+80 pistons

[muskrat]

G'day all.
Having a re-think on the Cafe rebuild. The bores will clean up with a +80 bore but I can't find any pistons to suit. Any ideas?
The reason for the re-think is I bought new Hepolite liners but the OD is too small. The barrels had already been linered with an OD much grater than the Heps. I don't think it would be wise to put a liner inside a liner  .
Cheers

[Clive54bsa]

I had an 80 over rebore done by SRM years ago, didn't last too long though.

[Klaus]

The bore for a A10 liner is 73mm.
Or had I misunderstand your writing?
Pistons plus 8 are not common. The only way is to catch AMC pistons for a 650 Matchy only Export may be 1958 or 1959.
I know one version can fit the A10, but the are hard to find.


cheers Klaus

[muskrat]

Thanks Clive & Klaus.
The Hep liners I purchased are 73.1mm OD, it looks like the liners in my barrels are 75mm OD so +80's will work or I get new liners made to fit.
I looked at the re-line route first as I have as nice set of +10, 10.5:1 racing pistons (offset wrist pin) I would like to use but would be happy to use +80's at a lower comp rate If I can find some.
Cheers

[Klaus]

Propper reading is  much importand

With a 75 bore you can use A65 pistons


but the rest of the barrel is verry thin

[muskrat]

That thought did cross my mind Klaus. As you say the skirts of the barrels would be very thin, about 2mm wall thickness and I've seen the damage when a skirt drops.
Cheers

[Klaus]

2mm thickness is enough, but with 75mm bore the compression rise up 11 and more.

[bsa-bill]

but with 75mm bore the compression rise up 11 and more.

took my Flash the liner way back to standard bore, bit more expensive ( to bore twice) but worth it I reckon.

Higher compression = possible pinking sessions, I had a lot of this when I went to higher compression on my RGF, plus abysmal starting/sparks, strangely curing the sparks with Pazon ignition also cured the pre-ignition (maybe better mapping)

[chaterlea25]

Hi All,
Musky,
I remember reading or hearing somewhere or other that Mazda car pistons could be used on a max overbore??

A flleabay search 
http://www.ebay.co.uk/itm/Mazda-323-Familia-1300-from-1971-73-50mm-pistons-rings-Jowett-Jupiter-/252070464190?hash=item3ab0920abe:g:foIAAOxyUylTTSOi


John

[muskrat]

Thanks John. So many possibilities with too many differences. Pin size, crown height etc. Now that I have nice new R&R rods I don't want anything chewing on those.
Cheers 

[Klaus]

Hi Muskart,

AMC No 024034  STD CR 8.5:1   G12 1958 only USA Models

Hepolite 15242

these are the pistons will fit A10 barrels with  +80

good luck to find them.

[Beeza]

Hi Musky, I have heard in my travels that oversize B31 pistons (40 or 60 thou) will get you to 80 over.
Maybe worth investigating, good luck.
Thomas

[trevinoz]

A clever bloke like you could machine a custom set from scratch.

[mikeb]

+.080 JPs? as per this thread: http://www.a7a10.net/forum/index.php?topic=10657.msg79625#msg79625
they do a higher comp set too

[muskrat]

Thanks Mike, I've shot him an email. Fingers crossed.
Cheers