How to change gasket: Timing cover I6-250

[thelawdoc]

Gentlemen, has anyone changed the round gasket/seal that goes in the shaft opening for the timing gears' cover for the '66 Chevy C10 250? I need an idiot's instructional. Thank you.

[70inline6]

Youtube is your friend... The vid is for a v-8 cover, but same on the 250 - tap it out, tap it in -

Installing a Timing Cover :: Modern Muscle X -...

Slow and steady...

[thelawdoc]

70inline6, Thank you. I pretty much figured that is how to install the new seal. I was concerned about removing the old one. I suppose I can just punch it out, but I am wondering about the direction from which to push it out.

[68gmsee]

Pop out from inside to the outside. If you have the cover off use a backing of some kind when tapping it back in. I use couple of pieces of 2X4. If it's on the engine just tap it in carefully so you don't damage the edge. Also, I coat the edge of the seal with gasket sealer just in case.

Another thing you can do if the cover is off is to leave it loose so the seal centers itself on the crankshaft and slowly tight all around until snug before tightening all the way down.

Forgot to add: As an FYI. Installing it without removing the cover is not recommended. I've only done it once and it went in okay.

[thelawdoc]

68gmsee, Thanks. The cover is off. I will tap it out from the inside. I like the idea of leaving it 'loose' when reinstalling the cover, but then I will not be able to put any gasket seal around it, right? I mean, it seems to be a tight fit in the cover. Or, I will put some gasket seal on it, tap it in, and install the cover. I am not sure that the seal will be loose if I have to tap it into the cover.

[68gmsee]

I use a thin coating on the crankshaft seal in case of abnormality. Yes it's a tight fit but I always do this on all seals. Even rear transmission seal. Force of habit.

The reason I mentioned to snug (finger tight) the cover bolts all the way around before tightening to spec is that I once had a crankshaft seal that wasn't centered on the crankshaft and it leaked on me.

[thelawdoc]

68gmsee, Understood. I will put a thin coating around the seal before tapping it in to the cover plate, and then I will immediately install the cover. Thanks.

[thelawdoc]

Guys, I was just about to change out the round seal for the timing cover when I noticed that the new round seal appears just a teeny-weeny bit smaller than the one now in the cover. I called the vendor, Parts Geek, and they are insisting that I have correct seal. My old seal seems still good and I am very nervous about punching it out. Any thoughts?

[thelawdoc]

Correction/Update: Ok, so I finally managed to take out the old seal. I could not simply punch it out from any side because it sits within the cover and on a shoulder. I had to put a wide flathead screwdriver into it at an angle, from the inside, and a couple smacks on that with a hammer sent the seal on its way out. Now, my new seal seems to fit fine, however, it is not a real 'interference' fit. That is, I can push it into place just with finger pressure. Also, when I compare the old seal with the new one, the new one seems cheap-like to my eye. But having no experience with timing covers, seals, gaskets, etc., I am hoping that it will all work out ok. (I am using the timing cover set from Felpro, TCS 45264.) On Monday a buddy will give me a hand to re-install the cover, and re-mount the balancer, fan, and radiator. Then we will set timing. Any comments from the forum will hopefully give me better sleep this weekend. Thanks, guys.

[Lugnutz65]

I did my seal. I think I pulled/pushed it out in much the same way you did.
I used a seal driver kit to install the new one. It should be a tight fit. If you can push it in and out with just your fingers, then I'd go get a new seal at the local auto parts store. My seal came with my Felpro engine gasket kit which included all seals and gaskets, so I don't have a part number to help you with selection.

My 1971 250ci has a press fit balancer. No bolt. I was given this advice and it worked well for me. If you have a bolt on kind, then nevermind.

Put some grease on the snout of the crank. Heat the center of the balancer with a torch until water will sizzle. Smack the center section of the balancer with a mallet to knock it onto the crank. Do not contact the outer ring or the center and ring could separate. I made a custom wood block that I used as a driving tool. The square part fit inside but did not contact the outer ring. I am usually fearful of the unknown and this was my first time ever to do this. See photos.

[thelawdoc]

Lugnutz65, Thank you for responding. Actually, I misspoke somewhat about my seal. It goes in about half way of thickness easily. But I see that I will have to carefully smack it in so that it goes all the way in and seats itself on the shoulder. I will use a piece of wood to protect it as I do that. My balancer is also a press fit, with key. I will be installing it as you did yours. Lug, in your topmost photo, I am looking at your timing cover. I observe that the lip at the top of it (from 9 to 12 o'clock) on yours is nice. Mine is somewhat bent/dinged here and there along its edge. Is that an issue?

[Lugnutz65]

There is a rubber seal that goes there. It has little spikes of rubber that poke up through holes in the cover to hold it in place and align it. If the lip is distorted, then the seal might leak from uneven contact pressure. Of course, use RTV sealant all along the lip on both sides of the lip gasket.

[thelawdoc]

Lugnutz65, My rubber sits nicely in place, though there is room to spare along either side of it along its length. The deformations that I speak of are in the 'lip' that is 90 deg to the rubber. In your topmost photo, said 'lip' hides the side of the rubber from view. It does not seem to have any relevance to sealing (hopefully).

[Lugnutz65]

The lip is rolled to give the metal more rigidity. Sounds like what you have will work fine.

[thelawdoc]

Thanks, Lugnutz. This is my first time playing with the timing gears. And hopefully, the last, lol.

[Lugnutz65]

Here's what I found under my 250 timing cover. YUK!
All cleaned up now and runs well. No smoke! Not bad for a free engine!

[Lugnutz65]

One more thing. I used a crank socket to center the timing cover gasket while I bolted it in place. If it's not centered, then the balancer installation can damage the seal. Just a thought.

[thelawdoc]

Wow, Lug. You are probably the first to open that up since the truck left the factory. Mine was pretty clean, obviously because it was recently done. I had no pressing reason to get into mine. My timing was off due to my balancer beginning to separate, but I decided to have a look-see at the gears and clean up my cover since I was already there. Fortunately for me, the gears are new and it was just my balancer. Bought a new one from Parts Geek. Any ideas what I might do with the old one? Somehow it just does not feel right to toss it in the trash. Paperweight? Clock face?

Yeah, I do not know exactly how I will center the cover. I do not have such a crank socket. I will have to think about that.

[Lugnutz65]

Maybe it could just be a paperweight for now. Mine was a double groove and in decent condition. I put it back on in hopes I could find the parts needed for PS. Then about 5 months ago I found an original PS pump and brackets off a 1969 Skylark with a 250. Salvage parts are the best! Reusing what others see as having no value.

[68gmsee]

Since you had it all out, I would have also replaced the timing gears. Looks like that camshaft gear has fiber outer ring and they do tend to strip. I've had them do that before.

If you haven't done it already: when replacing the harmonic balancer, it's best to heat it up before tapping (or whacking) it in. I boiled mine in hot water for several minutes and used leather gloves to handle it afterwards.

Use an old pot and after you get it to boiling bring the whole pot and water to the engine. Just be careful you don't get burned.

[thelawdoc]

Lug, mine seems in pretty good shape, but the inner ring appears to have slipped out about 1/8-1/4". Initially, I thought I could just smack it back in. But a buddy/mechanic said that cannot be done and that I have to replace it.

68, the hot water sounds easy enough. I figured I would use like a pencil torch. I just want to be careful about heat getting to that elastomer ring. I have gears in there that look rather new to me, no chain ('65 I6-250).

[68gmsee]

Man, I'm too full of leftovers....

Lugnutz the first part of my post was for you. The second for lawdoc.

[68gmsee]

Originally Posted by thelawdoc

Lug, mine seems in pretty good shape, but the inner ring appears to have slipped out about 1/8-1/4". Initially, I thought I could just smack it back in. But a buddy/mechanic said that cannot be done and that I have to replace it.

68, the hot water sounds easy enough. I figured I would use like a pencil torch. I just want to be careful about heat getting to that elastomer ring. I have gears in there that look rather new to me, no chain ('65 I6-250).

A few minutes of 212 degrees won't hurt the h-balancer. I have used a heat gun in the past but I wouldn't use any flame on it. Also, most shops (and professional mechanics) cringe when you talk about smacking or whacking anything but I've done it with no ill effects. However, the last 250 I overhauled I had the crankshaft drilled an tapped for a bolt. Lot easier to install the h-balancer.

[thelawdoc]

68, Yes, I know what you mean about smacking stuff. (A 12 lb sledge was my go-to tool back in the early seventies when working on tanks, lol.) I cannot do the tapping at this time, though a bolt would make it all easier. Also, I do not have a real lot of space to work with; the engine is in the truck- I just took off the fan and the radiator. Hopefully, with a piece of wood to cushion the blows, a heated balancer will go on with gentle taps. I think I will do the water thing. Surely, I should not have to go into these gears again in my lifetime, knock wood.

[Lugnutz65]

Originally Posted by thelawdoc

Hopefully, with a piece of wood to cushion the blows, a heated balancer will go on with gentle taps.

Yes, The wood block I made allowed me to cushion the blow. I wouldn't say it went on with gentle taps though. Each one is probably a little different. The wood block evenly distributed the blow to the center of the balancer. I drilled out the block of wood so it would not bump into the crank.