Rebore or not

[rodb]

Hi All,
My 56 G11 . I have removed heads and barrels revealing it has had a +0.025 already, i removed the top piston ring and inserted it into the bore approx an inch down and gapped it ).018. Am I correct in thinking the gap should 0.006 and does this mean it needs a rebore.
If so does anyone know a good engineering company they can recommend in the midlands.

rodb

[SPRIDDLER]

The gap according to the workhop manual is Min 0.006" to Max 0.030".

See page 80 here;
http://archives.jampot.dk/book/Workshop ... .NEILL.pdf

If it's not burning oil and it's running O.K. it'll probably see you out.

For future ref this firm, T&L Engineering, Bedford, is familiar with our engines and well respected.

https://vintage-engine.net/

[rodb]

THANKS SPRIDDLER

[1608]

The rings in my G12 have been at +18 thou for ages with no problems. +6 thou is from new or re-bore and even that is a bit tight in my opinion.

[SPRIDDLER]

The rings in my G12 have been at +18 thou for ages with problems. +6 thou is from new or re-bore and even that is a bit tight in my opinion.

Doncha mean without problems, John?

[ajscomboman]

The rings in my G12 have been at +18 thou for ages with problems. +6 thou is from new or re-bore and even that is a bit tight in my opinion.

Doncha mean without problems, John?

No he probably means that the piston gaps and bores are ok but everything else is falling apart!

[SPRIDDLER]

The rings in my G12 have been at +18 thou for ages with problems. +6 thou is from new or re-bore and even that is a bit tight in my opinion.

Doncha mean without problems, John?

No he probably means that the piston gaps and bores are ok but everything else is falling apart!

I doubt it as I'm pretty sure he'd have brought it back to you, Rob.

[ajscomboman]

I doubt it as I'm pretty sure he'd have brought it back to you, Rob.

It would have had to to have been here first for him to bring it back!

[1608]

Ta Nev, duly edited

[g5wqian]

hi rod ;
my 56 ajs mod30 has GPM pistons and i use a .010 - .012" ring gap ..
if you ever use GPM pistons and allow a fair clearance in the bores to stop seizures you may find the new rings are already at quite a wide gap ie .020" , what i have is .040" oversize pistons and i used +.060" rings and then filed them to give me the tighter gap , it has ran fine for over 2000miles now and can rev it freely , flat out whatever i like without issue ..
be carefull filing the rings, best to get a ring filer as opposed to putting them into a vice and risk cracking or breaking them .

ian