2000 XJ 4.0L Popping / Sputtering Problem

[Talyn]

Clearwater is fine. The crack is between #3 and #4 valve spring pairs.

You also will want to investigate what happened to the pushrod. They usually don't bend in a stock engine. Also, since you mentioned taking the block apart you will want to keep the lifters in order so you put them back on to the original cam lobe. However, I think you have a deeper problem than the head. That is unless you find a broken valve spring or stuck valve.

What the history on this XJ? It looks pretty rough on all accounts.

 

[5108696]

You might try here http://www.ebay.com/itm/JEEP-4-0-LITER-TUPY-REBUILT-CYLINDER-HEAD-/141426247073 cracks on the 0331 head are usually between #3 cylinder and #4 cylinder rocker arm towers. Sometimes they are really hard to see without hot tanking and magnafluxing. Google images however has lots for you to see.

That looks great! Especially the return shipping.
Has anyone reading this had a bad experience with this vendor?

 

[5108696]

Clearwater is fine. The crack is between #3 and #4 valve spring pairs.

You also will want to investigate what happened to the pushrod. They usually don't bend in a stock engine. Also, since you mentioned taking the block apart you will want to keep the lifters in order so you put them back on to the original cam lobe. However, I think you have a deeper problem than the head. That is unless you find a broken valve spring or stuck valve.

What the history on this XJ? It looks pretty rough on all accounts.

I have my suspicions that it overheated first blowing the head gasket - since the popping wasn't present when I shut it down. I then think when I restarted it, the water in the #6 cylinder couldnt be compressed and wreaked havok with the valves. When the exhaust valve couldnt open, the uncompressable water in that jug went into the intake every time the valve opened. I think it then compromised the gasket into cylinder #5 which pumped it out the tailpipe.
Unfortunately, while pulling the head, I forget to preserve the order of the pushrods. With the lifters still in place, I can keep them straight.
Since I have a bent pushrod, do I have to replace all of them now as a set? I can't wrap my head around this: if pushrods are a close tolerance item, as long as they are straight, why is it important that they be reinstalled in the same order. Just a question of logic; not the expertice of those who are tirelessly offering their help.
Thank you again.
Rick

 

[n5xl]

In the case of pushrods, lifters and rocker arms, these components all develop wear patterns that are unique to the imperfections of the components they are mated to. Once these items are mated they need to remain mated to maintain even wear patterns for the longest life. If you swap individual items around in a previously mated component set, the imperfections and existing wear patterns found on one item can accelerate the wear of the new set until all of the pieces they can come to a wear equilibrium again. In some cases, this accelerated wear can cause the system to go out of specification for clearances. This is the case with many rotational and precision items. Bearing and races, for example, are a matching sets. If one or the other shows signs of wear or is failing they should both be changed as a set for optimal life. You wouldn't deliberately mix and match old bearings to new races and expect it to give you the same operational life as a matched set. Broke down on the side of the road and needing to get back to the shop would be the only exception that you would deliberately introduce a new item to a matched set. Maintaining matched sets of valvetrain components is considered good shop practice...even though someone is going to chime in that they always mix pushrods around and have been "fine" for years.

 

[n5xl]

Forgot to add... I was taught to always replace the pushrods, lifters and rocker arms when going in with a new head. If you consider the wear of valve train components wearing as "a set", this is logical advice. You dont HAVE to swap in new pushrods and lifters but it might be foolish not to, particularly since you've gone to all this trouble so far. Dont forget to inspect your cam for in-specification lift and clearances, dont forget to prime the lifters and dont forget the good ZDDP oil or assembly lube going back together!

 

[Talyn]

Unfortunately, while pulling the head, I forget to preserve the order of the pushrods. With the lifters still in place, I can keep them straight.

Not a problem with the push rods. Clean them up and check for straightness. You don't have to replace them all. I also wouldn't consider a stock 4.0L pushrod a close tolerance item, especially given the range of acceptable preload on the lifter. Which is also why the lifter is there. To take up slack tolerances and wear.

There is 100% no need to replace everything when swapping a head. Check for problems, yes, replace, no. That is just a waste of money.

As far as wear patterns are concerned the only critical parts in his scenario is the lifters to cam and the rockers to their pivots. Yes, it is good practice to keep everything where it was, but not necessary with exception to the two mentioned.

 

[5108696]

In the case of pushrods, lifters and rocker arms, these components all develop wear patterns that are unique to the imperfections of the components they are mated to. Once these items are mated they need to remain mated to maintain even wear patterns for the longest life. If you swap individual items around in a previously mated component set, the imperfections and existing wear patterns found on one item can accelerate the wear of the new set until all of the pieces they can come to a wear equilibrium again. In some cases, this accelerated wear can cause the system to go out of specification for clearances. This is the case with many rotational and precision items. Bearing and races, for example, are a matching sets. If one or the other shows signs of wear or is failing they should both be changed as a set for optimal life. You wouldn't deliberately mix and match old bearings to new races and expect it to give you the same operational life as a matched set. Broke down on the side of the road and needing to get back to the shop would be the only exception that you would deliberately introduce a new item to a matched set. Maintaining matched sets of valvetrain components is considered good shop practice...even though someone is going to chime in that they always mix pushrods around and have been "fine" for years.

Very logical. Thank you.
So based on that, you would recommend a complete set of pushrods and keep the lifters in order, correct?

 

[5108696]

Not a problem with the push rods. Clean them up and check for straightness. You don't have to replace them all. I also wouldn't consider a stock 4.0L pushrod a close tolerance item, especially given the range of acceptable preload on the lifter. Which is also why the lifter is there. To take up slack tolerances and wear.

There is 100% no need to replace everything when swapping a head. Check for problems, yes, replace, no. That is just a waste of money.

As far as wear patterns are concerned the only critical parts in his scenario is the lifters to cam and the rockers to their pivots. Yes, it is good practice to keep everything where it was, but not necessary with exception to the two mentioned.

Thank you also. That will save me a few bucks on reusing straight pushrods - providing any of them end up being straight.

 

[5108696]

Forgot to add... I was taught to always replace the pushrods, lifters and rocker arms when going in with a new head. If you consider the wear of valve train components wearing as "a set", this is logical advice. You dont HAVE to swap in new pushrods and lifters but it might be foolish not to, particularly since you've gone to all this trouble so far. Dont forget to inspect your cam for in-specification lift and clearances, dont forget to prime the lifters and dont forget the good ZDDP oil or assembly lube going back together!

That is sound reasoning. I think at this point, since I am doing everything else, I may as well include pushrods and the cam kit.

Thank you.

 

[5108696]

Does anyone see any problem with this remanufactured TUPY head or have knowledge of any negative dealings with the seller?

http://www.ebay.com/itm/JEEP-4-0-LITER-TUPY-REBUILT-CYLINDER-HEAD-/141426247073

Thank you.

Rick

 

[5108696]

Update: After ordering (Wed evening) the above listed head from Cylinder Heads Intn. via ebay, it arrived Monday.. If it functions as well as it looks, I will be back in business quickly.

OK, Here is a question for the experts.

After carefully removing and segregating the lifters, in going back to inspect them for wear and function, I have discovered that most of them DO NOT have the same springy, cushion'y feel to them as does the one new one I purchased to replace the #6 exhaust lifter (the one with the bent, derailed pushrod.

Can any of the experts tell me if you should be able to depress this with a pushrod as if there were a spring inside (like the new one)?

Also, I disassembled the one I am replacing to "see how it works" and only found the retainer spring, the cup that the pushrod rides in, and a small disk with four holes.... Is there more to this?

Ultimately, I am looking for guidance on whether I can clean the existing lifters, use a recommended procedure to test them for function, and re-use all of them that I can.

As always, Thank you in advance for your expert guidance.

Rick

 

[Talyn]

If they aren't spring its means that they are filled with out. Fine. If they are springy it means it bled down possibly due to sitting with a valve open on it. Fine too.

As for your lifter it sounds like a Johnson hylift lifter because that is the only one I know of that has the 4 hole disc. It also sounds like you only took the cup part out, not the inner sleeve. Check out the Crower lifter in the pics below. Crower uses the Johnson Hylift lifters.

More where those pics came from: http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=1262

 

[5108696]

If they aren't spring its means that they are filled with out. Fine. If they are springy it means it bled down possibly due to sitting with a valve open on it. Fine too.

As for your lifter it sounds like a Johnson hylift lifter because that is the only one I know of that has the 4 hole disc. It also sounds like you only took the cup part out, not the inner sleeve. Check out the Crower lifter in the pics below. Crower uses the Johnson Hylift lifters.

More where those pics came from: http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=1262

You are absolutely correct on all counts. I took them the rest of the way apart and found them crudded up to the point the spring wouldn't work, the oil passages were stopped up, and there was no way they were working correctly.

I was able to clean them all and get them working properly again.

I also found that the oil pump screen was so stopped up that the oil probably wasn't pumping much at all causing it to dry inside the lifters and who knows where else.

Thank you very much for the lesson on lifters. I'm sure it well help others as much as it did me.

Now I need to investigate the excessively high oil pressure reading which I'm sure is due to a faulty sending unit or gauge itself.

Rick

 

[5108696]

UPDATE
I got the engine back together and finally back in the XJ.
Of course, the first setback to cranking it came when the stainless fuel line sprung what I have learned here is the textbook leak resulting from the metal clamp wearing through it.
I got that repaired today and attempted to start it.
Unfortunately, the Shifter linkage is now out of adjustment and the NSS will only allow it to turn over in gear...... I bumped it to life, but only let it run about 15 seconds as the oil pressure gauge still has a problem. Where it originally pegged at the 80 PSI limit, after replacing the sending unit, It was barely off the 0. Hmmmmmm...
Still need to adjust those items again before trying it again.
Rick

 

[5108696]

OK, I'm in need of guidance from the experts...
The engine is completely in. Upon getting all of the minor things addressed, I primed the oil pump and bumped it to see if it would start. While it did crank right up, the exhaust was not installed and it was a bit loud so I shut it off about 15 seconds in. After completing the exhaust, I tried it and it would not start.
Since then, I replaced the eng oil pressure transducer, the Crank pos Sensor (factory unit), and tried it again.
I have since pulled the coil pack, indexed the #1 piston to TDC on the compression stroke (confirmed blowing with valves closed) removed the cam pos sensor cap again to confirm alignment of the two holes, and clocked it parallel with the engine block.....

Remember back in the days when your carburated engine got flooded and you held the gas to the floor until it sputtered slowly to life? I know that you shouldn't need to introduce gas (apply pedal) into a fuel injected engine, however this is the only way to get it to even try to start and when it does, it runs rough a second or so as you pump the gas.

I have had a buddy with a pretty impressive diagnostic box scan it and the only thing he mentioned was that it didn't register engine RPM. He also checked the rail pressure getting >50psi, then bled it.

I have a fully charged battery, AND had the charger connected just in case.

I am 99.9% confident that the timing chain and gears were aligned correctly as I watched the #1 valves do their thing as I turned the crank, then with the piston at TDC on the compression stroke (both valves closed) I aligned the tic marks facing each other and aligned with both shafts. I also did the 'count the pins' thing someone had posted here.... Lastly, assuming the clocking of the flex plate was important, I marked the flexplate and the crank with paint and re-aligned it upon re installation.
I am at my wits end....

Any ideas?

 

[n5xl]

If you can start it like you did and it ran fine then you shut it off and cannot restart it without flooring it, try cleaning the IAC motor. I would remove the TB, clean it and the IAC, then reset the PCM.

Resetting the PCM forces the PCM relearn the correct IAC pintle position. It does this by commanding the IAC stepper motor to the fully closed position, then step it back to a known, factory default position. Procedures on how to clean the TB, IAC and reset the PCM can be found with a forum search.

It costs nothing but a few minutes of your time to clean the IAC and TB.

 

[5108696]

If you can start it like you did and it ran fine then you shut it off and cannot restart it without flooring it, try cleaning the IAC motor. I would remove the TB, clean it and the IAC, then reset the PCM.

Resetting the PCM forces the PCM relearn the correct IAC pintle position. It does this by commanding the IAC stepper motor to the fully closed position, then step it back to a known, factory default position. Procedures on how to clean the TB, IAC and reset the PCM can be found with a forum search.

It costs nothing but a few minutes of your time to clean the IAC and TB.

Thank you. I will look into that.
While it did start and sputter till I shut it off after about 10-15 seconds, I wouldn't consider it 'running'. I neglected to mention it, but I did remove the throttle body and clean the inside of the bore and the butterfly assy. Not sure what the other items are but I bet I can find it in the forum.
Thank you! Rick

 

[5108696]

TaDa!! It Runs! arty:

Finally, after waiting three weeks, the cam pos sensor finally arrived. Had it not been an outstanding price of $33 for the complete sensor / drive / gear assy, I would have bought the sensor only from O'Reillys for $60 and been done with it.

Luckily, that was the magic bullet that fixed my problem. The Viper coil mod ended up being a piece of cake as well and it lit off and purred with a touch of the key.

Unfortunately, while the oil pressure was 40 psi when cold, as it warmed up, it dropped to 10 at an idle and climbed to 40 at 3-4k rpm.

I am starting to wonder if I need to pull the new oil pump and new pick-up and braze the two together as I suspect I may be sucking air.

What say the experts?

Rick

 

[Talyn]

What was the oil pressure prior to the pump change?

 

[5108696]

What was the oil pressure prior to the pump change?

No idea. It was experiencing the pegged needle syndrome which was corrected with the replacement of the sending unit and confirmed with the addition of the manual gauge.

I suspect it was just the same.

From what I am hearing / reading - as un-comforting as it is, I think I will have to settle for the 7-10 psi per each 1000 RPM minimum acceptable range.

Although I never got the milky oil when the head cracked (zero in the pan as well), I suspect some coolant must have gotten into the bearings and degraded the oil pressure.

I have some comfort in the fact that I have quality oil and Z Max additive to maximize the slipperiness. I also have a high capacity Wix filter to replace the FRAM on this and all of my vehicles as they get serviced.

Rick