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I recently purchased one of the aluminum valve covers for my 4.2L to fix a leak in the old one and dress up the engine a little. Upon trying to install this valve cover, the bolt holes dont line up correctly with some not even being close to lining up. I have been looking online everywhere for the factory valve cover with no luck. I even tried the plastic cover and that one didnt line up. Any help or suggestions is greatly appreciated.
 

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Is that a pic of your new valve cover? It looks like one for a 1991.

My YJ is a 1987 and I did the same thing as you are trying to do. The valve cover I bought was for 1986 and older CJ. I had to drill the two alignment holes on the left side (drivers side) of the head about 1/8" deeper and tap them with a 1/4-20 bottoming tap. Then I could bolt down the left side of the VC.
My old cracked plastic valve cover was held down by large washer backed rubber grommets on the extended head bolts.

The reason I say the pic looks like a 1991 VC is I bought a 1991 4.2 core motor to rebuild and the VC on it looks like the one in your pic.
The first pic is the engine ID code. The first number indicates the year (1). I take it to be a 1991. I don't think it can be a 1981 block that was installed in a 1991 as a used motor.
The second pic is the valve over. This valve cover is different from the one on my 1987. To me, it looks like the one in your pic.

Take a look on Quadratecs website at part # 917401.15. Then look at the installation instructions. This may be the VC you are looking for.

Good Luck, L.M.
 

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The reason I say the pic looks like a 1991 VC is I bought a 1991 4.2 core motor to rebuild and the VC on it looks like the one in your pic.
The first pic is the engine ID code. The first number indicates the year (1). I take it to be a 1991. I don't think it can be a 1981 block that was installed in a 1991 as a used motor.
The second pic is the valve over. This valve cover is different from the one on my 1987. To me, it looks like the one in your pic.
Good Luck, L.M.
L.M., your motor cant be a 91 as a C indicates a 4.2L. 1991 was the first year of NO 4.2L engines. That's going to have to be a 1981 block. The head is a later year, 88-90 4.2L, or maybe a 4.0L head(?)since it has the 15 bolts. The front position of the oil cap and mounting triangle indicates its a 4.2L VC. 4.0L VCs have the cap in the middle and no mounting triangle for the carbed air cleaner
 

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I recently purchased one of the aluminum valve covers for my 4.2L to fix a leak in the old one and dress up the engine a little. Upon trying to install this valve cover, the bolt holes dont line up correctly with some not even being close to lining up.
Is your original valve cover plastic or aluminum

How many valve cover bolt holes are in your head? 15? 5/7?

How many are in the new cover you bought?
 

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L.M., your motor cant be a 91 as a C indicates a 4.2L. 1991 was the first year of NO 4.2L engines. That's going to have to be a 1981 block. The head is a later year, 88-90 4.2L, or maybe a 4.0L head(?)since it has the 15 bolts. The front position of the oil cap and mounting triangle indicates its a 4.2L VC. 4.0L VCs have the cap in the middle and no mounting triangle for the carbed air cleaner
I can't disagree with you DREDnot because the second and third numbers indicate the month (December), making the motor to be installed by the factory in a 1992 model. I don't think this would have happened. I guess that most likely it was installed new in a 1982 model CJ. Maybe even a '72.
The Jeep it came out of was a 1991 model. The previous owner pulled it and put in a 4.0 out of a Cherokee.

The year of the block doesn't really matter to me unless there is a difference between earlier and later 4.2 engine internals. Since I plan on doing a complete overhaul, I only hope the block hasn't been bored to the max spec.

I'm sure the head is a 4.2 head because it had a carb and it didn't look like anything was cobbled up. Perhaps the Jeep it came out of had a short block installed at some time in the past. I searched the entire block for a rebuilders tag and found none. Again, it doesn't matter to me as long as I can have the block bored to .030 over. Even .040 over wouldn't be too bad.


According to a sticky in the YJ General Discussion Forum, titled "YJ Guide" by MikeMTJ, the 4.2 was used in 1991. How far into 1991 is anyones guess but I'm positive there were no 4.2s used in 1992 YJs.

Thanks for your input. It'll help when sourcing internals.

Good Luck, L.M.
 

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Looks really familiar...mine is a 90 and it's 4.2...the triangle on the top is how the factory airbox bolted on. Luckily I was able to just clean mine up no cracks.
 

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'89 YJ 4.2 with MC-2150 Carb & HEI, 2-1/2" Ex. AX-15, NP231 SYE, Adams shafts, F&R ARB, 3
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OK, so all of the Valve covers I've seen on this thread are off 4.2's. OP's question was has anyone found a suitable replacement? Seems I saw a pic at some point of L.M.'s 4.2 valve cover that had an aftermarket Logo. Fess up L.M. where did you get it? Or did you inherit it with your purchase?
 

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My valve cover is (I think) for 1986 and older CJs.

Quadratec part #917404.15. Look at the pic in the Qtec ad and then click on installation instructions.

I drilled the two locating holes on the drivers side of the head about 1/8" deeper and then tapped them with a 1/4-20 bottoming tap. I had to use allan head bolts because hex head bolts wouldn't fit the recess in the VC.

Good Luck, L.M.
 

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I actually looked for one...gave up and got out the dremel and fine sanding attachments...I would like to know...IIRC from my research the 89 and 90s, and now maybe 91s if there such an animal in the zoo, were the only one like th OPs...and every replacement I saw would have to be modified some less than others...
 
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