rear main seal small block

[Joe L.]

Re: rear main seal small block

VERY Cool, Joe...love those D-spoke Torq Thrusts on the '68, too!
thanks so much for sharing!

Mark------


Those were actually not American mag wheels although they looked very similar. I originally bought those for my 1966 Chevelle SS 396 and removed them when I traded it in and transferred them to the 1968. The brand name escapes me at the moment. It was kind of brand "X" when I bought them but they became very popular later. The name might have been "International". I let them go with the 1968 when I sold it because the Chevelle wheels were 14" and the Corvette wheels 15" so I had no further need for them. I didn't want to change the Corvette wheels anyway and I never did.

[Bruce W.]

Re: rear main seal small block

Ed,
Well I followed your advice about checking behind the valve covers. Had some leakage behind the valve covers on both sides. Here is what I don't understand. I replaced those valve cover gaskets a few months ago. i used Fel pro and put silicone on the gaskets, how could they be leaking? Do you have any tricks to prevent this? I picked a bad hobby!!!!!!
Bruce

[James G.]

Re: rear main seal small block

Love your chevelle - the entire set up, L78 M22 Black with the 5 spoke wheels and redlines. I was Born 20 years too late.

You are correct about the price differential -
I often tell people that the best value in classic hi-performance cars are the early C3's - a LT1 is half what a similar Camaro Z28 would cost you, and you can buy a 69 L89 vette for what I have seen 69 Camaro RSZ's trade for lately.

[E S.]

Re: rear main seal small block

Joe- Great pictures- (My parents lived/worked at the Furnace Creek Inn for the winter seasons during the 80's- Loved the area)
Also -Love that color!- I owned a Riverside Gold 69 435 (auto); and I was going to order my new 69 in Riverside Gold- but my wife to be convinced me to get Silver.
Then, a friend showed up in a Riverside Gold 69 L-88 Cpe. (what a ride!!) Anyway- Love the old pictures!
E.J.

[Paul Y.]

Re: rear main seal small block

I always use cork gaskets and seal only the valve cover side with a sealer that tacks up.

Ed,
Well I followed your advice about checking behind the valve covers. Had some leakage behind the valve covers on both sides. Here is what I don't understand. I replaced those valve cover gaskets a few months ago. i used Fel pro and put silicone on the gaskets, how could they be leaking? Do you have any tricks to prevent this? I picked a bad hobby!!!!!!
Bruce

[Tom B.]

Re: rear main seal small block

Does anyone have info on the offset seal to use with worn crankshafts ?. Cant seem to find it.

I get them from NAPA. Victor brand I think. They put the sealing lip over just a bit so it seals against a smooth virgin area on the journal.

Tom

[Joe L.]

Re: rear main seal small block

Love your chevelle - the entire set up, L78 M22 Black with the 5 spoke wheels and redlines. I was Born 20 years too late.

You are correct about the price differential -
I often tell people that the best value in classic hi-performance cars are the early C3's - a LT1 is half what a similar Camaro Z28 would cost you, and you can buy a 69 L89 vette for what I have seen 69 Camaro RSZ's trade for lately.

James------

The strange thing is that when there was a delivery delay on my 1969 Corvette, my good friend who was also my salesman at Central Chevrolet, tried to talk me into getting a Camaro Z-28 from dealership stock. He was also the Z-28 expert at Central and ran their Z-28 club (he got new Z-28 demonstrators every year and actually once had a 1967 Z-28). I turned him down, though. I had my sights set on a Corvette. Even if I had gotten the Z-28 I very likely would not have had it today. I would have traded it in after a few years for something else and probably have gotten very little for it. The Corvette "stuck", though. I'd only have regrets today if I had decided to get the Z-28 and forego the Corvette.

By the way, my good friend and salesman, Frank Camilleri, passed away at a relatively young age 22 years ago after surviving more than 13 years with a heart transplant. He used to love to go flying with me. He's one of the small group of people that I miss the most and think about often.

[Richard M.]

Re: rear main seal small block

Ed,
Well I followed your advice about checking behind the valve covers. Had some leakage behind the valve covers on both sides. Here is what I don't understand. I replaced those valve cover gaskets a few months ago. i used Fel pro and put silicone on the gaskets, how could they be leaking? Do you have any tricks to prevent this? I picked a bad hobby!!!!!!
Bruce

Bruce, I too have had issues over time, as many others I would surmise.....

What I used for best results over time was this process. I don't ever use RTV as it's a bear to clean off later.

I use acetone and rags to clean the head surfaces to remove all oil traces. Also on the valve cover itself. I coat both the valve cover mating surface and the gasket with Permatex brush on sealer(iirc the #1 Permatex, the brown smelly stuff with the brush in the can). I let it sit for 5 minutes or so until it becomes tacky. I then apply the gasket to the cover, pressing it along the entire mating surface of the cover and let it sit a while to make sure it sticks.

I then completely coat the now exposed gasket surface with the Permatex, AND the head mating surface, but only the front and rear sides and lower front to rear length of the head. Again I let it all sit for a while until tacky.

For ease of cover alignment, I insert two 1/4-20 studs(slotted tips for a screwdriver) into the head at a diagonal. THis helps keep the gasket from sliding around.

I then set the cover with assembled gasket over the studs and down to the head. I install the other bolts snugged up a bit, then remove the studs and replace with the bolts.

Slowly and diagonally I tighten the bolts just enough to compress the gasket. Not too tight, especially if cast aluminum. If steel, I ensure the mating surfaces were flattened out before installation, particularly at the bolt hole locations. After a while I go back and snug the bolts a bit more.

I've done this for both SB and BB valve covers over many years and it helps keeps them leak free. Only caveat is if it's a solid lifter engine it makes it harder to get them off for adjustments.

Rich

[Mark F.]

Re: rear main seal small block

...For ease of cover alignment, I insert two 1/4-20 studs(slotted tips for a screwdriver) into the head at a diagonal. THis helps keep the gasket from sliding around...Rich

Hi Rich,

When you say "at a diagonal", do you mean one stud on top left (or right) and the other one at the bottom opposite the top as shown below?

One Stud here?	open	open	open
open	open	open	Second stud here?

[Richard M.]

Re: rear main seal small block

Mark, Yes any opposite corners. Your diagram would be for BB. SB has only 4 so either way.

As simple as it may seem, I always have trouble lining up the bolts without the gasket shifting so this helps prevent that.

I use the stud trickery for other things like fan clutches(1 location nutted to align to pulley so it doesn't fall while inserting the bolts), C1 water pumps(to hold engine mount plate), harmonic balancers(to rotate crank), C1/C2 hood hinges, C2 wiper motor mounting, transmission to bell housing, etc.

Rich

[James G.]

Re: rear main seal small block

I also use the cork gaskets and glue them into the covers using the brown stuff which smells like old doping.
As soon as I pull them I clean them and glue the new ones in - then use 4 - 1/4 -20 bolts and bolt them together to dry in place while I adjust the valves.
Before installing I wipe a thin coat of axle grease on the head mating surface.
100_1310.jpg

[Gary B.]

Re: rear main seal small block

[Richard M.]

Re: rear main seal small block

Rich,

For the reading impaired among us, if looking down at the head surface with the valve cover not yet in place, does this mean you coat three of the four sides of the rectangle where the valve cover touches the head? So, just the intake manifold side isn’t covered with Permatex? What would be the downside of coating that fourth side, other than making it a little more challenging to remove the valve cover in the future?

Gary

Yes, 3 sides, not the horizontal close to the intake, and yes, doing that horizontal would also make it a bit harder to remove.

Since the oil puddles at the lower horizontal and corners up about a inch or so, it appears that helps keep those pesky leaks from getting on the SB exhaust manifold too where it puddles dead center, then if unnoticed, on startup gets smoky and black.

Rich

[Bruce W.]

Re: rear main seal small block

Rich, thanks for the input. Haven't started it yet. we shall see how it works.
Bruce

[Gary B.]

Re: rear main seal small block

Does anyone have any updated experience since this past Sept/Oct or recommendations among: GM #10121044 fluroelastomer rear main seal; Fel-Pro fluroelastomer seal #BS40013; Cometic one-slit, C5379? Specifically, regarding the Cometic 1-slit?

Thanks,,

Gary