Piston movement in cylinder (engine building)

[Donny_Dog]

Generic french tin rebuild advice required.
Below is cylinder 1 of my forged TUJ4 engine.
I get acceptable movement north to south with the piston, yet east to west is very difficult, if any movement at all. All the others pistons are fine.
The gap to the cylinder wall on one side is smaller than the other and I suspect it is a slightly un-straight little end bush. This appears to then 'favour' the piston in a very slight direction to the west (looking top down).
I believe forged pistons require a bit of expansion room over cast pistons, so I'm wondering if this will be OK to run or if anyone has run worse!?
I would hope that it could be a case of just being bed in, but having no experience with bottom ends has made me nervous.

 

[NorthloopCup]

Generic french tin rebuild advice required.
Below is cylinder 1 of my forged TUJ4 engine.
I get acceptable movement north to south with the piston, yet east to west is very difficult, if any movement at all. All the others pistons are fine.
The gap to the cylinder wall on one side is smaller than the other and I suspect it is a slightly un-straight little end bush. This appears to then 'favour' the piston in a very slight direction to the west (looking top down).
I believe forged pistons require a bit of expansion room over cast pistons, so I'm wondering if this will be OK to run or if anyone has run worse!?
I would hope that it could be a case of just being bed in, but having no experience with bottom ends has made me nervous.

Your forged pistons should've come with paperwork stating what bore clearance they need mate. Without that, it's a bit of a guessing game.

 

[Donny_Dog]

Your forged pistons should've come with paperwork stating what bore clearance they need mate. Without that, it's a bit of a guessing game.

They were 2nd hand I'm afraid. But alas, there is information on the Internets. the measurements though, are from the skirt side up. My conundrum is top down which I can't find any info on.

 

[NorthloopCup]

They were 2nd hand I'm afraid. But alas, there is information on the Internets. the measurements though, are from the skirt side up. My conundrum is top down which I can't find any info on.

Oh I see what you're saying now! The piston is slightly lower on the west side (aiiiiiiiiii) in relation to the bore. I'm afraid you need to find the cause and rectify the problem mate. The thrust loading will be all wrong and it'll wear the bore out.

Have you tried the piston on other rods?

 

[Donny_Dog]

Oh I see what you're saying now! The piston is slightly lower on the west side (aiiiiiiiiii) in relation to the bore. I'm afraid you need to find the cause and rectify the problem mate. The thrust loading will be all wrong and it'll wear the bore out.

Have you tried the piston on other rods?

No, just put it back together last night and noticed this on cylinder 1.
I had the little ends machined to fit this size gudgeon so I reckon it hasn't been machined level or something.
Balls.

 

[NorthloopCup]

No, just put it back together last night and noticed this on cylinder 1.
I had the little ends machined to fit this size gudgeon so I reckon it hasn't been machined level or something.
Balls.

Ah right ok. Yeah that sounds like it's been machined on the piss then bud

 

[Scrooge]

Well that sucks!