Cat 3304 pushrod

[JustinG]

Does anyone know the part # for a pushrod on a 3304 78P engine? Had a top end knock on my 951C and found cylinder #3 pushrod broken.

 

[kshansen]

From what I see the push rods are 5S5918 Original Equipment or 3940903 Cat Classic. The Original ones are about $25.00 each and the Classic about $8.00

 

[JustinG]

Thanks for the quick reply. That's not a bad price.

 

[Nige]

While replacing the obviously-damaged pushrod just make sure that both the cam follower and the rocker adjusting screw are in good condition. You may find that you also need to replace one or both of them.

 

[JustinG]

I pulled the follower out and checked cam lobe and follower. Both are fine, I have to pull the head. The valve spring is loose, I can move the valve and spring about 1/8". I believe the loud knock was the piston tapping the valve. The valve spring retainer is still holding, not 100% sure why it has that much movement. It was only ran long enough to get it out of the woods and on a trailer.

 

[Nige]

With those symptoms you'll probably find either a badly worn valve guide or at worst a broken valve and piston crown damage.
It would appear that your pushrod damage is consequential to another failure.

 

[kshansen]

While replacing the obviously-damaged pushrod just make sure that both the cam follower and the rocker adjusting screw are in good condition. You may find that you also need to replace one or both of them.

True!

Had a problem with a 3406, which has roller lifters, a couple months after dealer did a rebuild on the engine it developed a noise in the engine. Pulled valve cover to find a bent push rod. Lucky it was still right there and picked out with no problem. After discussing with dealer they said try putting a new one in and see how it runs. New push rod in and adjusted started and sounds fine. That was easy! Well until a few weeks later it happened again! Same push rod. Removed valve cover and just as I touch the rod to remove it it disappears sounding like a ball in a pin-ball machine, and I did not get Replay, just a dull clunk when it hit the pan.

Long story a bit shorter found the problem in this case was a broken 305-6843 SPRING-GUIDE. That's the clip that goes around the lifter to keep the roller inline with the cam. When it broke the lifter was able to rotate out of line and besides destroying the lobe on the cam the broken clip gouged the heck out of the block. Got a free reman short block out of that one! Not sure if anyone ever checked to see if the clips were replaced when engine was rebuilt the first time as is recommended.

As far as I know the 3304 does not use roller lifter, at least none of the 3306's I worked on did, but there is a reason the push rod bent. I believe the lifters can be pulled out of a 3300 from the top using a wire bent with a hook on the end. Just looked in SIS and they show using an extendable magnet to pull the lifters. If you don't find the cause it will most likely happen again and next time could cost much more than a $8.00 Cat Classic push rod and a valve cover gasket. I'd also be checking the other 7 very close, as what happened to the one may be damaging the others.

 

[JustinG]

Someone has put a reman head on this engine before I bought it, not sure how old it is though.

 

[Bob/Ont]

Check the cam over good for a chipped ramp, they tend to last about 16,000 hrs in an engine that lasts about 20,000 hrs.
Later Bob

Someone has put a reman head on this engine before I bought it, not sure how old it is though.

 

[JustinG]

Well, got the head off and it's not good. Piston and head damaged, looks like valve seat came apart. Will post pictures later. Is it possible to do a inframe on a 951?

 

[JustinG]

The pictures of the damage

 

[Bob/Ont]

Yes you can.
Later Bob

 

[JustinG]

Good to know! The parts ordering begins.

 

[JustinG]

Been looking at engine kits, anyone have any experience with Interstate Mcbee kits? My local engine shop sells and use them also. I've used FP diesel kit, but never a Mcbee. The Mcbee is a little cheaper.

 

[kshansen]

Can't speak for Mcbee, as I have been away rebuilding engines for a few years, but at least you found the cause of the broken push rod

 

[tctractors]

To strip out the engine in frame is a bit of a pain as the engine needs lifting up around an 1" usualy to get the sump off, thats the flat plate the oil pan is fixed to, as you say the engine is a 3304 the loader must be a C series with a good few digits in the serial No, a picture of the water pump area might be worth posting to confirm the engine series, the valve lift is 330 thou as a matter of interest, I always check the lobe lift hight with a lift gauge as sometimes cams look good but are knackered, its often easier to pop out the engine, the engine must have sounded like a Tank running on pebbles??
tctractors

 

[JustinG]

I'm going to try to remove the oil pan today. It does look like a pain to do in frame, but stuff like this makes you appreciate the easier things.
The engine knock was pretty loud, I'd say your right about running on pebbles. I found the other Pistons had pieces of the valve seat from cyl #3 embedded in them. I'll check that cam over good once I get the pan off.

 

[JustinG]

Can the arrangement number be looked up by the serial number on these?

 

[Bob/Ont]

The old parts book and micro feicsh had a chart of the arrangement ### for the respective serial ###. The arrangement is relative to the machine the engine is used in and directs you to the proper piping, lines and attachments aswell as internal parts.
Later Bob

 

[Nige]

Can the arrangement number be looked up by the serial number on these?

What's the engine Serial Number..?