Temp lead killing compression

[JGR32]

I’ve been told that running a temp lead can make you lose compression?Any truth?

 

[alvin l nunley]

Maybe a small inconsequential amount.

 

[flattop1]

Yes it's true . Temp lead is about .038 thick . Spark plugs is 14mm dia .
Therefore you lose the equivalent cc in volume from the combustion chamber .

 

[alvin l nunley]

Yes it's true . Temp lead is about .038 thick . Spark plugs is 14mm dia .

I never ran the spark plug washer with the temp lead. You have to subtract that from the temp lead thickness.

 

[MO Predator Racer]

Does it really make that much of a difference? I dont know how much it would affect it.

 

[flattop1]

It just so happens I have a mychron and a zero to 1 mic here at my desk .
Turns out it's .058 thick .

 

[flattop1]

Does it really make that much of a difference? I dont know how much it would affect it.

That's the reason for the 3910x take up space in the chamber .

 

[MO Predator Racer]

That's the reason for the 3910x take up space in the chamber .

Which thus gives it a little bit higher compression?

 

[flattop1]

Yes , it's approximately . 220 cc .
Get the cc too the minimum . Install plug your removing that came it can't be teched . Because the plug has to be out to cc it .
They could mandate a spark plug .

 

[Renegade]

Why don't you just machine the spark plug? Use a set of dial calipers and get a rough estimate of how far below the plug the piston is at TDC. Then just cut that much off the plug. I used to sell them by the hundreds cut to go .065 deeper.

 

[flattop1]

--- ----
The definition of ; I`LL Eagle is a sic bird !

 

[Bumpy]

You could just leave it alone and not worry
about it. If winning vs not winning is
depending on that small of a compression
decrease/increase you would have to be racing
at the top .01% level of all racers in the U.S.
The formula for cubic inches is bore x bore x stroke x .7854
So 14mm = (.55) .55 x .55 x .058 x .7854
I get .0137798 cubic inches for the temp sensor thickness.
Al can check my math. His answer will be correct if different from mine.

 

[JGR32]

You could just leave it alone and not worry
about it. If winning vs not winning is
depending on that small of a compression
decrease/increase you would have to be racing
at the top .01% level of all racers in the U.S.
The formula for cubic inches is bore x bore x stroke x .7854
So 14mm = (.55) .55 x .55 x .058 x .7854
I get .0137798 cubic inches for the temp sensor thickness.
Al can check my math. His answer will be correct if different from mine.

I was just wondering. Every little bit counts.

 

[Kj26]

Why don't you just machine the spark plug? Use a set of dial calipers and get a rough estimate of how far below the plug the piston is at TDC. Then just cut that much off the plug. I used to sell them by the hundreds cut to go .065 deeper.

And I used to buy them lol, then I decided the heck with the temp lead, like most others I see.

 

[jsf74]

You could just leave it alone and not worry
about it. If winning vs not winning is
depending on that small of a compression
decrease/increase you would have to be racing
at the top .01% level of all racers in the U.S.
The formula for cubic inches is bore x bore x stroke x .7854
So 14mm = (.55) .55 x .55 x .058 x .7854
I get .0137798 cubic inches for the temp sensor thickness.
Al can check my math. His answer will be correct if different from mine.

That could be true but add up all the little tiny minuscule things and they together can be the difference between winning and loosing. Why leave performance on the table when its so easy to do right?

 

[alvin l nunley]

Maybe I'm doing the math wrong, let me know, but I see the spark plug adding only .021 CC to the combustion chamber with the temp lead installed. I'm pretty sure that's insignificant.

 

[1fasttiller]

No temp lead and no washer, sink that baby in the head! We need all we can get!

FYI- Read what Renegade said above guys and read it again. There is power to be found there

 

[One Fast Kat]

or use a Champion C53VC racing plug, comes in two depths, The long one may need to use spacers to clear the piston.

 

[OVALTECH1]

NGK makes 14mm plugs with a 1.000 reach that way you can still use your temp lead on your unrestricted clone to keep an eye on things and you can then take it off when you want that last 3/10ths of a horsepower or tdc piston stop!