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Engine gasket re-seal

2K views 2 replies 3 participants last post by  zeke67 
#1 ·
Brother-in-law was asking for some help on re-sealing an engine in his Camaro … and it hit me, it’s been 10yrs since I’ve actually had an engine apart. I remember most of the basics, but what are some other tips out there.

Motor was just re-sealed, and he’s found coolant in his oil. Engine is a SBC in a ’68. We’re going to pull the motor, and put on a stand.

I guess before we pull the motor, what would be the best way to tell where the leak occurred. I’m assuming probably an intake gasket, but I’d like to avoid removing the head gasket. Just don’t like taking a head off, if it’s not needed.

We’re going to start with the oil pan gasket … no coolant down here, but it leaks in the corners. In general if I remember right, there’s a gasket that wraps around the timing cover, along the side rails, and then a second rope gasket that goes into a groove in the thrust bearing. Basics here are just to make sure the timing cover and oil pan are flat, put a dab of silicon on the four corners, and then install the gaskets. Is there much else there? Probable stick with Fel-Pro’s all the way around.

I want to check his galley plugs also. I don’t think they go into any coolant passages, but he wasn’t for sure they were installed. In reality, they probably were never removed … no big deal.

Anyhow, then on top of the engine.

Assuming I have to replace a head gasket … what the best method on those. Seems like I scraped everything with a gasket scraper, but I used to use scrotch-brites after that. Recent conversations sound like I shouldn’t use abrasives? Put new head gaskets on dowel pins, then the heads, then just torque to spec. Don’t remember it being much more involved than that?

Intake gasket I think was what 4pc, and everyone threw out the front/rear pieces. I remember always using all 4pcs myself, but making sure I had a good amount of silicon on the 4 corners. What do you guys still throw out the front/rear, and fill it full of silicon too?

Then as far as valve covers … quite honestly, I don’t think I ever did get one that wouldn’t leak. What’s the story there, how do you make a valve cover gasket not leak?

Oh well, figured I’d ask for a basics to engine re-sealing. I’d really like to see him get his car back on the road, but with antifreeze in the oil he hasn’t driven it in about a year.

Thanks, Neal
 
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#2 ·
I would only hope that the coolant in the oil problem is due to an intake gasket. Best of luck on that.

With respect to scotchbrite the general consensus here is not to use it because it is so very hard to get the residue out of the engine.

Other than the extra work don't be hesitant to pull the heads. I clean all gasket surfaces with a scraper.

You don't mention how many miles are on the car but if its a significant amount this would be an excellent time to recondition the heads. If nothing else put new valve stem seals on them.

With respect to torquing the heads; as I recall the spec was 65ft/lbs. I did mine in three steps. 25/45/65 ft/lbs. I never apply full torque to one headbolt at a time. There are any number of manuals that will give you the tightening sequence for head and manifold bolts.

You live in wintertime country so I would also take this opportunity to replace EVERY core plug in the engine. You northerners call them freeze plugs but thats a misnomer. Murphys law dictates that the core plug that leaks first is always the one behind a motor mount. :)


With respect to gasket surfaces I put a light coating of silicone on ALL stationary gaskets except head and manifold gaskets. Both sides. Then I put a light coating om both surfaces of the engine part being sealed. Thats light coating X 4 surfaces. Metal/gasket/gasket/metal. I mention stationary gaskets because you don't want your silicone on anything that moves.

My personal rule is that any silicone that squeezes out from under two mating surfaces is WASTED silicone.

With respect to leaking oil pan gaskets generally that is due to over torquing the pan bolts. Same for the valve cover bolts. Here's what I do when I assemble an engine. ( Remember I am retired. I have lots of time on my hands).

ALL SEALING IS DONE BEFORE THE ENGINE GETS PAINTED. Make sure that all surfaces are oil free and clean.

I fully assemble the engine on the engine stand. I then invert the engine and I take that orange silicone and to apply it to every mating surface on the oil pan , timing chain cover , valve cover ,core plugs. absolutely EVERY mating surface where something could leak.

I don't go crazy with gobs of the stuff. just a thin bead applied with a finger where the sheet metal meets the iron. I carefully wipe off any excess.

This includes the crankshaft seal in the timing chain cover but being very careful not to get the silicone on the sealing surface.

With respect to tightening gasketted sheetmetal : As you tighten, the instant you see any deformation of the gasket you are done tightening... PERIOD. To go beyond that is to invite a leak. Besides if you take my advice and do the inverted engine/silicone thingy you only need to tighten gasketted sheetmetal gently.

With respect to the intake front and back seals most of us are now discarding them in favor of a bead of silicone across the rails.

Usually what I do is put a daub of silicone on all 4 corners to assist in holding the manifold gaskets in place. I let the silicone set up a bit and then I plant the manifold gaskets in the silicone such that it holds them in position.

After that I run a bead from side to side on both ends of the motor.

After a few minutes of set up time I install the intake manifold being careful to lower it into position straight down such that I don't smudge the endrail silicone beads. I do not use silicone on the manifold gaskets themselves. Nor any other compound for that matter.

Finally the rope seal. How well I remember them. They can be tricky.

You start by installing the rope seals into their grooves. Push them firmly into their grooves by hand. There will be excess sticking out of each side. After I install the rope seals in their grooves I roll them flat with a hammer handle firmly. Once the seal is in its groove and relatively flat I then trim off the excess with a razor blade leaving a 1/32" or so sticking up in both ends in the main cap and the block.

The excess takes care of any parting line leakage issues.

Lastly I generously coat the rope seal and the sealing surface on the crankshaft with white lithium grease.

You never want to start your engine with an unlubricated rope seal. It'll burn up long before the engine lubricates it.

After all this is done I take CRC Brakekleen and spray it all over the engine. That has two purposes. It carrys away any residual oil and it evaporates very quickly.

Finally the engine gets a coat of paint. In my case I painted the engine black except for the aluminum manifold. Just my choice. Besides black radiates heat better than orange. There's a reason why radiators aren't orange. The paint adhere's nicely to the silicone and if you applied your silicone carefully no one will ever see it.

One thing I should mention. I adjust my valves as folllows. #1 TDC I adjust #1 intake and exhaust. I then rotate the engine 90* and adjust #8 intake and exhaust, another 90* #4.....and so forth thru the entire firing order. I tighten each rocker nut such that the pushrod barely resists movement and then 1/4 turn more. This is my final valve adjustment. I don't go back after cam breakin and readjust the valves. Its not necessary with my camshaft. I don't know that you can do that with radical cams.

There you have it. One man's method. Good luck:)
 
#3 ·
I do things basically the way Charbilly described it, with one difference. I use Permatex brush sealer on oil pan rail, v/c gasket, intake, water pump and fuel pump gaskets. Silicone on everything else just as he explained.
 
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