Thread: Broken studs/Push Rod--> From bad Gas?

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Lack of oil didn't even enter my mind. I was stuck on mechanical interference. Way to go 76GMC1500.

" Techinspector1: I'm not quite sure what you mean by 'stacked solid'. But, that thing looks like it was heated, and oil 'burned' on."

I was thinkin' extreme pressure caused the overheating. Of course, it was caused by lack of lube.

OK. I have the blower and manifold off, and the head. I got a spring compressor and looked at the valves. They look good.

However, the lifters I'm thinking are bad. Not at teh lobe. But, some appear frozen. I cannot push two of them down at all, others vary.

Sound like the culrit to you?

I"m headed up to the parts store. Plan to replace lifters, push rods, and broken parts.

If you look at fluid in a pipe, the fluid immediatly adjacent to the pipe wall will not be moving and the fluid in the center will be moving the fastest. That stationary layer next to the wall forms a sort of an insulating barrier. Detonation is usually detected by a rise in cylinder head temperature or CHT (many aircraft measure this by a thermocouple in the shape of a washer in place of the spark plug's gasket). Some speculate that this spike in CHT is a result of the explosive ignition of fuel (detonation) disrupting this boundry layer. With the hot gasses closer to the combustion chamber, greater rates of heat transfer occur and the CHT's rise. What I'm getting at is maybe the detonation caused an increase of heat transfer to the exhaust valves which caused the valves to expand and stick in their guides. Judging by the way the rocker arm tore away from its base, I would say there was a stuck valve. It could be that a overheated/stuck valve was causing the engine to run poorly and you misinterpereted it as detonation. Were all of the damaged components on exhaust valves?

This all seems too weird and I want to know what happened. I'm just throwing out everything that runs though my head right now.

Here are the ones that had problems:

Cylindar 7
Exhaust - Split Rocker, Burnt end on Push Rod
This is one of the ones that had a 'solid' (won't push down in center) lifter
Intake - Slightly bent push rod
Cylindar 5
Intake - Broken Rocker Stud
Cylindar 3
Exhaust - Broken Rocker Stud
Intake - Very bent push rod

I'm in the process of putting the motor back together now. I'm very anxious to see oil flow when I fire it back up.

This is all puzzling. I feel quite confident that I had water in the gas and detonation. I saw white smoke out both exhausts...particularly when we pushed down on teh gas, as opposed to cruising. When I gased back up, the detonation quit, and I was left with a miss.

I drove ~ 400 miles like that, and within 20 miles of home is when the studs broke.

I find that I also have a second lifter that is 'solid'. But not sure which one it was. Already out of engine before I found that. Others some others are somewhat short on the push.

So, it seems evident that the lifters are the culprit to the breakage/bending of the components. What puzzles and concerns me is what is the cause of the lifters going bad, and is there any relation to the bad gas.

I may never know. Again, I am anxious to see if the engine oils when I get it back together.

By the way, I am replacing ALL lifters, so I will be disassembling the other bank. I'll see if any of those lifters seem messed up.

[edit 9/19]
I got the engine running yesterday afternoon. It seems to be oiling good.

Ok. Here's where I am now.

I'll preface this with a little background: I am not a mechanic, but have built engines several times over the years. But, it's been 5 years since I built this one. However, my personal troubleshooting inside engine problems is not extensive at all.
This problem leaves me a little paranoid.

So, as you see from earlier post, I had decided that my problem was the lifters. But, with further reading, I'm not sure. So, some questions:

Lifters
1.) Once the engine is cold, are hydraulic lifters supposed to be able to be pushed down, or solid? That is, I pulled it out, put on bench, and pressed down with a push rod. Seems solid as a rock on most of them. A few I could push down.

2.) Is this normal? From some reading I have done, they are supposed to do that...at least while the engine is running.

3.) If not normal, what would cause this? Over-revving? I didn't rev the engine too high over the weekend that I had the problem, but I won't deny that I've done that.

Regarding the suggestion of anti-pumpup lifters earlier, I had already purchased new lifters by the time I saw that suggestion. With a little further reading, it appears that I need to get different rocker components if I use anti-pumpup lifters. Although not sure. I keep reading "If you get these you need to get an adjustable rocker set". Well, of course, I consider the stock lifters adjustable.

Oiling
While I stated that my engine was oiling, as I think more about it, I am not sure it is oiling like it should. Here is what I witnessed:

When I first started it, it seemed dry for a period. I had put in oil blockers on the rockers at first to keep from throwing oil all over under the hood. Then, pulled some off. At first, it was dry. Ultimately (I'd say once the engine heated up), it did push oil up through, but it did not 'squirt' like I have witnessed in the past.

So, I'm left wondering if I have a problem with oiling or not. I really don't remember what it was like in the past when I built the engine.

BTW...I am getting good oil pressure on the guage. And the rockers do appear to be wetting good with oil.

Whatch think?

Since replacing the lifters, the engine is running very well. Oiling is fine.

Since this fix, the engine is running stronger, and starting quicker and easier, than in quite some time.

Thanks for everyone's help and input.