Engine failure question

[Chevy454]

Let me first apologize for the non-S/S question...

A truck puller friend of mine called me this morning...he had an engine come apart over the weekend, and upon the tear down he found some rather alarming things...which leads me to my questions:

(1) will piston-->head contact result in bearing failure? (looks like there's been contact for a while)

(2) what is the protocol in regards to reusing roller lifters on a different cam? (builder put in a different cam, but threw in a used set of rollers he had on the shelf, and one of the "connectors" between the pair of lifters broke, naturally allowing the roller to spin)

My thoughts are that the piston to head contact is a no-brainer, considering the fact that detonation can take out bearings, and actual contact will be a LOT more violent than that! As for the roller lifter question, I'm an old fashioned solid-lifter guy, so rollers may be different...but I always thought if they weren't Shubecks, then a lifter change with a cam change was cheap insurance...but again, I don't know how it is in the land of rollers.

Anyway, he's hooked to the sled exactly TWICE this season on this engine, yet he said it's had a severe miss/stumble since he got the engine from the engine builder, and on the 3rd try it came apart in a bad, BAD way...as of now, the engine builder ain't exactly offering to help my buddy out on the engine.

[rustbucket79]

1) It could, but I would expect the piston to take a bunch of damage before hurting the bearings, and the bearing damage should show up on the upper bearing only. If there is signs of heat and the whole bearing is torn, it isn't because of the piston to head contact.

There is nothing wrong with reusing roller lifters, the link bar failure sounds like an odd one though.

What ultimately happened to the engine, total carnage?

As a race engine, few machine shops will warrantee them, and none should with used parts.

[rustbucket79]

Oh, and the obvious question, if there was a severe miss, why did he run/race the engine? That is just asking for destruction, and despite what was causing the miss, the operator assumes responsibility of damage if he chooses to run the engine that way.

[Bob Pagano]

Forget about the driver, how dose a so call engine builder let an engine out without checking the deck and headgasket or piston to valve for that matter. Sounds like no mock up was done to me and I am no engine builder.

[Rob Petrie E395]

Originally Posted by Bob Pagano

Forget about the driver, how dose a so call engine builder let an engine out without checking the deck and headgasket or piston to valve for that matter. Sounds like no mock up was done to me and I am no engine builder.

There are some awesome engine builders out there for any form of motorsports. Then there are the rest of the crackerjacks with a 180 piece craftsman tool set and a business card that reads "Professional Engine Builder" it simply amazes me when I talk to people what it takes to call yourself a "engine builder" these days. With the machine work being the exception I do build my own engines for my bracket car but I am not a engine builder.

[Moparteacher]

The piston-to-head contact can be a result of the failed bearing.

A misfire or abnormal combustion puts an extraordinary load on the bearing. A misfire can load up the cylinder with fuel resulting in a hydraulic cylinder and that crushes the bearing causing the bearing shell to lose it's crush and allowing the bearing to spin.

Detonation and/or preignition will crush a bearing also, resulting in a spun bearing and piston-to-head contact.

Piston-to-head contact is usually a result of a spun bearing and not the other way around, unless of course the builder is incompetent and fails to check clearance.

As already posted, resolve of the missfire is priority to making a run. If the run was made with knowledge of the missfire then the engine builder has no liability and the owner bears all.

Gary Weaver
College of Southern Nevada

[Chevy454]

Ok, stopped by my buddy's garage and saw the destruction, so let's jump right in...I apologize for the length!

In the cylinder that came completely apart, rod bolts broke, rod broke, wrist pin just about broken out of piston, cylinder split, etc, etc...usual destruction stuff. But, EVERY piston had been hitting the head, in the exact same spot, and looked exactly the same...so much the same, that it looks like someone had an assembly line set up! Anyway, the piston was hitting the head at the point in the combustion chamber where the valve reliefs come together (if that makes any sense)...every piston/combustion chamber had the exact same marks...like someone had taken a punch and repeatedly beat the aluminum head in this exact same spot...had to have knocked the point down close to 1/8 inch. As for the tie bar on the lifter, the lifter looks amazing considering it rocked sideways and lived through everything else...some slight scuff marks here and there, but it still rolls perfect...nothing like the solids I've had that had quit rotating. Now, to answer some questions...

1) It could, but I would expect the piston to take a bunch of damage before hurting the bearings, and the bearing damage should show up on the upper bearing only. If there is signs of heat and the whole bearing is torn, it isn't because of the piston to head contact.

The engine won't turn over a lick, but I had him pull another piston...you could tell on the upper bearing where it had been in a bind and had worn that way...no blueing or grooving, just odd wear marks.

Oh, and the obvious question, if there was a severe miss, why did he run/race the engine? That is just asking for destruction, and despite what was causing the miss, the operator assumes responsibility of damage if he chooses to run the engine that way.

Touche, but it was down to nut-cutting time, as the guy played the old "it'll be ready next Thursday, nope, we'll try for next week, nope, for sure by Tuesday, nope..."...it was basically down to the wire to get the engine in before the first pull of the season. But, here's something I only found out last night, when my buddy first fired it, it had a bad miss, so they pull a valve cover, and one of the rockers was mega loose, like it had never been tightened (he's running a girdle)...so he ran the valves, and fixed the miss @ idle...but under the heavy load of the sled, it still had a miss. Remember, this is a pulling truck, and with the gearing/setup, the only way to "test" it is to "hook" it...his first 2 hooks he didn't even complete because the truck wouldn't get out of it's own way, so he swapped ignitions and carbs I believe and on the 3rd hook the engine let go...

The piston-to-head contact can be a result of the failed bearing.

A misfire or abnormal combustion puts an extraordinary load on the bearing. A misfire can load up the cylinder with fuel resulting in a hydraulic cylinder and that crushes the bearing causing the bearing shell to lose it's crush and allowing the bearing to spin.

Detonation and/or preignition will crush a bearing also, resulting in a spun bearing and piston-to-head contact.

Piston-to-head contact is usually a result of a spun bearing and not the other way around, unless of course the builder is incompetent and fails to check clearance.

Exactly...but it would show up in the bearings, right? It was #3 that spit it's guts out, so I had him pull a piston *ahead* of that cylinder and check the bearings, as my assumption was the bearings should look worse furthest from the pump, right? Anyway, as mentioned above, they looked good considering the amount of junk in the engine, except for the funny mark on the top bearing. The pin was locked up also, and I'm gonna guess every other hole will be the same, seeing as the thing can't be turned over.

My buddy talked to the engine guy last night while I was there, but as you can imagine, it was kind of tense...the guy was real quiet, and agreed that it sounded like a clearance problem and even admitted that with that head/piston combo that that part of the chamber is supposed to be taken down...but then he crawfished back around and told us basically we weren't seeig what we were seeing...the main thing that worried me, is the guy had no idea what parts were in the engine, and yet he put it together within the last month? I just called a guy about an engine in one of our cars that put the engine together 19+ years ago, and the guy told us each and every part in the thing, and how it was set up...and my local builder can tell me everything about my personal motors as well...but this guy had NO CLUE.

The scary part is, this guy not only just built my buddy's engine, but his dad's engine, and another friend's engine...and they all have a miss, and one has a serious vibration...!

And I should mention, I understand not to expect a 5&50 warranty with a race engine, but at least check things out and give it a *chance* to live...