4.0 ohv rebuild

[Explorin'VA]

My 94 explorer has just under 200k on the original motor and it has always ran perfectly despite being a noisy motor naturally. But today I noticed a constant ticking at idle that wasn't there until now. It's not a deep knock, but more like a clock ticking rapidly. When I step on the gas it's not as noticeable as the exhaust drowns it out. It still runs and drives fine, as does my buddies 86 ranger that has the same tick, but it's an annoyance considering how much work I've put into the truck. Before any more damage is done I'd like to try replacing the rocker arms and pushrods because I've heard that's the primary cause of ticking in these trucks. I've never torn down a motor before but I'm mechanically inclined and confident that I can do it.

Does this sound like a good project to take on based on the symptoms? If it's the lifters I may just want to swap in a good used motor rather than pull the heads. I'm open to any advice on good parts to use and what to pay attention to during this project. Thanks.

 

[natenkiki2004]

If the oil has been changed regularly, it's likely the rocker arms/pushrods/rocker shafts. If it was neglected, there's likely crud inside the lifters and you won't get it out.

The previous owner of my Explorer replaced the rocker arms and pushrods and it cured the tick. Then it was passed on to his son as a beater for school and it suffered. I replaced the rocker arms and pushrods and despite seeing wear, it didn't make any difference in the noise.

It's kind of a gamble. I purchased Sealed Power pushrods and rockers. I have no problem with the pushrods but the rockers suck. They're not consistent and I had to return 2 of them due to poor casting and machining. It was more of a hail mary for me since the engine's got other issues and I didn't want to pay much. If it was an engine I really care about, I'd suggest going with OEM if you can.

It's an easy job, just take your time. I had an issue with a rocker hanging on the shaft and ended up mushrooming the end of the shaft slightly trying to get it off. Some can come off difficult while others will practically fall off. About 1/2" of each end of the shaft isn't really used so I just ground it down with a file and the new ones slid right on. It is a good idea to rotate the shaft 180 degrees, you'll see wear on the bottom side.

I took pictures when I did mine but I also did a lower intake gasket and injectors. You can take a look here:
https://www.dropbox.com/sh/n9kgwunpupgoztv/AAA765iXdGYIyUM9t7d1HtYua?dl=0

 

[jd4242]

Easy job..i havent had any issues with sealed power other than they are thicker than stockers..not a issue if you run stock spring spacers

 

[Explorin'VA]

So with the sealed powers I will need to order spacers for the springs?

 

[jd4242]

So with the sealed powers I will need to order spacers for the springs?

No.the springs are the spacers..they use to make aluminum spacers for performance world..they had to be an exact size to fit between the rockers and alow them to still rotate. Sealed power rockers are thicker and the aluminum spacer had to be cut down..

All irrelevant if you run stock spring spacers..

You can see they are even thicker where they contact the valve tip and pushrod.sealed power and stock comparison

 

[malohnes]

If the oil has been changed regularly, it's likely the rocker arms/pushrods/rocker shafts. If it was neglected, there's likely crud inside the lifters and you won't get it out.

The previous owner of my Explorer replaced the rocker arms and pushrods and it cured the tick. Then it was passed on to his son as a beater for school and it suffered. I replaced the rocker arms and pushrods and despite seeing wear, it didn't make any difference in the noise.

It's kind of a gamble. I purchased Sealed Power pushrods and rockers. I have no problem with the pushrods but the rockers suck. They're not consistent and I had to return 2 of them due to poor casting and machining. It was more of a hail mary for me since the engine's got other issues and I didn't want to pay much. If it was an engine I really care about, I'd suggest going with OEM if you can.

It's an easy job, just take your time. I had an issue with a rocker hanging on the shaft and ended up mushrooming the end of the shaft slightly trying to get it off. Some can come off difficult while others will practically fall off. About 1/2" of each end of the shaft isn't really used so I just ground it down with a file and the new ones slid right on. It is a good idea to rotate the shaft 180 degrees, you'll see wear on the bottom side.

I took pictures when I did mine but I also did a lower intake gasket and injectors. You can take a look here:
https://www.dropbox.com/sh/n9kgwunpupgoztv/AAA765iXdGYIyUM9t7d1HtYua?dl=0

Ive done this job too and it's simple, if a bit involved. Nate and JD are right on. JD helped me a ton when I did mine.