Flathead rebuilds
Hi Frank
Tony is on the money about the valve grinding paste, and Geoff has a good point about the cracked blocks.
Back in the 70s, I worked for a parts place which received large numbers of these engines for reconditioning, and I must have pulled at least 70 of them down to send to the reconditioners.
Valve problems were fairly rare, although I did see some which had burnt valves, usually these had been genset engines.
Cracks were very common on the later 8BA engines, the ones with the distributor high up. It was the first thing I'd look for once the heads came off. Surprisingly hardly any Mercury engines had cracked blocks. Usually the worst thing to deal with was sheared head bolts on the 8BA and getting the studs out on the Mercury engines.
The engine shop dealt with any which were too difficult.
The adjustable lifters were like gold because they saved a lot of time grinding valve stems at the workshop.
As for valve seats, I recall occasionally seeing an engine with inserts - you can only grind the seat a certain amount before this is necessary. The other good thing a rebuild shop will do is to properly crack test and repair the block, and also resurface the block for the heads.
The only engines we couldn't do anything with and usually didn't even buy were those which had been in boats in salt water.
Hope this helps. There is a lot of knowledge out there on the subject and a lot of these engines are still being completely rebuilt, although it's an expensive business now.
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