EBS/Millenium Cylinder roughness - should I worry

[racing97]

It seems to me that Porsche spec for oil consumption is a qt or a ltr every 1000 km

[gsxrken]

Originally Posted by wjdunham

I spoke directly with a tech at Millennium this morning, and he checked the EBS racing spec. sheet and they call out 8 Ra on all Porsche cylinder work. He said this spec. has been in place for a long time and not changed.
Bill

That may be their spec, but Trond will tell you his came back as 20+ and he redid his rings three times. Proceed with caution, which you seem to be doing.
good luck

[shoooo32]

Another data point: Here's one of my 3.2ss cylinders plated by Millennium in 2018 (16 Ra)



And a 3.6 cylinder plated in 2020 (5 Ra)

[Helix8]

I went back through my emails with EBS (they sent my cylinders to Millennium) this is dated June 28, 2019.

(my builder's name is "X'd" out) and my cylinders Ra measured as high as 26 not 20.

Best advice is to specify Ra if using EBS and verify when received.

This is from Don:

I do apologize for the delay in getting back to you on this issue but I felt, since this is essentially a “defective parts” claim, it prudent to collect the best information I can from some of the respected, brand name manufacturers we work with such as Mahle Motorsport, Total Seal and NPR. Below are some technical sheets provided by Mahle which covers a wide range of cylinder materials including Nikasil. When asked very specifically about their Nikasil finish on the cylinders that come from Germany, the specification is 12-16 Ra.

Conferring with Total Seal (who actually supplies many ring packs to Mahle Motorsport) they specify 10-20 Ra.

NPR, which supplies rings for most of the “off the shelf” Porsche air cooled pistons from JE and CP, specifies a range of 15-35 Ra.

Millennium’s target for our cylinders is 15-25 Ra with XXXXX measuring 18-20 Ra which makes sense as it lands in the lower/middle part of that range. I believe that XXXXX wanted cylinders at 8-10 Ra which is below any of the ring manufactures recommendations, below that of new Mahle Motorsport cylinders and below the recommendation of Millennium for most applications. The exception being if the engine is carefully broken in on a dyno under carefully controlled conditions.

Unfortunately, this comes down to XXXXX personal preferences which are not generally backed any of the manufacturers. Of course, we had no way of knowing this during the initial order phase as we could have had them made to his custom specifications, regardless.

Thank you,
Don Weaver-EBS Co.
don@ebsracing.com

800-357-2088
775-825-2217

www.ebsracing.com

[Marwil]

After reading the initial posts and posting myself I inquired of Millennium through their Canadian subsidiary about the Ra of the Millennium cylinders. The rep indicated that, without specification, Millennium hones their Nikasil to Ra 20-25. He offered to look at what EBS specified for my cylinders based on the serial numbers that Millennium stamped on my cylinders. According to their research regarding the order they were specified for an Ra of 8-14. I must say that Millennium has been most helpful and forthright in this matter, any issue is not theirs. At the time I placed my order I was not asked as to what Ra I wanted on the cylinders - this is something that I think EBS could do on their end. I understand the notion of builder responsibility; however, continuing the food analogy in an earlier post, even if I go to a high end restaurant and order filet mignon the waiter will ask how I want it done. If I'm a regular customer the waiter may say as per usual sir and as a new customer would be obliged to ask. That's the way the service industry should work.

Beyond the discussion regarding business practice lies the technical aspect of Ra. I've read multiple threads and items regarding initial Ra. One post that stands out is that an Ra of 5 on replated cylinders is appropriate for racing applications where people want immediate seating of the rings for that application. For standard break-in procedures then an Ra of 10 to 15 is appropriate. The key for ring sealing appears to be the plateau of the peaks in the honing process.

The next question should be is there a possible way of creating a plateau without excessively abrading the Nikasil finish? Is there a home honing method? Woodworking tool supply companies sell diamond surface sandpaper in extremely fine grain size. Lee Valley has diamond lapping film 15 micron (1000x) grain size and finer in 3"x 6" sheets; the finest sheets are 3, 0.5 and 0.1 microns. Could these be used in the manner that red scotchbrite is used for deglazing used cylinders? I am not an engineer and am asking out of pure curiosity as to whether this is a viable method or not. The core issue for excessive ring wear based on my reading on the matter appears to be the initial Ra and specifically the roughness of the peaks on the plateau portion of the honed finish.

Lastly, Henry Schmidt, in one of his postings on the matter, pointed out that people "will believe what they want to believe, as they should." He tempered that with the notion that belief may be out our lack of knowledge or the refusal to acknowledge what is known. I only hope that I can gain enough understanding about this to make a reasoned decision I can hang my hat on. So, on that basis, I may be comfortable living with the Ra of 8-14. I would be really happy if we can arrive at a reasonable, unexecessive manner to create the plateau effect without having to have cylinders stripped, replaced and rehoned. This last possibility scares me at $329 CAD per cylinder.

[faapgar]

I agree that the final Ra is important.So the ring pack is important as well.A few times I have had cylinders cleaned with a hone where the Ra is 3-5.Using Total Seal gapless on the top ring which not cast iron is hard to seat.But the end result is 1 percent leakage when broken in.Not for a DIY guy.But once broken in they last a long time.The soft cast iron ring just gets chewed up over 8-10 Ra.Some of my best results have come from cleaned up original cylinders with a custom slightly larger piston.Because you are using an original cylinder you can control the Ra better.I should probably not mention this.Lo siento mucho.Ciao Fred

[Marwil]

I found the post I was referring to earlier regarding Ra 5 and racing application. See post #11
Millenium Cylinder Fine Grit Honing Is the Right Way to Go

[Trackrash]

This was all thoroughly hashed a few years ago, sorry if it was mentioned here already.

Check out post #40 here. do I need to hone this? Then go to the last page for more info than necessary.

[wjdunham]

I used the JE ringset that came with my pistons. Seems that this issue is quite dependent on the ring materials/manufacturer. Most of the discussion is around the Goetz rings, haven't seen any comments on JE. Anyone have any experience good or bad with the JE rings?

[Trackrash]

Originally Posted by wjdunham

I used the JE ringset that came with my pistons. Seems that this issue is quite dependent on the ring materials/manufacturer. Most of the discussion is around the Goetz rings, haven't seen any comments on JE. Anyone have any experience good or bad with the JE rings?

FWIW. I used new JE pistons with the supplied Goetz rings in my old Mahle cylinders. SC motor, unknown miles, and I used the scotch brite method to deglaze the cylinders. They were in spec so not refinished. Seemed to take for ever, maybe 700 miles to fully seat the rings, but it seems fine now. Believe me I did not baby the motor. The first drive was a spirited 70 mile drive with the local club, then several autocrosses, plus a track day. I was concerned at first since there was smoke coming from the oil tank when warmed at idle. I now have around 6K miles on the motor and it runs great. I wasn't paying close attention to oil consumption on my last oil change, but probably less than a quart per 1000 miles. Plugs are not showing any oil. No smoke on startup.
Cylinder before scotch brite.

[Marwil]

Bringing this up again regarding the possibility of "cleaning" new cylinders in the manner of red scotchbirite but using 1000 grit or finer diamond lapping film as described below.

Thoughts please - possible or just nucking futs?

The next question should be is there a possible way of creating a plateau without excessively abrading the Nikasil finish? Is there a home honing method? Woodworking tool supply companies sell diamond surface sandpaper in extremely fine grain size. Lee Valley has diamond lapping film 15 micron (1000x) grain size and finer in 3"x 6" sheets; the finest sheets are 3, 0.5 and 0.1 microns. Could these be used in the manner that red scotchbrite is used for deglazing used cylinders? I am not an engineer and am asking out of pure curiosity as to whether this is a viable method or not. The core issue for excessive ring wear based on my reading on the matter appears to be the initial Ra and specifically the roughness of the peaks on the plateau portion of the honed finish.

[wjdunham]

Quick update on this thread now that I have the motor seemingly broken in. I've been using Lucas 20W50 break in oil, 20 minutes at 2000 RPM (changed oil), 50 miles somewhat spirited shakedown driving (changed oil), 375 miles so far of more spirited driving, lots of hills to get engine braking from 5000RPM down to 1500 etc...

No smoke at startup or under any driving conditions, no signs of oil in the plugs, no noticeable oil consumption and the butt-dyno indicates that the engine is pulling as I would expect up to 6000 RPM. I pulled the #2 plug today and ran a leakdown test, which showed a 2.5% leakdown (I think the actual is better since I don't think I the insert was fully sealed and I could hear a bit of air coming from the spark plug hole). All of the plugs looked exactly the same with no oil residue or signs/smell of fuel so I didn't bother to run the leakdown on all six cylinders. I'll probably get to that on the next oil change when I adjust the valves.



So the moral of the story is, at least in my case, looks like my rings have seated fine and the engine is performing as it should. The only long term issue could be excessive ring wear which would not show up for quite some time, but based on the early results I don't think I'll loose any sleep over it.

[colingreene]

interesting that this thread should come up now.

I just tore down my motor for using excessive oil. I had EBS re plate and provide me rings.
They did sell me the a single piece cast iron oil ring, later when I brought my concerns to EBS about the smoking and oil use they said "you should not have that" as a ring.
Ill have to call them tomorrow and see what happens.
I suppose at this point having been run a bit the RA will be impossible to determine.
That being said while it consumed tons of oil the leak down numbers did test very good.

[Dpmulvan]

Originally Posted by colingreene

interesting that this thread should come up now.

I just tore down my motor for using excessive oil. I had EBS re plate and provide me rings.
They did sell me the a single piece cast iron oil ring, later when I brought my concerns to EBS about the smoking and oil use they said "you should not have that" as a ring.
Ill have to call them tomorrow and see what happens.
I suppose at this point having been run a bit the RA will be impossible to determine.
That being said while it consumed tons of oil the leak down numbers did test very good.

You’ll be able to measure RA.

[stownsen914]

One piece of advice faapgar (RIP) gave me - clean the living crap out of the cylinders after they've been honed, to make double sure all the debris and sanding grit is out or the rings will not seat. Makes sense to me. He recommended putting the cylinders in an oven to like 250 degrees, and then rub with a rag and some solvent until it comes off clean. Took my probably 10-15 minutes of wiping per cylinder until no more residue comes off in the rag / paper towel.

Anyone else do this?

[reclino]

Yes, I did this hot cleaning with clean white rags and ATF. First @150 deg F then 200deg F then 250 F. Double layer of nitrile gloves reduced the burning to my hands. Even new Mahle motorsports cylinders were not clean enough.

[RSstop]

Faapgar is right.
As a kid reading Hod Rod magazines, I remember those builders were meticulous in cleaning their bores.
They used soap and water as the final step.
I use multi stages.
Brake clean solvent, ATF and acetone, then really hot water and Dove dish detergent scrubbing in a 5 gallon bucket. Really hot as reclino says.
Plateau honing creates a flat cap to the surface. The hone grove below needs to be open and hold oil for break in.

[mikedsilva]

Originally Posted by stownsen914

One piece of advice faapgar (RIP) gave me - clean the living crap out of the cylinders after they've been honed, to make double sure all the debris and sanding grit is out or the rings will not seat. Makes sense to me. He recommended putting the cylinders in an oven to like 250 degrees, and then rub with a rag and some solvent until it comes off clean. Took my probably 10-15 minutes of wiping per cylinder until no more residue comes off in the rag / paper towel.

Anyone else do this?

yep.
Just installed a brand new set of Mahle cylinders and pistons.
It took many passes of solvent and lint free towels to get all the residue out of the cylinders. The first pass, the rag came out nearly black.

[trond]

i had horrible experiences with plated cylinders from both EBS/Millenium and US Chrome. Had my set in cylinders in twice to rectify and paid more than a new set. + time and cost for 2 needless rebuilds. Final result after the struggle is 5 cylinders are OK wrt surface roughness and 1 is a loss with porosities. Take extreme care

[Jeff Alton]

We had a similar experience years ago, 10 years or so. Pulled apart a 3.4 (98mm) build 3 times. It was in otherwise stock 72 911. Very cool car. Sent cylinders back twice, and to hedge our bets the last time installed total seal gapless rings. All worked out, learned a very expensive lesson. We were dealing with the businesses mentioned in this thread as well....

That said, since then, we have had good success with other bored and plated cylinders. At the end of the day, the onus is on the engine builder (us in this case) to ensure that the parts we are installing meet OUR specs. We did not do that and relied on the reputation of others, which was a massive mistake. A mistake we have never made since....

We learn and grow.

Cheers