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oversize component code B, so what?

AK47NA

NAXJA Forum User
Location
Drenthe
1994 xj, 2.5 l stick shift 4wd, 220,000 miles. I need advice on the oversize component code B stamped on my engine block on the distributor side. The 1994 FSM says all cylinder bores are .010 inch oversized. Am I correct to assume that if I had the cylinders rebored 0.01 inch over then I have to install .020 over components (e.g. rings and pistons)?

I am here in Holland and would like to be sure before I do something stupid.

Thanks!
 
That's how I would read it. Piston and rings are already .010" (.254mm) oversize. Next step up would be .020" (.508mm).

I would wait for others to respond before buying anything.
 
Thanks, @Saudade. I figured the same but wanted to hear what others think. I'll know more about the condition of the cylinders when I disassemble the engine and will decide what size to go then.
 
You should consider having a machinist take a look at the block before you order pistons and rings. If the cylinders have a lot of wear, it would not be unusual for them to recommend that you go to 0.030 over. I have seen stock blocks that required a 0.040 overbore in order to get the cylinders into usable condition.
 
Yes, a friend is a machinist here, helping me on the side. I just wanted to be sure about the piston and ring sizing because of the component code B stamped on the block. But he will be doing the measurements during the teardown. Thanks.
 
The final reading made by your machinist is the important one. If you were only doing a re-ring or replacing pistons with out major block prep, the .010" over would be important. But, as I said previously, once the block has been prepped for assembly, then the numbers the machinist punched it to are all that matters.
 
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