Top End Ate two cranks.

[afleetcommand]

How could that be? Just speculating.....(maybe a little more than speculation) Had a saw waste a rod bearing. I blamed the crank.....top end survived. Built another bottom end, put the top end from saw wreck one on the second.....wasted that rod bearing in about the same period of time. SO what about a top end can perpetuate the carnage??? Guessing bore alignment. Is that possible? Stuck on an arbor on the lathe seems to support that theory. Around a .010 wobble (side to side, not front to back) measured at the base. Maybe a bit more. Picked up the anomaly first measuring from the flange to the squish band...but figured the combustion chamber could have been out...but the arbor.....a bit annoyed so I'm venting. Wasn't FT BTW. BUT now its out of my life...tossed it in the Town transfer station trash bit....so I would not be tempted to give it a third try with a "trued" up base.

Of course I'm as annoyed at myself....noted there was ever so slightly a binding at BDC..so looked and went through the usual motions but never really figured out what it was on the builds...never dawned on me to check for the top end in that way. Not with those cylinders....maybe on the lower end ones....

 

[BrokenSVT]

Sounds like the belt sander bandit struck?

 

[afleetcommand]

Sounds like the belt sander bandit struck?

Nope...as it came out of its box. No mods. Not even a base gasket delete.

( Do all my cylinder base trimming on a lathe anyway)

 

[MG2186]

What saw/kind of top end

 

[BrokenSVT]

Nope...as it came out of its box. No mods. Not even a base gasket delete.

( Do all my cylinder base trimming on a lathe anyway)

Ahh. So it was the Chinese belt sandal bandit.

 

[TreeLife]

Sounds like the belt sander bandit struck?

Cmon dude, let's be honest...we could blame Brad too lol

 

[stihl livin]

Cmon dude, let's be honest...we could blame Brad too lol

I thought everything was Brad’s fault regardless?

 

[TreeLife]

I thought everything was Brad’s fault regardless?

QTLA

@blsnelling

 

[angelo c]

I thought everything was Brad’s fault regardless?

Yooz guyz is so silly....everything is Trumps fault...

 

[Al Smith]

In reading the opening post are you saying the side to side ,measured using a centering arbor is 10 thou out? If that's the case the cylinder is machined off center .
Due to the fact most if not all modern manufacturing use CNC machinery ,either somebody screwed the program up and this one snuck past the final quality control checks .It happens every so often try as they may to produce good parts .
However if 10 thou out would be enough to trash the big bearing I should think there would be some indication looking at the piston skirt .

 

[Mastermind]

I see OEM jugs out a few thousands all the time. So on an aftermarket jug of any price range, I am not surprised.

 

[afleetcommand]

Didn't eat the skirt. Did "ding" the skirt. wasn't thickness from bore to edge of the flange. It was the literal thickness , "tilting" the cylinder...could see it when the cylinder was on the arbor, first "cut " ( I did trim it true before tossing it along with all the carnage in the trash this weekend....need to clear the shop of that carnage! Really annoyed) dinged one side before working across the bottom...so it was the bore itself at an angle relative to the cases.

( Probably would have been fine if the "rock" was front to back...but side to side loaded the rod bearing.)

I have to say here are plenty of them out there working fine...mine was the exception not the rule. The only reason I brought it up on my channel is I had made the assumption the cranks were suspect in the first blowup...then after hand grenade two realized I needed to first do a little more measuring and second, set straight the perception the crank was at fault in that first one.

 

[RI Chevy]

Damn Russians.

 

[RI Chevy]

What saw/kind of top end

What saw are we talking about here?

 

[Mattyo]

Off center and tilted are two different things. I think Walt is sayin this cylinder was tilted from the factory.

Off center from the bolt pattern is different...and I gotta assume that a little off center isn't a problem. Tilted front to back isn't much of a problem either....side to side...ng.

 

[brandonstclair20]

I have seen weird stuff. I have a new wiesco piston that is out of round. It does makes me very skeptical of the quality of the manufacturer.


Sent from my iPhone using Tapatalk

 

[Cut4fun]

More then a few sneak by. Should see some of the ones that get posted.
I'll go see if I can find past pics of affm crap folks get in their boxes when they arrive for rebuilds.

 

[Cut4fun]

The worst one

 

[Al Smith]

Years ago when I bored out the Mac 125 block to sleeve it it took me two hours to tram in the Bridgeport mill before the bore cut .Not measure twice cut once but rather measure 10 tome before .If the bore is screwed you've lost the race,it's junk after that .

 

[Al Smith]

So in general terms sometimes it causes some alarm if the bore is out of spec and it could be the piston pin is askew on some of this after market stuff .Then again if the crank and pin bearing had some slop it might not have happened .For that matter it might have ran forever until it rattled itself apart .