I got the front cover off and see that I can rotate the camshaft gear a couple of degrees back and forth while the crank stays put. The chain is nowhere near coming off the sprockets or anything, its literally a few degrees. I'm thinking this means a new chain will do me some good, but if a new chain is going to be as loose I'll keep what I have. Never been this far into a 4.0L before. Thanks.
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Timing chain question
- Thread starter md21722
- Start date
Original_MudButt
NAXJA Forum User
- Location
- In the eighth dimension
What year?
Sounds like it's time for a new one to me...
But then again, I've never been inside one either.
There is a buffer or what the factory calls a "snubber". It somehow attaches to the inside of the timing chain cover and looks like it takes up slack in the chain to keep it quiet.
The real test is deflection. You'll need the specs from an FSM and a couple of straight edge scales (rulers). I'm sure there is a procedure as how to accurately measure the slack.
Perhaps someone who knows more about this will chime in...
Sounds like it's time for a new one to me...
But then again, I've never been inside one either.
There is a buffer or what the factory calls a "snubber". It somehow attaches to the inside of the timing chain cover and looks like it takes up slack in the chain to keep it quiet.
The real test is deflection. You'll need the specs from an FSM and a couple of straight edge scales (rulers). I'm sure there is a procedure as how to accurately measure the slack.
Perhaps someone who knows more about this will chime in...
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Its a 1997 4.0.
I found somewhere a reference to the FSM specification and took a second look at the FSM. Sure enough, its in both the 1997 FSM and 2001 FSM. From the 1997 FSM:
"If the timing chain deflects more than 12.7 mm (1/2") replace it. The correct timing chain will have 48 pins. A chain with more than 48 pins will cause excessive slack."
Mine deflects 3/8" of an inch.
Thanks!
I found somewhere a reference to the FSM specification and took a second look at the FSM. Sure enough, its in both the 1997 FSM and 2001 FSM. From the 1997 FSM:
"If the timing chain deflects more than 12.7 mm (1/2") replace it. The correct timing chain will have 48 pins. A chain with more than 48 pins will cause excessive slack."
Mine deflects 3/8" of an inch.
Thanks!
Original_MudButt
NAXJA Forum User
- Location
- In the eighth dimension
Cool... Just be careful when reinstalling the timing chain cover. From what I hear, the snubber can be a little finicky...
notamos
NAXJA Forum User
- Location
- Fort Collins, CO
The snubber isn't bad to keep in the slot on the timing chain cover - but just remember to put it back in. 12k miles later, I *still* don't remember if I put mine back in or not. ;-)
It's interesting that the FSM says not to use chains with more than 48 links. From what I can tell Cloyes are 62 pin chains. Poking around Amazon I found one review that says the Cloyes had more links. One manufacturer, Diamond Power, appears to have a 48 pin chain.
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- Location
- Southern Maryland
count the links on your existing chain and get the same thing
Also of interest, the 1997 FSM shows describes the procedure to install a new chain, with a picture. The sprockets are placed at a specific position, 0's are indicated on the sprockets, and there are to be 15 pins when the sprockets are aligned per the picture. Clearly this would not work on a 62 pin chain. I believe I have a Cloyes chain on my 97. With #1 and #6 at the top of their stroke, the "I" marks on the sprockets are lined up and the rotor is at #6. While lining up the spockets seems more straightforward with the Cloyes setup, the FSM warns against using the 62 pin chain because it causes "excessive slack". I am guessing, but Cloyes may specifying the older 258 or earlier chain and sprocket parts for our 4.0's.
I looked at the chain stuff more, and found that somewhere between 1997 and 2001, Chrysler changed the number of pins in the chain. Both state 1/2" deflection maximum. My 1997 FSM specifies the 48 pin chain and provides the 15 pins between the marks procedure. My 2001 FSM does not make any mention about number of pins and show a different procedure. Chrysler has since specified the 64 pin chain for model years 1994-2006.
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
Don't pay attention to the links part. Its only for the OEM chain. Yes, you can get an OEM style, but just get a chain for your engine and it will be fine. I recommend a Cloyes set for a stock replacement.
