Hey mate cheers for reply. I currently have a 1298cc 1200 coupe race car i have had for 15 years. in this at the mo is a A12 bored to 1298cc using 4G32 mitsi cordia pistons making it 77 or 77.9 in the bore. To do this you need to have the block sonic tested for any weaknesses as the room between the bores and gallerys is make or brake when started up.Also you will have to take alot of meet out of the piston skirts so they clear the crank, cant remember cam grind and keen to build another. the engine in the car racing at present puts a healthy 128 at the wheels and revs to 9.5rpm

Quote:This is a link to the Tighe Cams site. They have a good chart that could give you a guide to what you are looking for.

Have a cruise around in there & be sure to click on 'Selecting the Correct Camshaft' for a guide on what's good for your application.

Oh, & you can look at the Wade cams chart via here.
Click on 'Popular profiles' in the thin bar across the bottom & navigate your way to the Datsun A series engines.

Quote:
Supercharged A15.

The a12 i had in my 1000 was 1298cc using
Datsun sports option pistons (cast) that was
a 76.85 mm piston & a standard 73 mm stroke.
This was because there was no 3% tolerance at the time, it had to be less than 1301 cc or you were cheating. Now i'd just use 1 mm over a14 pistons & still be legal. It was even worse in class 3 offroad where you couldn't even bore it .5 mm, so they just threw the block away when it was worn. The a15 that was in the sunny sedan has 78.85 mm Cosworth pistons because it was built under the same rules, making it 1598cc. Now for the cam. I used a grind i got from Arthur Jackson, who is now working at Stewart Wilkins Rallying at Windsor. It was a speedway design, had a large range, pulling well from around 3500 to past 8000, & i've still got it in an ammo box in the shed. Well not the original cam but the same grind.It didn't work as well in the A15 that i mention as being 1598 cc, so we swapped it out for an Arthur Johnson grind that the supplier doesn't want to tell me the specs of.
it too pulls from surprsingly low in the rev range. Both businesses (SWR & Arthur Johnson) are in Sydney.
Another engine was the 1298cc engine a friend built for his 1200 coupe (back in about 1989).put about 600k's on the engine driving from Sydney to Goulburn down the Princes Hwy, across to Goulburn, up the old Hume, up the Putty road to Singleton,down the old Pacific Hwy to sydney, in about 8 hrs. Went to a supersprint next weekend, both agreed wouldn't rev it past 7000 until it had freed up a bit.First time off the startline,it's off the end of the 8000 rpm tacho, & never came under that figure. Back to the Pits, ' remember that rev limit' "yeh" 'Forget about it, rev it til she wont stop'"Okay". all it had was a 54/86 & some 40dcoe webers.

Quote:
A 5% allowance in the 1300 class would, presumably, allow an engine with an actual displacement of 1365cc. A standard second oversize A13 bore of 77mm provides a displacement of 1303.85 cc[1304] which is well within the 5% limit, negating the need for the really oddball sizes described below or the need for a specific 1298cc capacity.

I would suggest that for the classes that these two engines [below] ran in, there may have been no additional capacity allowance whatever, which would then justify these bore sizes.

Ferals A13 engine uses a bore size of 76.76mm for a displacement of 1295.7cc [1296] & the pistons are Tomei forgings that were specifically made for this application. Feral link

This is a link to a page on TnPshow's website showing one page of a magazine article on the restored Tomei 1200 Coupe race car. In amongst the Japanese characters, under the heading 'Tuning Data' is the bore & stroke details. This engine used a bore size of 76.85mm for a listed displacement of 1298cc [1298.78 actual, I'd have called it 1299] & again, these would be almost undoubtably Tomei race forgings.

I was looking for confirmation from Jarad of my calcs & some info on what the donor engine was for the pistons, assuming they were sourced from a production engine, or if not, then the true source as I could be interested in something like this myself.
No, Tomei don't offer these pistons anymore.

EDIT
Oops, Jared's engine has not yet been built & I was getting all excited for nothing.
Bummer, I was hoping he knew something that the rest of us had missed in the piston department.
Sorry.

Dodgeman usually there is a 5% over allowance in the rules.

That's cutting it pretty fine to stay under the 1300cc limit.
What bore size do you use to get 1298cc. & what pistons are used?

EDIT
This engine has not yet been built, so the question is irellevant, as is my follow on post. Sorry.

Cheers mate appreciate it. whats in your beast?

Talk to kelford camtech in Christschurch. They have all sorts of different grinds. I'm failry sure they do a pretty nasty grind for the minisprint boys.

has anyone built or have a race prep A12 that is bored out to 1298cc.any specs on good cam grind that will pull hard up to 9500rpm