L9H Engine Failure - What to do now? HELP

Black Denali Canada · July 12, 2017

Whoa !

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007matman · July 12, 2017

That's nasty. Metal fatigue/fracture?

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newdude · July 12, 2017

I see marks on the intake valve seat that match the piston left side. I'm going with lifter failure or broken valve spring, possibly a bent pushrod as well, and maybe slapped the valve to the piston and some debris from piston or valve flew around and did the rest of the damage. I see some damage top of the cylinder wall right at the top. Time for a trip to a machine shop with that whole engine and overhaul it or drop in a new GM crate.

L9H 2 LM2 · July 12, 2017

Haven't looked at the lifter too close but nothing obvious looks ou tof place or broken on it and the push rod is straight as can be. Havnt removed the valve spring either but it still seems to be intact and as well. Heck even looking through the top of the head, the valve doesn't seem to be bent but the top of the seat on it has a chunk missing out of it. It was getting late when I got the head off last night but I will find out more when I get off work this evening and look into it more.

Im not sure what caused it but looking at about the 6 o'clock in the pic of the piston you can see a large chunk missing out of the piston all the way down to the ring. My guess was either the piston fractured and started all the carnage (which I find unlikely) OR the rod bearings went causing excess travel in the piston and allowing it to hit the valve on the way up.

Bad thing is, I was looking at some other pics this morning and noticed on the next cylinder down there appears to be a little damage to. I will post that pic up for yall to see when i get home. If it is in fact damage to that cylinder that makes me think even more that the source is something in the bottom... like rod bearings...

L9H 2 LM2 · August 3, 2017

Well its been a while since I updated basically because not much has not happened since I last posted. The motor is still in the shop and "should" hear something by no later than this evening on what route I will end up going. To catch everybody up, I brought the motor to David McMurtry with McMurtry Automotive who builds racing engines and is very well known here locally as well as in the racing scene. Anyways, basically my options will be, (A) Try boring .010 over and see if that will take care of the damages in the cylinder (B) If Opt. A don't work, he said he will look into a .020 over bore. He said "look into" because he knows it can and has been done but he personally has never done it on the stock sleeves in these blocks so he wants to make sure it will be reliable before doing it, Or © Worse case he said he will bore a 6.0 iron block (being a new L9H block is $1500) and put my internals in it. He is also going to do a few other minor mods (i cant remember exactly what) regardless of which option I have to go with, to beef up and eliminate a few "weak links" he tends to see in these block so I wont have to worry about potential future problems being my luck with engines lately.

Even though I havnt got my motor back yet, I am already very pleased with this guy. Obviously he is very knowledgeable, but what sold me on him was that he was very willing to help me out however he could and actually showed concern in the situation i am in. He understood this was not a "planned cost for me" and ensured me he would get me back on the road for cheap as possible by helping me out with a replacement head and other parts for way cheaper than I could get anywhere else but also ensured me I will have an engine I can rely on when he get done with it. That in itself meant a lot to me because he could have very well turned me away at the door simply because he don't have to deal with the potential headache that sometime comes along with "on a budget" daily driver repairs. 90% of the customers he deals with seeks him out specifically because of his reputation in the racing world and are more than happy to pay whatever price he names for his engines.That's big deal to me and was a breath of fresh air. Makes me feel that I made the right choice and am in good hands. Hopefully this marks the turning point for my luck and everything will go smooth from here on out and I can get this whole nightmare behind me.