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  #121  
Old 09-17-2019, 08:05 AM
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Does anyone know the weight stock flathead valve springs compress at?
Also, some of you may know I want to retard the timing on my flathead a bit for extra torque. I plan to lap the flywheel and file off a bit of the timing key to do it. Is the amount removed/degrees changed ratio the same as say, a Predator 212?
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  #122  
Old 09-17-2019, 08:31 AM
Randy H Randy H is offline
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I could be wrong but I believe retarding the timing from stock will cost you power across the entire RPM range.
Here's a good read.

https://foxvalleykart.com/timing2.html

Page 1 of article.

https://foxvalleykart.com/timing1.html
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  #123  
Old 09-17-2019, 08:39 AM
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I was thinking 0.5 to 1.5 degrees of retardation. 'Sid suggested it BTW. If other people chime in and tell me it's just a waste of time, then I'll probably just leave it with stock timing.
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  #124  
Old 09-19-2019, 06:29 PM
txluke txluke is offline
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Quote:
Originally Posted by JTSpeedDemon View Post
I was thinking 0.5 to 1.5 degrees of retardation. 'Sid suggested it BTW. If other people chime in and tell me it's just a waste of time, then I'll probably just leave it with stock timing.
https://youtu.be/wcdZesGse6s
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  #125  
Old 09-20-2019, 05:56 PM
txluke txluke is offline
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Here is a link to the Briggs Facebook group I get a lot of good info from. https://www.facebook.com/groups/1669946656352890/
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  #126  
Old 09-21-2019, 08:53 AM
Randy H Randy H is offline
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https://www.ebay.com/sch/i.html?_fro...retor&_sacat=0

https://www.ebay.com/sch/i.html?_nkw...=briggs+691922

This is a good combo. ^^

There was some discussion on valve springs. It's a belief that stiffer valve spring will allow higher RPM. That's usually true.

In stock Briggs Racing class where rules dictate a stock lift cam, conventional wisdom does not apply. So called slapper cams or block breaker cams had an aggressive ramp profile. They didn't require super stiff springs. They operated in a controlled valve float state. The valve would be tossed increasing lift, duration and increasing RPM and power. Just as if a larger can was installed .

This was hard on the lifter bores, especially the exhaust because the area was thin. That's why a lot of old racing blocks have welded lifter bores.

By the way, stock cam lobes were broached, you can easily see this.

I'm (apparently, lol) a poor explainer. I hope some one can make sense of this.
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  #127  
Old 09-21-2019, 03:57 PM
wenee9w wenee9w is offline
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Slapper cams bring back memories of a fish scale and special built valves for setting spring tension.
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  #128  
Old 09-21-2019, 04:37 PM
Randy H Randy H is offline
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Just saw this on the DynoCams site.
I've got a pile of old stock cams. Was gonna use em for metal art. Maybe I should donate them to Dynocams. Or to the scrapyard. Lol.


As of July 30th, 2019, DynoCams will no longer be able to provide flathead cast cores for stock or hot stock grinds. These cast cores have not been produced by Briggs and Stratton for many years and there is no secondary supplier. We will, however, still grind stock profiles if you can provide a cast core meeting the following criteria:



Cam journals free of rust, damage, or excessive wear

Cam gear is free of rust, damage, or excessive wear

The intake and exhaust base circles are no less than .725
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  #129  
Old 09-21-2019, 05:29 PM
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Yeah I read that about a week ago.
It sucks.
I hope my core is good enough, 'cause I'd like a 94SS in my flathead.
Or maybe I can track a secondhand one down, ya never know!
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  #130  
Old Today, 11:49 AM
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Some helpful info I wanted to pass on.
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