fire damage
 

Would like to some of your thoughts on fire damage, in particular engines and drive lines. Are there any telltale signs such as babbit still in place or not, aluminum parts melted or not that would indicate weather the cast iron has reached a temp that ruins it? Are there any tests that can performed on cast iron? Does a complete engine have a better chance than. a bare block to survive? I know that all the machined surfaces will have to be redone but I was more interested in the reaction of cast iron to high temp. As you might have figured this all is related to a fire loss in Northern California 3 fresh rebuilt long blocks and 4 crack free B blocks and cranks, Thanks for any input!

Re: fire damage
 

The hottest place in a house fire will reach temps of about 1200*F. research melting temps for babbit and aluminum and the affects that 1200*F would have on cast (if anything) and go from there. Anything with hardened surfaces (like a camshaft) would be finished i would think.Because the temp in such a situation rises and cools slowly, there is a good chance that the structural things like engine blocks and heads would be fine.

Re: fire damage
 

Although cast iron has a very high melting point and may not appear damaged due to the fire, I suspect that the high temps would cause distortion and negatively affect the metallurgy of the block. Cracks and distortion will occur if cold water was applied. I think this will lessen if block was allowed to cool slowly (normalize) in the open air. Did the bearings,pistons, seal retainers or any other parts of the engine melt? That may give you an indication of temperatures reached. Would be nice if you could have the cast iron metallurgy tested/examined.

The type of cast iron produced depends mainly on the % carbon content, what other elements are added and the temperature and duration of the heating and cooling process.This also determines the physical, mechanical and machinability characteristics of the cast iron. If engine blocks are made from a specific alloy of cast iron, the reheating and cooling induced by an intense fire might alter the original characteristics of the block. Not good.
Trouble is, you wouldn't know until after you have rebuilt and used the engine.

I personally would not reuse a bar-b-que'd engine. it would be great if a foundry engineer/metallurgist from an engine company would chime in.

Re: fire damage
 

I once bought an engine that was in a fire hot enough to take the temper out of the valve springs. No tension left. Springs on the valves that were open stayed at that height when removed. All I did was a typical valve and ring job (new springs, of course), put it in my car and left on a round trip from Arizona to New York. And drove it for several years after that. Did not need to rebore it. Did not need to mill the heads.
If a block doesn't get hot enough to melt, I don't think the metallurgy would be affected. Blocks are not heat treated at the foundary. Liquid iron is poured into the molds, allowed to cool, then machined and assembled.

Re: fire damage
 

A bought a nailhead that had the intakes melted and run down into the valves.
The block & heads seemed fine.

As the guy above said, it takes a fair bit to damage them beyond repair. Clean them up & see what needs doing.

Re: fire damage
 

Thanks for the input. I believe the cooling process was probably very slow and the only picture I have seen shows a lot of rubble on top of where my stuff should be. Still no time line on when we can view the remains. Lots of debris and burnt cars,downed power and telco, teams looking for the missing. ………...

Re: fire damage
 

So sorry you lost so much. Fortunately you made it out and as my late brother used to say "it always could be worse".

Re: fire damage
 

Our fleet of vehicles at work had to constantly go up and down a 7000' mountain under a heavy load with the gas pedal buried to the floor for long periods of time. At night the exhaust manifolds became a dull red. They do eventually warp to the point the bolt holes do not line up with the heads holes by half the bolt diameter They even make a tool to spread the manifold so you can get the bolts lined up. Eventually the pressure on the bolts snap them off flush with the head. But how many heating and cooling cycles did that take, hundreds maybe even thousands of times before the manifolds finally warped, cracked or broke bolts. All you can do is make sure the crank's line bore is straight,the block deck is not warped and there are no cracks.

Re: fire damage
 

Sounds like 350 Chevy pickups of the70's-80's era. I think that was a design flaw. Other brands didn't have this problem.

Re: fire damage
 

Not uncommon to have exhaust manifolds on the old mechanical Cat engines glowing bright red, the turbo as well.

Re: fire damage
 

Due to emission dictated retarded timing.