3.0 Liter OMC (Looper) Block
This engine was first produced around 1987. Referred to as the “open deck” block, it has a 3.685" bore x 2.858" stroke…183 cubic in. We started playing with this engine on my own pleasure boat in 1987 and are still developing it today. With the stock bore and stroke we have seen close to 500 hp and have turned these engines over 10000 rpm (many times over 11,000 rpm) for over 20 years. The basic bore /stroke rod ratio and exhaust design is very good but as with all the Johnson/Evinrude products it involves hundreds of hours of porting and many aftermarket parts to achieve these type of results.
In the late 80’s and early 90’s we were already achieving 400 hp with the stock electronics, front half and plastic carburetors. Unfortunately it took a solid 100 hours of porting and a bunch of trick parts to do this. Today using modern fuel injection and cdi or high output inductive ignitions we are in the 470 hp range with very good power to 9000 plus rpm very reliably. As it was 20 years ago it still takes massive amounts of time to port one of these engines and still the same trick parts to achieve this. The fact of the matter is if the block were cast correctly like a Yamaha or Honda motorcycle these things would come stock with this type of power. Unfortunately OMC only had a target of 225 hp and that came easy along with horrendous castings…ports…and electronics. We have won dozens of rounds racing the 3-liter format.
Over the years there have been numerous companies and engine builders that have developed parts to modify this engine. It is mind boggling to think back to all the tests good and bad that we have performed on this engine. At one point we were able to fill a 55-barrel drum with used pistons, many with holes. We have made over 2000 dyno pulls on this block.
I am pretty sure we were one of, if not the first shops to fuel inject this 3-liter. Today this open deck block is still competitive. The main advantage to this engine is it was originally built in England and had a well designed exhaust. But more importantly when you want to see high rpm the exhaust chest has large headers that make this possible. This is the common block of choice for the few high-end OMC builders…we punch them to 3.3 liter. This is an amazing amount of work and depending on the builder it can be very expensive.
In a 3.3 configuration, this block has seen well over 500 hp and over 400 ft/lb of torque from this 1988 fishing engine. This is a drag race only configuration. The 3-liter version of this engine, depending on components and electronics, make mid 400 hp readings with F-1 reliability.
We are currently developing optimized engine kits that are finger port based. They work. I won Jasper with a 3-liter finger ported engine. We are working on both a 3-liter and 3.3 that use a number of parts including, pistons, sleeves and heads we build and will come with a preprogrammed ECU for this design. The main idea is bolt on and haul ass reliably. We are deep into this development and are offering do it yourself versions (you do the porting) or you can pay us and we can do it to a spec we know works. We are also working with other engine builders that are qualified to do the proper port work so you can achieve near the same results as we do. We will soon have a list of shops. Porting is very time consuming. Very difficult.
We have a goal of 500 hp with a 3.3-liter finger port design using this block. This will be less labor intensive and not require all the welding, warping, and line boring we do on behind the liner versions. When this is up and running it will be the ultimate sleeper.
We also have extensive testing background with the old 3-liter stock carburetor engine. We were contracted in the early 90’s to build a competitive and reliable F-1 engine. We did and they didn’t buy it. They chose to go with the Ficth block and there record speaks for itself. It is possible to use this old front half and bolt on EFI and make over 400 hp. Actually you can do it with carbs.
Please call to discuss your project.
Back To Technical 101
In the late 80’s and early 90’s we were already achieving 400 hp with the stock electronics, front half and plastic carburetors. Unfortunately it took a solid 100 hours of porting and a bunch of trick parts to do this. Today using modern fuel injection and cdi or high output inductive ignitions we are in the 470 hp range with very good power to 9000 plus rpm very reliably. As it was 20 years ago it still takes massive amounts of time to port one of these engines and still the same trick parts to achieve this. The fact of the matter is if the block were cast correctly like a Yamaha or Honda motorcycle these things would come stock with this type of power. Unfortunately OMC only had a target of 225 hp and that came easy along with horrendous castings…ports…and electronics. We have won dozens of rounds racing the 3-liter format.
Over the years there have been numerous companies and engine builders that have developed parts to modify this engine. It is mind boggling to think back to all the tests good and bad that we have performed on this engine. At one point we were able to fill a 55-barrel drum with used pistons, many with holes. We have made over 2000 dyno pulls on this block.
I am pretty sure we were one of, if not the first shops to fuel inject this 3-liter. Today this open deck block is still competitive. The main advantage to this engine is it was originally built in England and had a well designed exhaust. But more importantly when you want to see high rpm the exhaust chest has large headers that make this possible. This is the common block of choice for the few high-end OMC builders…we punch them to 3.3 liter. This is an amazing amount of work and depending on the builder it can be very expensive.
In a 3.3 configuration, this block has seen well over 500 hp and over 400 ft/lb of torque from this 1988 fishing engine. This is a drag race only configuration. The 3-liter version of this engine, depending on components and electronics, make mid 400 hp readings with F-1 reliability.
We are currently developing optimized engine kits that are finger port based. They work. I won Jasper with a 3-liter finger ported engine. We are working on both a 3-liter and 3.3 that use a number of parts including, pistons, sleeves and heads we build and will come with a preprogrammed ECU for this design. The main idea is bolt on and haul ass reliably. We are deep into this development and are offering do it yourself versions (you do the porting) or you can pay us and we can do it to a spec we know works. We are also working with other engine builders that are qualified to do the proper port work so you can achieve near the same results as we do. We will soon have a list of shops. Porting is very time consuming. Very difficult.
We have a goal of 500 hp with a 3.3-liter finger port design using this block. This will be less labor intensive and not require all the welding, warping, and line boring we do on behind the liner versions. When this is up and running it will be the ultimate sleeper.
We also have extensive testing background with the old 3-liter stock carburetor engine. We were contracted in the early 90’s to build a competitive and reliable F-1 engine. We did and they didn’t buy it. They chose to go with the Ficth block and there record speaks for itself. It is possible to use this old front half and bolt on EFI and make over 400 hp. Actually you can do it with carbs.
Please call to discuss your project.
Back To Technical 101