Timing chain slack test

[The_Handier_Man1]

From: Derrek  (Original Message)
Sent: 9/24/2004 2:35 PM

Hello everyone

  A while back ( like a year and a half ago) someone posted a procedure to check the slack in the timing chain. It involved removing the distributor cap and turning the crank in one direction and marking that spot on the crankshaft pulley and then turning the crank in the opposite direction until the rotor moved and marking that position.

I have done the test but I forget what the specs were. I tried using the search feature but didn't have any luck. There is a procedure in my service manual, but it requires measuring the chain with a machinist rule with the timing cover removed. Does anyone remember how many degrees of rotation was considered to be acceptable?



From: denison
Sent: 9/26/2004 7:54 AM

I dont recall the procedure either, sorry. If the intake manifold was off you could look down into the camshaft gallery and get an idea. But even there you have the possibility that the camshaft would move slightly as you turned the crankshaft just from the pressure of a cam-lobe that had the valve spring pressure bearing down on a lifter.

Timing chain wear goes up along with the type of use as much or more than mileage.
Wildly changing rpm, like you get on a truck in an urban environment and with a manual transmission, accelerates the wear, as does very dirty oil. In a motorhome so much of the mileage is at fairly consistent rpm, that I expect my timing chain to far outlive the piston rings and valves - at some mileage above 250k. I changed my timing chain at 91k miles because I had the radiator out and wanted to renew the front main seal. This was due to the age of the seal, not a leak. And while I was staring at the old timing chain and had already long since bought the new chain, why not replace it? Based on the wear of the old chain at that point, it had another 200k still left on it. 



From: Derrek
Sent: 9/26/2004 8:44 AM

Thanks Denison! From doing the test, the chain appeared to have very little slack in it, somewhere between 4-6degrees of crankshaft rotation.

I read several threads at www.imperialclub.com about timing chains and was suprised that many members found the teeth on the sprockets to be worn down even before 100,000 miles. If I understood correctly, this was due to aluminum and nylon teeth that were used to reduce noise. I would think that this would only be on the 440-1 engine and that Dodge would use a heavier timing chain on the 440-3. Or should I say, I am hoping they used a heavier chain! Thanks again for the info!

                                                                                       Derrek



From: denison
Sent: 9/26/2004 6:43 PM

For the 440-3s as well as the 413-1s its a double row roller chain, and certainly the cam and crank sprockets are both steel, and hardened steel at that. 



From: Derrek
Sent: 9/27/2004 8:00 AM

Thanks Denison! I can breathe a little easier knowing that Dodge did use a heavier timing chain set on these engines.



From: Derrek
Sent: 9/27/2004 8:16 PM

Ok, I found it!  http://www.misterfixit.com/chanslop.htm