Briggs opposed Twin Model ID?

[Arkie]

I have a Briggs Opposed twin (L-head) that was given to me and did not have a air cowling.

Anyone have any idea about how to go about determining a Model number?

For example does the Briggs opposed twin block have any kind of reference ID numbers or ????

[bgsengine]

pretty much would start with bore measurement to determine the base model series , then follow the model number reference guide to get a rough idea.. then you might be able to measure crank and compare to crankshaft drawings to come up with a crank part number,and a fitment search to narrow it down to model-type, from there, you can probably use that for parts lookups until you hit on a part that fits only one type number, that is used on your engine, and voila..

Other than that no way I know of to positively identify from anything on the block.. except you can know it is somewhere between 400000 to 440000 model series probably

[Arkie]

pretty much would start with bore measurement to determine the base model series , then follow the model number reference guide to get a rough idea.. then you might be able to measure crank and compare to crankshaft drawings to come up with a crank part number,and a fitment search to narrow it down to model-type, from there, you can probably use that for parts lookups until you hit on a part that fits only one type number, that is used on your engine, and voila..

Other than that no way I know of to positively identify from anything on the block.. except you can know it is somewhere between 400000 to 440000 model series probably

I suspected what you indicate, was hoping might be some type of ID numbers on the block or ??.

A was given a opposed twin engine with no air cowling and no carb.

When I started testing the engine the #1 cylinder has 90-100#'s and number #2 35 lbs and leak down test indicated valves ok but leakage past piston/rings. I removed the 42-2 head and the cylinder bore indicated a slight rust but nothing major so I suspect rings may be stuck from some water getting into the cylinder. I'll check the bore size and try to get a match up for rings, head gasket and sump gasket if bore with-in specs by using a spec chart you indicated.

I've noticed that several of the Briggs opposed twin engines have same model numbers but Hp's vary by several HP's going by the Briggs glued on decals

[bgsengine]

I removed the 42-2 head

chances are good you will have a 420000 series then but still wanna check bore x stroke to be sure it's 42 CID nominal

They can change the power output with carburetor jetting, restrictor plates in the intake, governor spring, etc to match the labels but bore x stroke = CID and the nominal CID is generally the first 1-2 digits of the model series , so , likely a 420000 series.

[KE4AVB]

The problem with that is that some of the 420000 series had different hp labels even on the same exact model, type, and trim codes. I personally had three of them on Craftsman mowers at the same time in the shop a few years ago. No difference in the parts between those three engines.