[nas t eh]

Background.

Engine assembled a few years ago with a solid roller cam, so I picked up a new valley pan from Butler to ensure I would not have clearance issues with the lifters. I think it's the Tomahawk pan. Still finishing up the rest of the car, so engine only gets started up every couple of months or so, the whole car with engine in it is stored in my garage.
Block and valley pan were painted, aluminum heads, timing cover and intake were not.

The other day I notice the whole valley pan from front to back is covered in rust and pealing paint. I guess my engine builder did not prep the new pan properly but I'm surprised it corroded this badly sitting inside the whole time and I thought the pan I picked up was plated. I thought maybe leaking gas or antifreeze could be the culprit, but careful checking with the engine running and I can't find any leaks.

Wondering if I'm the first with this issue?

[Baron Von Zeppelin]

Seems like your bare aluminum parts would be speckling with white oxidation too if the environment was the main issue.

Paint probably kind of burned loose or lost adhesion and condensation set in underneath it ?
Better prep , scuffing , self-etch primer (rattle can) , color coats

[Half-Inch Stud]

While agitated, Dehumidify the garage?

[pont3]

Seems to me the aftermarket timing covers have the same issue and I wonder if they were designed to use the later coolant formulations.

[chuckies76ta]

I have two of these valley pans in garage for the past couple of years and they still look brand new. Our climate is very dry here in Edmonton. Wondering if maybe you got a bad one. I have three on running engines with no issues. Hopefully there is no issues on the underside with it. Maybe remove it and check it.

[goat69SD]

Another suggestion would be self etching primer under the engine paint. I use that on parts that are subject to rust or have paint bubbling issues. Seems to really work for me.

[chuckies76ta]

Originally Posted by goat69SD

Another suggestion would be self etching primer under the engine paint. I use that on parts that are subject to rust or have paint bubbling issues. Seems to really work for me.

I've done the same but used high temp engine primer and paint. Never had any issues. I'm wondering if he used high temp paint.

[nas t eh]

Thanks for the responses, seems like it’s just me, ...I’m so lucky.

I’m going to pull it off and see if the underside is the same. Given that it is exposed to oil, I’m expecting it’s fine. But I think I’ll replace it with a stock pre EGR pan I have and just check that it clears the lifters.

Too bad I didn’t cheap out and do that in the first place. But that usually never works out in my favour, in this case it might have and I never would have known.

It is/ was painted Pontiac metallic blue, but I have no idea what product was used and I don’t think he primed it at least I can’t see any evidence it was primed.

[chuckies76ta]

I can sell you one if your interested. I can just order a new one.

[nas t eh]

Thanks for the kind offer, I know it’s just me, but this has left me hesitant to use another aftermarket one.

I’m not in a rush either, I have lots of things to work on before I must get to the valley pan. My goal is to get the car on the road this Summer, so I could order one and I think it would get here before I really need it.