Hi I was just wondering if I used an a15 head on an a12 engine apart from the inlet manifold would I need to change anything else?

Could I use an a12 carb on the a15 inlet?

I have blown a head gasket and will be building up an a15 in the next few months anyway so I thought it best to service the a15 head rather than the a12..

To use A14/A15 head on A12:

A12 type
* if fitting to an old-style A12 block (1970-1973), create the oil passage needed for the head
* if fitting to a new-style A12 block (1974-1994) it simply bolts on

Exhaust pipe
* A14/A15 uses 3-bolt exhaust flange. Most A12s use 2-bolt pipe

Manifolds
* A14/A15 head might be round-point, or oval port. Get matching manifold set
* Head might use water-cooled manifold, so get matching manifold set
* use matching intake & exhaust manifolds. Divorced exhaust manifold won't fit Heat-riser type intake, and vice versa. So get a matched set

Chamber Type
* Some A14/A15 have a quench head, meant to be used with offset-dish pistons
* Late A15 (some 1982-up) have a large chamber head 35cc compare to typical 31cc of early heads. This is enough to cause a small loss of power unless fitted with small-dish pistons

Thanks as always DD

Quote:Yes. A12 carb on A12 engine is ideal. On a A15 because it is a smaller carburetor (venturis of 20/26 instead of 23/27) it means HP would be down. You can also run A15 carb on A12, but A15 carbs are jetted leaner (if the engine is adjusted spot on it will be OK)


Quote:Why service the head? Just check it for flatness use a straightedge and feeler gauge. No need to service the head unless it's severely warped. By using the A12 head again, your A15 parts are available for assembly, and you won't have to take your car off the road again to get the A15 ready

To prevent head gasket failures:
* clean head and block surfaces fastidiously, removing all gasket traces and all oil
* Clean head bolt holes DO NOT OIL
* Torque to spec in 2 stages and in correct pattern as per the service manual
* Retorque every 24 months/24 thousand miles

Thanks again DD! I love this place I always learn more every time im on here