Hello, i have a Briggs 16 hp L head engine, I use it for a pulling tractor, it needs rebuilt, I was wondering if I would be able to make it into a 20 HP engine. Do they use the same block, heads, crank, pistons? do I need to bore it out? Im not finding a lot of info on these engines, but i love my little Briggs
16HP TO 20 HP BRIGGS L HEAD
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bertsmobile1
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IT all depends upon which short block your 16Hp engine is
The thing we need is the model number
The first 2 numbers are the engines capacity ( approx ) in Cubic inches
If your engine is a 40 incher then you should be able to get more out of it but if it is a 35 incher then tough luck.
The easiest way to get some extra grunt would be to go to a mower race shop and get a hotter cam .
There is a limit on over boring and a bigger limit on upping the compression.
However you can fill in the head to make actual inlet & exhaust tracts much along the lines of what HD did with the K series
You run the inlet along the bottom of the cylinder so it directs the incoming charge at a tangent which scavenges the exhaust better
That makes a sort of funnel shape to direct the exhaust out of the cylinder
As I have been told many many times, the limit to the available Hp is the thickness of your wallet.
However on a governed engine it tends to be a bit of a zero sum game as you still have the transmission to deal with and adding 4Hp while it sounds like a lot does not add that much extra torque which is your pulling power.
The thing we need is the model number
The first 2 numbers are the engines capacity ( approx ) in Cubic inches
If your engine is a 40 incher then you should be able to get more out of it but if it is a 35 incher then tough luck.
The easiest way to get some extra grunt would be to go to a mower race shop and get a hotter cam .
There is a limit on over boring and a bigger limit on upping the compression.
However you can fill in the head to make actual inlet & exhaust tracts much along the lines of what HD did with the K series
You run the inlet along the bottom of the cylinder so it directs the incoming charge at a tangent which scavenges the exhaust better
That makes a sort of funnel shape to direct the exhaust out of the cylinder
As I have been told many many times, the limit to the available Hp is the thickness of your wallet.
However on a governed engine it tends to be a bit of a zero sum game as you still have the transmission to deal with and adding 4Hp while it sounds like a lot does not add that much extra torque which is your pulling power.
PTmowerMech
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Bert, does boring one actually give an engine more HP?
bertsmobile1
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It can
What it generally does is restore the original Hp that has slowly dropped off.
What it will do is up the torque.
Got a couple of old 500cc motorcycles that I removed the sleeve & run big pistons directly on the iron cylinder .
Don't go 1 mph faster but does have a tone more grunt so uses a lot less fuel despite one of them going from 500 cc to 720 cc
Welding & profiling the head did push up the Hp particularly as one engine went form 5.7 : 1 to 7.3:1
No use trying for CR's much greater than 7:1 on a side banger because all you do is burn the bridge region of the barrel .
What it generally does is restore the original Hp that has slowly dropped off.
What it will do is up the torque.
Got a couple of old 500cc motorcycles that I removed the sleeve & run big pistons directly on the iron cylinder .
Don't go 1 mph faster but does have a tone more grunt so uses a lot less fuel despite one of them going from 500 cc to 720 cc
Welding & profiling the head did push up the Hp particularly as one engine went form 5.7 : 1 to 7.3:1
No use trying for CR's much greater than 7:1 on a side banger because all you do is burn the bridge region of the barrel .
Tinkerer200
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Hmm, a 35 inch "L" head 16 hp B&S has me curious?
Walt Conner
Walt Conner
bertsmobile1
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1942 Wm20 BSA linerless CAST IRON barrels from 1948 & 1952
Nothing made in Japan post WWII will have iron barrels save the Meguro then Kawasaki W 1 & 2 .
British bike & most USA ones had cast iron cylinders with austelitic iron or steel pressed in liners .
The occasional one had a liner with the alloy fins shrunk around it .
They are easy to tell because the head is through bolted to the crankcase so it sandwiches bore .
The iron was low grade & quite porus .
Advances in metallurgy to produce aero engines led to far better processing & quality control to the point that liners became unnecesary .
Nothing made in Japan post WWII will have iron barrels save the Meguro then Kawasaki W 1 & 2 .
British bike & most USA ones had cast iron cylinders with austelitic iron or steel pressed in liners .
The occasional one had a liner with the alloy fins shrunk around it .
They are easy to tell because the head is through bolted to the crankcase so it sandwiches bore .
The iron was low grade & quite porus .
Advances in metallurgy to produce aero engines led to far better processing & quality control to the point that liners became unnecesary .