Filling Rust Pits on Blocks

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My rebuilder called to let me know the machine work is complete on my ’29 block. The block has some areas of significant pitting that would still be noticeable after a good coat of engine paint, so I am going to get the block, apply an etching type primer, fill areas as needed, then apply the Eastwood ceramic type engine paint. As with radiators, the goal is NOT to apply a bunch of paint, as it will reduce the engine’s ability to dissipate heat. I am also trying to provide a finish that emulates the factory cast look, not make it smooth (which also affects the engines dissipating capability). Having said that, what does everyone do to fill the pits on engines? I am thinking of using either the all-metal type putty, JB weld, or another similar product.

Comments welcome.

Bob

Thoughts, anyone?

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That rough surface might look a lot better, and good enough to paint, if you just aggressively sand the rough, pitted areas. Sometimes just taking the high-points down instead of filling the low spots will look pretty good, and not leave you with trying to have the areas look like ‘bonds’ was applied on them. And the possibility of the filler coming loose after a few years..

Something else to think about,, Take a look at a photo of a ’29 engine compartment.. There really are not any large areas of the engine block that exposed or visible.. Most of the right side of the engine is hidden behind the intake and exhaust manifolds, and carburetor. Only the fairly narrow ledge at the bottom of the block where the oil pan is mounted is really visible..

The other side, is roughly equally hidden behind thee starter, the generator/water pump, and oil filler neck . Even the linkage coming up from the end of the steering column tends to mask any large open areas of the block..

The separate front and rear motor mounts that bolt to the block have some exposed and noticeable areas that might look pretty ugly if they are in really rough condition..

In general, the cylinder head has the largest exposed and visible surface area.. And they do not look ‘right’ when they are ground and filled and look like that are cast out of plastic.. Which you did say yo were planning on avoiding..

Just my thoughts,

Greg Long..

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Can you post a photo or two of the rougher rusty spots on the block??

Another method that might work, is to use a needle-scaler to ‘dimple the surface of the block after you ground down some rough rusted areas..

I’ve bought some reproduction cast parts for cars, that had a lot of flashing, and casting pour columns still n the new part, and those ‘leftovers’ from the casting process are not left on the parts at the factory.. So I’ve used a grinder to remove the flashing, and the casting pour tubes etc..

Then I use an air powered ‘needle-scaler’.. This is an inline air hammer with a couple of dozen hard steel rods, usually about 1/8″ diameter, protruding from the working end,, when activated the air hammer makes each steel rod be driven out and back about 1″. Each steel needle acts like a tiny pick-hammer. The finish of an iron casting is massaged with the needle gun, and the result is all the indications of a grinder having been used to clean up the casting are GONE..the needles leave a random-dimpled surface nearly identical to the casting’s normal surface..

Greg Long

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Greg, that is a ’29 distributor cap but that downdraft carb and air cleaner are definitely not ’29.

I guess once all the usable UU2 castings disintegrate all of us early 8 cylinder guys will have to use downdraft carbs.

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Hi Craig, yep you are correct, that is a ’33 carb, air cleaner and manifold set on my roadster’s engine. They were installed sometime in the ’50’s by Eric Rosseneau when he owned the car, I don’t know if he did it for the extra horsepower and driveablilty or if the original updraft was not rebuildable,, almost for sure the exhaust manifold would have been cracked too.

But the engine is a ’29, that is noted by the lack of a belt to drive the generator and water pump, 1929 was the only year that a Pierce 8cylinder had a timing chain driven generator.. maybe a ’30 model C’? not sure on that..

The front and rear motor mounts are the timing chain enclosure on the front, and the flywheel enclosure on the rear. Both bolt to the crankcase.

This car is a daily driver during the summer, so the downdraft carb is appreciated, as well as the 3.55:1 Phill Hill rear gears.. the car really flies .

Greg Long

Here is the car with it’s most enthusiastic rider.

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Sandy says he is also the best looking!

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I will post a picture when I get the engine back, hopefully on Wednesday. You are right about the scaler, I forgot about them, as I don’t have one in the tool inventory. This engine block is a replacement, as my original one was cracked through two cylinders (2 and 3) between the bore and the valves due likely to overheating. The head is fine, though it was repaired at some point around the water outlet.

More later. Thanks for the thoughts so far.

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What? It’s done already? It hasn’t been 7 years yet! (that’s how long he took on one engine I don’t want to think too much about!)….great news! If you go to get the engine, I know where there’s a Rat Fink waiting for you….

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Greg, I’m sure the added drivability of the downdraft more than makes up for the lack of originality.

And since it was installed by a Pierce expert I’m sure it was done right.

David, that is a great looking Rat Fink. It is extremely clean for its age.

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