Rebuilding Apex motor after overheating

[rxrider]

My friend got hold of a overheated Apex engine from a dealer. Motor was going to the graveyard, but may be rescued. Motor has 25 kilometers or 15 miles on it, the owner did crash his sled and then returned home. The crash damaged the coolant line going to the oil cooler and lost coolant on his way back home after the crash. Eventually the engine overheated before he was home. He did not drive the sled hard on the way home. The motor may have run 5 miles on the most while overheating. Motor still had all oil in it but the oil smelled like it has been fried.

My question is what damage will overheating do to the engine?

Plan is to rebuild the engine to have it as a spare, my friend is going big on his Apex turbo project and have two blown engines in his past. He figured having a second engine would minimize down time the next time the engine goes he can't help himself from turning up the boost LOL.

Ok - we started the tear down today (my 6th on the RX-1/Apex motor), here's some pics of the motor.

Took it out of the crate and put it on my workbench.

We started by taking off the coils, they were melted onto the plugs and had to be destroyed to be removed. Then we took off the head cover. And removed the cams.

One of the cam journals is suspeck and will have to be changed out. It has deep grooved in the bearing surface.

Here's what the corresponding cam looks like. What do you think? I can't feel any grooves in the bearing surface on the cam.

Then we took off the head.

Here's what the cylinders looks like. The cylinders are intact

But one of the pistons may have detonated due to high heat. Here's what it looks like.

The corresponding combustion chamber and spark plug.

We still have to tear it completely apart to have a look at the crankshaft bearings and rod bearings. It may be worthwhile rebuilding this motor.

Any input on this engine are appreciated, the pros or cons and whats needed to properly rebuild this engine.

I have never had my hands on an overheated engine before, it may be toast or it may be rebuildable, let us have it.

Thanks
rxrider

 

[1CrazySledder]

Might want to make sure the head isn't warped.

 

[rapeape]

great pics

 

[kinger]

When I oil starved mine the head looked MUCH better then that and it was junk. I say the whole top end is garbage.

 

[ROCKERDAN]

i have over 100 pics similar to these when i rebuilt my motor last summer.....mine let go due to NOS....my head was just slightly out of spec(warpage)and I had one cylinder pushed out 10mm into an eggshape....so I had to get a new upper and lower case....along with piston,rings and rod.

its a great motor to work on once its on the bench,very easy IMO....its removing it from the sled that sucks the most..lol.

Dan

 

[wantboost]

you can't get that cam cap byitself,you have to buy a complete head.

 

[TurboJamie]

Yes the head is line bored from what I know all in one piece. The cam caps cannot be bought seperately.

 

[gsxr]

800 518 7220 / 418 335 7220
ADRIANNE BERNARD LTE

CAN FIX THE HEAD !!!!! AND BLOCK !!!!!

 

[TurboJamie]

Good to know Glen! I talked to Randy this morning btw.

 

[rxrider]

Randy Swensen? How's his MCX Nytro running?

 

[rxrider]

800 518 7220 / 418 335 7220
ADRIANNE BERNARD LTE

CAN FIX THE HEAD !!!!! AND BLOCK !!!!!

Thanks for your offer