A little more progress. I measured the bore gauge at the readings I was seeing. It appears the cylinders are in spec for std bore pistons and measure out to be 3.578-3.580 inches on each in various locations. This in fact is a little under 91mm described. It also seems the manual has the wrong standard dimensions listed at 3.700 inches... That doesn't work out to be 91mm..
So all this to say I'm pretty comfortable getting standard bore pistons now.. I think...
A little more progress. I measured the bore gauge at the readings I was seeing. It appears the cylinders are in spec for std bore pistons and measure out to be 3.578-3.580 inches on each in various locations. This in fact is a little under 91mm described. It also seems the manual has the wrong standard dimensions listed at 3.700 inches... That doesn't work out to be 91mm..
So all this to say I'm pretty comfortable getting standard bore pistons now.. I think...
Yeah. That 3.7008 to 3.7020 bore diameter range for standard pistons is rubbish.
But did you read immediately below that where Toyota says those bores can acceptably wear to more than SIX AND A HALF INCHES in diameter before a recon is necessary!!! (I wish.)
Feet and Inches are ridiculous units of measurement and who-ever wrote the FSM was clearly having conversion difficulties..
Here's that excerpt with the offending dimensions circled:
And here's some better information from the older 2H FSM for the sleeved engine:
But how accurate are your measurements?
Your bores appear to be below minimum spec .... like a brand new engine that is yet to be machined/honed to finished specs
Ya that was my concern as well. I used an industrial bore gauge made specifically for measuring cylinder bores. It was repeatable measurement each time I used it a values were consistent across all cylinders. Crosshatching is still visible in cylinders which I expect indicates minimal wall loss. The bore gauge doesn't have an absolute measurement and the gauge itself must be measured. I used an 3-4" micrometer borrowed again from an industrial tool crib. Any error's I expect are my fault. I feel I'm within 0-.002" though on my measurements. As mentioned it was repeatable and I felt good about the readings.
I still think things are looking good. It just a big investment to get pistons and rings if they end up not fitting. Also a big investment to get the bores machined out to accept larger ones though too...
it never did. I ended up picking up a troopy and went for a power plant more modern and mod firendly in a 1hdt. I always like the 2H but was asking to much of it.
Ah, thanks. I seem to have a intermittent head gasket leak that might be getting worse. Found one source in Australia for a metal head gasket so might get that one.
(I wish.)
