Jeez, I wanna see the A12 with 142hp at the wheels....
Not that i'm saying it cant be done or anything ;)

11.5, 12.5 ... some drag racing engines use 14:1 compression. Not sure if that could be used on a daily driver or not.

It

14:1 would be O.K. with methanol injection. But not much else

yer,it's an a14 i picked up for $50 bucks without a crank,& i used the old crank from my business partners a15,leftover when we rebuilt that.the compression really is way too much for the street,but as i was building the engine to put in the 1000 coupe in my avatar purely to sell it off,it was basically a throw together,not even balanced.i then threw the engine into my sunny van to run it in,& in the meantime sold the 1000 as a rolling shell.so,1 a14/15 engine,no car,what do i do.buy a sunny sedan & fit it.it pings mercilessly on 98 octane unleaded,i use a bottle of wynns race boast with each tank,& only when it's got proper 100 octane can i use full throttle.(stop complaining,you love it). it had the speedo needle off the end through the chase at bathurst during the speed weekend last december,flat in 4th,no lifting.i was beaten by a very quick cooper s,however,as it was quicker in a straight line.

Choosing cams is a bit like choosing your wife. When you fit it you have to live with it or go through a messy process to get rid of it.

From the info you sent me, I would choose something with around 304 to 308 degrees nominal duration (around 250 degrees @ 0.050" lift). Depends on what cam grinders you have access to.

How far do you want to go with pistons?
The easiest pistons would be 77 mm flat tops with 33mm compression height. 1.2, 1.2, 2.8 mm rings. You will need flycuts for valve relief for any decent cam.

That head is impressive, good flow and swirl as well. Having slightly smaller valves can help breathing as there is less shrouding at low lift.

I can send you copies of the dyno sheets if you like ........ plus the engine specs, so you can see how we've got 142hp at the wheels from a A12A

Heyaz

Correct my if im wrong but isnt the A14 and A15 conrods the same unit. The only difference being stroke and piston height?

My A14 was built by Jeff Taylor and is a real screamer. Has around 150hp and hits power round 4500rpm. Still work in progress but...

I've just realized, my 1200 has been off the road for 3 years.. Its about time i get off my arse and get it engineered.. You Sydney guys will love this thing. I'll take it to eastern creek as soon as its regoed..

Scott
Davo

Quote:


Yes you are correct. The only difference between A14 and A15 ( besides bore and pistons) is the stroke in the crank. 5mm from memory. The rods or interchangable.

Cheers

Errol if the info you just posted is about my engine.....thanks.
Wanna sell me some pistons and a cam ???
Bear in mind I have 20mm gudgeon now as I modded it to suit the mazda pistons I have (flat tops- 0 deck height) . No valve reliefs in them either and they are std cast ones.
I guess I could go back to 19mm pins but I'd need another set of rods which I don't have any lying about. Should I stick with the 12.9:1 compression ?
Wanna sell me some pistons/cam/rods ????Did you find a local guy here who's trustworth enough to fit it all up for me. I now have an adjustable cam gear thanks to 1200rallycar.

Appreciate your reply.