No compression in 4.0 SOHC

[Bgunner]

There are marks in the pistons from where the valves hit. Without physically seeing and inspecting them I can not tell how bad they are or aren't. I would bring the low end also and have the machine shop look and make the determination for you. If the low end needs work Hit the junkyard since you will not save money, of course unless you want to rebuild the low end also then go for it.

Of course this is just my take on it. Lets see what @Uncle Gump has to say about the pics.

EDIT: on a plus side the valves did not tip to the side or break off because if they did the pistons would be shot for sure.

 

[Uncle Gump]

Oh... those valves are "tipped"... if they weren't they would close.

I would certainly pull the other side and see about damage. Seems like all the ones I've seen had a hole in a piston.

Not saying you couldn't do a set of heads and run it for another 100K... but without a complete tear down it is hard to really tell if it cause lower end damage.

 

[Sharky146]

Thanks guys. I dropped the heads off at the machine shop. They’re going to fix them up for me. I think the pistons are fine. I’m going to gamble on the bottom end. I’ll put it back together when I get the heads back. I’ll report back with the status. Thanks again!

 

[RonD]

Yes, the 4.0l SOHC is an interference engine but barely, pistons and rods will be fine,
As said the valve bent out of the way enough so just the one strike for each valve and then engine dies, or if just one OHC slipped then it would barely run on 3 remaining cylinders, but valves that hit are already out of the way

 

[Uncle Gump]

I've held pieces of broken piston/valve/spark plug in my hand that say "barely" is enough to cause some serious damage.

 

[RonD]

Piston must have had a manufacturing defect

 

[G8orFord]

Take your chances with the bottom end if you want to, but, as long as the cylinders are still round and in spec, another 3-4 hundred bucks probably gets you new pistons, rings and bearings and you know the bottom end is good. That may sound like a lot right now, but it won't when one of those "touched" pistons ends up with a hole in it. It's a gamble, the odds are in your favor but that never helps me much.

 

[RonD]

+1 ^^^

Go buy a Lotto Ticket
If you don't WIN then just do the heads, use your good luck that way, not winning the lottery used up the bad luck

But IF YOU WIN, you can do the whole engine, maybe even a crate engine
Win-Win for the cost of a lotto ticket

 

[Bgunner]

If those shiny marks in the piston heads have any rough edge to them you will end up with a hole in the piston.

I mentioned this in the beginning that damage to the tops of the pistons can and usually does end with holes in the pistons. Blowing a hole in a piston can lead to other bad parts that at this point are reusable if you put a little extra in the low end now.

 

[alwaysFlOoReD]

I would polish the marks on the top of the pistons. Dremel and some polishing compound. Use some clay around the edge to prevent compound from getting down the side of the pistons.

 

[Dirtman]

Engines is goes vroom...

 

[adsm08]

Engines is goes vroom...

Not this one.

 

[Sharky146]

Hey guys. Here's an update. I got the heads back from the machine shop. They ended up doing a valve job, replaced the seals and resurfaced the heads. They also needed to replace all the exhaust valves, which were bent. As I mentioned before, I replace all the timing components as well. I finally got the engine back in the truck last night. Turned the key and it started right up and it ran for about five minutes. I sat there at 1am admiring my handy work and basking in the glory of victory, then...I heard a dull thud and the motor quit. I tried to restart it, but the engine just turned, but didn't fire. This morning I did a compression check and there is zero compression. I suspect that the timing jumped again and the valves hit the pistons...again. Basically, I'm in the exact same position I was in when I picked up this project, except now I have about $800 invested in engine parts and machine shop work.

Needless to say, I'm pretty disappointed. It was a lot of work to get the truck to where it is. I still don't know exactly what happened. Did I install the timing components incorrectly? I think I did it correctly and I used the Ford 4.0L timing tool set. But, it was my first time doing it, so maybe I screwed something up. Is there some other, non-mechanical issue that is causing the timing to jump wildly? Maybe a cam synchronizer or something?? Something in the PCM?

Oh well, no time for tears in my beer. Now it's on to the next step. The way I see it, I have three choices:
1. Redo all the work i've already done, and hope for the best. Not sure I have the stomach for that...
2. Sell the truck for parts
3. Buy a known-good 4.0L to swap in.

I found a 4.0L SOHC out of an 08 Mustang. Any idea if that will work? I'm sure I'll need to use many of the parts from my truck engine, such as accessory brackets, valve covers, intake manifold, etc. Just wondering if there is any fundamental differences with the newer Mustang 4.0 SOHC motors when compared to my 2001 4.0L SOHC. Will the PCM be able to run the mustang motor?

Thanks for all the help along the way guys. Any further guidance is appreciated. Take care.

 

[RonD]

Bummer.....................

Yes, the 2008 4.0l SOHC will be fine to use in your 2001 Ranger
Yes, you will need to swap over intake to match wiring and exhaust manifolds I think
Lower oil pan maybe
Probably brackets and accessories

The car 4.0l will have a different cams for less torque but more horse power, I doubt you will notice the difference
Computer will run the 2008 engine just fine

 

[Sharky146]

Ok, thanks for the info. I’ll probably pick up the 08 motor.