Is it piston slap?

[Shtty6point4]

2016 Ram 2500 6.4l HEMI 4x4 Tradesman
236,000 miles

About a week ago, I hit the gas to clear an 18wheeler merging onto highway while already doing 75mph. Immediately after I felt the truck was off and the engine light popped on flashing. Knew something was up and figured misfire. Got to a spot to exit and check it out. Cylinder 8 misfired. Ran rough from idle to drive where I could physically see the hood shaking. Later on, the tick came into play. Not the hemi tick that I’ve had and been very familiar with as I’ve learned my truck and all it’s sounds. This is much louder and coming from what seems to be the passenger side near cylinder 8. Easy to tell through the wheel wells with plastics off. Also very easy to hear from under the truck near front of trans. Can’t pin point where it’s coming from but it’s louder than it’s ever been. It seems to go with rpm but sometimes it fades away for a min or two then comes back. Definitely ticks or clacks faster with rpm though. Loudest at cold start 40F-50F and low rpm’s but definitely still there at higher speeds jusy only able to hear with window down and driving past say a wall or something so it bounces off and is easily heard. One more thing I should definitely mention, I took out the spark plugs for cyl 8 and the plug closest to the firewalls gap had completely closed. Touching. Very confused on that as I know it wasn’t that way when I installed them. Yes they are the right NGKs for the truck.
High mileage truck that was used for daily hauling welding trailer and metal.

Any ideas would be appreciated. Also thinking about switching over to the redline 5w30.

First time post but I’ve been in these forums a while now always reading to learn more about the problems I’ve experienced. Thanks guys.

 

[fireflymedic]

Don't think piston slap would cause mis fire. Or have piston kiss the plug. More likely something wrong with valves broke spring or something. Just a guess I'm no mechanic though. Good luck. That's a lot of miles so any thing could be wore out but only timing (and that would effect all 8) or valves not closing or something got sucked in that cylinder could cause plug gap to be closed. Imho

 

[Shtty6point4]

Don't think piston slap would cause mis fire. Or have piston kiss the plug. More likely something wrong with valves broke spring or something. Just a guess I'm no mechanic though. Good luck. That's a lot of miles so any thing could be wore out but only timing (and that would effect all 8) or valves not closing or something got sucked in that cylinder could cause plug gap to be closed. Imho

Let me also say there is an intermittent loss of power when trying to hit the gas. Sometimes it gets up and goes and sometimes it just feels like the pedal is dead and weak. Only reason I suspected slap was a response from U&A to Burla in a thread about best oils for 6.4. I have replaced the water pump and thermostat, took off the EGR tubes and intake manifold to clean, then replace gaskets. While top was off I cleaned each injector with a diy method. Changed all 16 spark plugs and 8 ignition coils. I took the valve covers off as well just to peak since I am still trying to understand motors and how everything works. While covers were off I replaced the gaskets for those as well but didn’t try and mess with anything with lifters and springs. I was saving that for another day which might be around the corner now from the problems I’m experiencing. All of that was done maybe 12500 miles ago or so.

With all that being said I covered myself when removing everything by covering up the sketchy spots and cleaning any debris before doing anything else.

I do feel comfortable with working on the motor whether or not I understand it yet, I’m competent enough to replace the vital parts and get deep into it. I use ALLDATA for the in depth stuff so if everything under the valve covers needs replacing I think I can do it. I just want to make sure that when I open it up and see something as a problem, that it actually is an issue and that the issue is causing the problems I’m experiencing.
I understand it’s not a cheap or fast fix especially with me double checking myself and taking my time the way I do. But I don’t want to throw money into parts when it’s not the parts that are needed to fix the issue that needs attention. Im pretty positive that it could definitely use replacing either way but I’d hate to jump in and tear it all down just to come back to nothing changing. If you could refer me to a replacement kit with everything needed to replace and fix the lifters and valve springs etc. that would be fantastic. Or the best website to use for sourcing all the necessary parts for the price and quality.

Thanks for the reply and any future help

 

[fireflymedic]

Hopefully someone smarter than me maybe a real mechanic will reply. But I really don't like that sparkplug gap being closed. Sounds like piston or something in cylinder hit that sparkplug. If you could get a bore scope for a cell phone (Hopefully it's cheap not sure) you could look in that cylinder and see if it looks like piston has mark were it did hit the sparkplug. Obviously something caused the gap to close

At least do a compression check on all cylinders that should be cheap **** to do. If that cylinder has low compression it's either the rings or the valves.

 

[Burla]

Not piston slap, PS only happens when pistons due to their metallurgy and size shrink faster then the solid iron block. As the engine heats quickly, piston slap is gone til it gets cold and shrinks again, it generally only happens when cold as far as hemi's go. Piston slap rarely if ever effects performance, it most surely isnt the issue. Is there a reason you don't think it is cam lob number 8? Much evidence points in this direction. So the pistons will shrink at a rate higher then solid metal block. Maybe you got lucky and broke a valve spring?

 

[Burla]

cam bible thread

You could have checked the rocker movement with the cover off, you most surely will have to do this to diagnose. If one lifter doesnt lift or lifts way less then the others, well there ya go cam lob is done.

 

[Curt Gobbell]

Given the problem started after a "throttle mash", I suspect one of the following in this order:

1. Collapsed lifter
2. Collapsed/broken valve spring
3. Bent push rod

 

[Shtty6point4]

T

cam bible thread

You could have checked the rocker movement with the cover off, you most surely will have to do this to diagnose. If one lifter doesnt lift or lifts way less than the others, well there ya go cam lob is done.

Thanks for the help guys
Burla, I have read much of what you have had to say in different threads and see you have quite the understanding of how motors work. So I appreciate any help with finding the source. I do agree on needing to open up the cover and check straight to the source, I will do that. Can I ask you this, would an oil change a day or two before this cause anything like you’re suggesting? I used the same oil I always have the 0w-40 mobile 1 euro formula (trying to get away from it after reading your research) and a can of LIQUI MOLY 10oz I think it was or something.

Thank you Curt for the reply as well, I think y’all are leading me the right way in finding what happened and fixing the damaged parts.

Would either of y’all know where I would be able purchase good parts for that area at a fair price? I wouldn’t know what a fair price is honestly. Thanks guys, I’m at work so reply’s may be a little slow.

 

[Shtty6point4]

cam bible thread

You could have checked the rocker movement with the cover off, you most surely will have to do this to diagnose. If one lifter doesnt lift or lifts way less then the others, well there ya go cam lob is done.

I also I want to mention, the valve cover was off back when I did all the parts and spark plugs, not after the incident. If I can’t pop it off this evening then I will get to it Friday and report back with pictures and what I find. Thanks

 

[Burla]

In our early research, at one point 6 reported cam fails in a row happened to have a none moly oil in the sump. So no real way an oil change could have done this in anyway, and in fact new oil has fresh vii's which makes it a super lubricant for at least 500 miles, especially 0w40. So unless the level was low or a filter had a bypass failure, there is zero chance the oil change caused this. What filter did you use and does it have a bypass relief valve? 0w40 is a thick oil, so when it is cold the filter is in bypass. Below is a uoa of your oil, point being it has 70ppm moly, so in no way can that oil be the cause, especially with extra noly.

m1 0w40 euro