Overheating Atomic 4

[San Juan Cruiser]

Epic rookie mistake here, I forgot to open the through hull for the cooling on my atomic 4 engine and ran it for about 30 minutes before it died. No cooling whatsoever (I thought it was a little smokier than normal *sigh...*). What kind of damage am I looking at here and what kind of repairs should be made? I have not attempted to start it since.
It was in need of repair and I was going to overhaul it any way, so far I have removed the head, exhaust manifold, intake manifold and carburetor. I'm in the process of replacing all the gaskets and rebuilding the carb, not necessarily because of the overheating it just needed it. What else should I do?

 

[kendall]

if you're lucky

True the head and new rings at most, possibly just a head gasket.

I've seen those things (and a few other engines) overheat so bad that they couldn't be turned over with a prybar, and after they cooled for a bit started right up and ran as good as ever.

Nothing that you wouldn't expect to do during a normal overhaul anyway.


Ken.

 

[Benny]

Should have diagnosed the damage before

begining teardown. It will be hard to tell now whether you have a cracked head or cylinder block. Also a compression test cannot be performed until the engine is reassambled. Does the engine turn freely? It would be a good sign if it does. Check cylinder walls for scoring. For sure you will need to replace the impeller and check for rubber pieces that may have gotten into the cooling passages. Also test the thermostat for proper operation and make sure to change the oil. I would just replace the head gasket, place a new impeller and reassemble the engine to see if it will run and be able to conduct proper diagnostics. Good luck.

 

[Joseph Shirley]

I hate to tell you this but

Other engines have intermediate main bearings but the atomic four has no intermediate main bearings. If you overheat it and seize one or more cylinders there is a good chance that you bent the crankshaft. With the head off you can check that by individually checking the lift on each cylinder. Overheating that much without coolant means that the engine continued to get hotter after it seized. That much heat could have warped either the head or the block or both. I think your best bet would be to yank it out and take it to a marine engine shop that does A4's. It's not that heavy of an engine, especially if you've got the head off.

Good Luck

Joe S

 

[jviss]

Prevention

I know this won't help the present situation, but just for the readers out there, what I do is always place the key (on a string) on the handle of the closed sea cock. If the key is removed the seacock is opened; if it's replaced, the sea cock is closed.

 

[Ross]

All excellant advise but also check the exhaust system

It too is water cooled and much of it is rubber.