B&S Diamond I/C 15.5HP Repair / rebuild

[bertsmobile1]

Hello,

Why should the carbon ring around the bore be left? Is it to prevent any lip from damaging the rings at TDC?

Thanks.

The rings take a beating from the burning fuel
The lip of carbon around the top of the bore goes a long way to alleviating the pressure & heat that is almost instantly applied to the rings .
So unless you are removing the piston you leave the carbon ring alone
Professional mechanics use a tool called a Ridge Reamer to clean the carbon ring off when removing pistons and it is just about the most expensive tool I have particularly when you consider it gets used once or twice a year at best .

The absence of the carbon ring was one of the big problems to overcome when developeing hydrogen powered engines because there is no carbon build up to protect the top ring so that required a total redesign of the piston rings and some engines now use 4 rings & / or a double thickness and deeper radial depth top ring .

 

[slomo]

Clean the block and cooling fins. In the pic where the push rods live, looks like steel wool slash grass and dirt around the cooling fins. Dirty fins cause over heats. Block and fins should look like a new engine. This is a yearly maintenance item in your engine manual.

 

[geertv]

Replaced the gasket and set the valve clearance. After mounting everything again, she runs like a charm !
Many thanks for all help, this was my first gasket repalcement

 

[slomo]

Good news you got her going again.

Hope you lapped/sanded/trued up the head and block area where the gasket sits. Piece of plate glass and some 220, 400 and 800 grit wet/dry paper. Every one I've seen has some warpage in them. Even engines that are not known to blow head gaskets. If you remove any head, check it out.

 

[gamma_ray]

The rings take a beating from the burning fuel
The lip of carbon around the top of the bore goes a long way to alleviating the pressure & heat that is almost instantly applied to the rings .
So unless you are removing the piston you leave the carbon ring alone
Professional mechanics use a tool called a Ridge Reamer to clean the carbon ring off when removing pistons and it is just about the most expensive tool I have particularly when you consider it gets used once or twice a year at best .

The absence of the carbon ring was one of the big problems to overcome when developeing hydrogen powered engines because there is no carbon build up to protect the top ring so that required a total redesign of the piston rings and some engines now use 4 rings & / or a double thickness and deeper radial depth top ring .

That makes sense. I wonder if CNG conversion vehicle have the same issue as the H2 engines, or is there a carbon buildup with burning CNG as well? I have a propane powered whose house generator and also a dual fuel "portable" generator, and your answer makes me wonder about those engines as well. I suppose there would still be a carbon deposit on those as well.

Thanks for your reply!
Gamma

 

[bertsmobile1]

That makes sense. I wonder if CNG conversion vehicle have the same issue as the H2 engines, or is there a carbon buildup with burning CNG as well? I have a propane powered whose house generator and also a dual fuel "portable" generator, and your answer makes me wonder about those engines as well. I suppose there would still be a carbon deposit on those as well.

Thanks for your reply!
Gamma

LPG engines will also build up a carbon ring although it will be smaller and take a lot longer to build up
H2 engines can not do this because there is no carbon in the fuel in the first place