mashed / squished push rods

[clinter36]

Hello,

I purchased a non-running skid with a Shibaura N844LT engine (2L 4 cyl). Also a Cat 3024c and Perkins something.

As I am just getting into the engine, it appears all of the push rods are mashed at the ends. The tips look to be blue ish from overheating also (see pic)



I am curious if anyone can tell me the possible cause of this... ? ether? or possibly filling the oil too fast and hydro-locking (owners manual warns of filling the oil too fast as it will flow into the intake)

I guess I should pull the head and have it rebuilt while replacing the push rods. Does anyone think the damage could have extended into the bottom end of the motor or do you think I am OK with heads? Obviously I will have to inspect the pistons more when I pull the heads.. I would like to avoid pulling the entire engine if I can do just the top end work.

Thanks for the input.

 

[ruffdog]

Hydro-locking normally bends connecting rods. When you pull the head, check your piston to deck height on all cylinders for bent rods. Push rod damage mostly happens when the valves contact the pistons. If all the push rods are damaged, I would look at the timing gears between the crankshaft and camshaft.

 

[kenmbz]

Timing chain or belt break or if direct gears, missing tooth or gears not meshing?
That would cause such a massive overlap easily

 

[pmsmechanic]

To me it looks like the push rods are blue from the welding process during manufacturing. It's common for industrial push rods to have a bell on one end and a ball on the other. Take it to a dealer or an overhaul shop and a mechanic should be able to tell you what is normal for that series of engine.

 

[clinter36]

Yeah, you may be correct. I looked at a couple pics of new ones and they do appear to be blue on the ends. But certainly this cap has fallen off and the rod is clearly deformed a little at the ends. The machine has 4k hours. Just debating on pulling the engine out and just doing a full overhaul or do push rod / head work and call it good. I guess I will know more when the head comes off.

 

[dodge man]

I would think if the damage was from valves hitting pistons not all the push rods would be damaged, just a couple. Is this the kind of engine you adjust the valve clearance on. Would the valve lash be totally out of whack cause this? A problems with the rockers?

 

[TractorGuy]

Just bought a VW sand rail with the same issue. Not likely it was a hydro locking problem on an air cooled engine.

The ones in mine were aluminum and I replaced them with chrome moly.

 

[ericm979]

You can hydro lock an air cooled engine. Hydro locking just means getting too much of a liquid (i.e. water or fuel) in the combustion chamber that the piston can't fully compress. For example driving it into a stream above the air intake. (which may also hydro lock the driver if the air intake is up high, but you get the idea)

It's not that uncommon for push rod caps to come loose. If it's been loose for a while it'll damage the softer metal of the tube. The blue looks factory.

 

[Gem99ultra]

I would expect some cam damage as well. Safe thing to do is to pull the engine and go completely through it. No telling what else you'll find that needs repair. Better to catch it all on one pass than to keep running into problems later.

 

[Tinhack]

Yeah, those ends are typically "spin welded" to the shaft. I've seen them come apart on engines with excessive valve lash or a really worn cam. That would have been a noisy engine!