Originally posted by Icecream
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Cylinder leakdown higher after engine rebuild?
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Do you know the ring material and coatings?
Unfortunately many modern steel rings and coatings need a specific hone to work properly as they are not as forgiving as older school stuff.
If you watch total seal videos on YT they go onto very high levels of detail about what is needed, how to measure it and how to achieve it. The deep valleys in the hone holds oil to stop rings and bores wearing and to seal air. The plateau supports the load and quickens the breakin process.
Many shops are shooting blind by using old school methods (stones, equipment and processes) on modern rings and have no idea whether what they produce is optimum so this is why many aftermarket forged builds have issues.
Im not saying this is the cause here but I like Mahle MS as they do offer a PVD moly ring and the moly is good because it’s porous and retains oil so the valley on the hone is a bit less critical for holding oil.
you should not be rebuilding an s54 without using a torque plate and using a shop that has a profilometer to ensure the hone is good. If you don’t do this it’s a lotteryLast edited by digger; 05-16-2023, 06:10 PM.
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Originally posted by digger View PostDo you know the ring material and coatings?
Unfortunately many modern steel rings and coatings need a specific hone to work properly as they are not as forgiving as older school stuff.
If you watch total seal videos on YT they go onto very high levels of detail about what is needed, how to measure it and how to achieve it. The deep valleys in the hone holds oil to stop rings and bores wearing and to seal air. The plateau supports the load and quickens the breakin process.
Many shops are shooting blind by using old school methods (stones, equipment and processes) on modern rings and have no idea whether what they produce is optimum so this is why many aftermarket forged builds have issues.
Im not saying this is the cause here but I like Mahle MS as they do offer a PVD moly ring and the moly is good because it’s porous and retains oil so the valley on the hone is a bit less critical for holding oil.
you should not be rebuilding an s54 without using a torque plate and using a shop that has a profilometer to ensure the hone is good. If you don’t do this it’s a lottery
I reached out to the front desk at Lang and explained the new information to them that I have. I sent them the pictures but andrew had left for the day so I should be expecting a call in the morning.
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Originally posted by Chanman1029 View Post
Ring material should be chrome, coatings I am unsure. As far as procedures go, im sure lang racing probably uses a torque plate and anything else that is necessary. Its not secret they do great work, but someone went wrong, thats what I’m trying to get to the bottom of.
I reached out to the front desk at Lang and explained the new information to them that I have. I sent them the pictures but andrew had left for the day so I should be expecting a call in the morning.
CP often use gas nitrided steel. You would want the ducks lined up and its not to be assumed they are.
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Originally posted by digger View Post
They will likely be farming machine work out (hopefully) as they cant be near best practice if doing internally based on the services offered being so broad.
CP often use gas nitrided steel. You would want the ducks lined up and its not to be assumed they are.
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Originally posted by Chanman1029 View Post
Ring material should be chrome, coatings I am unsure. As far as procedures go, im sure lang racing probably uses a torque plate and anything else that is necessary. Its not secret they do great work, but someone went wrong, thats what I’m trying to get to the bottom of.
I reached out to the front desk at Lang and explained the new information to them that I have. I sent them the pictures but andrew had left for the day so I should be expecting a call in the morning.
https://store.langracing.com/product...long-block/
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Originally posted by Slideways View Post
They have a detailed description of their Stage 1 engine rebuild - no mention of a torque plate. I wonder how the factory blocks are machined?
https://store.langracing.com/product...long-block/
I know for certain they outsource for that kind of work
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Originally posted by Chanman1029 View Post
When does a torque plate get used? During block machine work?
I know for certain they outsource for that kind of work
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Originally posted by Slideways View Post
Yes, it simulates having the cylinder head torqued down which, in theory, distorts the bores ever so slightly. I would think cast iron does not distort much and BMW didn't do this when machining a new S54 block. The description on the site is pretty detailed, so one would assume they would add that bit about the torque plate.
I’m really hoping for the best here, I really dont want to sink more money into the motor.
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Originally posted by Slideways View Post
Yes, it simulates having the cylinder head torqued down which, in theory, distorts the bores ever so slightly. I would think cast iron does not distort much and BMW didn't do this when machining a new S54 block. The description on the site is pretty detailed, so one would assume they would add that bit about the torque plate.
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Originally posted by digger View Post
Didn’t you see the thread where the German fellow measured this and the bores distorted a lot. Even VAC know this and that says something
I wonder what the procedure is at the factory or is it just a combination of the pistons, rings and hone that get the engines to last 100k+ miles.
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Originally posted by Chanman1029 View PostI assembled it lmao, and that’s exactly what they will say even though he assembled the short block, I only mated the block and head.
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Cylinder 5 is by far the worst, and even has what looks like multiple spots of corrosion on the cylinder wall. This alone was pretty disturbing for me to find.
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Originally posted by sapote View Post
So you didn't look at the newly honed cylinder walls before bolting down the head?2003.5 MT JB/B - CSL SCHRICK SUPERSPRINT EISENMANN JRZ SWIFT MILLWAY APR ENDLESS BBS/SSR DREXLER KMP SACHS RECARO AR SLON MKRS GSP DMG KARBONIUS CP AUTOSOLUTIONS KOYO
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Originally posted by Chanman1029 View Post
Gotcha, my assumption was based on the fact that blackstone said the chrome in the oil was most likely coming from rings, and lang agreed aswell. But tbh I dont know for sure. We will see how our conversation with Lang goes tomorrow.
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Originally posted by sapote View Post
So you didn't look at the newly honed cylinder walls before bolting down the head?
first timers mistakes
I only have a few photos that I took, but I didn’t spin the motor to inspect walls. Looking through my photos and few videos I have, its clear that many of these marks were not there.Last edited by Chanman1029; 05-17-2023, 06:26 AM.
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