I have a 1996 Ram with V10. I recently dropped a valve (the head broke off) and damaged a piston. I would say the piston has about 3-4 divots close together the deapest of which is about .09". They are maybe .125" wide by about .75" long. The cylinder walls look fine and according to my mechanic the rings are still good. I am running a mild performance cam but still have stock compression (8.4:1). No blower or nitrous.

Question: Do I absolutely need to replace piston? Or should this be OK assuming rings and cylinder are OK?

Please only comment if you have any direct experience and/or special knowledge.

I don't really know how thick the top of a piston is but would think that if it is 1/4" thick or so the risk would be pretty small.

Thanks for your help

 

close up pics would help, i'd just buy a new one, not like its an odd ball or anything, its a 360 piston, then you wouldn't have to worry about it.

 

Thanks Mr. Ruckuss. Just not sure what you mean by 360 piston. Do you mean it should cost about $360 to fix? Yes, if it is only that much I will surely fix.

I need to get quote but imagine it would be a big job requiring motor to be pulled etc.

On top of that, I don't have a hell of a lot of confidence in the shop my truck is now broken down in. They installed a new higher lift cam, but didn't bother to check appropriate valve train clearances. I think coil bind is what killd my valve. I had an experienced head person in mind, but my mechanic insisted on his head/machine shop. They are telling me I told them the parts should work togther as is and no checking was required. Its amateur if you ask me. If you are putting in a bigger cam it should be standard practice to check clearances. If you need to do some machining on the head to get clearances right then you do some machining.

 

He is saying the V10 uses the same pistons as the 360ci 5.9L V8 Magnum. I thought this was correct before but my service manual shows the V8 pistons being much heavier. They do have the same bore though.

I would be wary of using the piston as if there are gouges there could be hot spots in the combustion chamber that could cause detonation. There could also be bearing or wrist pin damage from a hard hit like that.

It may be possible to remove and replace the piston with the motor in the truck but i think it would be difficult.

 

Thanks Gerehead. I hadn't thought of how that may contribute to detonation. I need to get it fixed or it will pray on my mind.

Anyone have an idea of what I should reasonably pay to have this done. I think my mechanic should theoretically cover it but I am willing to split the difference with him. I just want my truck back running correctly.

 

uh your going to pull the engine to get the piston out, i doubt seriously it could be done with the engine in the truck. What did your mechanic say about the piston? is he wanting to replace it or use the old one? What/where did you get the mild cam? i've been looking for one

 

If you already have the head off then it should be easy to replace the piston with the engine in the truck. You'll need to pull the oil pan to undo the rod bolts and you can take out/put in the piston from above. Not an insignificant amount of work, but much less time and effort than pulling the engine out completely.

As was said, those divots will now become hot spots that will likely cause failure in a short time. Replacement is necessary. I would also check the wrist pin for damage as well as the rod and the crank bearing.

 

I might be the one and only here but I would check all the bore sizes while I was at it. I had small nicks and crap on the pistons. When the machine shop checked it out the bores were all funky. Might as well fix it all if it needs it.

me being paranoid probably lol

 

its a dodge, there's no such thing as being paranoid.

 

Not gonna say what's on my mind cause you'll pick on me about that too