Frank's Looper Restoration
Frank,
I would most definitely say no to jet hot coating the engine block. The water system in your C Looper is marginal by today's standards, although it was contemporary for the 1960's time period in which it was designed.
I think that jet coating is primarily designed for exhaust systems and performance uses where insulating the heat of the exhaust advances the horsepower. With the Looper, I don't think the aluminum should even be painted. It's possible that Quincy Welding painted a few Loopers, but I am certain that the vast majority were left natural cast aluminum to better dissipate the heat.
Frank, we sold engines in kit form, assembled power heads and complete engine packages with lower unit and drivehousing. That being said, people can be and were creative in assembling their Loopers. It is possible yours was painted by the original owner. To my knowledge, I don't ever recall us painting a Looper block. We did paint the head gaskets and when looking at your pictures of the disassembled block, it appears your head gaskets were painted.
Now back to the surface cleaning of the block. I've seen some very poor looking finishes due to improper media blasting the block. I think, at the current state of auto, cycle and outboard restorations, that unpainted aluminum block surface/finish restoration is an ongoing science. I would cautiously proceed in determining how and what you use to clean the block. The original new-like patina is the goal to recreate but I don't know of any "one method fits all" considering there are so many degrees of aged aluminum surfaces to deal with in the restoration process.
I am myself experimenting with a chemical process that is highly temperamental and too complex to try to explain effectively here at this time. It's still an experiment in progress right now, although the results so far have been spectacular in terms of luster and original looking patina. I'll get back to you once I've worked on this some more.
Richard Ollhoff has his restoration finishes on unpainted aluminum surfaces down pat and if his procedures and finishes satisfies your needs and requirements, then go with his system. I posted his phone numbers to this thread previously.
There is another gentleman that restores old outboards and race engines by the name of Bob Dunlap. His restorations are meticulous and spot on original. He is a member at BRF and he would be a good one to consult too.
R C Hawie is another expert restorer, although he is not hooked up to any computers at this time. I have personally witnessed his assemblies and restorations and he is one of the few people I would trust with my priceless collectable engines.
Frank, I hope this helps you with your restoration. I will be watching your progress as I am sure others will too.
thanks,
Paul A Christner