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merli , I am happy to meet you halfway and install your bits on our car?

I've got a great idea,,,why don't we all go to Merli's place on Sunday,,,have a peeky-boo at all his great shiny stuff,,,watch the big race,,,get him pissed as a fart so he falls asleep on the lounge AGAIN and then raid his garage.

He has a track record I do beleive. Now where is that wonderful pic again.

Love as always

Neil.

haha I'm keeping that pic for blackmail....but yes it is out there....

I don't know what other purty stuff that car has coming, but I did see its 4" titanium exhaust on the floor at UAS.

And speaking of UAS our rear subframe roll centre adjustments are being finished up atm, should have it for the weekend. Shame I've got no car time this w/end. Well lots of watching time but no working time.

im in the process of setting up the old kart frame in the lounge room infront of the projector, use it for playstation but this weekend is serious, ill even have the helmet on. no spanners this weekend. im driving lol.

haha I'm keeping that pic for blackmail....but yes it is out there....

I don't know what other purty stuff that car has coming, but I did see its 4" titanium exhaust on the floor at UAS.

And speaking of UAS our rear subframe roll centre adjustments are being finished up atm, should have it for the weekend. Shame I've got no car time this w/end. Well lots of watching time but no working time.

head bolt washer?

no there is lots stil lto be done, and I reckon andrew has lots of pretty bits ready to go on his......cmon get it finished too :banana:

You now have a couple of washers to play around with!

Andrew will have a nice Pretty shaft soon to pinch!!

Again, I need to point out that I'm no expert, more just trying to suck up info from different sources and trying to understand it better.

me too! 100%.

Rich,

I understand the theory, but when you were talking to others about it, was there any discussion of decking the head to drop compression back down? From what I get from your post, removing one or more squish zone would essentially increase the volume of the chamber thus reducing the compression.

If this is the case, and lower compression is desired, couldn't a similar result be achieved by using a thicker head gasket.

My discussions with the engine builder involved more profiling the squish zones and then decking the head so reduce the compression back to a desired point. It was more about developing exhaust velocity and terminal speed on the piston.

from what I understand though removing the squish zone isn't just about reducing the compression, that's more a by product, and as you pointed out can be returned by skimming the head. I think it's also about the shape of the chamber. obviously with those 2 pads removed you get larger volume but also the shap is different. I think the idea is having a smoother bowl shape gives less hot spots. in a normal head you get hot spots where there are any little angles or casting imperfections and the can cause pre-igntion or uneven combustion. by removing the squish pads you raise this threshold. the aim of course is you can run more timing and more boost which i'm told outweighs any other loss you might have (on a race engine). what convinces me further is that of the fastest GTRs I know in oz and OS, the ones kind enough to share with me what they do headwise they tell me they remove them. I should point out again for a street car the trade of probably isn't worth it (unless you have silly power) as you want be running enough boost and power to make the most of it. but doing one side is aparently a good compromise. for a race car most of these guys tell me both sides is the go. :banana: my own head? I did one side. I'll dig up some pics for you in a bit.

personally I reckon the headstuds are more trouble than they are worth. drilling out the holes, plus the length problem giant mentioned etc add up to too much hassle for not too much benefit. brand new bolts went into mine. on the other hand if you have the super power, and run the super boost then you may need them so not really have any choice.

definately either remove the squish area or atleast round off the square edges (if you want to keep compression up ) or they will light up like a christmas tree, and youll get pinging a whole lot earlier

of course there are some other things as well , i cant remember but removing one side helps clear the gases too.

Edited by giant
Maybe look at a group buy for head work?

If it was for a good price, surely there would be enough people with spare motors lying around :)

No more group buys evor!! haha

tho i do have a spare head at home.....

definately either remove the squish area or atleast round off the square edges (if you want to keep compression up ) or they will light up like a christmas tree, and youll get pinging a whole lot earlier

of course there are some other things as well , i cant remember but removing one side helps clear the gases too.

this head i picked up yesterday thats going in a street gtr. JHH Engineering in qld did all the work. I took them a std head, gave them the plan of the car and said go nuts.

You can see the chambers rounded off as russ was saying (crappy pics but i'm taking more tomorrow :))

johnshead001am9.th.jpgjohnshead002hq4.th.jpgjohnshead003ai6.th.jpgjohnshead004sv0.th.jpgjohnshead005iv4.th.jpg

I've got a great idea,,,why don't we all go to Merli's place on Sunday,,,have a peeky-boo at all his great shiny stuff,,,watch the big race,,,get him pissed as a fart so he falls asleep on the lounge AGAIN and then raid his garage.

He has a track record I do beleive. Now where is that wonderful pic again.

Love as always

Neil.

ihateyou.jpg

lol that pics is close but not the same. I'll keep it for another day :P

Mark and I were doing something silly and adding up the other day. The head prep, porting, springs, shims, valves and cams cost more than the rolling shell. or the cage. or the bottom end. or the intake and turbos. or all the suspension bits put together. In fact it is the most expensive bit of the car so far.

Shane that head looks good and even looking at it you can see why it would make a difference with the smooth curves. For now we will stick with what we have but we might clean up the squish zones once our wallets have recovered.

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