97grand4.0

200k on it, tap tap for the last 40k, think it might be lifters valves or slap or manifold.. Plan now is take the head off and send it out and check for slap. Tear-down has begun at 0830, will update.

97grand4.0

As predicted, the last 2 lower manifold bolts are hard to get at.

97grand4.0

First look inside the head shows the valves a bit worse than expected, the usual, a bit of wet black carbon cake crumbs crud on the intakes, but just near the spark plug, probably oil seals leaking a bit though I thought they were fine, exhaust ports caked with a mil or so of soot, all the way out the head..thats odd...light brown soot you can scratch with a screwdriver...exhaust valve stems jet white i dunno what thats about, ..heads coming off next

engine side of the e manifold shows a hairline crack with white powder an inch long on #3
gasket looks leaky and wet
exhaust mani loose last nut by #6

dave1123

When I replaced the exhaust manifold on my 97, that last nut I could only get with a box wrench, so trying to figure torque was a exercise in frustration. It doesn't surprise me that it was loose. When removing the manifold, I took all the bottom bolts out first, letting the two hang on just the top bolts. It was easier for me to remove the lower bolts from underneath and on the reinstall, it was a real pain to torque everything in order by going from the bottom to the top, crawling under it for one, then getting up to do the next, etc. At that time in my life I was getting to the point that I needed to grab the fender to help myself to stand!

Something to remember when you reinstall the head. You probably know this already, but this is a reminder. The #11 head bolt, the one in the front by the thermostat, is the only one that's threaded into the water jacket. It needs to be thread sealed or coolant will wick up thru the threads and get into the first exhaust manifold stud threads and leak around the nut. I forgot this when doing my 0331 swap on my WJ.

If my recollection is right, white exhaust valve stems show the valve seats were not sealing well enough so the heat could not transfer to the head and they were getting too hot. In engines that burned leaded gas, this deposit was usually a brownish grey and hard as ceramic! When cleaning this off with a wire wheel, we had to use a mask or get a weird feeling in the back of our throats from the lead deposits! Not good!

Carbon in the intake manifold is oil coming thru the CCV system and deposits on the intake stems as well. You can usually see clean spots in the intake ports where the fuel injectors have washed them clean.

My opinion is to run some Mr. Gasket "Cataclean" thru the fuel system to clean out the convertors. It made a BIG difference in my WJ.

97grand4.0

Thanks Dave, aware of the bolt, working with a 98 fsm, very detailed. The ex manifold did have a hairline crack as well as one of the donut bolts was gone. Other one the nut came right off with a bit of blaster. So the manifold, mine anyhow, idk if it is already replaced or not, but it is all steel tube, with big flowing welds. I was able in about 3 minutes to reweld it with my little arc welder, flowed beautiful both sides. Not that I think that is my tapping, but it cant hurt to do it. Will look closer at this stuff after I drop the head off. Yeah it is a possibility for sure with 200k the seats and faces dont mate and the ex valves get too hot. Intakes were clean except for about 30% of them right by where the plugs are, so thinking the flame there is roasting the carbon on, Not alot of it but it is there and nasty. I run seafoam a few times it always helped. Would have been cool to stick a camera in could have seen it there. My fuel trim is good now so snot really thinking it's fuel, more likely just bad intake seals.
Probly gonna have him replace the ex valves, when I was taught how to do a valve job this was sop.

97grand4.0

WELL head is off, I was looking for scuffing on the cylinder walls, thinking maybe piston skirt, and while it is a bit shinyer ?(sp) on the outside wall where the lower skirt rides, it's certainly not scuffed. Also, checked each piston at TDC to see if it 'rocked' and while they all can move a tad, nothing seems odd. Anyone with machine shop knowledge of how to check for piston wear/slap with the slugs in the block , please chime in at this point.

97grand4.0

Dropped head off at the machine shop. The owner, who I know, talked with me about the I6 head. Big thing, he says, is these particular valves make it hard to get the height of the installed valve spring right. (not the Installed height, something I didn't quite understand) Says there is only a .030" window of adjustment, because of the non adjustable valvetrain, and machining the ends of the valves is tricky because there is not a lot of room between the valve keeper and the end of the valve. Cut too much and you weaken the keeper. So if the seats are pounded badly, like on the exhaust, ..they have to play around carefully to get it right. He does a CNC 3 angle job, no grinding stones. Also says he expects the springs are shot. Most of the heat is transferred from the face to the seat and if they ain’t closing, they ain’t transferring heat. Contrary to what I thought, he will not automatically replace the exhaust valves, says always measure first anyway just to see ...guides and stems..though he may end up replacing them.
Described the cylinder walls and my slap suspicion, but he says a light polishing sounds normal and thinks my tapping is lifters.
Check for head warp too.

97grand4.0

Lifters going in. Every one collapsed. A good 1/8" between each plunger and retaining clip. Hope this was my rattle. Would not do this without the tool from NAPA makes it a snap.
Edit: Every one of the lifters was collapsed significantly. By that I mean the seat that the pushrod sits in. You can see where the plunger is riding 1/8" or more below the C - clip. No need for a C clip there,! heh. Of course at the root of the failure is the plunger spring at the bottom of the plunger.
# 6 cyl both were more varnished and came out a little tougher.

97grand4.0

Head back from the machinist. Recondition head, resurface 3 angles, 6 exhaust valves, 24 keepers, 6 in seals, 6 ex seals, and 12 new springs. Magniflux and vacuum tested.
He said for 200k miles it was in excellent shape. Lifters were a bit flat but said no need for a cam. As noted above the lifters were beat silly. Said start it up and hold a high idle till the new ones pump up.

Oldbaja

What was the Napa tool? A tool for removing the lifters? Would you have the part # for the tool?

97grand4.0

Evercraft hydraulic lifter remover....776-9248 $15...I had to remove 2" from the shaft and re thread it. Otherwise it wouldn't fit under the hood cowl for the last 3 lifters., which were also the most stuck. You might be able to f ind one shorter. Overall this was 14" to begin with.

Oldbaja

Thank You!....... Very helpful!

97grand4.0

Hows the weather out there? I hear it's nice out there.

Oldbaja

We have great weather here. Its a little warm this August, should you ever want to visit San Diego, Oct-Nov are the best months.
Good luck on the head and motor work.

dave1123

If you are so inclined, you can prefill the lifters with oil by submerging them in oil and compressing them until you don't get any air bubbles out of them. Sometimes it takes a LONG time for some engines to fill them up. I've done that with Chevys for a long time.