ISO .020 over rods

Renegade

Member
I have .010 in stock but the .020 I don't have. With the new rules for 2014 anything over 2.375 is illegal so a .015 is as big as you can go. Yes we will start working on that .015 over rod as soon as possible.
 

will_ivy

Member
I have .010 in stock but the .020 I don't have. With the new rules for 2014 anything over 2.375 is illegal so a .015 is as big as you can go. Yes we will start working on that .015 over rod as soon as possible.

You got them .015 yet
 

alvin l nunley

Site Supporter
Not that every little bit wouldn't be a help, but come on, the Rod length to stroke ratio is so far off, how much help could .015" be? There are so many things you could do, which would be so much more helpful, I'm pretty sure that the purchase of a longer Rod would be way down on my, "things I need to do to go faster" priority list.

The next time you replace the Rod in your engine, sure, get the long one, but I wouldn't be going to a lot of trouble before that.
Comments compliments criticisms and questions always welcome.
 

jdg

Member
Not that every little bit wouldn't be a help, but come on, the Rod length to stroke ratio is so far off, how much help could .015" be? There are so many things you could do, which would be so much more helpful, I'm pretty sure that the purchase of a longer Rod would be way down on my, "things I need to do to go faster" priority list.

The next time you replace the Rod in your engine, sure, get the long one, but I wouldn't be going to a lot of trouble before that.
Comments compliments criticisms and questions always welcome.
If you have a engine with the piston .020-.025 in the hole its a lot easier and cheaper to buy a $10 .015 longer rod than try to find someone to deck the block. I don't think the performance difference would amount to anything, other than a small increase in compression.
 

W5R

New member
that small increase in compression from going from .025 in the hole to .010 in the hole makes a pretty good difference in stock class racing. Modifieds, not so much.
 

alvin l nunley

Site Supporter
that small increase in compression from going from .025 in the hole to .010 in the hole makes a pretty good difference in stock class racing. Modifieds, not so much.
the only thing you're forgetting is, there's a minimum CC's in a stock class engine. If your stock class engine was at the minimum CC's before you put the longer Rod in, you would have to do something else to increase the CC's to meet the legal requirements.

The definition of the word "dynamic" is something is moving or changing. Nothing is moving or changing in what you call "dynamic compression ratio". I don't understand why you can't see that?

I've read your link, and calling something dynamic doesn't make it dynamic. In fact, in my opinion, calling it dynamic is wrong. Measuring the volume above the closing point of the valve, which doesn't change, would better be understood if you called it the "effective" compression ratio. Much like in a 2 cycle where the volume above the exhaust port closing is called "effective" compression ratio.

Comments compliments criticisms and questions always welcome.
 

W5R

New member
.005 to .010 is ideal, but wouldnt go any less than .005. Be sure to check your CC's if you are considering using a longer rod to bring the piston up in the hole more, and check your piston to head clearance as well. You need to account for rod stretch also at the kind of RPM we turn these engines with the stock rods.
 

W5R

New member
the only thing you're forgetting is, there's a minimum CC's in a stock class engine. If your stock class engine was at the minimum CC's before you put the longer Rod in, you would have to do something else to increase the CC's to meet the legal requirements.

The definition of the word "dynamic" is something is moving or changing. Nothing is moving or changing in what you call "dynamic compression ratio". I don't understand why you can't see that?

I've read your link, and calling something dynamic doesn't make it dynamic. In fact, in my opinion, calling it dynamic is wrong. Measuring the volume above the closing point of the valve, which doesn't change, would better be understood if you called it the "effective" compression ratio. Much like in a 2 cycle where the volume above the exhaust port closing is called "effective" compression ratio.

Comments compliments criticisms and questions always welcome.

I believe you have me mixed up with someone else, i have not posted any link or said anything about dynamic compression in this thread, Al. I am also not forgetting that there is a minimum CC check in a stock class engine, that is the only class i run and i know the rules very well. Typically if i use a longer rod to bring the piston up in the hole, ill use a thicker head gasket to get the correct CC's, which is also what most other's i know do as well. Also, dont confuse 2stroke engine basics with 4stroke engine basics, while i agree some things are the same, alot of other things are different, and are viewed as that also.
 
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