2001 jeep grand cherokee head
04-04-2015, 09:28 AM
#1
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2001 jeep grand cherokee head
So I have bought my daughter a jeep grand cherokee it's a 2001 two wheel drive and it's a mess. I looked it over I thought pretty good but the gremlins have come out to play. So my problem is that the previous owner replaced the motor over the time he had it and for some reason put a older cherokee motor in a newer jeep. That's where all my problems start. It started acting up and found out that it's running on three cylinders after scanning it took a look at the coil pack and it was zip tied on? Did further looking and the bolts that bolt the coil pack on are not installed. Well further looking there's no bolt holes for the coil pack to be bolted in being it's an older motor. Great the previous owner for that. So my question is if I buy a newer head that has the provisions for the coil pack with the newer head bolt up to an older block?
04-04-2015, 01:47 PM
#2
Old fart with a wrench
Welcome to CF!
First of all, you've got the 630 head from the earlier 4.0 made prior to the engine block redesign in '99. If your engine is bolted in with standard mount (not custom made mounts), your engine was made after '98. Another clue is the oil filter. If it is screwed into the side of the block, you've got the original motor or one the was made after '98.
The gremlin here is the 0331 heads for the 4.0 made from '99 to '01 were weak and cracked between the #3 and #4 cylinders. I'd be willing to bet the PO replaced his cracked 0331 head with a 630 head. It functions perfectly and bolts on properly. There are 2 differences between these heads. Chrysler redesigned the exhaust passages for better flow and enlarged them. People tell me there is a port alignment problem with the exhaust manifold when using a 630 to replace a 331. Also, the bosses for the coil pack aren't there.
Clearwater Cylinder Heads has a heavy duty new-cast 331 head for $455 complete with valves. There is no up-front core charge and they give you a return shipping label. You have 30 days to return the core or you get charged for it. Also, they are guaranteed for 60 MONTHS against cracking!
Long story short, in '99 they had to relocate the motor mounts to allow the 4.7 V8 to be installed in the jeeps, therefore the 4.0 block mounting bosses had to be moved. This caused a problem with the oil filter, so THAT had to be moved. Again, I'll bet you have the original motor with the older head.
Let us know what you find out.
First of all, you've got the 630 head from the earlier 4.0 made prior to the engine block redesign in '99. If your engine is bolted in with standard mount (not custom made mounts), your engine was made after '98. Another clue is the oil filter. If it is screwed into the side of the block, you've got the original motor or one the was made after '98.
The gremlin here is the 0331 heads for the 4.0 made from '99 to '01 were weak and cracked between the #3 and #4 cylinders. I'd be willing to bet the PO replaced his cracked 0331 head with a 630 head. It functions perfectly and bolts on properly. There are 2 differences between these heads. Chrysler redesigned the exhaust passages for better flow and enlarged them. People tell me there is a port alignment problem with the exhaust manifold when using a 630 to replace a 331. Also, the bosses for the coil pack aren't there.
Clearwater Cylinder Heads has a heavy duty new-cast 331 head for $455 complete with valves. There is no up-front core charge and they give you a return shipping label. You have 30 days to return the core or you get charged for it. Also, they are guaranteed for 60 MONTHS against cracking!
Long story short, in '99 they had to relocate the motor mounts to allow the 4.7 V8 to be installed in the jeeps, therefore the 4.0 block mounting bosses had to be moved. This caused a problem with the oil filter, so THAT had to be moved. Again, I'll bet you have the original motor with the older head.
Let us know what you find out.
Last edited by dave1123; 04-04-2015 at 01:49 PM.
04-04-2015, 04:16 PM
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My gremlin
Thank you so much for the reply. I didn't get in to the other issues I have found to not have to write a book. The cherokee does not have original motor to frame mounts.the original mounts nor the frame mounts our in the Jeep. It has some crazy after market ones in that don't really fit.
04-05-2015, 01:53 PM
#4
Old fart with a wrench
Ah ha! So now you have a bastard rig. Sorry about that. So now we get to work out the problems.
Yes, the newer head will bolt up perfectly, I'm assuming you are using the original intake manifold? How about the original exhaust manifold? It should be a split header with 2 downpipes into small cats. My '00 WJ has no downstream cat, just the 2 precats, I think. Last time I was under it I didn't see one. It's supposed to have 2 02 sensors, but again, I haven't scoped it out. Both these are wired into the PCM for mixture control, so if your rig has a downstream cat and sensor, (the older manifold) The PCM is getting confused.
The 2001 intake manifold flows better so many guys have put them on the older 4.0's. Chrysler claims the intake and port redesign gained 10 hp output. That brings it up to a whopping 195 horses!
Without the bolts to hold the coil pack in place, it's probably shorting out the insulators on the plugs. Do that long enough and it will toast the coil pack.
Check out wjjeeps.com for lots of info about your jeep.
Chrysler hasn't admitted they have a problem with the '99 to '01 heads but how come they recast them in '02? They said any heads that cracked were due to poor maintenance. BS!
This should give you someplace to start. Keep us updated on what you find.
Yes, the newer head will bolt up perfectly, I'm assuming you are using the original intake manifold? How about the original exhaust manifold? It should be a split header with 2 downpipes into small cats. My '00 WJ has no downstream cat, just the 2 precats, I think. Last time I was under it I didn't see one. It's supposed to have 2 02 sensors, but again, I haven't scoped it out. Both these are wired into the PCM for mixture control, so if your rig has a downstream cat and sensor, (the older manifold) The PCM is getting confused.
The 2001 intake manifold flows better so many guys have put them on the older 4.0's. Chrysler claims the intake and port redesign gained 10 hp output. That brings it up to a whopping 195 horses!
Without the bolts to hold the coil pack in place, it's probably shorting out the insulators on the plugs. Do that long enough and it will toast the coil pack.
Check out wjjeeps.com for lots of info about your jeep.
Chrysler hasn't admitted they have a problem with the '99 to '01 heads but how come they recast them in '02? They said any heads that cracked were due to poor maintenance. BS!
This should give you someplace to start. Keep us updated on what you find.
04-05-2015, 02:18 PM
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Ah ha! So now you have a bastard rig. Sorry about that. So now we get to work out the problems.
Yes, the newer head will bolt up perfectly, I'm assuming you are using the original intake manifold? How about the original exhaust manifold? It should be a split header with 2 downpipes into small cats. My '00 WJ has no downstream cat, just the 2 precats, I think. Last time I was under it I didn't see one. It's supposed to have 2 02 sensors, but again, I haven't scoped it out. Both these are wired into the PCM for mixture control, so if your rig has a downstream cat and sensor, (the older manifold) The PCM is getting confused.
The 2001 intake manifold flows better so many guys have put them on the older 4.0's. Chrysler claims the intake and port redesign gained 10 hp output. That brings it up to a whopping 195 horses!
Without the bolts to hold the coil pack in place, it's probably shorting out the insulators on the plugs. Do that long enough and it will toast the coil pack.
Check out wjjeeps.com for lots of info about your jeep.
Chrysler hasn't admitted they have a problem with the '99 to '01 heads but how come they recast them in '02? They said any heads that cracked were due to poor maintenance. BS!
This should give you someplace to start. Keep us updated on what you find.
Yes, the newer head will bolt up perfectly, I'm assuming you are using the original intake manifold? How about the original exhaust manifold? It should be a split header with 2 downpipes into small cats. My '00 WJ has no downstream cat, just the 2 precats, I think. Last time I was under it I didn't see one. It's supposed to have 2 02 sensors, but again, I haven't scoped it out. Both these are wired into the PCM for mixture control, so if your rig has a downstream cat and sensor, (the older manifold) The PCM is getting confused.
The 2001 intake manifold flows better so many guys have put them on the older 4.0's. Chrysler claims the intake and port redesign gained 10 hp output. That brings it up to a whopping 195 horses!
Without the bolts to hold the coil pack in place, it's probably shorting out the insulators on the plugs. Do that long enough and it will toast the coil pack.
Check out wjjeeps.com for lots of info about your jeep.
Chrysler hasn't admitted they have a problem with the '99 to '01 heads but how come they recast them in '02? They said any heads that cracked were due to poor maintenance. BS!
This should give you someplace to start. Keep us updated on what you find.
04-05-2015, 02:47 PM
#6
Old fart with a wrench
This thread gave us some good information. There ARE aftermarket mounts to do this swap. I've been telling guys you can't put the older 6 in the newer jeeps. It seems I was wrong. This opens up a whole new range of options for guys that need to replace their engines. I'll have to research where to get them. Thanks for that!
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