Porting AJP8

[tofts]

Looking at the heads, there isn't really a lot of scope for massive gains. I mean, they are fairly good, so my plans were to smooth off and nasty bits and make it look pretty and lovely.

Well yes, but in all seriousness, my thoughts were to polish the long radius (top) and side walls, keeping the short radius (floor) rough (ish) to promote turbulence through. There is no where to take any serious amounts of metal out that would hurt the head, there's nothing you can do about the sharp 90 degree exhaust outlet that wouldn't hurt the area behind the seat.

Also, then sort out the step inside the butterflies that would be good to sort smooth out, but apart from that, I see no way of getting anything out of it that would hurt it.

I think thats about it really, just need to balance the combustion chambers and then I think we are done.

Thoughts?

[gruffalo]

I believe the heads have almost too much capacity for the engine and so the gas slows a bit in the head so I guess you are correct there is not much to be gained.

[450Nick]

Yeah if you want more bang out of AJP heads you need to ADD material to increase gas velocity - the heads are too big for both the 4.5 & 4.2 engines.

[tofts]

Funny, as there should have been more in that post than there was. Must have been in my head... toooo much going on.

I must have already spent about 12 hours cuting polishing and generally cleaning everything up, even with the light amount that needs to come off. Takes a LOT of time!!

The car will be a 4.7, so I beleive as a rough guide that this should take me close to the optimum for the 4.5l head, in theory.

I think really you have both confirmed what I thought, and just take off all the crap and give it a general polish.

Edited by tofts on Thursday 25th February 11:45