Heymow - Lawnmower Racing Forum

Engine Help => Briggs Flathead => Topic started by: Leon_Johansson_ on October 30, 2018, 09:06:00 am

Title: Briggs model 28 piston
Post by: Leon_Johansson_ on October 30, 2018, 09:06:00 am

I just started building a briggs model 28 i/c flathead with the arc dog bone and connecting rod but i just noticed that the cylinder bore is 3.3 inches (83.7)mm wide when it’s supposed to be 3.4 inches (87.7) mm. So i was wondering what piston should i get? One that is short enough for the arc rod and just 3.3in wide. Maybe the briggs model 49 piston?

Any help is appreciated.

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 09:40:12 am

Standard bore on model 28 flathead or ohv is 3.4375",
the only 2 briggs engines that use 3.300" bore is 21 ohv horizontal and 49 intek twin

Title: Re: Briggs model 28 piston
Post by: Leon_Johansson_ on October 30, 2018, 10:44:52 am

Thanks, Do you have a link to the model 21 ohv horizontal piston?

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 11:10:19 am

Did you buy an ARC rod??If you did what did you buy 6280 or6281,they are both designed to use the model 28 and 31 AVS piston ,you should do some better measuring of bore,i think you are mistaken!

Title: Re: Briggs model 28 piston
Post by: Leon_Johansson_ on October 30, 2018, 12:39:38 pm

Well i bought the 6280 rod and i have measured both the piston and the bore with a caliper and all.
But it always comes out as 83.7mm and thats quite a bit of difference from the 87.7 that it’s supposed to be. Maybe i should get the model 21 piston and try.

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 01:09:15 pm

Might want to try some different measuring tools,Like an inside mic

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 03:53:30 pm

You will need the Biggs 792307 piston and 697099 wrist pin.
Good Luck

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 03:56:14 pm

I also have a few nice used performance cams for your motor!!

Title: Re: Briggs model 28 piston
Post by: Leon_Johansson_ on October 30, 2018, 08:38:32 pm

Thanks for everything and if you’d ship to a different country i would be happy to pay you through paypal.

Title: Re: Briggs model 28 piston
Post by: PJG56 on October 30, 2018, 09:30:52 pm

Where are you located

Title: Re: Briggs model 28 piston
Post by: Leon_Johansson_ on October 31, 2018, 04:49:13 am

Sweden