screw it in here and just turn the bolt with this 20 inch wrench and it comes right........tug, pull, strain, groan, puff............puff............off.    I could actually hear the aluminum straining under the stress.  God only knows how you'd get the sidecover off if you were................let's say .............at the track for a school or a club event.    Do you really take ALL of your special tools when you go somewhere ??  I don't.  Don't need 'em.

I just happen to have son's 1990 851 along that weekend and we needed to go inside the left sidecover to replace a shifter pawl.  I had been in and out of that sidecover several times over the past 10 years and never had a leak.

Using a 4 inch Allen wrench, the hit of the palm of the hand and off it came ...........lo and behold..............a gasket.  Thin paper, well greased and in perfect condition.    Amazing.  I smiled :))))
I will admit that the paper gasket (no longer available from Ducati) was cleaned off and a thin (and I mean thin) smear of Hylomar applied to both surfaces of gasket the last time I was there.  The Hylomar was still tacky and in perfect condition and didn't even need reapplication.  Just put it back on.

But it wasn't my bike anymore and Adam chose to go with advice of another and use the Wacker Silicone.   I will be the "fly on the wall" when the sidecover needs to come off the next time.................and I do not have the sidecover puller.    I never needed it.

In a final note.  Hylomar was developed by Rolls Royce for their engines and I found out about it via Ted Porter, formerly Service Mgr. of Bob's BMW, and now chief of service at San Jose BMW.  A truly gifted, well balance human that likes to consider the big picture when he offers services to his customers.  Ted uses Hylomar exclusively.

For me ?? Hylomar has sealed everything I have asked it to seal, with or without gaskets.   It goes on a bit tacky and will hold a gasket in place extremely well, for assembly.  It allows separation with ease and if kept clean, it will allow reassembly without reapplication and you can use the vehicle immediately.  I love the stuff.

Hylomar use to be a bit hard to find,  but I have recently found it being marketed by Permatex as "Hylomar HPF, Gasket Sealing Dressing and Flange Sealant" item #25249 (1 oz. tube) for $2.99.  I found it at my local Trac Auto.

The SP5 motor I'm building right now will use the Wacker for the cases and other semi-permanent areas, but not the side covers or rocker covers.

You choose what serves YOU.

Mike Cecchini

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