Mahle Piston Rings.

[Ironworker15]

The ring pack that came with my Mahle Racecast pistons is part #4075MDK-D, Steel DSL ringset. I know the OEM replacement rings for 01-10 are part number 41909 and have a ductile iron top ring , and the newer style rings part number 42160 and have a stainless steel top ring. I looked in the Mahle catalog and it doesn't state what material these new rings are made of. I read a few posts on here regarding the older rings not lasting as long and having gap issues. I'm not trying to go back into this motor once it's together for a while. Anyone who has run these pistons know what this ringset it made out of? I emailed Mahle last week and haven't received any info yet. Any help would be appreciated thanks.

 

[Ironworker15]

Here is a picture of the box they came in.

 

[Ironworker15]

Still no answer from Mahle. But on their Power pack piston brochure it says the forged pistons come with a PVD coated stainless rectangular top ring. Doesnt say for the cast. Anyone have an answer for me? Is it worth sending these back for the other rings?

 

[Ironworker15]

Just received this email from Mahle. Just in case anyone else has a similar question. This ring pack does include the stainless top ring.

 

[1FastBrick]

By chance do they have a recomended Bore Finish for that ring pack?
RpK
Rk
RvK

 

[Ironworker15]

I'm not sure on that. I will email the tech and get back to you. I'm sure one of the more experienced builders on here who have run these pistons would have the answer though. I do know cylinder wall finish has just as much to do with the rings seating properly and the longevity of them as the material the rings are made of so I would venture to guess Mahle must have some spec.

 

[1FastBrick]

I'm not sure on that. I will email the tech and get back to you. I'm sure one of the more experienced builders on here who have run these pistons would have the answer though. I do know cylinder wall finish has just as much to do with the rings seating properly and the longevity of them as the material the rings are made of so I would venture to guess Mahle must have some spec.

I have been looking but everything I found online is older information. I think the ring packs may have changed since then so I wanted to be sure.

So if they have a specific recomendation for these current ring packs I would like to pass it on to my machinist. They actually do a have a profilometer and can verify the surface finish is correct.

 

[Ironworker15]

There was a few posts on here recommending stone grit and different Ra #s. But nothing specific to these pistons. I sent Mahle an email and will let ya know what I hear.

 

[Ironworker15]

Cylinder wall honing surface finish & ring gap

What is the preferred surface finish for seating rings on Mahle's race cast pistons/rings? I have 240 and 320 grit hones available. Also what ring gaps are preferred (compression and second ring)? Running small twins and maybe a small nitrous jet to clean up as needed.

www.duramaxdiesels.com

 

[1FastBrick]

Yes, Thats the thread I found with Post #8 giving a finish spec. of
RPK of 12-18,
RK of 35-40
RVK of 50-60
with a 45 degree included angle.

My machinist found some other material That suggested a larger range and possibly higher numbers on the finish.

RPK of 10-20,
RK of 25-50 for high pressure/ forced induction 55-65
RVK of 30-60 for high pressure/ forced induction 65-75

There is actually more to honing with different types stones, not just grits, as well as Plateau Brushes that all effect the final finish.

I think the ring pack may have changed at least 1 or 2 times since the original post from 9 years ago. I would be curious to see what they currently recommend. I just haven't had time to call them.

 

[Ironworker15]

I will let you know what I hear.

 

[TheBac]

....and here I used a simple dingle ball hone on a drill, and the 41909 rings.....go figure....

 

[Ironworker15]

Probably fine , if I wasn't over boring.020. If I was going stock replacements , I'd of done the same thing.

 

[kidturbo]

Now I'm gonna have to dig thru all my pics again...

 

[Ironworker15]

Ask and you shall receive. Here is the email I received from Mahle. Attached is the spec sheet as well.

 

[1FastBrick]

Ask and you shall receive. Here is the email I received from Mahle. Attached is the spec sheet as well.

Wow, Thank you so Much!

 

[Ironworker15]

No problem brother. That's what this forums about as far as I can tell. I've gotten a lot of good tech info on here so far. I'm sure each machinist/engine builder has their own personal preference when it comes to honing , but this seems to be a good starting point. Good luck with the build. Did you end up getting those Brian Crowers? I'm interested to see how they hold up myself. I did check all the pins and pin bosses on mine and no issues at all.

 

[1FastBrick]

No problem brother. That's what this forums about as far as I can tell. I've gotten a lot of good tech info on here so far. I'm sure each machinist/engine builder has their own personal preference when it comes to honing , but this seems to be a good starting point. Good luck with the build. Did you end up getting those Brian Crowers? I'm interested to see how they hold up myself. I did check all the pins and pin bosses on mine and no issues at all.

I ended up with the Callies. They just came back in stock. Hoping they show up this week.

 

[Ironworker15]

Nice. I've heard nothing but great things about them as well. A buddy of mine has them on his drag truck. Over 1000 to the wheels according to his 1/4 times and has had no problems so far. I almost went with them as well but they were out of stock everywhere when I was buying parts.

 

[1FastBrick]

Nice. I've heard nothing but great things about them as well. A buddy of mine has them on his drag truck. Over 1000 to the wheels according to his 1/4 times and has had no problems so far. I almost went with them as well but they were out of stock everywhere when I was buying parts.

The BC rods do look nice. I don't plan to push mine nearly that hard. Mainly towing and some occasional fun...
I am in the same boat, I couldn't afford to buy everything at once. I am slowly piecing it together. I think I have just about everything at this point.