301 Engine - bent pushrods

[dhermesc]

My son snapped the gear drive off the cam about 2 years ago. Sucked a piece of metal into the hydraulic pump and jammed it. I bought a cam from a salvage yard and he installed it. Him being his grandfather's grandson he has wasted 2 years in the assembly. He claims the timing marks lined up and according to the shop manual the cam was properly lined up (we have the actual shop manuals the Allis dealership was tossing). He installed the head and turned it over - to test things. Immediately it had several bent pushrods (4?). About the only way this could happen is the timing on the cam is off and the valves struck the piston - correct? There is no difference in the 301 cams is there? This camshaft was represented as coming off another 180.

 

[teddy52food]

My son snapped the gear drive off the cam about 2 years ago. Sucked a piece of metal into the hydraulic pump and jammed it. I bought a cam from a salvage yard and he installed it. Him being his grandfather's grandson he has wasted 2 years in the assembly. He claims the timing marks lined up and according to the shop manual the cam was properly lined up (we have the actual shop manuals the Allis dealership was tossing). He installed the head and turned it over - to test things. Immediately it had several bent pushrods (4?). About the only way this could happen is the timing on the cam is off and the valves struck the piston - correct? There is no difference in the 301 cams is there? This camshaft was represented as coming off another 180.

Are the valves stuck?

 

[dhermesc]

No.

 

[Fritz Maurer]

If you sheared the gear off, whatever valves were open at that time are going to stay open while the crankshaft slows down... entirely possible that a struck valve could propel the camshaft enough to open a couple more before everything comes to rest.

 

[dhermesc]

If you sheared the gear off, whatever valves were open at that time are going to stay open while the crankshaft slows down... entirely possible that a struck valve could propel the camshaft enough to open a couple more before everything comes to rest.

The head was removed and sent to the machine shop when the broken cam was pulled.

 

[Fritz Maurer]

The head was removed and sent to the machine shop when the broken cam was pulled.

I thought you were talking about bent push rods at the time of failure.

If the push rods were all straight at the time of reassembly, then yes it is out of time.

 

[farmersamm]

And.............bar an engine before you use the starter.

 

[rustred]

Exactly! How else would you set the valves. You would feel a restriction !

 

[Fritz Maurer]

To modify my previous statement, it IS possible to bend push rods and still be properly timed.

Nothing is known about the disassembly or reassembly methods, other than it sat apart for two years.

Possibly foreign material has fallen down onto the tappets or the adjusting screws were out too far. In short, if the valve spring stacks up solid before the end of push rod travel, the push rod will bend. The engine may very well be properly timed.

Also possible that the push rods were bent at the time the rocker shaft was tightened down, before he even turned the engine.

Another possibility is the wrong springs or other hardware installed at the machine shop.

 

[dhermesc]

This project has caused more that few issues between my son and I. I am ready to send it off/contact to "a guy" that works at AGCO that does a "private" work at home on weekends. The timing cover is back on with the water pump but a lot of the engine is still removed - including the radiator. With the cam installed he can remove the timing gear - rotate to the correct position and install the timing gear - correct? I will probably have him time the injector pump at the same time. Then we/I will finish the assembly. I want to put it together and get rid of it. Obviously since it hasn't been used in two years we don't need it.

 

[dhermesc]

To modify my previous statement, it IS possible to bend push rods and still be properly timed.

Nothing is known about the disassembly or reassembly methods, other than it sat apart for two years.

Possibly foreign material has fallen down onto the tappets or the adjusting screws were out too far. In short, if the valve spring stacks up solid before the end of push rod travel, the push rod will bend. The engine may very well be properly timed.

Also possible that the push rods were bent at the time the rocker shaft was tightened down, before he even turned the engine.

Another possibility is the wrong springs or other hardware installed at the machine shop.

At this point I can't get a civil answer from my son on what has been done or hasn't been done. At the time we did not know what had caused the engine failure and the only indication was that the engine died while driving across the field. I do know it was repeatedly attempted to start after it died. I know the push rods were not bent at that time.

 

[rustred]

This project has caused more that few issues between my son and I. I am ready to send it off/contact to "a guy" that works at AGCO that does a "private" work at home on weekends. The timing cover is back on with the water pump but a lot of the engine is still removed - including the radiator. With the cam installed he can remove the timing gear - rotate to the correct position and install the timing gear - correct? I will probably have him time the injector pump at the same time. Then we/I will finish the assembly. I want to put it together and get rid of it. Obviously since it hasn't been used in two years we don't need it.

hopefully you have the manual. to set the timing on the gears you need to actually pull the camshaft outward and then slide it back in while aligning the marks. you dont just remove the gear and turn it as it would be on a keyway. all timing gets done including the pump following the manual. then its just start it and done. while i dont have experience on this particular engine , an engine is an engine.

 

[dhermesc]

hopefully you have the manual. to set the timing on the gears you need to actually pull the camshaft outward and then slide it back in while aligning the marks. you dont just remove the gear and turn it as it would be on a keyway. all timing gets done including the pump following the manual. then its just start it and done. while i dont have experience on this particular engine , an engine is an engine.

Remove the gear and turn the cam shaft - then slide the gear back on when the shaft is correctly timed.

 

[dhermesc]

I guess I might need to check the valves to make sure none are frozen. This sat outside for quite some time with the valve cover removed. I was more concerned about water in the pistons and taped the exhaust shut.