Remove head without removing timing cover

[rbtconsultants]

Hello - I'm obviously new to the forum. I've been reading a lot and this seems to be a great forum for KJ owners. Glad to be here.

So, I have what I believe to be a dropped valve seat in my 2002 liberty limited 3.7l. The frost plug on the rear of the passenger head sprung a leak and I overheated badly. The engine still ran after I let it cool down but made a severe clattering noise so i shut it off immediately. I ran a compression test and I have good compression in 7 cylinders and 0 in the rearmost cylinder on driver side. So great, I have to pull both heads, one to replace head and one to replace frost plug. Hopefully I won't find anything more catastrophic when I pull the head.

I have read and read, including the FSM several times. My question is, why do I have to remove the timing cover to remove the head? Why can't I just use the wedge tool to hold the timing chain and then remove the camshaft sprocket and then remove the head? Is there something here I am missing?

Thanks,

Bob

 

[dougmac]

If you are crafty enough to keep it in time, I don't see a problem. Without removing the cover, there is a pretty good opportunity for things to go sideways with the timing.

 

[rbtconsultants]

Thanks. Isn't this the same as removing the camshaft sprocket or camshaft without removing the head? FSM says to set the balancer to TDC which sets the camshaft sprocket to have v6 marking on top. Then lock the chain with the wedge tool. Then remove the sprocket, leaving the chain locked in place.

So, then remove the head. I assume that the sprocket can only go back on one way, that it is indexed somehow, so when I put the head back in I just set the camshaft so that the camshaft sprocket and chain go back on with the v6 mark on top. Just don't rotate the engine while the sprocket is off.

I already the have the head ready to unbolt and I have the spanner tool for the sprocket. Tonight I picked up the tool to remove the balancer from autozone when this occurred to me, I'm going to try this and see if the head won't come off this way, unless someone knows a reason why not. I guess if there's a reason why it won't work I'll find out

If it works I have a balancer installer and a timing chain special locking tool I have to return to Amazon. Off to make a wooden wedge tool.

Thanks

Bob

 

[dougmac]

You wont be able to reset the tensioners . They are spring-loaded and have a ratchet that wont let them retract once they have extended.

That could be the deal breaker for not removing the cover. I dont know if you will be able to keep it from extending once you remove the sprocket from the cam.

Here is a picture from my engine. The tensioner is to the left of the big idler gear in the center.

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[mx3_ryder]

7 good cylinders? You mean 5 good cylinders? If it was overheated that badly, I would consider sourcing another engine. I would be afraid that there was further damage done even though you currently show good compression readings in the other cylinders. Without rebuilding both heads entirely, you could be looking at more problems down the road as far as valve seats dropping, warped heads causing head gaskets leaking etc.

 

[rbtconsultants]

Yeah sorry, 5 good cylinders. Spending took much time working on my son's 289 mustang I will be replacing the head that dropped the seat. I will have the other head off to replace the frost plug and will evaluate it to see if I should just consider relplacng it also. Research shows that many people have overheated and dropped a valve seat without throwing out their engines so I'm not sure why I would need to consider that, unless I see significant damage in the cylinder with no compression.

As far as the tensioner goes, I'm thinking if the wedge is in there, and I zip tie the tops of the tensioners together at the sprocket then it would prevent the tensioners from ratcheting. Apparently this had been done a lot by the 4.7l guys after further research.

I'll report back. I'll know more this weekend.

Bob

 

[mx3_ryder]

Yeah sorry, 5 good cylinders. Spending took much time working on my son's 289 mustang I will be replacing the head that dropped the seat. I will have the other head off to replace the frost plug and will evaluate it to see if I should just consider relplacng it also. Research shows that many people have overheated and dropped a valve seat without throwing out their engines so I'm not sure why I would need to consider that, unless I see significant damage in the cylinder with no compression.

As far as the tensioner goes, I'm thinking if the wedge is in there, and I zip tie the tops of the tensioners together at the sprocket then it would prevent the tensioners from ratcheting. Apparently this had been done a lot by the 4.7l guys after further research.

I'll report back. I'll know more this weekend.

Bob

Trust me, you can't determine if your valve seats are good just visually. To do it properly you should have both heads rebuilt which will run you half the cost of a new engine. When you factor in a timing chain set and all gaskets needed as well as new head bolts because you can't reuse your old bolts you're getting closer to the price of just buying another engine. IMO would be better off in the long run if you're keeping it. This is what I had to consider when I did the engine in my 02.
I actually went a step further and had my old heads rebuild only to later sell them to put the cash towards another engine. How many miles are on your block?
Check out my worklog. http://www.jeepkj.com/forum/f222/mx3_ryders-02-limited-57124/

 

[dougmac]

Yeah sorry, 5 good cylinders. Spending took much time working on my son's 289 mustang I will be replacing the head that dropped the seat. I will have the other head off to replace the frost plug and will evaluate it to see if I should just consider relplacng it also. Research shows that many people have overheated and dropped a valve seat without throwing out their engines so I'm not sure why I would need to consider that, unless I see significant damage in the cylinder with no compression.

As far as the tensioner goes, I'm thinking if the wedge is in there, and I zip tie the tops of the tensioners together at the sprocket then it would prevent the tensioners from ratcheting. Apparently this had been done a lot by the 4.7l guys after further research.

I'll report back. I'll know more this weekend.

Bob

Good luck! I hope it all works out as planned!

 

[rbtconsultants]

So, to follow up, I ended up deciding to remove the timing cover. After looking at things after I had removed everything that needed to be removed, there wasn't much left to do but remove the balancer to get the timing cover off, and I had already bought the timing chain locking tool and rented the balancer puller and already ordered a long-reach balancer installer from amazon so I said the heck with it and pulled the timing cover.

A few things I learned. My cheapo harbor freight air impact wrench did not have enough power to remove the balancer bolt, and there wasn't enough room for my electric impact without removing the radiator, so I tried the rope trick but the spark plugs holes are so small I didn't get the rope stuffed in good. Turns out a big screwdriver jammed in the balancer and a breaker bar with a 22mm socket was all it took.

The puller I rented from autozone was for chrysler engines and fit the balancer well but the rod in the kit to push against is just too short. I just ended up using the rod to hold and center two stacked short sockets, used as spacers, to give me enough travel to pull the balancer off.

I bought the pin spanners to remove the cam gears. I'll be sending them back. They suck and the bolts holding the cam gear on were too tight to loosen while holding the stupid pin spanners which kept slipping out if I didn't hold them exactly square while trying to work a ratchet to get the bolt off. Stupid design. And I was risking turning the engine. So, before I pinned the chains with the tool I just used my electric impact wrench to break the cam gear bolts loose. It was quick and easy and the engine didn't move at all. Then I pinned the chains and removed the cam gears and tensioners and chains.

Hope these tips help someone.

Oh, and I learned the valve seat did drop and apparently was basically pounded into dust as far as I can tell. There was one light imprint of the valve in the piston top. There was no debris but lots of rough hammered surfaces in the head chamber and some rough hammered spots on the piston top, but no cracks on the piston and not a speck of any damage on the cylinder walls .

I speculate the seat dropped, held the valve open, piston hit the valve and broke the seat, which was quickly pounded to tiny fragments. That was the noise I was hearing, as well as the valve now opening and closing with no seat, making noise and no compression. When I did the compression tests there were no plugs so the tiny debris from the seat got shot out the plug hole.

So, new head for $350 and I'll be good to go. Piston is roughed up a little bit but plenty usable. I see no reason to consider a new engine or anything beyond the new head. I still have to pull the other head to fix the frost plug and will check it out, but I'm reluctant to spend another $350 for a head if it looks fine. Many people seem to have replaced the head that dropped the seat and went on their merry way.

Thanks,

Bob

 

[M38 Bob]

Rough, hammered spots on piston will create hot spots and cause detonation(ping) unless smoothed off.

Bob

 

[rbtconsultants]

So, after further thought and advice from here and elsewhere, I decided to go further with this. After basically disassembling the entire engine in the car, I pulled out what was left. I dropped the oil pan and removed the piston. Glad I did, picture below. The piston that looked roughed up on top turned out to be a catastrophic failure.

Ended up replacing the one head with a rebuilt, and had the other head completely redone at a local machine shop. So, remanned heads with new valve seats on both sides, new MLS gaskets and new head bolts.

Picked up two new pistons - #5 is below, #3 didn't look nearly as bad, but turns out the top ring was pinched. Checked gaps on new rings, checked out good. Put two new pistons/rings on existing rods, ball honed the two cylinders and reinstalled using existing bearings (new rod bolts).

Two tensioners were so brittle they cracked on removal so I bought a new timing chain set and installed it. Picture below at initial timing. Also added new balancer and seal. Motor turns over smoothly, easily with wrench on crank. Timing marks are spot on, v6 at 12 o'clock on both cams at TDC after many rotations.

Since debris had traveled through the intake manifold and damaged two different pistons and was rattling around inside the intake I ended up picking up a used intake with throttle body on ebay for 65 bucks. It will go on with new intake gaskets.

Also added new oil pan and windage tray/gasket. Also new motor mounts. New valve cover gaskets. New exhaust manifold studs and gaskets. All new brass freeze plugs. Freeze plugs were all perfect except for the one that rotted in the passenger head and caused all this, which I thought was weird. Why one goes that bad and all the rest were perfect?

It's really a shame this happened because the engine was immaculate. Single previous owner took impeccable care of it. The rod bearings looked like new and there was no sludge in the engine, bottom end so clean you could have eaten off of it. There was a fair bit of carbon on the existing piston tops but the 3m gasket remover I was using took that right off, so combustion chambers will be like new now. Happy to be ready to put it back in the jeep and get her running again.

I'd like to get it in, get oil in it, get it attached to the transmission and starter installed so I can spin it and check compression. Assuming good compression I'll get injectors in (picked up new o rings and pintles], fuel rail, plugs (new platinum) and coils in, electrical connectors and accelerator cables connected, and fire it. Assuming that's all good, I'll get all the accessories (new belt) and cooling (new Zerex g-05] hooked up and the fan back in, tighten the motor mounts and be done with it.

Total investment about 1k, more or less.. Motor should be good for a long time.

'll report back when it's in. Hopefully tomorrow.

Bob

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[Logan Savage]

When you pulled the engine did you leave the exhaust manifolds bolted to the exhaust pipe & just remove the bolts that bolt them to the heads or did you pull them with the engine . I'm getting ready to replace an engine in mine . On different engines I have pulled in the past I've been able to leave the exhaust manifolds bolted to the exhaust pipe . Just wondering , those exhaust pipe bolts can be a bear .

 

[mx3_ryder]

Much easier leaving the exhaust manifolds bolted to the cylinder heads for removal and install.

 

[TwoBobsKJ]

Much easier leaving the exhaust manifolds bolted to the cylinder heads for removal and install.

^^^^^ That


There is a V-clamp that holds the catalytic converter to the exhaust manifolds on the '02 thru '04 models. The later 05 thru 07 models have a different method but in either case you're better off leaving the manifolds on the heads. Too hard to get to the lower bolts.

If yours has the V-clamps only use Mopar replacements. I bought a set from Summit Racing (they're right up the street) but they didn't hold the cat to the manifold tightly enough and had exhaust leaks. Put on the Mopar clamps and they're perfect.

Bob

 

[Logan Savage]

Thanks , I'll leave the manifolds on & disconnect the pipes / converters .

 

[rbtconsultants]

So, I actually had removed the heads first before I pulled the engine, because at the time I wasn't planning on pulling the engine. I pulled the heads with the exhaust manifolds and cats on. I had cut the spring bolts connecting the cats to the exhaust pipes with a grinder. I was trying to stay away from the v clamps because they looked impossible to get to from under the car, and you have to replace with new ones and they are not cheap. New spring bolts were cheap.

We are planning on putting the engine back in in the morning with the manifolds and cats on. If it won't go then I'll figure out what to do, but I think it will. There is more room than it looks, and the heads came out with the cats on, and I did find one pic of a guy on the Internet who shows his engine going in with the cats on, so....

I plan on getting the engine hanging over the engine bay halfway in and plugging in all the o2 sensors and then dropping the engine the rest of the way. .

So, I'll let you know how I make out.

Bob

 

[libertybob]

Cost???

When you tally up the cost of parts, was it less expensive to rebuild your existing engine versus purchasing a rebuilt one? Rebuilt engines vary greatly in price but I expect one by a reputable source to be in the $2500-$3000 range. So, how did you make out price wise? Thanks for sharing your experience.

 

[Logan Savage]

I have no idea how much it cost the op to rebuild but in my search for a good used or rebuilt engine I found your numbers to be right in the ball park for a rebuilt engine . It will be interesting to find out what his rebuild cost .

 

[rbtconsultants]

Heads - $670 ($350/$320)
Gaskets - $80
Pistons/rings - $70 ($35 each)
Timing chain set - $140
Freeze plugs - $20

So that's $980.

Stuff that I bought that wouldn't come with a reman long block anyway

Ebay intake manifold - $65
Exhaust manifold studs - $30
Oil pan $60
Oil pan gasket $25
Balancer - $46
Belt $30
Motor mounts $80

That's like another $330.

I already had an engine lift and stand. I already had most tools. Spent probably another $150 on miscellaneous tools and supplies (balancer installer, ball hone, frost plug installer, timing chain tool (unnecessary))

Bob

 

[TwoBobsKJ]

...We are planning on putting the engine back in in the morning with the manifolds and cats on. If it won't go then I'll figure out what to do, but I think it will. There is more room than it looks, and the heads came out with the cats on, and I did find one pic of a guy on the Internet who shows his engine going in with the cats on, so....

I plan on getting the engine hanging over the engine bay halfway in and plugging in all the o2 sensors and then dropping the engine the rest of the way. .

So, I'll let you know how I make out.

Bob

Don't know if you saw this pic, but anyway I installed my new engine with the manifolds and cats installed just as you describe above. Put some tape over the O2 sensors and slowly dropped it in with help from my dad (Loved having my 85 year old dad around - he taught me how to change the engine in my '73 Roadrunner...)

No way was I going to put those V-clamps on from underneath. Did that once when I replaced the cats and took FOREVER :thumbsdown:

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Bob