The Stovebolt Site Forums The Shop Area Engine Shop Assembly Lube? Gasket Sealant?

I am about to reassemble my 1951 235 and I just have a couple of questions before I get started. What do you guys recommend for assembly lube. Any specific brand or type?

As for gasket sealant, is it necessary? I have a copper head gasket, so I know I need the copper gasket sealant for that, but do I use it on both sides of the head gasket? What about sealant for the rest of the gaskets?

Also, where can I find the specs for all the different torques on the engine. I know the head bolts for the 51 are 75-80 lbs, but what about the main bearing and connecting rod torque? Are there any others?

Thanks, guys. I know I'm asking a lot of questions, but I want to get it done right.

I won't "touch" the sealant question except to say with todays "modern" additives/sealants I would probably follow the manufacturer's suggestions unless some experienced mechanics have a specific recommendation. Jerry, where are you?!!

You can get the torque info from the online manuals from the link below.... but I'd still buy my own shop manual and assembly manual. They are not pricey... well worth the money and you can keep them handy in the shop.


http://chevy.oldcarmanualproject.com/

Using the black rtv sealant myself...walmart has it about six bucks a tube.Here's a link for the torque spec's and more.


http://www.secondchancegarage.com/public/373.cfm


Hank

I pretty much despise silicone sealants, although I admit there are a very limited number of places where they work well.

For most gaskets I use Permatex #2, a very thin smearing on both sides, just enough that when installed it squeezes out a tinny tiny bit and you can see you used it, but not enough to squeeze out a blob that you'd then want to wipe off.

For valve cover gaskets I use contact cement, sold by Caterpillar as gasket adhesive and often called "cat glue". apply it to the cover and one side of the gasket, stick them together. Leave the head side dry, or some folks use a dab of grease, but the idea is to not have the gasket stick to the head, then valve adjustments are easy and the gasket is reusable for years and years.

I've used the copper gasket spray on head gaskets, and think it works OK but really don't have an opinion on it.

For the rubber seals on your oil pan around the main bearings I would use a dab of black RTV in the corners. Then permatex #2 for the side gaskets as mentioned.

Grigg

NAPA or any of the local stores care Lubriplate assembly grease,
http://www.lubriplate.com/products/greases/no-105-motor-assembly-grease.html
Use plenty of it, and use plenty of camshaft assembly grease,
http://www.compcams.com/products/250-267.pdf, or your choice of cam manufacturers. Use plenty of this stuff as well.

Its best not to wait to long to start the engine after assembly because the cam lube will run off, and with the oil problems now a days, you need all the cam lube you can get.

Read up on oils if this is a new camshaft, your engine isn't like a full on race engine with tons of valves spring pressure, but you still need to be aware of the dangers and concerns with modern oils.

Joe

Thanks, guys. This is extremely helpful. Is the lubriplate safe to use on the cylinder walls? If not, then what? Also, and I've received different opinions on this one, what weight engine oil should I use???

straight 30 weight oil is a good start, that's what I used.
It's also good to use on the pistons/cylinders and anywhere else in the engine you don't use a special assembly grease or oil.

Grigg

For assembly I use GM assembly lube, you can get it at any GM dealer shop off the shelf. It can be used inside the cylenders and spread liberaly on everything else. There is also the cam assembly lube, it's a bit thicker to keep it from being wiped right off, but not absolutely needed with the lower spring pressures in our old engines.

As far as sealants, I'm partial to Gunk Aviation Form-a-gasket for most surfaces, I've had pretty good luck wit it overall. Still, making sure you have good clean and flat surfaces for your gasket makes all the difference.
Not a fan of silicone anything on engines, I always find it squeezed out internaly & it ends up inside water passages & oil galleries.

Again, thanks guys for all the helpful information. One last question: should I use synthetic oil or not? Grigg, when you say straight 30 weight, do you mean SAE 30? I don't know much about oil except for what's going on in the gulf.

Yep, that's the stuff.

I'd be hesitant to try synthetic because I've had a very difficult time finding it in a straight weight, all of it seems to be a multi weight (like 10W30 for example).
There is probably some you could use, but I don't have any recommendations or knowledge on the subject.

Grigg

One advantage to Permatex RTV is that it dries inside outward and cures properly and quick. Some of the off brand budget stuff doesn't. Just my .02.

Hank

SAE 30 it is. Thanks again, guys. Extremely helpful. Sorry for all the questions. I have one more (hopefully the last for a while): should I use the gasket sealant on the manifold and carburetor gaskets? Probably a stupid question, but I thought I'd ask anyways...

Could use the copper spray gasket stuff on the hot manifold gaskets. I usually don't use anything.

Don't usually use anything on carburetor gaskets either, including the base to manifold gasket, unless there is a problem, then I'd lightly use Permatex #2.

Grigg

Thanks, Grigg, and thanks everyone else. I'll keep you guys updated. Expect more questions to come...

RTV should only be used in places where it is going to be the gasket, or at points where 2 gaskets join as Grigg said. It is not intended nor does is work very well as a sealant with a gasket.

And to add to that,
If their was originally a gasket then use the gasket, don't substitute RTV.

That'll help whittle down the list of places to use that stuff, getting really close to zero on these old trucks.

Agreed, with only 1 exeption. I would not have an issue with using rtv if a replacement gasket simply isn't available, but that isn't an issue with any Chevrolet engine.

I like to use Permatex Super 300 brush-on liquid sealer to coat gaskets such as for the water pump, timing cover, and other thin paper gaskets. I use yellow trim cement to stick gaskets like the valve cover and the oil pan side rails down before bolting them into place, usually on one side only. It's not really necessary for sealing, it just makes the oil pan and valve cover easier to install. Ditto for the side cover, especially if it's one of the tall ones with the small cork circles around the spark plug holes.

Head gaskets- - - - -solid metal ones need some brush-on sealant to help seal water, not compression. Put a sandwich-type gasket on dry, but be sure both surfaces are completely clean and free of debris. I use anti-sieze compound on all bolts that are torqued, rod and main bearings, head bolts, etc. Cam & lifter lube- - - - -either use what the cam grinder supplies, or lithium-additive grease such as Lubriplate to coat the cam lobes and lifter bottoms. Another good break-in lube for a cam is lightweight grease with a Molybdenum Disulfide additive. Always do a 20-minute breakin of a new cam at 2,000 RPM or so to assure plenty of oil thrown off the crankshaft to flood the cam with lube while it's establishing a running fit with the lifters.
Jerry