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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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 Posted: Thu Jan 28, 2021 8:36 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| Last thing I ever expected to see added to the catalog, must be an interesting story behind it. |
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Jake Raby
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Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Thu Jan 28, 2021 8:38 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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LN has been supplying Mahle Motorsports with their cylinders for a few years. I have the first 6 cylinder set in my 3.9L 993 engine.
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ekacpuc
Samba Member
Joined: December 08, 2010
Posts: 1414
Location: ketchikan alaska
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| Posted: Thu Jan 28, 2021 9:59 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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Okay I got a question for ya..
Would it be acceptable to just swap out the AA rings for something else (deves, grant whatever) and leave the cylinder finish?
A knucklehead like me can do some damage pretty quick with hone.. I’ve done it on a 350 and sure it “worked” I suppose but I didn’t really care about them.
It’s not much more to go with forged mahle but I was just gonna use the forged AA like I did on last motor BUT now this post has me thinking that might not be the way. I had a rod fail at about 10k miles so I’m starting over.. I did a compression check at around 8k and iirc I was still around 160 PSI on all but.. that’s been awhile now.
Last edited by ekacpuc on Thu Jan 28, 2021 10:04 pm; edited 1 time in total |
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Jake Raby
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Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Thu Jan 28, 2021 10:02 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| ekacpuc wrote: |
Okay I got a question for ya..
Would it be acceptable to just swap out the AA rings for something else (deves, grant whatever) and leave the cylinder finish?
A knucklehead like me can do some damage pretty quick with hone.. I’ve done it on a 350 and sure it “worked” I suppose but I didn’t really care about them. |
You could do whatever you want..
This exact thing is what I spoke about earlier. If the surface finish isn't proper, it WILL kill the rings. Good rings just take longer to die.
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell" |
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ekacpuc
Samba Member
Joined: December 08, 2010
Posts: 1414
Location: ketchikan alaska
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| Posted: Thu Jan 28, 2021 10:06 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| Jake Raby wrote: |
| ekacpuc wrote: |
Okay I got a question for ya..
Would it be acceptable to just swap out the AA rings for something else (deves, grant whatever) and leave the cylinder finish?
A knucklehead like me can do some damage pretty quick with hone.. I’ve done it on a 350 and sure it “worked” I suppose but I didn’t really care about them. |
You could do whatever you want..
This exact thing is what I spoke about earlier. If the surface finish isn't proper, it WILL kill the rings. Good rings just take longer to die. |
Right I saw that mentioned. I don’t remember seeing if the surface finish was wrong along with the poor quality of rings..
Just trying to figure out what I can do. Might just go mahle I suppose if they’re better. I’ll have to look into it.
I have to do all the stuff myself so I tend to buy new (bad case anyways). Just trying to figure out what the acceptable way to deal with AAs is. |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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| Posted: Fri Jan 29, 2021 3:21 am Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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I suppose the issue is, most of us don't have the means or knowledge to make sure we have piston rings and cylinders that are going to play nice for years.
I had some cylinders deglazed years ago and it was pretty clear there were low and high spots, but I had no means to fix it.
Likewise, I buy a new set of cylinders, even if I could check the quality of the hone job along with the hardness, ring tension, material compatibility etc etc, I can't correct any of that.
Leaves you at a loss... £1000 gets a set of wiseco pistons and cylinders from CB. But they're nothing fancy, they just come with the correct hone and rings, what you might be forgiven for expecting anyway!
Luckily, there's another option coming to market soon... but in the mean time. What's the average Joe meant to do?
Have a 280grit flex hone up and down until piston skirt clearance is where we need it. Install a set of grants and hope for the best?
Seems were over flat cam-gate and well into leaky cylinder-gate.
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StefansBus
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Joined: November 20, 2015
Posts: 242
Location: Germany
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| Posted: Fri Jan 29, 2021 1:37 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| UK Luke 72 wrote: |
Luckily, there's another option coming to market soon... |
I might have missed this or forgotten. Luke, could you give a but more detail, please?
Thanks
Stefan |
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Jake Raby
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Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Fri Jan 29, 2021 4:24 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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I hope someone makes something worth a damn!
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell" |
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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Fri Jan 29, 2021 6:34 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| UK Luke 72 wrote: |
I suppose the issue is, most of us don't have the means or knowledge to make sure we have piston rings and cylinders that are going to play nice for years.
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Never stopped you before, I don't see the big deal.
Some things are better, other things are worse, but it was never a golden age.
If you take the BEST of the past, things look pretty good, but there has ALWAYS been crap and problems that need to be fixed and idiots.
The way some talk you'd think pistons made of crumbly aluminum with wide rings was some kind of golden age but that's ridiculous.
Things were pretty good 20 years ago but even then the professional engine builders would be re-honing the cylinders and installing different rings of their choice, and the do-it-yourselfers bought a lot of breather boxes.
THREE generations of motorheads learning how to run iron rings on an iron cylinder and all that is different today is we are slightly better at it than before on all sides... machining metallurgy and lubricants and air filtration, to the point the life of the parts has doubled from what it was in the 70's
It was better in the past... I don't buy it for a minute, and neither should you. just different. |
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KROC
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Joined: February 20, 2006
Posts: 359
Location: Vancouver B.C.
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| Posted: Fri Jan 29, 2021 8:14 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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If you purchase a quality set of rings from a company like total seal, Ask them for the recommended surface finish required. Then take your barrels to a reputable machine shop and have them finish hone to that specification.
Do a decent break in, you will have success without breaking the bank. |
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ekacpuc
Samba Member
Joined: December 08, 2010
Posts: 1414
Location: ketchikan alaska
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| Posted: Fri Jan 29, 2021 8:54 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| KROC wrote: |
If you purchase a quality set of rings from a company like total seal, Ask them for the recommended surface finish required. Then take your barrels to a reputable machine shop and have them finish hone to that specification.
Do a decent break in, you will have success without breaking the bank. |
Sure In a perfect world. Trouble begins when there is no machine shop on a tiny island in southeast Alaska. Once you pay machine shop and super expensive shipping each way AAs don’t make as much sense.
I’m going to just hone them myself. I have a case that is bored for 90.5/92 and plan on using the heads for 94s so going with the thickwalls made for the smaller case. |
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UK Luke 72
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modok
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Posts: 26790
Location: Colorado Springs
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| Posted: Sun Feb 07, 2021 11:44 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| 1.5 x 2 x something |
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UK Luke 72
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Location: Little Britain
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Brian_e
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Joined: July 28, 2009
Posts: 3293
Location: Rapid City, SD
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| Posted: Mon Feb 08, 2021 9:48 am Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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The AA "A" pistons have the thicker 2mm top, and the AA "B" pistons have the thinner 1.5mm top. That is on 92 and 94mm anyways.
Brian
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UK Luke 72
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FreeBug
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Joined: March 12, 2012
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Location: deepest, darkest Switzerland
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| Posted: Tue Feb 09, 2021 3:32 am Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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Several people have asked the same question (and I was about to, too) : what can a caveman who could break a hammer in a sandbox do to better prep his cylinders at home, without access /money to bring it to a shop?
So far from what I've gathered (correctly or incorrectly):
-Use a 280-320 grit dingleberry thingy of proper diameter, to provide a pressure of ?????, and you run it at ????? rpm, and aim for a pitch of ?????. Put diamonds into the equation someplace using ?????, for best results.
And then,
-Use the rings which came with the kit, especially if it's factory Mahle, if you can somehow determine if they are good or not.
-Use Grant rings if you need something operational fast, and believe that ring longevity is the least of a VW engine's long-term wear issues.
-Use Deves if you can prepare the surface better.
-Use Total Seal if you really know what you're doing.
-Use Toyota rings if you can if you're using thick-wall 92s (just something I remembered from another post).
-The best thing you can do to keep a good ring/cylinder relationship going is to filter the intake air as well as you can.
 Of course, this is just to improve the surface finish; the shape of the cylinder you can do nothing about at home, except mock it up and somehow torque it down to operating shape, and check how that measures out, and hope it's better.
-Our cylinders (AA or Mahle?) are somehow harder than your avarage cast iron cylinder?
-Hypereutectic (sp?) pistons are hard, expand less than forged when hot, so can run tighter clearances, which is good for ring seal, but they are more brittle, less strenghth compared to forged. Whill crack and scatter if hit.
Now, by carefully analysing the remarks, corrections, and derisions people make about what I wrote, we might learn what you're really supposed to do.
So I'll affirm that this is all 100% correct, and wait for the truth to come out... |
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ekacpuc
Samba Member
Joined: December 08, 2010
Posts: 1414
Location: ketchikan alaska
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| Posted: Tue Feb 09, 2021 5:36 am Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| FreeBug wrote: |
Several people have asked the same question (and I was about to, too) : what can a caveman who could break a hammer in a sandbox do to better prep his cylinders at home, without access /money to bring it to a shop?
So far from what I've gathered (correctly or incorrectly):
-Use a 280-320 grit dingleberry thingy of proper diameter, to provide a pressure of ?????, and you run it at ????? rpm, and aim for a pitch of ?????. Put diamonds into the equation someplace using ?????, for best results.
And then,
-Use the rings which came with the kit, especially if it's factory Mahle, if you can somehow determine if they are good or not.
-Use Grant rings if you need something operational fast, and believe that ring longevity is the least of a VW engine's long-term wear issues.
-Use Deves if you can prepare the surface better.
-Use Total Seal if you really know what you're doing.
-Use Toyota rings if you can if you're using thick-wall 92s (just something I remembered from another post).
-The best thing you can do to keep a good ring/cylinder relationship going is to filter the intake air as well as you can.
Of course, this is just to improve the surface finish; the shape of the cylinder you can do nothing about at home, except mock it up and somehow torque it down to operating shape, and check how that measures out, and hope it's better.
-Our cylinders (AA or Mahle?) are somehow harder than your avarage cast iron cylinder?
-Hypereutectic (sp?) pistons are hard, expand less than forged when hot, so can run tighter clearances, which is good for ring seal, but they are more brittle, less strenghth compared to forged. Whill crack and scatter if hit.
Now, by carefully analysing the remarks, corrections, and derisions people make about what I wrote, we might learn what you're really supposed to do.
So I'll affirm that this is all 100% correct, and wait for the truth to come out... |
Haha. I tried asking the same...
I would be interested to know the same with a emphasis on if the forged mahle p/c are any better.
I tore apart two motors. One had forged slipper AAs the other cast “hyper” slipper AAs. Both didn’t look like they burned oil. Little carbon up top but not much. One ran a set of IDFs and the other dellortos. I did a compression test on the 94mm forged set and had 160 PSI all around just before I destroyed the motor.
Years ago I took apart a 1776 that ran Kadrons. I didn’t know what I was doing and those clearly burned oil but I think the rings failed due to the MASSIVE unmarked idles the “pre jetted” kits came with and I didn’t know any better.
If mahle isn’t any better my plan is to just put the $78 difference between them and AAs into new rings and I believe I have a 4” 320gr ball hone...
When I was a kid I re-ringed a 350 and a few dirt bikes. All I did was use a hand drill on a slow speed and fed it in and out as quick as I can for 10 secs or so. With a VW my concern would be removing too much material. I figure I have 2 sets of cylinders I can test it out on.
I’ll continue to watch this thread though. I wanna know about mahle along with any input given to what you posted.
Hell worst case cyls are cheap and easy to change I guess. |
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jpaull
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Joined: February 22, 2005
Posts: 3466
Location: Paradise, Ca
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| Posted: Tue Feb 09, 2021 4:51 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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I have a question for Jake Raby or anyone who knows:
How much would a piston/cylinder/ring set cost with the SUMEBore coating applied and proper hone finish? For Type 1 or Type 4 |
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evanfrucht
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Joined: July 24, 2016
Posts: 2180
Location: Laurel Canyon, CA
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| Posted: Tue Feb 09, 2021 9:15 pm Post subject: Re: AA pistons RINGS REALLY BAD caution! |
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| jpaull wrote: |
I have a question for Jake Raby or anyone who knows:
How much would a piston/cylinder/ring set cost with the SUMEBore coating applied and proper hone finish? For Type 1 or Type 4 |
I'd guess about 5 grand if you can even find someone to do 1 set for you. No one makes this or sells them so it would be a custom commission job.
After reading this whole thread I think it makes the most sense to just use the AA things as long as they aren't soft.
If you are using AA pistons and cylinder set you are already a cheapo so why make them a money pit? 
If anything have a machinist with proper honing equipment who you trust and actually knows what they are doing work them out for you. Ideally a machinist who specializes in honing and has done the research first hand. Then pay generously to have a precise job done.
Part of me still thinks that cast iron rings are best for a cast iron bore.
Grant rings may have a place under the right circumstances
I bet there are hundreds of motors out there running the AA sets as supplied with absolutely nothing done/changed on them, possibly not even cleaned, and they broke in fine and are running 160-180 psi right now.
You can only polish turds so far... it eventually becomes a waste of time and money... just spend a grand or two on one of super fancy piston and cylinder sets currently on the market.
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