8 replies to this topic

[topcat]

Hi, Just about to check the valve clearances, in the Haynes Manual it gives 0.30mm for all engines except 12A and 0.33 to 0.38 for 12A engines.

1. What does 12A mean?

2. I have a 1991 cooper carb. What should the valve clearances be?

Thanks alot.

[dan__wright]

look on the head, it was have a casting number on it, will be a mix of letters and numbers, thats what it refers to.

[The Matt]

I think the 12A was a lower compression engine but not 100% sure. I imagine yours is a 12H but you can tell by looking at the engine number on the front right of the block (alternator end) the 12 means 1275 and is the start of the engine number. There should be a little plate there to help you ID it.

Edited by mini mad me, 30 December 2005 - 10:47 AM.

[The Matt]

but this says it could be a 12A??

engine codes

[Bluemini]

Close them down to 10 thou, gives a little more lift than standard and is perfectly ok to do so before people start saying otherwise.

[topcat]

Cool thanks alot everyone

[The Matt]

Close them down to 10 thou, gives a little more lift than standard and is perfectly ok to do so before people start saying otherwise.

sounds like good advice to me! IIRC Bluemini does have alot of experience with the top ends of A-series engines (lots more than me anyway)! :wink:

[Sprocket]

12A or 12H is the first three digits of the engine number, either stamped into a plate riveted to the front right of the block above the alternator or is laser etched in the same place but on the later blocks.

:nugget:

Edit: Already been posted

Edited by Mini Sprocket, 30 December 2005 - 04:16 PM.

[Sprocket]

Now here's a thought. :smartass:

Exhaust valves by thier nature run hotter than inlet valves and as such will expand that bit more. Has any one thought about setting the inlet valves clearance that little bit less than the exhaust. Might make the engine run that bit quieter rather than make it more powerfull. Duno?? Anyone??? Just a thought??? :fear: