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freshening a replacement engine...

F

FreemansXJ

NAXJA Forum User
Location
Spring Hill, Ks
Well, I finally found a replacement engine for my 97 Cherokee. It is a 98 4.0 with 97k miles. It runs great and the price was right....so onto my questions.

I have my old engine out and the new one sitting here next to it. I am planning on changing/replacing the following items before I install it:

rear seal
pan gasket
valve cover gasket
intake/ exhaust gasket
clean injectors
new plugs/ wires.

Anything I am missing? Also, what gaskets have you had the best luck with when it comes to the pan and valve cover?

Thx agin,

JOhn
 
O-rings on the oil filter adapter should be on the list too. You might want to replace at least the rear freeze plugs as well.
 
Great suggestions..thank you. I would have remembered the oil pump when I pulled the pan...thanks for saving me another trip to the parts store :cheers:

I've done timing chains on V8 fords and Chevy's, any problem areas with the 4.0 in this area? Are the freeze plugs difficult (usually had new ones put in at the machine shop).

thx again,

JOhn
 
I don't know if you want to go this far, but I would take off the head, replace the gasket, retorque it all, and while it's off take the time to hand scrub the combustion chambers/pistons/valves and pour some sort of carbon cleaner down on the rings.
 
...and hey, if you have the pan and the head off already you're almost there with a basic 4.5L stroker....:greensmok
 
FreemansXJ said:
I've done timing chains on V8 fords and Chevy's, any problem areas with the 4.0 in this area?
Click to expand...

Not really a problem, but when you take off the timing cover, there is a rubber timing chain damper (CLOYES Part # 95337 at rockauto.com) on the cover that is probably hardened up and worn. Also, on the cam sprocket, watch out for the pin in the center. It has a spring behind it, and might pop out.
 
Wow said:
...and hey, if you have the pan and the head off already you're almost there with a basic 4.5L stroker....:greensmok
Click to expand...


LOL...I still have the old engine that needs new pistons....so I may build that one in the future. The engine I bought came with all the sensors and wires, which will help if I need a spare. I have done some reading on the timing chain and I think I may wait on it. The general consensus is that the 97 up 4.0 chains are good for 150 to 175k miles. This will be a part time toy that probably gets 5k a year at the most..and with a 97k engine....(insert murphys law here..lol)...it should be okay.

Thx again for the suggestions.
 
id say do as little as needed. what you mentioned on the original post. if your going to do the oil pump, head gasket, timing chain, ect, your better off doing it to a fresh engine. use the new to you engine (97K isnt that much) untill you rebuild/build the old one. if thats your intention.
 
I just freshened one up myself, these seemed to be the problem areas:

Oil pan gasket (save the headache and get the one piece gasket instead of the 4 piece)
Oil filter mount o-ring
Front seal (in timing chain cover)
Timing chain cover gasket
Water pump gasket
Thermostat and gasket
Exhaust/Intake gasket (Exhaust manifold upgrade would be a good idea too, Im sure its cracked)
Plugs, wires, cap, button
A lot of times the knock sensor (if yours has one) will crumble, may want to ahead and replace that too
Oil pump
Valve cover gasket
Belt
Vacuum lines
 
99XJWhitey said:
I just freshened one up myself, these seemed to be the problem areas:

Oil pan gasket (save the headache and get the one piece gasket instead of the 4 piece)
Oil filter mount o-ring
Front seal (in timing chain cover)
Timing chain cover gasket
Water pump gasket
Thermostat and gasket
Exhaust/Intake gasket (Exhaust manifold upgrade would be a good idea too, Im sure its cracked)
Plugs, wires, cap, button
A lot of times the knock sensor (if yours has one) will crumble, may want to ahead and replace that too
Oil pump
Valve cover gasket
Belt
Vacuum lines
Click to expand...

Thats sounds like everything I am doing except the timing cover and front seal. I am also replacing the freeze plugs though. I will take some pics as I go along in case anyone is interested.

2 quick questions though. I did a search and some reading on here and I am still a bit confused on the VC Gasket. I bought the nice Fel-Pro, but I dont know if I should lightly silicone/seal it also. I know on my other v8 engines I did, but a few I read on here said they didn't....any suggestions?

Also, when I bought the freeze plugs they said the 4.0 only has 4 in the side of the block (although I thought mine had 5). So I bought 4 and sure enough, I needed 5. I read a write up on changing them and the author even mentioned having 4 freeze plugs.....Do they change from year to year (Mine is a 98)??

Thx,

JOhn
 
I usually put a light coat of rtv on both sides of the gasket, make sure the surfaces are clean and dry. I went with FelPro for all of my gaskets and the only one Im not happy with is the oil pan gasket. It was a four piece and a PITA.

I didnt even bother with the freeze plugs. knock on wood, Ive never had one pop out of a 4.0. Sometimes you actually be taking a step backward when replacing them, the gunk and rust of time will normally hold the old ones in better than a person can put a new one in, no facts to prove that, just my opinion.
 
99XJWhitey said:
I usually put a light coat of rtv on both sides of the gasket, make sure the surfaces are clean and dry. I went with FelPro for all of my gaskets and the only one Im not happy with is the oil pan gasket. It was a four piece and a PITA.

I didnt even bother with the freeze plugs. knock on wood, Ive never had one pop out of a 4.0. Sometimes you actually be taking a step backward when replacing them, the gunk and rust of time will normally hold the old ones in better than a person can put a new one in, no facts to prove that, just my opinion.
Click to expand...

Thx for the gasket info. I figured that its not going to get any easier to change the freeze plugs than now (its sitting on an engine stand), so why not :)

John
 
FreemansXJ said:
Thx for the gasket info. I figured that its not going to get any easier to change the freeze plugs than now (its sitting on an engine stand), so why not :)

John
Click to expand...

I had a hard time with the freeze plugs on my rebuild. The rearmost side plug hammered right in, but then I couldn't get any of the others to seat properly. Took the block off the stand, set it on some cardboard on the floor, got some more plugs at the store, tapped them right in. Turns out there is too much bounce on the engine stand, and it's hard to get a good solid blow to get them started evenly into the holes.
They're cheap enough at NAPA, etc. Pick up a few extras just in case...
 
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