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s14 crank


Guest Anonymous
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Guest Anonymous

OK here's the scoop from what I've discovered from research on the s14 crank. The s14 crank is 4mm longer throw than an 02. Here's the problem that it causes. The stock 02 rod goes 4mm higher now and 4mm lower. Great cept that now our piston has gone 4mm into the head. If we get a custom piston made up to utilize the stock piston then the wrist pin is up into the oil ring and close to the second compression ring. OK for race but for street... prob not the best. OK so we've go to either custom rods or m3 rods. Either isn't going to allow us to use a stock piston. Aww fudge so now our quest for .2L of displacement has gone into a huge budget increase. We've gotta get m3 rods or custom rods and custom pistons. Faq it. Ok so we've spent big bucks and have our m3 rods and custom pistons made up and we're ready to assemble our 2.2L motor.. right.. WRONG!!! hate to tell you this but just keeping the stock bore your still just a tick over 2.1L. Thats one of the largest misnomers on the net. Just by putting in the crank just gives you the extra .1L of displacement.. to get that last .1L to goto 2.2L you've gotta goto 92mm overbore. Well after talking with several who have done this.. .. this is still a controversial subject. Jeremey at ireland says to build a 92mm race ready block they had to bore 5 blocks to get one to hone. They refuse to do them now. Others say it's easy. That's a 120 thousandths of an inch oversize. I personally don't like the cylinder so close to the water jacket at the headgasket area. What else could we possibly have to do? Well make sure you grab that s14 crank pulley and take your m10 front cover to your local machine shop. Have your front main seal boss machined out to fit your new s14 crank shaft cause it's a larger diameter. Anything else??? Nope but after doing some basic calculations on the dyno program expect a 10-15HP boost in HP and 10-15lbs in torque. Great but for the price we paid for the crank.. rods... pulley.. pistons etc. Did we get our money's worth? I'll let you decide.

Party On

Kris

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Guest Anonymous

Wait a second here. The S14 2.3 Liter has an 84mm stroke. This therefore means the piston is 2mm into the head with stock M10 rods. You will need custom pistons to make this work. Though some esoteric euro piston from a bmw six cylinder supposedly works as well. However, the stock M10 piston pin placement is less than ideal, so you can easily move the pin up 2 mm without having to intrude into the oil ring.

However, the rod to stroke ratio of this S14 crank and M10 rod leave much to be desired. The M10 rod is 135 mm and the S14 rod is 144 mm. Ideally you'd look for a rod to stroke ratio of around 1.75. Stock the s14 is 1.714 close, the M10 stock is 1.688. With an S14 crank and M10 rods the ratio drops to 1.607. A lower ratio increases the piston side load and piston rocking. While many modern cars (hondas) use a low ratio, they get away with it because of the smaller bore size and tight piston to wall clearences. Main drivers of lower rod to stroke ratios are the packageing guys, lower hoodlines less drag smaller package less weight etc.

Ideally, you need to find a S14 crank/pulley/rods and custom pistons to make this viable. I'm looking into this option but it is expensive...it all matters how fast do you want to go. I've heard rumors of a Kerman stroker putting out 180 HP and that is a streetable combo not some highstrung race only setup.

Anyways to each his own. I'm looking to build a killer N/A M10 motor. But maybe if steve's supercharger looks good I'll have to rethink this whole deal.

-Bernard

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Guest Anonymous

Bernard is correct 2mm higher at top and 2mm lower at bottom with the S14 crank, 4mm total stroke increase. The S14's rods are much longer then the M10 rods, just over 9mm longer so I doubt you could use them even with custom pistons. So for ~.2L displacement(with larger bore pistons) your looking at a major expense, custom pistons, perhaps custom rods and the S14 crank modified to fit the M10 block. Not really cost effective for the potential gain as Kris noted. Now if you can find an evo crankshaft which I believe is 8mm more stroke, then perhaps it may be worth the expense, but your still better off with forced induction in the long run.

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Guest Anonymous

Like I said.. it's not exaclty cost effective.. I really didn't wanna get into the rod/stroke ratio as it would confuse alot but yes you are right.

Thanks

Kris

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