97 4.0 OHV engine noise

[974wd300]

Hey guys, I am new here and was hoping one of you experts might be able to help me out. I have a 97 Ranger 4.0 with the OHV. It has been a great truck, overall miles are 280,000 but the engine was rebuilt about 120,000 miles ago. That being said, I found out i had one head with a crack right between the valves. (pretty common on these heads). So i ordered a new set, with new gaskets and put them on. I also decided to replace the cam synchronizer so i would not have to worry about it, but i had to replace the oil pump intermediate shaft at the same time because the old one was slightly worn (twisted) and would not go in the new synchronizer. Got everything back together and on the first start up it had a pretty clear clatter from what i was sure was the rocker arms/push rods. I made sure I put each one back in its original position during re assembly. So not taking any chances and wanting to get it fixed, I bought new rockers and pushrods and replaced those as well. The noise did not change. I have a fairly good understanding of engines and the more i have looked and listened im starting to think it is something else. It is not like a lifter noise, more of a constant clatter, similar to rockers. But I was under the truck today and the noise seemed to be even worse under the oil pan around where the oil pump is. I know i have oil pressure because i have checked it. I am honestly a little stumped on where to go. Any help or experience would be greatly appreciated. Other than the noise the truck runs pretty good, and the clatter does go up with the rpm.

Thanks a lot for any advice

 

[gaz]

974,

Usually after completing a maintenance action, when a new issue pops up, gotta say "what was the last system worked on"; ANSWER, the intermediate shaft.

Now normally when someone hears what sounds like valve train noise I jump on the rockers and push rods, well in your case, you must consider that new push rods in an engine with 280,000 miles, may not actually be the correct length (since the valve train in not adjustable); they may not be long enough due to other component wear, requiring longer rods.

You can aquire a push rod measurment tool to determine if the new rods are able to provide the correct amount of lifter preload to keep your valve train working correctly, without the noise generated by loose components.

Like i suggested, I always go to the most recent maintenance action 1st

 

[974wd300]

Thanks gaz,

I do understand your logic on the pushrods. What keeps hanging me up on that is prior to the head replacement, the valvetrain was quiet and working properly. It just seems hard to think that the cleareances would have changed all of the sudden. It looks like I may need to think about dropping the oil pan or pulling the synchronizer to see if the intermediate shaft/oil pump is indeed where the issue is. Sounds like more fun !!

 

[gaz]

974,

I would DEFINITELY measure the needed push rod length 1st. If it's good, then you know it's NOT the problem. The tool to measure it isn't even $20.

Ah, if you changed heads, if the new heads were milled to make true, which is a normal machine service. Even on brand new components, heads, the matting surface is checked for true, possibly machined just for good measure. The machinist will also make the set the same; if one head required 0.003" and the other needed less, I would take the same off the other, so that the pair are the same.

This process, along with block decking will affect valve train distances. I hope that it is your rods. The only other components in a head change that can affect the valve train dimensions are the head gaskets, torque on the head bolts and rocker arm shaft hold down torque aside from wear components, which weren't changed.

 

[974wd300]

gaz,

Ok I will definately check them. I hope i can get that done tomorrow because i need the truck. But yes I torqued everything to spec and didnt try to cut any corners. I agree it is one or the other.

thanks again