# Briggs and Stratton 5HP piston orientation?



## steppinthrax (Dec 25, 2010)

I have a 5 HP verticle crank b&s engine that I"m overhauling. I wrote down but forgot the orientation of the piston. I'm looking at the underside of piston and notice a large "X" on wrist pin housing. Does this "X" indicate orientation?


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## jrrdw (Jun 26, 2010)

Clean the piston top off, the arrow points towards the valves.


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## steppinthrax (Dec 25, 2010)

jrrdw said:


> Clean the piston top off, the arrow points towards the valves.


I've actually placed the piston is a tank of degreaser for over an hour. I've cleaned it so wel you can actually eat off of it. I'm looking at the crown of the piston. I see no arrow or any mark indicating orientation. I see concentric circles on the crown of the piston. On one side of the connecting rod I see the number "13" on the other I see the letter "A". 

After looking at it for a while I also see a small hole drilled into the base of the connecting rod that exits on the cam journal portion...


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## jrrdw (Jun 26, 2010)

One side of the connecting rod points towards either the cam gear or govenor. I would have to look this one up so I need the engine numbers.

Model
type
code

They are stamped in the fly wheel cover near the spark plug. The little holes are oil passages.


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## steppinthrax (Dec 25, 2010)

jrrdw said:


> One side of the connecting rod points towards either the cam gear or govenor. I would have to look this one up so I need the engine numbers.
> 
> Model
> type
> ...


There is an "X" under the piston skirt right on the housing where the wrist pin goes through. I think this indicates orientation. But the hole that I last spoke about most likely indicates the piston is supposed to go twords the governer since that would sling oil onto that hole lubricating the cam journal.

Model 130902

Type 0258-01

Code 73032706

Where are you looking this up btw.


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## jrrdw (Jun 26, 2010)

I have factory service manuals. I have to go to my shop to look this up and will get back to you shortly, (before the new year).


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## jrrdw (Jun 26, 2010)

When re-assembling the piston to the rod there should be 2 identifying marks on the bottom of the rod, 1 on the cap and 1 on the bottom of the rod. Where the piston pin slides through the piston there should be a "F" stamped in the piston on 1 side. The "F" and the identifying marks at the bottom should face the same way. When installing the rod and piston into the block all the markings face the flywheel side of the engine.

It's this way for all aluminum engines EXCEPT FOR 300000 and 320000.


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## steppinthrax (Dec 25, 2010)

jrrdw said:


> When re-assembling the piston to the rod there should be 2 identifying marks on the bottom of the rod, 1 on the cap and 1 on the bottom of the rod. Where the piston pin slides through the piston there should be a "F" stamped in the piston on 1 side. The "F" and the identifying marks at the bottom should face the same way. When installing the rod and piston into the block all the markings face the flywheel side of the engine.
> 
> It's this way for all aluminum engines EXCEPT FOR 300000 and 320000.


 
I was looking for those marks you mentioned. I'm not finding them. I see no other marks or "letters" on the connecting rod other than and "A" on one side and a "13" on the other. I never took apart the piston to see what was on the top. I'm going to contact B&S monday to see what's going on.


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## steppinthrax (Dec 25, 2010)

steppinthrax said:


> I was looking for those marks you mentioned. I'm not finding them. I see no other marks or "letters" on the connecting rod other than and "A" on one side and a "13" on the other. I never took apart the piston to see what was on the top. I'm going to contact B&S monday to see what's going on.


I think I got it. I contacted B&S. They couldn't help. I used to remember when you spoke to someone who was an eng. But anyway, I got ahold of the B&S service manual. Twords the base of the connecting rod there is a protruding notch on the bottom. That needs to face away from the cam gear.


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