the cheap way to high compression???

[nolaws4evr]

alright, Ive got a buddy that owns a very large machine shop and this guy fabs everything for his own car. I was talkin to him one day about me car and what I was planning to do with it when he came up with an idea on how to raise my compression and net a few ponies for not a whole lot of money. He suggested taking off my head and have him machine it down several thousandths of an inch, and at the same time give me a good P&P on the intake since he has a flow bench. My question lies with the higher compression, is this safe and has anyone had experience with this before?? where you at nistech??? he said he could do all of that for about 300, which I take to be a great figure for somewhere around a 25-30hp gain. any input is welcome and always appreciated.

Josh

[toki]

milling the head is always an option, there are mathematical formulas this guy SHOULD have if he knows what he's doing to tell you exactly how much you can go safely, and how much it will raise it. Also, don't expect 30hp from a port and polish and raising the CR. Raising the CR rarely brings anything more than a few HP unless you are going from 8.5:1 to 12:1 or something like that.

[Turb0wned]

its better to have lower compression if ur planning on a turbo..

[deviousKA]

you would have to mill the head to much to gain any significant higher compression. The problem with this is that your valve train timing will be off due to the shorter distance between cam and crankshaft sprocket (you will have basically to long of timing chain). You can make this up with an adjustable cam sprocket which would have to be custom made (although there are adjustable sprockets available at very high price) It cost very little for a machine shop to mill a head so you are paying 250 for him to port it for you, a good port job can give decent gains in hp.

milling the head is the wrong way to gain compression ratio factor. You cannot mill to much off because the water passages will begin to not match up, and on the ka24e the intake and exhaust studs are very low on the head. Also you must consider valve to piston clearance as well as piston to combustion chamber clearance (minimum .030"). You can swap in some early ka24e pistons for 9.1:1 cr or you can buy custom cast or forged for more. I sell 10.5:1 piston kits if you are interested at a very good price considering the competion.

The only "mathematical" formulas are basic compression ratio calculations, milling the head will yeild less combustion chamber cc's. ka24e stock combustion chamber = 65cc

edit: just realized you most likely have ka24de. Swap in some ka24e pistons for 11:1 cr, easy and cheap

[nolaws4evr]

ok, i understand about the timing issues and everything. i was also questioning the valve clearences and piston clearance. im sure this guy knows all of the calculations and whatnot, so would it not be at all possible to figure out what it would take to get the timing right w/out adjustable gears?? how hard would it be to make some?? also, how much would I be looking at for the 11.1 comp pistons? he quoted me 250-300 for a good p&p w/flowbench testing. im not sure if i really want to go this route or not, its just something to think about. ultimately i plan on having an rb25, but I dont have the available funds for awhile. so I kinda want to make the ka a little faster w/out dropping a boat load of cash on it. thanks for the comments by the way

Josh

[deviousKA]

the only way to mill off a considerable amount and not need an adjustable gear is to take off enough to roll the chain over an entire link (wayyy to much ive already pondered the idea). You would then have way to much slack in the one side of the chain (half master link can make this up, but i dont think its the greatest idea). I think you should stray away from this on the ka, it is not worth it. You can get new aftermarket ka24e pistons for very very cheap. You can check the prices at your local auto parts dealers and such, or if you would like, i can get you a set. The one thing you should look out for when buying aftermarket pistons is the proper size. Many aftermarket pistons are not made exactly to oem spec (compression height, proper dish) the bore, ring, and pin sizes they usually get correct. Get some quotes from various places, then email me i can most likely beat their prices and you can be assured the pistons will be high quality and oem spec.

oh and about making an adjustable gear. You would have to enlarge the notch in the gear, and place a shim to take up the space. easy in theory, but really a waste of time as said before because milling is not the proper way to gain compression. Putting ka24e pistons in is to easy not to do.

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[lovemysan2]

Hey devious, Did you know motorsports sells an adujustable cam gear for the ka24e for $70ish

[deviousKA]

Really, that cheap huh. Still it is designed to adjust cam timing either retard or advance. If you were using it for a milled head all you could hope for is that it would bring your timing back to stock. You would also have to deal with the timing chain length. The tensioner system on ka24e's is not great to begin with, more slack=more problems.