Rebuilt head no compression

I have never done anything with these engines but, it would seem there must be a way to FORCE the valves to seat (if they can) by removing the rockers or pulling pushrods.????????????

 

I'm surprised no one mentioned this the head could be warped or have high and low spots very possible too then you wouldn't have any comp because there is big gaps I've seen it many times even on New rebuilt heads especially the longer ones just a thought
Good luck

 

Jeeps are known for cracking the head between plugs 3&4. Mine was cracked, this is why I got a different head.

 

Huston we have a answer, 6 bent valves, all intake. I never p*** the buck, but this one ****s. I got screwed, but I guess I just did not look close enough, in the end my fault.

 

Did clearance issues do that ? or is it on you? Head has not been cut since last running, but has it been?

 

Probably happened on the other blown engine when they tried to save it with a valve job.

Don

 

It's easy to tell when someone at a salvage yard is lying, their lips are moving!

 

Sorry man. I was really hoping for a better answer.

 

Me to but, but at least I know what I need to fix. It sure makes a guy feel like a dumb ***. Thanks for all the help.

Tony

 

Sorry to hear this. I have been keeping tabs on this one. I am thinking the bad thing is that this one doesn't sound like fun to work on.

 

Intake valves are about $9/ea., regular or 0.015" oversize.

My '96 4.0HO is about to make the 200K mark.

 

The wrangler in my avatar has 202,000 and the Cherokee was just bought for $500 for my 17 year old daughter and has 208,000.

31vickey, I have looked at some of your builds in the past very nice work.

 

Eh, we've all done similar things......some of us more than once.

Those 4.0's are a great motor and good performers for a 6. A decent valve job and you will be back on the road.

Don

 

Don't sweat it- we ALL have to learn the hard way sometimes...repair it,and call it done.

 

I have heard it said that wisdom is when you can recognize your mistakes when you repeat them.

 

Then I must be a very wise man.

Don

 

Me too!

 

Can someone explain what I'm looking at in post #64? I see small dark pieces at the intake valves(is it chunked out? Aren't bent valves bent at the stem? Thanks Pete

 

I'm guessing that's a piece of shim stock between the valve and the seat.
Usually the bend above the tulip and below the guide. Bending is caused by contact. Sometimes they stick first then get bent a split second later.

The junk yard engine must have had a bad timing chain issue?

 

Correct those are pieces of shim stock, to show that the valves are not closing.

 

Gotcha!! Thanks!! Pete

 

That is what I am thinking. The previous owner probably did have this head done but he installed it on the junk motor that had serious issues. The cam timing could have been so far off it caused the valves to kiss the pistons.

The junkyard guy may have been telling you the truth as far as he knew it. That head looks like it has been redone at some point, but it was evidently damaged after that.

Don

 

I checked over on the Jeep Cherokee boards and that is "not" supposed to be an interference engine according to what I read.

My guess is that someone used a hammer and socket with something hard behind the valves to pop the springs off to change the valve seals and bent all six valves exactly the same in the process. An off center spring compressor might do it too but bending all six that way sounds a bit of a reach.

 

Here is what I found on the head when I took it apart. I called the parts yard, they said I bent them, because they had the head checked. I talked to the shop that did the work they said that they only magnafluxed it. I talked to parts yard again and the guy says that they sell heads with the understanding that they need a valve job, I called ********. I then told them that the receipt say reman. head less than 1000 miles. He told me I have to talk to the owner, and he will be back on Monday. I figured I would get the run around, and I did. I just want them to sell what they say it is.

 

This is not an interference engine. You'd have to really be trying to make sure this happen at home.

 

Just out of curiosity why did you change the head if it hade 150 lbs or so of compression to start with??? and why did you not have the original head repaired? I'm not kicking you just wondering why

 

Agreed. But after all is said, IF the junk yard owner won't make it good, you still have the valves out of the cracked head. Grind them and regrind the seats. (New valves? I'd weigh the options)

 

Antifreeze was getting in the oil from the crack by the rocker post.

 

Thought it is unfortunate for you this thread has been very interesting to me(my sons vehicle has the same engine and same problem that we have to address) seems that the fix(although costly is to buy a new complete head,.new beefier casting) from Clearwater Head Service. Pete http://www.cylinder-heads.com/Home__.html

 

Drop a SBC in that thing .
Maybe a 5.3 swap