Wrist pin Noise?

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chuckl1966

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I have a 318 and have had a noise, which sounds like valve train. But I have eliminated any possibility that the noise is valve train related. So I believe my next step would by checking piston wrist pins. But what is the diagnostic procedure of checking wrist pins with the engine assembled, in the car and running. Thanks.
 
If its con rod knock, it is usually more evident when the engine is cruising..pull the wires one at a time and the noise should go away or be quieter on the cylinder in question

A wrist pin noise will be a double knock most evident at idle...check same way

piston slap is also a possibility..usually more like a clatter...less evident as the engine warms up
 
What do you mean by "piston slap"? I've heard the term but never knew what it ment. The noise is much less when the engine is at temp.
 
piston slap is the result of your bore/and or pistons being worn out
The piston skirts slap the cylinder wall as they rock back and forth at TDC
as the engine warms up, the metals expand and the clearances close...less noise
 
Does this noise also go away when the plug wire is removed? I almost don't what to know, but what is the cure for piston slap. This would make sense, this 318 was bored over .40. The engine had around 2000 miles on it when I got it. And I got it in and running last summer and I have been looking for the cause of the noise. Thanks.
 
chuckl1966 said:
Does this noise also go away when the plug wire is removed? I almost don't what to know, but what is the cure for piston slap. This would make sense, this 318 was bored over .40. The engine had around 2000 miles on it when I got it. And I got it in and running last summer and I have been looking for the cause of the noise. Thanks.
Click to expand...


I worked in a chrysler dealership for 16 years doing engines and transmissions. I remember one particular car that was supposed to have a piton pin noise. after many hours of diagnostics with help from the shop foreman we decided to pull the engine only to find a cracked torque converter drive plate. maybe you could check yours?

kenny b
 
Wrist pin is fairly common in Mopar 4 cylinders. Lidten to any 2.2/2/5 that has more than 75K miles on it, or my '97 Neon for that matter. My 2.2 Omni went 170K, the Neon is just reaching 95K. It's not fatal, and slightly heavier oil will help. So does warming up the car for 5 minutes when ambient temperatures are under 40°. Cold starts and cold driving will make it worse.
 
Sanguine. OK. I removed all the plug wires, one at a time, and the noise did not leave. Is there a test for piston slap? Or is it a prosess of elimanation?
 
this noise has been in it since you got it and it only has 2000 miles on it??

where did you get it?...who rebuilt it?

regardless, its sounding like a tear down and check job to me

repair for piston slap is probably going to be a rebore and new pistons, but since it was just rebuilt,sounds like someone made a mistake or did a half assed job somewheres
 
There really is no test for piston slap/ loose pistons. It is basically process of elimination and if the noise lessens as the motor gets warmer it is probably loose pistons.


Chuck
 
This engine is out of a 74 Barracuda. I bought the car as a donor car for a 66 Barracuda I’m working on. The guy I bought it from said the engine had been rebuilt. I tore it down to the short block, I could still see the berry ball marks in the cylinders so I put it back together. With the cylinders already bored .40 over, which is max, I’m screwed. I guess its time for a new block.
 
Depending on the application, that block may be fine for .060 over. But 318s are easy to find...
 
You can run it, loose pistons are more annoying than they are a problem as long as they are not too loose. Sounds like the rebuilder put forged piston clearances in the bores and it has cast pistons.

Chuck
 
Yea I also got one of them 318 engines that was REBUILT! .40 over pistons.30 over rods and .20 over mains.After we got the car almost completed! We put exhaust on it and it had an engine noise!Sounded like a main bearing so I decided to pull it out.My soninlaw and I pulled it out and tore it down.Found out that it was all the above tolorences and the bearings looked like crap! If the engine had been rebuilt it was not done right or they plain wore it out before I got it! It was a total JOKE! Except for the HEADS were pretty nice. So we had the engine builder build a nice little 340 for it.
 
Well, I was going to start on the bodywork this summer, so the car won’t get driven too much anyway. I’ll use that time to get a second and third opinion. And if needed find a new block and pull the motor over the winter. Thank for the info. You’ve all been a great help.
 
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