High Compression

[oem]

Is this a feasible option on a M30?

I am thinking of skimming as much as possible of the cyclinder head to make the engine high compression, for more power.

Anyone done this? If so what are the results? Any drawbacks?

Any info would be truly....

[euroshark]

The down sides to milling the head over spec are that you might have valve to piston interference, and by reducing the height of the head you will change the cam timing enough to need an adjustable cam gear. Other than those two problems I can't really see a downside to it...

I'm not sure how much you can actually remove but I doubt it would equate to a huge gain in compression. I'd look into custom pistons if you are looking for 11:1 or higher. If we have enough interest I might be able to arrange a group buy since we work closely with Wiseco.

[pegase747]

Euroshark,

what would be the gain in terms of HP for a 11.1 on an M30 ?

Also what would be the price for a group buy approximately ??

Apart from changing the pistons what should be done together with it to get the improvement ??

pierre

[oem]

So you think this will not work on the M30?

I need to skim the head anyway, thought it might we worth going down the high compression route. :-|

[euroshark]

It can work just fine, I'm just saying that if you mill too much material off you may have adverse consequences. The two biggest issues, as I said, would be valve to piston interference which can be countered with having reliefs cut into the pistons if necessary, and cam timing, which can be countered with an adjustable sprocket that are available from BMP Design and a couple of other places. On a budget this might net you a bit of power, but for the trouble, I'd be more inclined to get a different set of pistons and do it that way.

Look at the manual, they don't recommend milling much.