JCB 3CX 1982

[keven]

Only just joined this site desperately need some advice, so in hope someone can help here goes.
I have a JCB 3CX 1982 it breathes bad, I have rebuilt engines before many years ago but not like this.
I was advised wrongly and told that I could do the piston rings same as any other engine in situ.
So I proceeded, now find the pistons won't come out of the top the big end journal stops on the liner.
Now I don't mind if I have to put in new liners and the pistons and liners come out together
And of course go back together the same way,
However, after taking more advice I find I might still have a problem, because the person giving me advice said he had never done one like that only taken them out of the bottom, engine out.
His concern was that the big end journal might still not pass the cylinder wall, as the liner is very thin.
I thanked him very much for he observation and being truthful, unlike the the person I took notice of in the first place
and had no idea what he was talking about.
So hear I am can the job be done in situ or is it engine out?
Happy Days to all, although I'm not having one at the moment
Keven

[tctractors]

keven, the BMC and the Perkins engine both allow the pistons pinned to the rods to come out through the top of the bore, it might be easier to do with the rod bolts removed but out the top they will come, there is no engine that I know of from the 70's onwards that it is the done or do-able thing to pull the rods and pistons out from under the cylinder??? so whip out the bolts, and clean the carbon ring out of the bore top, then push up the rods using a piece of broom stick or similar, I hope you have better luck getting things back together?????????????

tctractors

p.s. what engine is it BMC 4-98 or Perkins, they still come out easy??

[keven]

Tony, I can't thank you enough your'e the only one that suggested taking out the bolts on the conrod, five other people two of them friends didn't mention them.
The bolts overhang just fractions and stop the piston coming out. Was not aware of that, other engines I've done 40 plus years ago the bolts came out with the conrod. Not easy to see the problem laying on ones back looking up into the engine, even with a torch.
The older I get the stupider I get, why did I not think of that? Then again why did so called mechanic friends I know not ask if I had done that? Well not to worry, thanks to you I can proceed.
Happy Days to you Tony your a diamond Keven