I picked up a flathead this weekend and tore it down and found rust on the top parts of a few cylinder. The old guy got it 40 years ago to put in a truck and never did. The whole rest of the motor looks new. No rust anywhere. Would it be ok to just have the cylendrs bored if I just want to stay prety close to stock. I will have him magma flux it first but all looks got to my eye.
Main thing on the flatheads is to clean it up and check for cracks in the valve to cylinder area,#3 seems to be a bad spot on the ones i've had.
How bad is the rust and how deep is it. may be cleaned up and run as is....... any ring ridge or noticable wear?
There are some pits in it only the top inch or so on three of them. The under side of the pistons are nice and shiny. I am going to take the rest apart and clean it with washing soda and a batterie charger this weekend to get it real clean.
I had one with similar history. I took the heads off and it looked good inside. I rerung it, honed the walls, and checked the bearing clearance on a random rod and main. Bearings were good so never changed them. Motor runs very good. If the rust can be honed out, would save you on the boring.
Reminds me of my post, several years, and several miles ago... http://www.jalopyjournal.com/forum/showthread.php?t=40282&highlight=flathead+rust Rich
Started the electrolysis stuff to day. I did one of the heads it took about three hours but it looks real good. Got every bit of rust and the old gasket off. Going to do the block this weekend.
It may not be necessary to bore the cylinder. From what you say the engine was rebuilt then never run. The cylinder is not tapered or worn and the piston is new. If the rusted areas are not big enough to snag the rings you can hone the cylinder, put in new rings and run it. I knew an old timer who did this during WW2. He needed a truck, he found a six cylinder International cheap that had been left outside with the head off. He honed the pitted cylinders put it together with new rings and crossed his fingers. At that time NO new cars or trucks were available and even parts were hard to get. He said the engine ran well but burned a little oil for the first few hundred miles then settled down and ran like new. Some years later he took it apart to do a valve job. The pits were still there, filled solid with hard black carbon and polished smooth with the cylinder walls. Like I said, if the pitted areas are not too big I would chance it, on a street engine. If it is some kind of high buck racing deal it would be different.
Have also seen a 1972 Chev six cylinder pickup that was the same deal. In this case the truck had been off the road for years then a new owner put it back in commission. He drove it for several years, it ran well but burned oil. When we took it apart we found the cylinders pitted with rust but the pits filled in with carbon. You could see where the piston had been sitting in each cylinder by the ring of rust. The reason it burned oil was , the rings were all stuck in the grooves. We honed the cylinders, replaced the rings and it ran like new.
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