hey grease monkey I've got a set of 12-1 pistons and a single side druaght Dell Orto I'll sell you cheap for your A12.

OK for street use you have a few issues: pump gas , the brake master cylinder is in the way of dual side draughts , if you use GX carbset up (SU's) you need the remote master cyl reservoirs of a FWD A-series car so that you'll have air filters.

Best bet is to go for an A-14 or 15 put in a moderate cam (something between GX and Race) 32/36 weber , header , 2 inch exhaust , clean up the ports , dual valve springs and some bigger valves..........you need a broad power band because the stock gearbox drop 2800 rpms between gears. Should get you to the 100-110 HP range

Just a note on full race A series , they do nothing below about 5000 RPM's have 14-1 compresion and get rebuilt abut ever 6 hrs of running.



Tom

I was wondering about my intake since I have a dual SU set up already I have the remote resevoirs already installed, aand I have what I believe is maybe a GX exhaust manifold also??

Rallytwit what are looking to get for the parts?

AS far as stroking the A-15 I was wondering with the right rods and pistons can you get any more

or how far can you over bore teh A-15

My general thoughts on this...

Use the A-15 block and an A-14 head for a nice street motor. If you have the dual SU setup allready, use them.

The A-15 heads are not very good. Half the intake port is closed off trying to make a swirl port. Don't breathe worth a crap at the higher end of the rev range...

Are your SU's the early round top type or the later models. the early carbs cold start enrichment is by moving the jet seat down. The later carbs have a choke plate in front of the carbs.

On the 2 A-15 street motors I built many years ago the cams were 260 duration, 420 lift. Good midrange torque and very nice on the street.

With the remote mount brake reservoirs you will have room for air cleaners, but it will take some futzing around to come up with something that works.

Hope this helps

Gary

P.S. Where is your shop? I'd like to come take a look...

Quote:

The only problem is the SU set up is for the A-12,

My Shop is located on Hwy 99 in Hazel Dell next to Kline Line Pond, used to be Garys brakes and alingment,

were not actually opened yet none of my stuff is there yet still worknig the other job as a heavy equipment mechanic, havent told them yet,

we will be open sometime around the middle of next month

we have another guy renting space he is a body guy

Hmm...

Are the ports on the intake manifold round or oval? I've never seen a dual SU manifold for round port 1200 heads.

Another option would be use a 1200 head to match your manifold (assuming round port) and doing a mild porting job to clean up the head and manifold. Would not give as much peak horsepower as a larger port engine but should have a broad power band and be nice to drive.

I know exactly where your shop is... I used to go to "Gary's" right after he opened up the shop back in the late '70's. My parents still live close to there. I'll stop by after you guys get settled in.

Gary

Quote:The standard overbore sizes for the A15 are 76.5mm, 77mm, & 77.5mm, but by using the right Mazda pistons you can get it out to 79mm. Offset boring is recomended at that size to try to maximise the gasket surface between the end pairs of cylinders.

As for stroking, ... when the A14 was stroked out to 82mm by the factory in order to make the A15, it became necessary to dimple the oil pan outward on one side to give the crank & rods some swingin' room. I would have a good look at the amount of clearance in the crankcase to see if it's worth it.

You could offset grind the crank down to the maximum undersize of 1mm [0.040"] in order to gain 1mm more stroke with stock parts. You would need to machine a nominal .5mm from the top of the piston to make it work.

With a bore of 79mm & a stroke of 83mm the engine will displace 1627cc

I havent pulled the intake from the A-12 it still is a runner, but I guess I shuld to see if I can use it.

I guess I need to get the A-15 and go from there

Greasemonkey.....$200 for the lot.

I after much heming and hawing I deicied to stay with the A12 for orignality sakes as that matters for vintage racing.

For street use of course things are wide open.

Tom

do you have any pics Rallytwit?