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[quote=”Hockeyclark” post=162644]Let’s just hope that the valve isn’t embedded in the piston.[/quote]
I think it is. Look at it’s position in the pics. Pointed straight down. I’d be surprised if it hadn’t imbedded itself in the top of the piston. I tried moving it with a screwdriver and it wouldn’t budge. Not to mention what kind of shape the cylinder walls are in. That engine is done in my opinion.
What a shame. From the video shots it seems like a fairly clean and tidy vehicle apart from the engine and surrounds.
If it has been run overheated, as you suggested was likely, there is possibly other significant damage as well like cracked cylinder heads.
I wish you luck in locating a decent engine for it so you can then make some money out of it for you and the family.
Just a note:
If you go to a Pull A Part for a new engine, bring the following stuff:
A spark plug wrench
Compression tester
Breaker bar/long handled ratchet with extensions and socket for crank pulley
Bore scope.Remove every spark plug from a prospective engine, look down in it to ensure there’s no dropped valve seat, and use the following trick to check compression:
Put your breaker bar on the crank pulley with all the plugs removed, screw your compression gauge into a cylinder, and spin the engine as fast as you can, I suggest putting some penetrating oil in the cylinders and letting it soak will help even more, but if you spin quickly, you should build SOME compression, I did this on a Civic SI motor from the junkyard and successfully got 60PSI in each cylinder, verifying the long block was likely to be good. Took it home and put it in my friend’s SI, the compression with the starter motor cranking averaged 120/cylinder PSI.
[quote=”Kazuo” post=162732]Just a note:
If you go to a Pull A Part for a new engine, bring the following stuff:
A spark plug wrench
Compression tester
Breaker bar/long handled ratchet with extensions and socket for crank pulley
Bore scope.Remove every spark plug from a prospective engine, look down in it to ensure there’s no dropped valve seat, and use the following trick to check compression:
Put your breaker bar on the crank pulley with all the plugs removed, screw your compression gauge into a cylinder, and spin the engine as fast as you can, I suggest putting some penetrating oil in the cylinders and letting it soak will help even more, but if you spin quickly, you should build SOME compression, I did this on a Civic SI motor from the junkyard and successfully got 60PSI in each cylinder, verifying the long block was likely to be good. Took it home and put it in my friend’s SI, the compression with the starter motor cranking averaged 120/cylinder PSI.[/quote]
Funny you mention this. Earlier this month I shot a video on “What to Look for in a Salvage Yard Engine” and “What Tools to Bring to the Salvage Yard”. I don’t think the compression gauge is necessary however. Also, I don’t think the readings would be accurate. Spinning the engine is important though. Learned that the hard way.
Apparently, this Jeep uses something called “UniFrame” construction, which is, as far as I can tell, a hybrid combining unibody and body-on-frame design elements.
Lifted this from Wikipedia’s “Vehicle frame” page:
” American Motors (with its partner Renault) during the late-1970s incorporated unibody construction when designing the Jeep Cherokee (XJ) platform using the manufacturing principles (unisides, floorpan with integrated frame rails and crumple zones, and roof panel) used in its passenger cars, such as the Hornets and all-wheel-drive Eagles for a new type of frame called the “Uniframe … a robust stamped steel frame welded to a strong unit-body structure, giving the strength of a conventional heavy frame with the weight advantages of Unibody construction.” This design was also used with the XJC concept developed by American Motors prior to its absorption by Chrysler, which later became the Jeep Grand Cherokee (ZJ). —including modern day sport utility vehicles (Jeep Grand Cherokee et.al.).”
If nothing else, it’s an unusual engineering feature that might help you fall in love with this thorn in your side. Or not.
Not that it helps you at this point, but a possible reason for the hammered valve could be that while the engine was in the process of overheating due to coolant loss, the driver probably jammed his foot through the firewall in an effort to keep the failing engine running. Could have over-revved the engine, causing valve float, which led to the piston tagging the valve.
[quote=”Evil-i” post=163279]Apparently, this Jeep uses something called “UniFrame” construction, which is, as far as I can tell, a hybrid combining unibody and body-on-frame design elements.
Lifted this from Wikipedia’s “Vehicle frame” page:
” American Motors (with its partner Renault) during the late-1970s incorporated unibody construction when designing the Jeep Cherokee (XJ) platform using the manufacturing principles (unisides, floorpan with integrated frame rails and crumple zones, and roof panel) used in its passenger cars, such as the Hornets and all-wheel-drive Eagles for a new type of frame called the “Uniframe … a robust stamped steel frame welded to a strong unit-body structure, giving the strength of a conventional heavy frame with the weight advantages of Unibody construction.” This design was also used with the XJC concept developed by American Motors prior to its absorption by Chrysler, which later became the Jeep Grand Cherokee (ZJ). —including modern day sport utility vehicles (Jeep Grand Cherokee et.al.).”
If nothing else, it’s an unusual engineering feature that might help you fall in love with this thorn in your side. Or not.
Not that it helps you at this point, but a possible reason for the hammered valve could be that while the engine was in the process of overheating due to coolant loss, the driver probably jammed his foot through the firewall in an effort to keep the failing engine running. Could have over-revved the engine, causing valve float, which led to the piston tagging the valve.[/quote]
I can’t see myself ever falling in love with a Grand Cherokee of this vintage. As I pointed out, I’ve seen way too many problems with them.
My father in law has Parkinson’s, not likely to be putting his foot through the firewall. Everyone agrees, this engine was a problem. It didn’t have anything to do with driver error.
[quote=”EricTheCarGuy” post=163323][quote=”Evil-i” post=163279]Apparently, this Jeep uses something called “UniFrame” construction, which is, as far as I can tell, a hybrid combining unibody and body-on-frame design elements.
Lifted this from Wikipedia’s “Vehicle frame” page:
” American Motors (with its partner Renault) during the late-1970s incorporated unibody construction when designing the Jeep Cherokee (XJ) platform using the manufacturing principles (unisides, floorpan with integrated frame rails and crumple zones, and roof panel) used in its passenger cars, such as the Hornets and all-wheel-drive Eagles for a new type of frame called the “Uniframe … a robust stamped steel frame welded to a strong unit-body structure, giving the strength of a conventional heavy frame with the weight advantages of Unibody construction.” This design was also used with the XJC concept developed by American Motors prior to its absorption by Chrysler, which later became the Jeep Grand Cherokee (ZJ). —including modern day sport utility vehicles (Jeep Grand Cherokee et.al.).”
If nothing else, it’s an unusual engineering feature that might help you fall in love with this thorn in your side. Or not.
Not that it helps you at this point, but a possible reason for the hammered valve could be that while the engine was in the process of overheating due to coolant loss, the driver probably jammed his foot through the firewall in an effort to keep the failing engine running. Could have over-revved the engine, causing valve float, which led to the piston tagging the valve.[/quote]
I can’t see myself ever falling in love with a Grand Cherokee of this vintage. As I pointed out, I’ve seen way too many problems with them.
My father in law has Parkinson’s, not likely to be putting his foot through the firewall. Everyone agrees, this engine was a problem. It didn’t have anything to do with driver error.[/quote]
My older brother had a Grand Cherokee a few years back , the V8 model , it was without a doubt the worst car I’ve ever experienced , the handling was vague to say the least , and surprisingly slow for a V8 as well , his taste in cars did improve albeit slightly , when he traded the Grand Cherokee for an Audi S6 Quattro .
For what it’s worth, Chrysler made many major improvements to the WJ (99-04 Grand Cherokee) in the later years. I’d frankly have to agree, the 99-01s particularly were problematic, especially with the 4.0 engine and 42RE transmission. But the 03s and ESPECIALLY the 04s are fantastic vehicles. My brother has an 04 4.0 now and it’s basically bulletproof. There are very few parts on the 2004 model year in common with earlier years. Then you have the DaimlerChrysler mess that is the WK, the newer Grand Cherokees are nice though. Available with a Maserati engine in 2018 or something? Haha.
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