Oil Pan Surface and Timing Chain Tensioner - Rebuilding Without Leaks

[kzite29]

Hi All! Here for a bit of help again..

Tore down the '99 motor and am in the process of rebuilding. I'm though the "hard stuff" inside and have a couple things to verify before I get too far.

1. Timing Chain Tensioners: The 99 has the iron ones, supposedly more robust. With about 70k on them, the tensioners seem fine to me, but when I compressed them to put back in I noticed some oil come up around the piston. Is this normal? Since they're constantly getting fed oil pressure I feel like this could be by design, but if this is an issue I'd rather spend $120 on new tensioners now than have to tear into it again later.

2. Oil Pan: The powder coating seems to be kind of flaking a bit on the sealing surface of my pan. To me, I want to say "it's not spotless, get a new one" but OEM pans are getting harder to come by these days and are pushing over $100. Has anyone just sanded the coating off and polished the surface? I also noticed some small "bumps" on the sealing surface, maybe warpage on the windage tray. They're about 5mm wide and 2mm tall, enough to feel a lump when you run your finger (whole finger, not just finger nail) over it. Is this something the fel-pro gasket can handle? OR alternatively, should I just slather this guy with black RTV and stop worrying about it?

All dubious advice appreciated.

-Kyle

 

[01yellercobra]

1) The oil has to go somewhere when you're compressing the pistons. That being said, $120 now will save you the chance of having to tear into the motor later on. It's a bit of a PITA to pull the timing cover off with the motor in the car. I speak from experience on that one.

2) Use a scuff pad to clean the surface. If the surface isn't flat you can put a piece of wood under the flange and tap the other side with a hammer to straighten it out. Had to do that with the valve covers I ran on a 351W. And don't forget the RTV at all the seams. I forgot that once.

 

[kzite29]

Thanks! I really appreciate the quick feedback.

On #1, I think the oil should go back out the galley it came in, not through the seals up the piston. But I'm really not sure if this is by design because they were working flawlessly when I took them out. No noise, no wear on guides, etc.

#2 I think the thing that gets me is the black powder coating on the pan. I'm sure the gasket is designed to seal against that and not the bare metal (iron based?) of the pan. Or maybe there's corrosion concerns? I could possibly recoat the sanded surface for less $$ and hassle than a new pan, but rattle can paints are hit or miss for surface finish. I'll give it a few whacks with wood under it though, sounds like it's worth a shot! Not sure how these little wrinkles in the surface happened to be honest, no dents in the pan.

All the best.

 

[01yellercobra]

I know the oil passes through the tensioner. I couldn't tell you how much is normal though. You can always try them. Just make sure the surfaces are clean and level.

The gasket doesn't know if it's sitting against bare metal or paint. The pan itself is steel. I've never had an issue with Duplicolor and VHT engine paints. Just make sure you get the stuff made for high heat. Just torquing the pan can cause things to move. It's just thin sheet metal.

 

[SecondhandSnake]

For the tensioner, that's totally normal. In fact high hp and high RPM builds often go to revised billet designs that leak much less oil. Not a concern for your average rebuild, or even all but the hardcore builds.

For the pan, I wouldn't worry about it too much. I would probably scuff/sand it down smooth, make sure it's flat and true, and then hit it with some rattle can paint. I've done it with rusty old pans before and much worse gaskets with no issues.