I building my 2.2l ohv for some nitrous. I wanted to kno if .75 mm overbore was ok for this engine. i have read that the max on these engines was +1mm with proper sonic testing

There is no need to bore the cylinder any bigger than is needed to have a true cylinder.



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

Cylinder overbore is usually to fix gashes and whatnot in the cylinder walls.

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srry what i was trying to say is i want bigger pistons and i was wondering if that oversize size would be alright for this engine.

Most people go slightly over, if anything. Usually like .20 over


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Primer Counts as Custom Paint Right?
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hmm i beliv its .020 not .20 lol


2003 White Cavalier LS Sport Coupe

ahhhh typing fails me lol maybe i should just stick with 20 over.....easier


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Primer Counts as Custom Paint Right?
BTW: This is my Sig.

.030 is actually more then .75mm. When you say 20 or 30 over, your talking inches, millimeters are 25.4 times smaller then an inch. If its possible to go 30 over, it would be safe to do .75mm because that is about .02955 inches...

Most engines can do 30 over. I'd be very surprized to find out that the 2.2 OHV couldn't take that.

Wade Jarvis wrote:There is no need to bore the cylinder any bigger than is needed to have a true cylinder.

true, but when you get to building these low horsepower and torque engines anything you can get to help is a good idea. is it wrong that i've had engines bored even though the block was perfect? i dont think so. boring does help performance dood

A 2.4L LD9 should gain about 2.5 hp on a stock motor from a .030" overbore. A 2.2L has a smaller bore and stroke which means even less. For the pure sake of inreasing horsepower, it doesn't seem worth it to me. Most people overbore because...

Rob Durrett wrote:Cylinder overbore is usually to fix gashes and whatnot in the cylinder walls.

If it can take an overbore of .030, then fine. But you really don't have anymore room left in the cylinder if something were to happen where you would need to bore it out farther. You would have to get another block or invest in sleeves.


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"Youth in Asia"...I don't see anything wrong with that.

For the price of a new 2.2 block, i think if you want to bore it out, go for it. You could probably find one for next to nothing.

I'm coming up on 3 years/ 44k miles with no problems on a .75mm/.0295" overbore. You'll need the pistons before they bore the cylinders, so they can bore it correctly. If your going to go nitrous and/or N/A, you can zero deck the block, get a copper headgasket in the .035"-.040" thickness (O-Ring the block)and deck the head, I Believe it was .015" for a 10:1 compression ratio. If you going to boost it then keep the stock compression. With the Hypereutectic pistons, be very conservative with the nitrous or boost, they'll handle a little more than a cast piston, but not much more. Have the head ported and get the +1mm valves. Do the LS6 valve springs and get a cam regrind with an intake duration of about 206-210* @ .050"(ground 1* advanced) and an exhaust of about 10-12* longer duration @ .050", ground on the stock center line. If this is a daily driver, stay on the milder side, for better drivability. This will give you an intake C/L of 108* and a lobe separation angle of 113*, which will work just right with the N2O, still run well with the PCM N/A with boost, the spooling will be slightly delayed, depending upon the size turbo you're running. Keep the total lift (lift at the valve, i.e. lobe lift X rocker ratio) to about .490"-.520" and measure your valve-to-piston clearance.

In all your posts, you've never clearly stated what your plans are, so we can't tell for sure exactly what you'll need. If you want to run a significant amount of boost and/or nitrous, I would recommend forged rods and pistons.