Jerms
NAXJA Forum User
- Location
- Northern utah
I'm attempting to put my dads 4.0 back together here is a little history.
The vehicle is a 2000 with the 0331 head. It overheated and warped the head. We had the head professionally checked for cracks and the head was determined to be usable. We had the head machined to straighten it out. We are now reassembling the engine and went for the first start of the engine and there is obviosly no compression on the whole engine. The starter will turn the motor over with very little resistance like cranking the motor with no spark plugs installed.
What we have done.
Removed the valve cover and loosened the valve rockers for all valves. With engine disabled cranking of the engine results in the sound of increased compression. When tightening the rockers, all of the valves seem to have been opened a little. 1 of 2 things is going on, the push rods are too long or the machine shop gave me back the wrong rockers.
Here are my questions.
1. are there different length pushrods for engines that have had the head machined.
2. are there differences in the rockers from year to year.
3. is there a way to determine how much material the machine shop removed, i was unable to find that out from them at the time they returned the head to me.
I have done several rebuilds of 4.0's but have never needed to have a head machined because it has been warped. Unfortantly i don't know how much the machine shop took of the head. I have never heard of having to purchase new push rods for this case, but there is a first for everything.
Any help that you can provide is deperately needed.
Thanks in advanced.
The vehicle is a 2000 with the 0331 head. It overheated and warped the head. We had the head professionally checked for cracks and the head was determined to be usable. We had the head machined to straighten it out. We are now reassembling the engine and went for the first start of the engine and there is obviosly no compression on the whole engine. The starter will turn the motor over with very little resistance like cranking the motor with no spark plugs installed.
What we have done.
Removed the valve cover and loosened the valve rockers for all valves. With engine disabled cranking of the engine results in the sound of increased compression. When tightening the rockers, all of the valves seem to have been opened a little. 1 of 2 things is going on, the push rods are too long or the machine shop gave me back the wrong rockers.
Here are my questions.
1. are there different length pushrods for engines that have had the head machined.
2. are there differences in the rockers from year to year.
3. is there a way to determine how much material the machine shop removed, i was unable to find that out from them at the time they returned the head to me.
I have done several rebuilds of 4.0's but have never needed to have a head machined because it has been warped. Unfortantly i don't know how much the machine shop took of the head. I have never heard of having to purchase new push rods for this case, but there is a first for everything.
Any help that you can provide is deperately needed.
Thanks in advanced.