I have access to a a12 engine that has been sitting for a while. I dont know the condition of the motor, but i want to build it to be a road engine, but a quick one.

Plan:
Bore out block to 1400cc
Fit 1400 pistons & rings
Replace head with a14/a15 oval port skimmed & polished
Use original carb from a15 engine or find weber DGV 32/36 or simillar
Change all gaskets with an overhaul gasket set
Renew crank bearings

Is there anything i am missing?

I also want to get extractors for the engine...

Many thanks guys.

Also, how much do you guys reckon i should spend on this lot? I also have to buy the engine.

You cannot increase an A12 to 1400cc by boring the block.

If you fit the A14 crankshaft, along with the increased bore, you can make a 1.4 liter (1397cc, just like A14). The crankshaft needs to be machined, counterweights made smaller to fit in the A12 block, then rebalanced.

You can fit A14 bore-diameter pistons in an A12, but the block probably needs to be offset bore, with sonic testing done to tell the machinest exactly where to bore it. This is because the A12 was not designed for such a large diameter piston and has barely enough cylinder wall to do it.

and a14 pistons(1400)wont fit on the standard a12 rods

When you suggest an offset bore, what then has to be done to get the rods sitting straight and square?

Machine the crank? what about your bearings etc?

I'd think the A12 would handle the over-bore to suit 76mm, perhaps test the wall thickness first?

The A14 pistons would go on the A12 rods, you'd just have to increase the gudgeon pin hole on the conrod to suit. No?

I'm not sure on the A14 piston compression height either as the piston crown may need so much machining that the crown thickness become too thin (risky!).

The piston skirt may also need to be reduced as it may foul with the crank (with the short rods).

Well then, i think i will scrap that idea! too much work right now. I need something that can be done in a couple of days but that will give my datto a lil more vip but still retain reliability & fuel consumption.

Perhaps i should just take my own engine out,
-get the bores checked for wear,
-replace rings if necessary,
-get the cam ground so it's a road-race cam,
-skim & port the head? or look for a a14/a15 head?
-find bigger carb (weber 32/36 or similar)
-overhaul gasket set &
-check oil, water pumps,
-re-brush alternator & starter....

What'ya reckon?

A12 rarely needs boring. And you can tell if the rings need replacin by running a compression test and see if it smokes.

Probably does not tearing down, unless is smokes while driving. Usually just needs the valve guides replace (sympton: smoke after starting).