Head question....

Post by **pfgiz** » Fri Aug 28, 2009 3:06 pm

I've finally managed to get everything together to go the engine swap, 7 days late..!!!!

In preparation I turned my attention to the head that came with the gold seal engine. It’s a CAM 4810 which, after a little digging, I have come to believe is not better or worse than a standard 948 head when matched with a 948 block. What it does give you is unleaded seats.

The issue I have is the valves. The 4810 is missing 5 out of its 8, all of the exhaust and one inlet. Is it possible to swap these with the standard values off of a MOWOG 21055? I’m suspecting not as the mountings are totally different but it’s worth asking… If not where can I get hold of the missing valves? I can use a 1098 head on the new engine for a while but would want to swap over at some point as it’s the head off of one of the Travellers.

All help and comments appreciated as always. I’ll also post pictures of the engine swap as the day progresses tomorrow.

Post by **bmcecosse** » Fri Aug 28, 2009 5:04 pm

If it's a 948 engine then yes - the CAM head is identical - BUT it doesn't have 'unleaded seats' - what it has is stronger exhaust valves better able to resist use with unleaded fuel. Unfortunately - you don't have the special valves! So - you would need to buy vlaves/cotters/caps from say Minispares - and frankly - it's just not worth it! These CAM heads are often given away free (because basically they are useless - as far as improving a Mini goes) - so you would be better to just get another head - and use that one for spare parts/door stop. The 12G202 head from the 1098 engine can be used - and will help with more power - but the compression ratio will be very low (even lower than normal - hard to imagine I know l!!) unless you have it skimmed by say 60 thou. This will also be beneficial when/if you refit it to a 1098 engine - so it's not a backward step.

linearaudio · Post by **linearaudio** » Fri Aug 28, 2009 10:25 pm

Would the 940 head fit on a 948? Surely that would be an easier performance hike than machining at least 60 thou off a less easily found 12g202

Post by **bmcecosse** » Sat Aug 29, 2009 10:39 am

Well - pfqiz says h already has a 202 in stock. But yes - a 940 head will go on nicely, after the exhaust valves have been sunk 40 thou into the head. I know this isn't necessary on all 940 heads - but for safety I have to recommend it! The valves will be quite big for a standard 948 engine, so there may be some slight loss of low-down performance, more than compensated by increases at the top-end! Larger carb and decent inlet manifold highly recommended too - and ideally - camshaft from a 1098 (AEA630) or better still from an MG Metro ! But this is getting way beyond a simple head-swap on a 948!!