Timing Chain Question
 

Hi everyone, I've got a question regarding my 88 Dakota sport 3.9, I recently been going through some issues on this recently acquired truck, I never recall hearing this noise when I got this truck a little less than a month ago but upon start up the other day I could hear a noise best described as a slight slappedly slap noise, that didn't sound like a knock or a bearing noise so I tried tracking it down with a small lenght of washing machine hose using it as a stethoscope to finally finding it under the vehicle up behind where the water pump is, I believe its a little slack in the timing chain, ( I Think), my question is how long can this go unreplaced, could I take it easy on the truck and stretch the replacrment out for the next 3 months until I can afford to change not only the chain, tensioner, water pump and radiator, the waterpump is fine but my understanding is the cover to accsse the timing chain is behind there and I just as well put a new pump on while I'm at it. Now when I say drag it out for the next 3 months I referring to and from work 40 miles both ways 5 days a week. The slight chain sound is only heard in a 2 seconds revolution, Thanks in advance.

It's a crap shoot. They rarely fail, but, still, it happens. You may be fine, or, it may break tomorrow. Or never. :) Yeah, lotta help there huh? :D

Moving this to First gen Dakota section.

I drove on my bad timing chain for many miles.

Owner reply
 

I looked up this part Cloyes chain kit, is this as good as it gets, I see no tensioner, I heard a buddy saying he thought they made was like a 2 chain made Oversized...Not bicycle chain but, the makings off one, anything to this this pic is what I can get through Anvanced Auto locally.
https://cimg7.ibsrv.net/gimg/dodgefo...35f40abcef.jpg

Should be able to find a double roller chain set for your motor.

They built the first gen without a tensioner at the factory and added the tensioner as a TSB. https://www.rockauto.com/en/catalog/...tensioner,5736
Timing Chain https://www.rockauto.com/en/catalog/...ing+chain,5724
Cam Sprocket https://www.rockauto.com/en/catalog/...+sprocket,5722
Cover Seal https://www.rockauto.com/en/catalog/...over+seal,5612
Crank Sprocket https://www.rockauto.com/en/catalog/...+sprocket,5723

Or a Timing set :) https://www.rockauto.com/en/catalog/...iming+set,5756

Most of the guys on here find RA very reliable. I have no complaints.

the one pictured is not a double roller, it is standard replacement style. Go double roller. very little added money, and a lot less likely you will ever have this issue again.

Double roller, or tensioner. Nothing less.

I did both; but that's just about "belt, suspenders, and duct tape".

RwP

I have never heard of having a tensioner for the timing chain in an LA series engine. I got a double roller set for pretty cheap some years back for a 318. Pretty sure the same timing chain should fit a 3.9 too.

SO, you only hear a slap when starting it? I wouldn't worry too much about it now. How many miles are on it? If it has the stock set, the cam gear may have plastic teeth. I'd be more worried about them breaking than a little slop sound at start up. If it runs good, just go with it for awhile. Don't forget about it as it can get worse overtime. If you want, check how much slack it really has. Pull the distributor cap, then slowly turn the engine backwards till the rotor moves. Take notice where your wrench is, then slowly turn the engine forward only until the distributor rotor starts to move. Do this a couple of times and get an idea of how much of a turn it takes to get that distributor rotor to turn. I really don't know how much is too much, but if it take 1/4 of a revolution to get that rotor to move, than that chain is pretty stretched out.

This reminds me, I got a Cherokee I should change the timing set in. You think yours sounds bad at start up, the little Jeep's 4.0 has slap slap slap while idling. Still running good though at 180K miles.

The LA and Magnums use the same timing chain and, for EFI LAs, same cam retainer.

The tensioner is actually for the MAGNUM; but fits and works fine for LAs.

OTOH, it wasn't released until the LA family was "No Longer Available" :icon_wink:

RwP