Chevy knock/piston slap... Prepping to rebuild

[Derick]

So I've got the Chevy knocking and was thinking about taking it in for a rebuild if I came into some money. Motor has 144k on it, sometimes it sounds nice and smooth and others its just tapping away. What might I expect to pay on that?

 

[iamdub]

Lifters tapping or rods knocking? I'd see if it's just lifter tap, which is common and expected, especially if it's AFM lifter-related. 144K miles is nothing on these engines to warrant a rebuild unless it's been abused. I'd do some accurate diagnosing first. If it just needs an AFM delete, the parts are around $500-$700. Labor costs vary wildly from shop to shop, but I'd guess all said and done it's a $2,000 job. Much less than a total engine replacement or rebuild and you'd eliminate 8 ticking (literally) time bombs from your engine. Of course, this is all IF it's lifter(s) ticking.

 

[Derick]

Well I don't believe my motor has the afm.... It's an iron block 6.0, 2007.

Sure I get the proper diagnosis bit.. What do you think?

 

[swathdiver]

Well I don't believe my motor has the afm.... It's an iron block 6.0, 2007.

Sure I get the proper diagnosis bit.. What do you think?

Offhand that sounds like a bad lifter. If I remember right, you've got a 2500 with the LY6 right?

Did you recently switch from regular oil to synthetic?

 

[iamdub]

I didn't know what motor you had. I just went by what I saw in your avatar. Sounds kinda fast to be a lifter, or at least a single lifter, or was it idling high?

 

[Derick]

Offhand that sounds like a bad lifter. If I remember right, you've got a 2500 with the LY6 right?

Did you recently switch from regular oil to synthetic?

I'm not certain of the exact motor model numbers yet but yea it's a 2500 with a 6.0.

I have only had it a few thousand miles but I did put mobil super synthetic in it when I changed it. Unsure as to what was in it before...this video was at idle, don't believe it was fast.

 

[Derick]

Ok yep you're right. It is indeed the ly6

 

[Derick]

Ok, so I finally had a chance to sit down and do a little more research with the guidance of the lifters that was given. I looked back and its been just over 3k on the oil change, and that was Mobil Super Full Synthetic.

So, I think the following will be my plan...run the motor medic engine flush as recommended by the sticky in the forum. Then I'll change the oil with Durablend High Mileage, and Rislone additive, and then when I have the opportunity, I will replace the screen and oil pressure sensor. No sense in doing that right now if there's some gunk in the case floating around.

I can't imagine that the motor flush is going to yield THAT much. I ran the 1/3 can of seafoam when I bought the truck, so it's had some detergent in the crank before. Much of my reading seems to be that these things are finiky about their oil change intervals, even though the dash says I've got 50%+ oil life left.

For the moment, I'll just say thanks for turning my onto the lifters. I thought it was the was piston slap that has been discussed in length, but all accounts of that issue seems to be that it clears after ~10 seconds or so. This is occurring once the motor is warmed up.

 

[thompsoj22]

if there is no rough idle/missfire than id guess it's a single cylinder wristpin? It also sound like valvetrain but a smooth idle should not accompany that noise. either way your going to have to fix/remedy that. Allthough the wristpin should rattle even when cold? It would be nice if it were somthing simple. what is the oil pressure when it rattles? Does it ever stop once it starts? Im old school and have never and will never "poke the bear" when it comes to "snake oil additives" specifically in relation to "CLEANERS". Leave all sediments where they "sit dormant" until you actually disassemble the component for rebuild. No offense to those who claim good results from using the products.

 

[swathdiver]

Derick, let's say your motor was run on regular oil until you got it and the owner changed it every 7500 miles or so according to the DIC. This probably left a lot of sludge build up which synthetic oil, not to mention your cleaners, is designed to remove. So now the stuff is broken up and flowing through the motor and doesn't play well with small passages like lifters. You might clear it by changing the oil a couple of times and continuing to flush it out since you started the process.

I think though, that you're going to have to pull the heads and put fresh lifters in there.