Cylinder leakdown higher after engine rebuild?

[Slideways]

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.

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/

[Chanman1029]

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.

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.

[digger]

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.

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.

[Chanman1029]

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 lottery

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.

[digger]

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 lottery

[Chanman1029]

I want to see if I can boroscope mine soon. Just rebuilt and did a hard breakin on conventional 5-40.
Not a master at this but I have heard not to use high zinc or anything like that and hopefully you weren't spending too much time at the same/low rpms. Are you getting driveability problems?

No driveability whatsoever, feels just as it should. And no, it was varied rpm, I’m made it a point to not stay in the same rpm for long periods of time, maybe just a few times on the highway for maybe 5-6 miles, but even then I changed it up periodically.

[Icecream]

Used 15w-50 conventional break in oil, with zinc. This oil was Langs, recommendation.

I did the first start up, let it idle to operating temp. Shut down, let it cool completely, then drove 1139 miles, never went above 4k rpm, and never gave it any considerable throttle until probably 500-600 miles in. At no point during the break in did I drive it hard.

I want to see if I can boroscope mine soon. Just rebuilt and did a hard breakin on conventional 5-40.
Not a master at this but I have heard not to use high zinc or anything like that and hopefully you weren't spending too much time at the same/low rpms. Are you getting driveability problems?

[Chanman1029]

How did you break in the engine?

Used 15w-50 conventional break in oil, with zinc. This oil was Langs, recommendation.

I did the first start up, let it idle to operating temp. Shut down, let it cool completely, then drove 1139 miles, never went above 4k rpm, and never gave it any considerable throttle until probably 500-600 miles in. At no point during the break in did I drive it hard.

[Icecream]

Just got the bore scope, I’m seeing some things, and what I’m seeing definitely doesn’t seem normal…

I will post pictures soon once I go to the store to get an SD card for the bore scope.

How did you break in the engine?

[Chanman1029]

Yeah, you might want to have Lang take a look at those pictures. There are a few S54 disassembly videos on youtube that show a stock used block. On those engines, there are some small wear marks towards the top of the cylinders, but no vertical marks like the ones in your pictures.

Skip to 58:00

I agree, I think he should see these, however I just kinda want to have idea first of what I’m actually looking at.

this is my first time ever really inspecting a cylinder wall, and although these marks do look abnormal, I just simply am not educated enough to know if they are acceptable or not. The corrosion is pretty much not ok with me. But as far as those wide dark marks go, I just dont know if those are some normal operations or not.

[Slideways]

Yeah, you might want to have Lang take a look at those pictures. There are a few S54 disassembly videos on youtube that show a stock used block. On those engines, there are some small wear marks towards the top of the cylinders, but no vertical marks like the ones in your pictures.

Skip to 58:00

[Chanman1029]

Ok, here it is. All the pictures are labeled which cylinder they belong to. Cylinders 1,4,5, and 6 all seem to have these wide dark spots of marking, while the other cylinders have small vertical scratch like markings. It is hard for me to tell whether those vertical markings are normal, or if they are problems during ring assembly.

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.

George Hill what do you think about these marks? mind shedding some light on if this is acceptable work by lang?

EDIT: looks like the file names didnt upload:

Cylinder 1: pics 1-3
Cylinder 2: pics 4-5
Cylinder 3: pics 6-7
Cylinder 4: pics 8-10
Cylinder 5: pics 11-15
Cylinder 6: pics 16-21

[Chanman1029]

Just got the bore scope, I’m seeing some things, and what I’m seeing definitely doesn’t seem normal…

I will post pictures soon once I go to the store to get an SD card for the bore scope.

[heinzboehmer]

Thanks for that info, I do have a question about it though bc I’m confused.

According to that spec sheet, there is a .035 difference from piston size to bore under stock conditions. currently my bore was honed to 87.25 and used CP pistons of same diameter. If there is a .0035 gap clearance now, wouldnt that mean my tolerance is tighter than before?

I’m not sure of the actual measurement my bore came out to be, however I will reach out to see if I can get that.

mm vs inches

[Chanman1029]

Yeah forged pistons need to have bigger tolerances simply for the expansion so I guess stock tolerances aren't that relevant in that case. Specs could help someone else though.

Found the specs

Thanks for that info, I do have a question about it though bc I’m confused.

According to that spec sheet, there is a .035 difference from piston size to bore under stock conditions. currently my bore was honed to 87.25 and used CP pistons of same diameter. If there is a .0035 gap clearance now, wouldnt that mean my tolerance is tighter than before?

I’m not sure of the actual measurement my bore came out to be, however I will reach out to see if I can get that.