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94 regal 3800 possible rod knock


regalman

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Changed vibration damper that went bad after changing leaky timing chain cover. Engine sounds like a rod knock. Noisy after warming up at idle with dull thump. Original damper was bad but I still have the noise .What is best way to Test for knock? Pull 1 plug at at time ? 135 k on the motor. Can i run heavier oil in it, Oil pressure seems fine. Never any oil/coolant mix, new upper an lower manifold gaskets last summer. L motor.

 

Thanks for any advice.

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I noticed today if I grab that belt and pull it the new damper will rotate a inch either way I should not be able to move it right?Or at least not that much?

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i talked to a friend of mine and he said the thrust bearing on the crank stiops that crankshaft from moving back and forth, and that could be bad, anyone ever heard of that, does it require dropping the crank t replace it..;.Please enlighten me!

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It could be just a bad harmonic balancer. Pull the belt off and see if you can rotate the harmonic balancer by hand. If so It probably just needs to be replaced. I've never seen it happen before but I'm sure it can. You should not be able to rotate it by hand at all.

 

The harmonic balancer acts as a dampener for vibrations between the crank and the belt drive. There's rubber in it that could have failed.

 

Also, I don't mean to be rude, but I'm still not sure why you call this motor the "L motor". There isn't any L in it's name except in it's RPO code, and basically every other gm engine also has an L in it's code (ie. L36, L67, L26, LT1, LS1, LS2, LSA, LHO, etc...). It's an L27, or a series one 3800. It's just something that bothered me and it probably confused others.

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Also, I don't mean to be rude, but I'm still not sure why you call this motor the "L motor". There isn't any L in it's name except in it's RPO code, and basically every other gm engine also has an L in it's code (ie. L36, L67, L26, LT1, LS1, LS2, LSA, LHO, etc...). It's an L27, or a series one 3800. It's just something that bothered me and it probably confused others.

 

Dont forget the Lq1 :lol:

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L is a proper designation for a 3800 S1.... 8th digit of the VIN will be L to indicate it as such. M in a 94 regal would be a 3100, X for any W-body of the era is the LQ1 and T for the 3.1.... GM reused SOME letters and numbers, but never two possible engines for a given application.

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Never mind about the thrust bearings.they stop crank from moving front to rear not rotating I think. Gotta be that cheap ass new damper I put on. I do not think that I am turning crank by pulling on belt. I will put wrench on damper tomorrow and see if it rotates and back section connected to crank does not. Its gotta be it, especially since I got it to rotate yesterday

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