Sorry to hear the bad news, but i guess any excuse for a displacement increase is a good one. Cant wait to hear how the a15 wil go! good luck

thanks for your condolences fellas, made me shed a tear ;)

interesting yours benny, my piston i think will look similar. It has scored the bore up towards the firewall end, bottom end is still together been flat out this weekend. here are some pics. i'm going to get the injectors flowed and tested but i suspect it was a bit too much timing for the old girl.

interested to know if anyone can read anything out of the colour of the valves. There is a big carbon buildup on the pistons which can't have helped and heaps of carbon on the back of the valves.










pic of the manifolds installed, no relevance to buggered engine, just looks cool :)

a little too much comp perhaps?? there heaps milled off that head...

Is it possible for inj to be blocked or not firing as it should?
It wouldnt help with heaps of comp either, not to mention fuel quality.

I milled 80 thou (2mm) off the head a while ago, seems to be the same amount that BigE milled off my super duper head, so i'm assuming its not too bad. not sure on comp tho.

pulled the bottom end apart and found that both piston 3 AND 4 had the marks similar to the pic that benny posted on the previous page.
the scraping damage is up the inside of each piston as in the bit that faces the other so the thin part of the bore. why would it do it on this side only? no pinging evidence on no. 4 piston.

will take bits to cylinder head guy to get checked over tomorrow hopefully

Exhaust valves look to of got quite hot, thats why the damage would be on the rear of the piston, I would put it down to timing over advanceing.
How do you alter your advance, through distributor or computer? I know that about 36 degrees is that max total spark you'd want to run in any datsun motor regardless of compression fuel or initial timing settings.

it runs 34 degrees i think (will check) at certain points, i will definately take a touch out. It is all in the ECU so that is easy enough.

Its the inlet valve side of both piston 3 and 4 that has the scraping marks up the sides. they are rooted!

Could dust accumulation around firewall on the last 2 cylinder area
at high rpm caused severe sand blasting and friction melt?
Thats if you had no filtration of course.

If you had $700 from an uncles engagement present you could go full offset
81mm sleeves, stock 4age or 7afe pistons 81x77 = 1587cc better freeway revs
than 82mm stroke.

thats crazy mans talk. plus machining, pistons, rods etc etc would surely be more than that. it'd cost me $300 just to overbore it by 20 thou!

I thought it was but if I supply the pistons (about 180 a set) they do the full sleeving with 83mm sleeves supplied all square to the crankshaft and honed for $500 at footscray engine reconditioning.
http://www.ferco.com.au/
I just checked again on the phone & will do it with 81mm sleeves supplied for $300 !!!!
Quoted from Steve for an a10, a12 or any a series with either 79,80 or 81mm sleeves.
He can work out the offset required with sonic testing and if grouting is needed he will have to send it out as they dont do it in house but he said he can sonic tested for free to check all tolerances which is more than fair.
I was interested in taking my a10 to 79mm using 1mm oversized mazda PISTON ASSEMBLY KIT 4KRY8041(1) 31.40 c-c and 20.000 pins but need Hayabusa standard conrods with 20mm G/pins
and a10 length 119.5mm from bike wreckers. They are perhaps a little narrower than A10 rods
which is the issue. big end and small end width 20.975mm and 38mm crankpins.
The other option is 4af or 4afe pistons with 18mm g/pins will fit a10 rod with enlarging.
After talking to my buddy with the idea of boosting an a10 I must admit I love the stock gearing with 59mm stroke it just works.