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08:04:48 - 04/26/2024
Dakota Performance
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athenianR/T
Dodge Dakota
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4/02/2005
17:37:34
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 Subject: diagnose timing chain looseness
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Message:
how would I go about diagnosing the timing chain to see if its loose? I don't have any symptoms, outside of a freakish timing light situation. the flashes appear to jump around in a eight to ten degree difference, I have been told it may be the balancer,( harmonic dampner) which I'm getting ready to check out. I don't want to tear down the engine YET, unless I have to, as I do have plans for a cam change in the future, as soon as I get the money together. I'm going for a new cam, timing chain, lifters, roller rockers and polished valve covers, which is a hunk of money, so it'll be a while till I get to that, but I don't want to toss the chain before then!
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athenianR/T
Dodge Dakota
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4/02/2005
17:45:55
| RE: diagnose timing chain looseness
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oh, yeah. its a 2001 R/T, with 65K miles... induction mods are the majority of my engine mods, if that helps.
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T-racy
Dodge Dakota
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4/02/2005
23:30:19
| RE: diagnose timing chain looseness
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The harmonic balancer itself can't cause erratic timing readings. Other than it spinning when the engine is running there's nothing on it that moves. To check the timing chain for slop turn the engine over until the balancer is where you can see the timing slot then grab the harmonic balancer and rock it back and forth about an inch or two. The timing chain is connected to a gear on the crank so you will feel it get tight at each limit when you turn the balancer back and forth. Watch the marks and if the slop seems to be more than 1/2" it's getting pretty loose and can cause the timing variations. If you feel 1/4 inch or less slop it's just fine. As a rule of thumb replace the timing chain and gears every 100,000 mi.
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.boB
Dodge Dakota
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4/03/2005
00:37:44
| RE: diagnose timing chain looseness
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Message:
Harmonic balancers can go bad. It's a center metal hub, and an out metal ring, with a heavy rubber ring in the middle to hold it all together. If the rubber comes apart, the outer ring can oscillate and give you those strange readings.
You could be getting erratic timing readings from the secondary ignition system. If you have a high voltage system, but didn't use wire seperators, you can get some cross firing. Or if the cap is bad/dirty, the spark will jump around. Also, make sure the timing like probe is well seperated from the other cables.
To check the timing chain, remove all the spark plugs, and the distributor cap. Turn the crankshaft a little bit, you don't need much. Just enough to make the distributor rotor move. Now turn the crank shaft the other way. The rotor should turn right away. If there's a definate lag in rotor movement, you have a problem. Most likely the timing chain, but could also the the distributor gear.
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OBIO3
Dodge Dakota
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4/03/2005
17:32:48
| RE: diagnose timing chain looseness
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Message:
If you deside it is the chain, when you start taking it apart take a close look at the half moon crank key > over the years i have seen some that was wore better then half way through > usually happens if the crank bolt is not tight enough > this can cause timing to jump and even sound like a bad rod knock
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