Cylinder leakdown higher after engine rebuild?

[Chanman1029]

If you were running stock pistons before the rebuild and forged CPs post re-build, then there will be increased oil consumption based on tolerances if I recall correctly.

As far as the increased metal I fear you will be chasing your tail for months to come based on your previous post about checking the oil so I don't see a resolution on the horizon, just endless postulating.

Yeah everything was stock prior to the rebuild. Is your comment about the metal just simply because of the amount of metal lingering in the oil will take many oil changes to flush out?

[Arith2]

If you were running stock pistons before the rebuild and forged CPs post re-build, then there will be increased oil consumption based on tolerances if I recall correctly.

As far as the increased metal I fear you will be chasing your tail for months to come based on your previous post about checking the oil so I don't see a resolution on the horizon, just endless postulating.

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

[jet_dogg]

If you were running stock pistons before the rebuild and forged CPs post re-build, then there will be increased oil consumption based on tolerances if I recall correctly.

As far as the increased metal I fear you will be chasing your tail for months to come based on your previous post about checking the oil so I don't see a resolution on the horizon, just endless postulating.

[Arith2]

The bore is 87mm and the stock pistons are 86.965mm. I'm still looking for the spec sheet but I have this so far.

[Chanman1029]

So I spoke with Andrew today, I showed him the my oil analysis reports and told him my numbers from my leakdown test, and this was his response,

“I looked through the results and showed them to our builder as well. He made the same comments I had, 4-6% leakdown is about as good as we ever see. We looked through the build sheet and we did run the piston to wall clearance around .0035". All other clearances on that bottom end really look pretty normal to us. When the oil consumption makes the engine unusable then I would suggest getting concerned, but until then I don't see any reason to be all that concerned on this engine. I do agree that chromium likely comes from the top piston ring, I am not sure that material is anywhere else in the engine.”

I’m not well versed in piston wall clearance, but it .0035 wider than normal and thus the reason for slightly more leakdown?

still doesn’t really answer the question of why I am getting so much metal in my oil. Anyone else have any oil analysis reports from a rebuild who can shed light on their experiences?

[tlow98]

It’s tough. There are a lot of variables. Get the facts, go from there.

[Chanman1029]

You still have some chance. If the cylinder walls are gouged then it’s kinda hard to say it wasn’t the machining. Please keep us posted. Lang seemed to do good work and talked a big game. Let’s hope they back it up.

My observation is the most prevalent BMW shops on FB groups in Houston like to really talk up how awesome they are but really aren’t better than any other shop…just better at separating you from more of your money for little to value in return.

Yeah i will definitely keep you guys posted. I’m not sure if you remember, but I’m the same guy that Lang took in my work, let the engine sit for 2 months while he took in and completed other peoples work, and when he got around to mine it sat at the machinist for nearly 3 months.

I definitely feel like I have somehow gotten all of the 1% of bad work lang does. I read nothing but great things about him, I feel played

[bigjae46]

I 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.

You still have some chance. If the cylinder walls are gouged then it’s kinda hard to say it wasn’t the machining. Please keep us posted. Lang seemed to do good work and talked a big game. Let’s hope they back it up.

My observation is the most prevalent BMW shops on FB groups in Houston like to really talk up how awesome they are but really aren’t better than any other shop…just better at separating you from more of your money for little to value in return.

[Chanman1029]

Zero warranty? Why would you let them touch your engine? Mistakes happen regardless of experience and years in the industry.

bc he doesn’t warranty any work that involves non oem parts. Its all over his website. Pretty sure he will only warranty a stock engine replacement if he’s the one who does it all.

[Chanman1029]

Who assembled the motor? If it wasn’t Lang then Lang will immediately blame the one who assembled the motor, right or wrong.

I 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.

[bigjae46]

Who assembled the motor? If it wasn’t Lang then Lang will immediately blame the one who assembled the motor, right or wrong.

[oceansize]

I highly doubt lang will stand behind any of their work as their website states zero warranty on any work they do.

Zero warranty? Why would you let them touch your engine? Mistakes happen regardless of experience and years in the industry.

[eacmen]

Not yet, I want to confirm if I actually have an issue yet before I bring it to his attention.

The loaner borescope unfortunately was not capable of viewing the cylinder walls, so I got one with a side camera coming from amazon tomorrow.

I'm really nervous of what I'm going to find tbh. The fact that I have more leakdown and more metal in my oil after the 2nd oil change is very concerning. But I guess we'll find out tomorrow

I would say its time to call them.


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[tlow98]

Yeah time call lang

[Chanman1029]

Did you reach out to Lang?


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Not yet, I want to confirm if I actually have an issue yet before I bring it to his attention.

The loaner borescope unfortunately was not capable of viewing the cylinder walls, so I got one with a side camera coming from amazon tomorrow.

I’m really nervous of what I’m going to find tbh. The fact that I have more leakdown and more metal in my oil after the 2nd oil change is very concerning. But I guess we’ll find out tomorrow