International harvester V8 bent pushrods

[fred d]

I have a 1978 international harvester scout. It has the V8 304 engine.
Did the prelude to make sure all the bearings and everything had oil because it had been sitting very long time
pulled distributor. Used a drill to run the oil pump, rotated the engine and ran the oil pump some more to make sure everything was freshly coated. Replaced it all back together and installed a distributor and fired it up.
Had an obvious noise on the driver side and I was thinking the lifters weren’t pupping up so I installed a mechanical gauge and found out I had 50 lbs of oil pressure at start up so I pulled off the valve cover and had cylinders 1–3-7 all had no push rod connected to the rocker arm on the intake valve. Was able to fish them out of the valley pan through the holes and they were bent. Decided to take a look at the passenger side as well and one of the pushrods had pushed through the rocker arm which is not uncommon for these motors.
I have more rocker arms and more pushrods. My question is how do I know what happened. There is theory that it was a stuck valve that didn’t collapse and bent pushrod when the hydraulic cylinder came up. Don’t want this to happen again when installing a new push rods. How do I make sure the valves are not stuck in the bore?
Penetrant fluid down the valve stem Brake cleaner, solvent, Or mash it with a dead blow hammer with the spring on
I know there’s some old-school ways for this old-school motor
Hoping I can find some answers here

 

[MJD1]

Hard to say what happened. Keep in mind that IH engines are timed and firing order is based off number 8 cylinder

 

[RoninB4]

If this has hydraulic lifters/tappets (as opposed to solid ones) I'd take the extra time/trouble to remove each one (one as a time to not mix them) and dis-assemble them for cleaning/testing. There's a tool for retrieving them easily.

 

[Wolley]

Make sure the valves aren't stuck. Tap on the top of the valve with a hammer or appropriate tool. Theoretically you could remove the valve springs with the head still on with the right tools. That would allow you to verify full range of movement. Could be lifters stuck up too. If you actually plan on driving it I'd say pulling the intake and heads is in order.

 

[2oolhound]

Pirate 4X4

The above thread points to cam bearings as a problem for these symptoms your 304 has.

 

[crewchief888]

I'd be checking the timing chain/gears. Maybe it jumped time

 

[engineer2]

Looks like that motor is rocker shaft oiling for the rocker arms and an oil galley feeds the lifters.


Is this the right diagram?

Use a hammer handle to push down the the ends of the rocker arms to make sure the valves move without sticking.

Another cause of severely bent pushrods is over-revving the engine. In the old days the valve springs were sort of a built-in rev-limiter. Sacrifice push rods to save the connecting rods. We used to pretzel push rods all the time in our parents' cars.

 

[Packard V8]

Most likely cause is stuck valves. Remove the rocker arms. Squirt Kroil or other Liquid Wrench type solvent down each valve stem and let sit overnight. With a brass hammer, smack each valve squarely on the top of the stem. If they're not stuck, they'll go sproing. If they are stuck, they'll go bonk and feel solid up through the hammer.

If you find some stuck, more Kroil, more smacks with the brass hammer.

jack vines

 

[finn]

Valves rusted in the guides.

Happens all the time to engines that sit for a long time.

Tap on the valves one at a time. Some, with good pushrods, will move. The valves with bent or missing pushrods will be stuck.

 

[Steve_P]

Is it an AMC engine? Not that it matters, but....
Either way, the cylinder heads are reamed and it's the valve on the iron head. So they can rust in place.

Manually make sure the valves all move freely. You can buy a cheap lever tool that's meant to compress the valves to change the springs to test this.

 

[isb cornbinder]

Make sure the valves aren't stuck. Tap on the top of the valve with a hammer or appropriate tool. Theoretically you could remove the valve springs with the head still on with the right tools. That would allow you to verify full range of movement. Could be lifters stuck up too. If you actually plan on driving it I'd say pulling the intake and heads is in order.

A stuck lifter will not band a push-rod. Do not remove the valve springs with the head still on the engine. It is possible to lose a valve down a cylinder.
Pulling the intake and heads is not required, yet. I do not know what this would accomplish right now.
The only good advice here is to tap lightly on the valve stems with a soft hammer. ( brass or composite.) If you do not have a soft hammer, a brass punch and a regular hammer will be a good choice. It is more than likely a few valves are stuck in the valve guides. If the valve stems have seals, try to put a very small pick between the seal and the valve stem so you can put a few drops of WD40 or similar between the seal and the valve stem. Do not pound on the valve stems and drive them down if they are not returning. This situation may put the valves at risk of contacting a piston and getting bent.
This is not the time to be concerned about oil pressure. High oil pressure does not necessarily indicate a good situation. High pressure indicates a restriction in oil flow. This could be because of the engine being in good condition or in the worst case, a plugged oil gallery.
If you get all of the valves moving and the rocker clearances set correctly, the oil pressure should drop a little as the engine warms up to operating temperature. stop the engine here and replace the thermostat.
These IH 304 V8 engines are robust and reliable. The 304 was the first engine swap I did in my 1953 R120. The 304 has a good sound with a Flow-Master muffler.
This is all I can think of for now. I will be watching. I am a retired mechanic with lots of IHC experience.

 

[isb cornbinder]

Pirate 4X4

The above thread points to cam bearings as a problem for these symptoms your 304 has.

This statement is totally incorrect.

 

[isb cornbinder]

Most likely cause is stuck valves. Remove the rocker arms. Squirt Kroil or other Liquid Wrench type solvent down each valve stem and let sit overnight. With a brass hammer, smack each valve squarely on the top of the stem. If they're not stuck, they'll go sproing. If they are stuck, they'll go bonk and feel solid up through the hammer.

If you find some stuck, more Kroil, more smacks with the brass hammer.

jack vines

Good advice. "sproing and bonk" Those are the correct sounds. LOL Only boys can mimic the correct sounds. Why is that?

 

[Wrench97]

I agree with stuck valves a old IHC engine.

 

[finn]

Is it an AMC engine? Not that it matters, but....
Either way, the cylinder heads are reamed and it's the valve on the iron head. So they can rust in place.

Manually make sure the valves all move freely. You can buy a cheap lever tool that's meant to compress the valves to change the springs to test this.

No. That’s a 304 cu in version of the International SV (small v) engine family. Other displacements include the 266, s45, and 392, and the platform spawned a couple of four cylinder derivatives used in the early scouts

 

[webscrounger]

Maybe you, maybe not, like my Jeep - Oil pressure 45-lbs+- at startup when cold, seemed normal. But warmed up, 0-lbs at idle until you get to 1200 - 1500 rpm where it raised to 3-5-lbs. That was using 20w50 knowing there were worn cam bearings. New cam, lifters and bearings required.

 

[Ricky Joe]

You can remove valve springs without removing the head. There is an adapter made that screws into the spark plug hole and let’s you apply air to hold the valve in place. Then you can press on the valve to see if it is corroded stuck. If it is, the only mechanically responsible thing to do is to replace the valve guides and possibly the valve.

 

[Showkey]

Been sitting for years………
As mentioned stuck valve bends push rods.
At this point ……..pull the heads and fix it right before the problems creates more damaged parts.

Same time pull the pan and clean the sludge and check and likely replace the rods and mains.


So doing it right means refreshing the engine………in the long run your money and future hassles …….your way ahead.

Sitting long term ……..means the complete fuel and brake system needs the same attention.