Hi.
Rebuilding a Grey motor and have been quoted $700-900 for a set of 3.125 pistons.
Any know of alternative pistons that can be fitted or have a few 3.125 or bigger piston that they would sell.
I know it would be more sensible to change to a Red!
Any ideas greatly appreciated.
Nick
Piston Alternatives
-
mrs ratbox
From what I recall , from memory, 149 cubes or thereabouts is about the limit for grey's and again , from memory this equates to about 100 thou ( maybe 120 thou ?? ) oversize ( without actually sitting down with a calculator and working out the cylinder volume ).
I'm not an engine machinist but 161 pistons in a grey would probably only be possible with cylinder sleeves , and probably only with a wet cylinder sleeve I'm guessing.
Can you remember rat whether the cylinders were sleeved at all??
I know a 149 red can go to at least 40 thou oversize 161 rebore ( I am running one ) but I'm pretty sure a grey wouldn't go that far on existing bores without sleeving.
Happy to be corrected on my thoughts if they are wrong
In the meantime, I'll fish out my 138 engine specs manual and have a captain cook.
I'm not an engine machinist but 161 pistons in a grey would probably only be possible with cylinder sleeves , and probably only with a wet cylinder sleeve I'm guessing.
Can you remember rat whether the cylinders were sleeved at all??
I know a 149 red can go to at least 40 thou oversize 161 rebore ( I am running one ) but I'm pretty sure a grey wouldn't go that far on existing bores without sleeving.
Happy to be corrected on my thoughts if they are wrong
In the meantime, I'll fish out my 138 engine specs manual and have a captain cook.
I can't think what to write here so this will do.
-
mrs ratbox
it had split bores 
it had me stumped i only got the 161 piston thing from a mates dad had and still has an FJ who was into the hot grey thing "back in the day" split bores but pistons marked std 
then he told me it was something that was done, so maybe he was wrong or confused, but he did say the engines were hit and miss and split bores were very common
it had me stumped i only got the 161 piston thing from a mates dad had and still has an FJ who was into the hot grey thing "back in the day" split bores but pistons marked std then he told me it was something that was done, so maybe he was wrong or confused, but he did say the engines were hit and miss and split bores were very commonThe bores were probably split because it was machined beyond what the bores could take with the stresses that are found on a running engine.When blocks are cast it nearly is always the case that one area of the bore sleeve is thinner than the other area due to casting core shift etc.
Nowdays there are ways of testing electronically how much metal is left in a bore but back in the old days before all this test equipment it was really hit or miss stuff as the old bloke Rat was talking about had said.
A block was machined to a large oversize, if it showed signs of being too thin after boring it was thrown and a new one found, with same procedure done until one was found that would survive the larger rebore and again, as has been mentioned , it was found that the EJ blocks were the best for this.
In those days, grey motors were everywhere.
Nick,
I've got a feeling that I saw a few years ago on the JP Pistons site that they had some 3.250 pistons for a grey which equates approx to about 149 cubes but they aren't, or weren't, cheap.
Nowdays there are ways of testing electronically how much metal is left in a bore but back in the old days before all this test equipment it was really hit or miss stuff as the old bloke Rat was talking about had said.
A block was machined to a large oversize, if it showed signs of being too thin after boring it was thrown and a new one found, with same procedure done until one was found that would survive the larger rebore and again, as has been mentioned , it was found that the EJ blocks were the best for this.
In those days, grey motors were everywhere.
Nick,
I've got a feeling that I saw a few years ago on the JP Pistons site that they had some 3.250 pistons for a grey which equates approx to about 149 cubes but they aren't, or weren't, cheap.
I can't think what to write here so this will do.