Briggs And Stratton Discussion

[JTSpeedDemon]

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?

 

[Randy H]

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

 

[JTSpeedDemon]

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.

 

[txluke]

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

 

[txluke]

Here is a link to the Briggs Facebook group I get a lot of good info from. https://www.facebook.com/groups/1669946656352890/

 

[Randy H]

https://www.ebay.com/sch/i.html?_fr...H0.XAnim.TRS1&_nkw=animal+carburetor&_sacat=0

https://www.ebay.com/sch/i.html?_nk...313.TR0.TRC0.Xbriggs+691922&sqp=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.

 

[wenee9w]

Slapper cams bring back memories of a fish scale and special built valves for setting spring tension.

 

[Randy H]

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

 

[JTSpeedDemon]

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!

 

[txluke]

Some helpful info I wanted to pass on.

 

[Smerft85]

Figured this would be appropriate here, the black 4hp is running strong, the white one sitting on top of the red one has no spark, the rest need work on fuel systems but I have heard them run with fuel dropped into carbs.

The one without spark will likely be cannibalized to get at least a couple of the others going, tanks that I have are all pretty rusty, and carbs that I have around are all needing work, I may see what luck I have getting a honda/clone carb to work with one of them, and I'm considering a complete tear down and rebuild using whatever performance parts I can get ahold of just to see how wild my abilities will produce, maybe try some of the home machining to the head and such with it. Otherwise I'll work toward just making as many as I can run.

Hope you guys enjoyed the briggs eye candy!

 

[JTSpeedDemon]

Cool! I love the silver 3 HP and the gold 5 HP! Snazzy!

 

[Smerft85]

Cool! I love the silver 3 HP and the gold 5 HP! Snazzy!

Actually the 3hp is more of a metal flake pink at this point, in person or better light shows it, probably was a salmon color originally. The gold 5hp purred like a kitten at idle till the fuel ran out. It's a '70 or '71 and one of the oldest of them.

Anyone know of an aftermarket plastic tank for these? I've seen carbs pretty cheap, but the new metal tanks are pricey for sure.

 

[Budget GoKart]

im working on getting a different 5hp briggs or 3.5hp but my briggs is almost fully screwed im gonna drain the tank, and the oil. im gonna take the head and side cover off. and im going to remove the govenor and check the bearing and crank for signs of complete oil starvation because they cylinder wall worries me with how bad it is... if its all good im keeping the engine.

whats the torque spec for the side cover, head, and rod?

 

[JTSpeedDemon]

Side cover is 120 in. lbs, cylinder head is 140 in. lbs, and the connecting rod is 100 in. lbs.
I'll email you my pdf copy of the manual, I have your email address.

 

[Budget GoKart]

Side cover is 120 in. lbs, cylinder head is 140 in. lbs, and the connecting rod is 100 in. lbs.
I'll email you my pdf copy of the manual, I have your email address.

Thanks jt I use ft lbs though

 

[JTSpeedDemon]

Then just divide by 12.
As long as it's close, it should be fine. I'd say con rod torque is most important.

 

[karl]

I need to do something with this , its a briggs intek 305cc 10hp snowblower engine

Its cool bore, but in very nice serviceable shape.

With a normal 3/4 shaft

Im thinking deleting head gasket, "stage 1" it, and keep the governor at 4k.

I need to make some linkage or find a donor as its a fixed RPM engine

Anyways I dont see many of the bigger inteks on the forum so thought id share

Edit-one for the flathead fanboys, +1 if you notice something out of place

 

[Budget GoKart]

I need to do something with this , its a briggs intek 305cc 10hp snowblower engine

Its cool bore, but in very nice serviceable shape.

With a normal 3/4 shaft

Im thinking deleting head gasket, "stage 1" it, and keep the governor at 4k.

I need to make some linkage or find a donor as its a fixed RPM engine

Anyways I dont see many of the bigger inteks on the forum so thought id share

Edit-one for the flathead fanboys, +1 if you notice something out of place

I spy with my little eye a tecumseh flathead... Cool!

 

[JTSpeedDemon]

Yup, and what looks like a short block.