I am working on rebuilding my personal service truck with an lmm in it. The cam pin sheared and bad thinks happened from there, as you all well know. Anyways, I stripped it down and to the machine shop it went. They called me today and it made .020 over on the bore. I just had them turn and polish the crank. Anyways, I need to get me a set of pistons. I know mahle race cast is #1 choice, but for a stock 1 ton service rig that don't see heavy towing, and don't run the quarter or pull the sleds, would the more budget friendly DK pistons hold up? I really don't feel like tearing it apart again for cracked pistons...that would be fun.
DK pistons, junk or good?
- Thread starter flyinwrenches
- Start date
Mahle Motorsport would be where I spend my money. For stock builds we use Mahle OEM replacement pistons or delipped GM LB7 pistons.
Well shoot, I just read your reply. I called DK this morning and got a really nice guy who kind of talked me into a set of pistons. He claimed they were exact replicas of Mahle. I asked him if it was the same alloy composition and he said yes. He claimed they were identical in every way. He was probably just blowing a lot of smoke to make a sell. In hindsight, I should have waited for you guys info. I guess I fell for his sells pitch. Anyways, we'll see. I may regret it.
you can cancel the order.No way I’d risk an expensive engine rebuild over those pistons. I’d rather put stock lmm in than those.
Well, have you guys heard bad things about them or seen guys have problems with them? I didn't strictly order based off of the sales pitch. I was reading some reviews from powerstroke guys and there was quite a few praising them as being good quality. However, I couldn't find much from the duramax community on their pistons. That's why I was asking. It seems like powerstroke guys have been running them.you can cancel the order.
No way I’d risk an expensive engine rebuild over those pistons. I’d rather put stock lmm in than those.
They already shipped, but I may just call and return them when they are delivered. I don't want to tear into it again, or waste a good block on bad pistons. I have a couple lmm blocks laying around and a couple sets of rods. I don't have much in the build. Maybe 3000 right now. My machine shop gives me excellent rates. However, all that aside, I still don't want to flush 3000 down the drain and go through the PITA of doing another rebuild. I am just being a tight wade on it I guess. I wouldn't do it on a customers rig, that's for sure.
I dont mine mahle OE but in also a firm believer in delipped pistons. Specially since you already have to buy new.
Dhd has done alot of testing on these pistons and ive personally used them. Wouldnt hesitate to use them in the setup you are doing
dirtyhookerdiesel.com
Dhd has done alot of testing on these pistons and ive personally used them. Wouldnt hesitate to use them in the setup you are doing
DHD Dualoy 20 Over Delipped Duramax Piston Set 2001-2016 6.6L
Add dependability to your Duramax engine build with this delipped Duramax piston set from DHD.
dirtyhookerdiesel.com
Forgive me for the million questions, but you are the guy in the know. I know Mahle has a huge global presence, including China. However, as you mentioned, Mahle Motorsport is strictly a US manufactured product from Morristown TN. DK pistons are NOT Chinese made. Their manufacturing facility is located in Turkey. I say all this to ask, people see Mahle and assume it's a good quality oem part, but are their Chinese parts also making there way over here? Mahle says that all of their North American parts comes from Morristown. However, I also remembered they were struggling with parts shortage and backorders. There just seems to be some pretty big price gaps is all I am saying. I mean, the price of the ones I posted from LDS is darn near on par with DKs pistons. I know you already specified to get it from Mahle Motorsport, because of this reason, but are they really "all" made in the US?
Last edited:
I just looked on their website and they charge a 20% restock fee on returned new parts. They got me coming and going. I need to quit being so gullible. ? That's about as bad as harbor freight. Heaven forbid you inconvenience someone to hit a few keys on a keyboard and walk it over to a shelf. Oh well though, you win some and lose some.
So, dumb question, couldn't a person just have the machine shop delip some mahle pistons? Also, they say the rotating assembly has to be balanced with these? Why I wonder?I dont mine mahle OE but in also a firm believer in delipped pistons. Specially since you already have to buy new.
Dhd has done alot of testing on these pistons and ive personally used them. Wouldnt hesitate to use them in the setup you are doing
DHD Dualoy 20 Over Delipped Duramax Piston Set 2001-2016 6.6L
Add dependability to your Duramax engine build with this delipped Duramax piston set from DHD.
You might as well buy race cast then as thats what they are but the composition of race cast and mahle oe are not the same.
Take what mahle says with a grain of salt. I have a post on her about how they fucked up their ductile iron rings and stainless rings and got nowhere with mahle. Then suddenly a few months later, numbering and descriptions all changed on rings. I know i wasnt the only having issues.
The pistons dhd sells is not within the same realm in weight as a drop in stock. What i dont remember is if they are lighter or heavier. Realistically you should be balancing the assembly with any pistons outside of oem. Hell factory isnt even balanced. I build these engines
*Piston Material/Brand*
Here's what you seem to be foregtting @flyinwrenches, just because DK or some other company CLAIMS the piston is the same dimension, shape, material spec etc doesn't mean it actually is. This is turning into the "you can lead a horse to water but can't make them drink" situation.
I am 100% with James and others on this stance. For example, Mahle made the OEM LB7/LLY pistons for GM yet the Mahle "OEM replacement" piston you buy from them is not the same material as the GM OEM piston. I have used 2 sets of Dualoy pistons and been fairly happy with them, I've had zero issues using them as a race cast replacement.
By the time you buy 8x OEM pistons at ~$660/side (which I am near the same price and support this page) then delip them you're better off going with a Mahle Motorsport ($1704.14 to your door and in stock) or Dualoy and being done once as the cost will be comparable at most machine shops. Also the Mahle Motorsport material is superior to the Mahle OEM replacement material. Mahle Motorsport do come delipped etc as they are a different bowl geometry than OEM, same with the Dualoy I use/buy/sell.
Also, your statement about Mahle pistons being junk because the come from China is about as far fetched as it can be. Most of the cast items you use/buy are not made in this country. Specification, quality control, and design all matter far more than the geographical location in which they're made.
*Balancing*
Please please please balance the engine with whatever piston you put in it, be it an OEM replacement/DK/Dualoy/Motorsport etc. These engines are not balanced as an assembly at the factory, they're set to standardized weight sets for the components so there is much to be improved over the OEM balance job.
Here's what you seem to be foregtting @flyinwrenches, just because DK or some other company CLAIMS the piston is the same dimension, shape, material spec etc doesn't mean it actually is. This is turning into the "you can lead a horse to water but can't make them drink" situation.
I am 100% with James and others on this stance. For example, Mahle made the OEM LB7/LLY pistons for GM yet the Mahle "OEM replacement" piston you buy from them is not the same material as the GM OEM piston. I have used 2 sets of Dualoy pistons and been fairly happy with them, I've had zero issues using them as a race cast replacement.
By the time you buy 8x OEM pistons at ~$660/side (which I am near the same price and support this page) then delip them you're better off going with a Mahle Motorsport ($1704.14 to your door and in stock) or Dualoy and being done once as the cost will be comparable at most machine shops. Also the Mahle Motorsport material is superior to the Mahle OEM replacement material. Mahle Motorsport do come delipped etc as they are a different bowl geometry than OEM, same with the Dualoy I use/buy/sell.
Also, your statement about Mahle pistons being junk because the come from China is about as far fetched as it can be. Most of the cast items you use/buy are not made in this country. Specification, quality control, and design all matter far more than the geographical location in which they're made.
*Balancing*
Please please please balance the engine with whatever piston you put in it, be it an OEM replacement/DK/Dualoy/Motorsport etc. These engines are not balanced as an assembly at the factory, they're set to standardized weight sets for the components so there is much to be improved over the OEM balance job.
Well, I think Bdsankey pretty much settled the discussion here. I wasn't saying mahle is junk either, I use them all the time. I just was stating that some of their products come from China, and that rubs people the wrong way sometimes. As long as it's good, then I don't care where they come from. You guys do WAY more rebuilds than me, so you know more. Especially since a lot of you been around the high hp crowds. That's why I came to you guys. I just fix all the stock junk that rolls in to me covered in 9 inches of grease, you know. I had never used DK parts on anything before, and my thinking was I would be the guinea pig on my own junk to see if I liked the parts, but that's probably not so smart after hearing how bad they potentially are. As a side note, I work part time as a machinist on heavy equipment parts, not engine machining, but hydraulic cylinders, flywheels, specialty pins and so on. Pretty much anything that you can chuck up in a lathe or mill. I also have my own diesel repair facility that I operate part time. I don't do performance builds or the like, but just fix junk. If it comes to me, it's broke. I see broken parts all day every day. However, I am not into the parts world or performance mods. I just wanted someone to thoroughly explain the piston topic with me and you guys have. I really appreciate the knowledge of this site and the great members that are here. You guys are a wealth of knowledge. Anyways, I think we resolved the topic pretty well. Thanks guys!
Just out of curiosity, you the same flyin wrenches thats on insta and deals with ford stuff all the time?
No, I am not. I had this username handle before them though. I seen their stuff before. I don't really do the social media stuff. I have some stuff on YouTube, and that's about it.
@Bdsankey hey, how do I find your products for sale? Unfortunately, I have the pistons ordered already, but I am going to need more parts and will need more in the future as well. What all do you sell? I contacted you once for a customer, but he ended up backing out on buying from you. Are you set up to do injector testing? Do you have a website?
I need main and con rod bearings, head gaskets (waiting on machine shop to know thickness), an engine gasket set, oil cooler, rod bolts, arp head studs, and more stuff I am forgetting I am sure...oh, injector seals and new injector hold down bolts, possibly some new injectors...if the old ones test bad. oh and a new cam gear bolt. All I have currently is a new set of gm genuine main cap bolts and a new balancer bolt. So, anything else I am still looking at buying. I have the cam, lifters, pushrods. Umm, that's all I can think of right now.
Edit- And new flywheel bolts and a thrust bearing set for the crank, I forgot that earlier.
Also, I would prefer to stay away from fel pro anything. I quit using their seals and gaskets. I have been having problems with them.
I need main and con rod bearings, head gaskets (waiting on machine shop to know thickness), an engine gasket set, oil cooler, rod bolts, arp head studs, and more stuff I am forgetting I am sure...oh, injector seals and new injector hold down bolts, possibly some new injectors...if the old ones test bad. oh and a new cam gear bolt. All I have currently is a new set of gm genuine main cap bolts and a new balancer bolt. So, anything else I am still looking at buying. I have the cam, lifters, pushrods. Umm, that's all I can think of right now.
Edit- And new flywheel bolts and a thrust bearing set for the crank, I forgot that earlier.
Also, I would prefer to stay away from fel pro anything. I quit using their seals and gaskets. I have been having problems with them.
Last edited:
Call him at the number listed in our vendor section.
Thanks, I had his number in my phone and lost it. My dumb butt self can't find it on here. When I pull down the top tab, it don't show a vendor option.