Help with a 99 wrangler head gasket job

gnawgahyde · 05-04-2012, 08:30 PM

Hi everyone,
hoping some one out there can help me out. I just did a head gasket on a 99 Jeep Sahara 4.0. I pulled the head had it machined labelled all the push rods and rockers and torqued everything to spec. However, when I went to start it after reassembly it turns over and sounds like it has no compression. Is it possible that i over torqued the valves? under torqued them? I tightened them to 22 ft/lbs.
Any ideas as to what I may have done wrong? it is not the first head gasket that I have done so it is making me crazy. Any help would be much appreciated. And yes it ran prior to dis-assembly but was smoking up a storm due to a bad head gasket.

AMCMasterTech · 05-04-2012, 09:23 PM

What was the original problem? Like, did it overheat, etc?

**wushaw** · 05-04-2012, 09:25 PM

Pop the valve cover if it ain't already off and see if the rockers are moving. Or screw in a compression gauge.

Ross00TJ · 05-04-2012, 09:52 PM

The capscrews (what I assume you mean by valves) are to be torqued to 21 ft/lbs per the FSM, so you are good there. How did you tighten the head bolts down, did you follow the correct order and method? You didn't reuse head bolts, right?

gnawgahyde · 05-05-2012, 12:56 AM

Head bolts were reused because it was the first time the head gasket was replaced. And yes, they were torqued in the correct order and to spec. the original problem was it overheated and it blew the head gasket. it was smoking like crazy and the oil was saturated with anti-freeze. hence the reason why I changed the head gasket.

justanotherjpr · 05-05-2012, 01:00 AM

Def use a compression gauge or pull the valve cover gasket and make sure the valves are moving.

Ross00TJ · 05-05-2012, 01:53 AM

Quote:

Originally Posted by gnawgahyde

Head bolts were reused because it was the first time the head gasket was replaced. And yes, they were torqued in the correct order and to spec. the original problem was it overheated and it blew the head gasket. it was smoking like crazy and the oil was saturated with anti-freeze. hence the reason why I changed the head gasket.

Never reuse head bolts. They only stretch once and won't have the proper clamping force. Pull 'em out and replace them.

Jeepsr4me · 05-05-2012, 06:52 AM

Quote:

Originally Posted by Ross00TJ

Never reuse head bolts. They only stretch once and won't have the proper clamping force. Pull 'em out and replace them.

Not according to the FACTORY manual. They can be reused ONCE like he said.

Quote:

CAUTION: Engine cylinder head bolts should be
reused only once. Replace the head bolts if they
were used before or if they have a paint dab on the
top of the bolt.

HOW much did you have milled off? Pushrods may be too long and keeping the valve open. Too early for me to look up specs.....

tailhole · 05-05-2012, 07:46 AM

You will be fine reusing the head bolts.
Your lifters are pumped up.
When you took the rocker and push rod out.
I have ran into it a lot and I just let it sit for a little then turn it over and let it sit. And then it will crank.
What you will be doing is pushing the oil out and pushing the plunger down. It will run rough till all are adjust them self.

gnawgahyde · 05-05-2012, 09:03 AM

Very little was milled off. It was done by a professional machine shop. I am going to recheck the firing order and fuel injector wires then pull the valve cover to see is the valves are indeed moving. I was going to try starting it with the valve cover off and didn't. I should have just gone with my first instinct. Will return to it on Sunday and let you know how I made out.
thanks for all the help guys.

AMCMasterTech · 05-05-2012, 10:07 AM

You've got some sound advice already. Without having the jeep in front of me it's all speculation, but here's some gouge.

Verify that your valvetrain is functioning properly, as has been mentioned. Too much meat removed from the deck or head will result in the rods not allowing the valves to seat. Verify your base engine timing. Verify your rings are sealing, as has been mentioned. You might try a few shots of engine oil in the plug holes, as the coolant might have washed your cylinders down, thus not much a seal (more common with overfueling), and re-run the compression test. Might want to get a service manual if not already done, and go thru the base engine diagnostics for no start, base engine.

Good luck.

**Showtime3492** · 05-05-2012, 10:13 AM

Just wanted to add if the push rods are too long you can get different length ones for a real fair price.

tailhole · 05-05-2012, 12:53 PM

You would have to remove a good bit off the head to need shorter push rods.
If the head had to be milled .030 or more, I would say you would have some more problems than that blown head gasket.

Did the shop rework the head? If a valve job was done, and was done by a reputable shop than they would have adjusted the valve stem height.

If you want to get into checking every thing the valve stem height is 1.775-1.805 for the intake and the exhaust.

The head thickness (new) is 3.465
And the minimum is 3.437 but I have gone more then that trying to get compression

gnawgahyde · 05-06-2012, 11:27 AM

ok I got her to run with no smoke. Only two problems to deal with. The distributor cap bolts broke on removal, going to be drilling. However, the Jeep is running at an extremely high idle (5000rpms) I am assuming that I have a leak around the intake manifold. Jeep is too hot now to take it apart.
What do you guys think? is there anything else that will make it run at that high an rpm?

**wushaw** · 05-07-2012, 12:32 PM

Your on the right track with the leak in the intake gasket.