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Engine basics => Engine set up tips => Topic started by: Motorman on December 09, 2017, 10:03:09 AM

Title: Blank
Post by: Motorman on December 09, 2017, 10:03:09 AM
Blank
Title: Re: Fox 36X Bore Size
Post by: pmackenzie on December 09, 2017, 10:18:59 AM
 Review here says .8":

http://sceptreflight.net/Model%20Engine%20Tests/Fox%2036X%20BB.html
Title: Re: Fox 36X Bore Size
Post by: Al Ferraro on December 10, 2017, 06:37:44 AM
Same as the 35 Stunt engine.
Al
Title: Re: Fox 36X Bore Size
Post by: Paul Smith on December 10, 2017, 04:11:01 PM
The Peter Chinn article is great.  He really studied the engines.

Fox made a logical business decision to stay with his standard .800 x .700 bore & stroke, which (no doubt) fit his tools.

He then realized that he could stroke the engine to .715" and use ALL of the .36 cubic inches under the rule.   Around my area, guys were scrambling to get the all-important "stroker" cranks.  I never heard even ONE guy mention the need to deal with the resultant .0075" loss of head clearance. 

But a 36X setup inside a Fox 35 Stunt case would be illegal under current rules that forbid increasing the displacement.

The whole thing was a moot point vis a vis the C35 and G21/35.
Title: Re: Fox 36X Bore Size
Post by: Paul Smith on December 10, 2017, 04:12:43 PM
The Peter Chinn article is great.  He really studied the engines.

Fox made a logical business decision to stay with his standard .800 x .700 bore & stroke, which (no doubt) fit his tools.

He then realized that he could stroke the engine to .715" and use ALL of the .36 cubic inches under the rule.   Around my area, guys were scrambling to get the all-important "stroker" cranks.  I never heard even ONE guy mention the need to deal with the resultant .0075" loss of head clearance. 

But a 36X setup inside a Fox 35 Stunt case would be illegal under current rules that forbid increasing the displacement.

The whole thing was a moot point vis a vis the C35 and G21/35.

Going from .352 to .360 was only about a 2% potential improvement, which was chump change compared to a "C".

Title: Re: Fox 36X Bore Size
Post by: Paul Smith on December 11, 2017, 09:02:36 AM
If the bore size is the same as a Fox 35 and you use the fox 35 crank then it's still a 35.

Correctomundo, sir.

You just can't use the .715" stroker.
Title: Re: Fox 36X Bore Size
Post by: Paul Smith on December 11, 2017, 04:35:04 PM
I wondered that about in Profile Carrier in the olden days at The Nats.  The answer was: Only if the losers complain or if it sets an AMA record.

The rules of Fox 35 Stunt speed are such a bowl of jelly, there's nothing much to inspect.

A few years ago, I was able to win Fox 35 Stunt Racing at Muncie and I was subjected to a tear-down, which I passed. But that was under the stock engine rule.
Title: Re: Fox 36X Bore Size
Post by: RandySmith on December 11, 2017, 07:49:18 PM
I wondered that about in Profile Carrier in the olden days at The Nats.  The answer was: Only if the losers complain or if it sets an AMA record.

The rules of Fox 35 Stunt speed are such a bowl of jelly, there's nothing much to inspect.

A few years ago, I was able to win Fox 35 Stunt Racing at Muncie and I was subjected to a tear-down, which I passed. But that was under the stock engine rule.


I did not  realize  that a  FOX  36  crank would  even fit in a  FOX 35 Stunt

Randy
Title: Re: Fox 36X Bore Size
Post by: Al Ferraro on December 13, 2017, 10:05:13 PM


I did not  realize  that a  FOX  36  crank would  even fit in a  FOX 35 Stunt

Randy
[/quote]
 The Fox 36 crank is to long. There are a couple of 35 Stunt engines that guys have installed a Fox 35 Black head 1/2 inch crank. It also has a larger crank pin than the Stunt engine, which could be ground off center to get more stroke if someone want to make a cheater crank. One guy was using a custom 12mm crank in his Fox 35 Stunt engine.
 The High Zoot crank that I bought from you retimed is the King of the hill in Fox Speed.
Al