I helped Trev fit this (when he was just starting out modding) I think my dub habid rubbed off on him It is actaully farely smooth, from what I can remember and was quite tidy, the picture reflections to make it look more uneven than it really is. The whole thing with a slightly rough surface is due to the boundary layer of the air flow if its dead polished theres less turbulance at the walls which changes the flow and mix of the inlet charge.
How do you know it has been done more than once or too much have you measured it to see if it is within limits ?. Also measuring is a good indication if it has been badly warped beforehand.
have you got a full pic of the machined surface of the head?? in particular in the middle of the head where the inlet manifold fits. part of the casting gives a good idea how much has been skimmed off it
Nah, never measured it or anything. Just going by the comments above. I need to have someone who knows what they are doing to take a look at it. Yeah I think I paid around 180ish for it. There were a lot of people bidding for it at the time a couple of years ago and I had one chap email me several times afterwards *pleading* me to let him have it because he forgot to bid... maybe I should have let him At least I know I'd get money back if I sold it again. Daz - I could certainly take some more pictures tomorrow to show the casting marks better It seemed to go rather well when it was fitted, but without a RR it's hard to know. But if it's not much good then it isn't much lost really. Edited by: Trev16v
Sh11te, my mistake Was looking at the wrong part of the head when i said it had been decked right down. I stand corrected. On the top pick of all, right under the oilo return hole on the front of the head is a step( you can just make it out, and has 2 cast circle in it) If the head has been skimmed dwon to or near here then it'll probably be under the minimum head thickness. Looks like its fine. Sorry to have mis-led everyone. Doh, I'll get my bus pass ready.
Minimum thickness as measured through bolt holes is 118.1mm(4.650") and warpage is 0.1mm(.004") apparently.
If you have a look at the pic there are two dark circles in the middle of the head towards where the inlet manifold fits. Heads can be skimmed down to these marker holes, quite a few manufacturers use this type of marker although VW will state you can take less off. This head was from TSR and had about 4thou taken off to clean the surface after the gasket went, so its probably only had two light skims.
It looks a bit rough to be honest, like the guy's been doing his best with limited tools. I think a satin 'as cast' type finish might be good for a mixing of the charge, but I would think that too much turbulence will just slow it down. The only real way to tell is to try it on a rolling road and see what happens. It's up to you whether you think it's worth the time and gaskets.
pppppsssshhhhhhhhhhhhhhhh aye exactly no like grit blasting, dig up the pics of essthrees head and have a shufty
Don't know Prof - is that like glass bead blasting (sand blasting often being too rough for an ally head) Here's a pic or 2...maybe you can tell. The other things you find with a Bill Blydenstein head is that he focuses on the area very close to the valve seats, and doesn't worry about removing casting marks down the end of the inlet/exhaust ports (I asked him about this, and he was adamant that there's no point on anything other than an ultimate full race setup - said the same about polishing 'only for F1 cars') So it's got multi angled valve seats, widened the valve throat as far as possible - the valve is hanging onto the seat by it's fingernails, rather than a 3-4mm overlap as standard - and the finish between the valve seat and head casting is completely flush - no lumps and bumps like you get with the standard head. 'unknown' has seen the head (yes it's still sitting on my table Jake) so ask him if you want an independent opinion. Edited by: mikehorsb
Is it worth me seeking to get this head 'tidied up'? (Please resist the temptation to say 'just scrap it' )
I was going to ask if it was on a block yet! I've had a very quick browse over the head and the work around the valve seat and throat/seat area in general is very nice indeed, the valves are definatly not shrouding the flow any. The rest of it is tidy but nothing showy. from what I have read/learned from people is that this is where all the gains are really made, not the sort of thing you can do at home sadly.
That means the head must be considerably shat. Thinking of getting a standard 16V head I have overhauled with new guides and using that on the 16V G60 instead. Then maybe I could look at buying a proper Shed head at a later stage. Shame... I was hoping this head would be better for a forced induction application having been opened out a bit.
