bgoetz

Ok, so you did see it running, that is nuts! I suppose the over rev could have been such that the damage cut oil supply from the head, then driving it cooked everything. So loss of oil supply caused by the overrev. That is more where I lean now.

Billman250

As soon as the top end starves, due to loose camwheel or blockage, the top end will start to fry. The cams will get red hot, expand, and crack open the cam caps. I'd imagine it could run for many miles or minutes in this destructive state. When I say the engine is toast in seconds, I mean the toasting starts immediately

tamadrummer1120

Mmk, I am with you here. As soon as we popped the valve cover I knew in the back of my mind this was oil flow related (I assumed low oil though, completely didn't think of the head being cut off). Because I noticed it got worse and worse towards the rear of the engine, much like how the ap1 oil jets would fry cylinder 4 first on boosted engines.

tamadrummer1120

Will be posting lots of pics once I get the engine removed and on an engine stand.

jetboater

Thanks tamadrummmer1120---this is a great thread-- very educational!!

There's/ a lot of folks learning a lot from you and Billman on this-- please keep us posted as you figure out what happened!

tamadrummer1120

Oh one another thing to note from the owner that I forgot to mention.

At some time between his oil change and this engine failure, he had a p1259 VTEC system malfunction DTC set.

Now I know this can be set due to many things, but the most glaring and fitting at this time is low oil. But that is not to a clogged screen as well. Supposedly he took off the vtec solenoid and cleaned the screen and the cel went away. Not sure about that

tamadrummer1120

Thanks man. I cannot wait to tear into the engine itself and sort what caused the head failure and see how the bottom end looks as well as see what billman thinks of it all.

tamadrummer1120

Small update.

I did not have any real time last night in regards to pulling the engine, but the following was found....

I got the cams out. Intake cam was seized back on cyl4 and required prying to be pulled out. Earlier suspicions that this head it completely toast were once again verified by the large amount of metal scouring on the cam journals.

Also, checked the torque on the front allen bolt that holds the cam idler gear. It was around 15-20 ft lbs. Aroound a 1/4 turn got me to the 36 ft lbs. Not sure if that is deemed loose enough to bleed off oil pressure or not.

windhund116

Sounds like head may have gotten warped from excessive heat. See any cracks in its surface?

ISADE

I was coming up with a theory on why oil was so low, if the top end was getting minimal oil and heating way up, what little oil did get through to the top end would it be burnt off? Over a few miles enough oil was burned off due to the top end being so hot and that explains the low oil level?