sbc 400
04-12-2011, 06:34 PM
#4
Senior Member
DYNO OPERATOR
Join Date: Jan 2004
Location: central Illinois
Posts: 459
SBC 400
I believe SRP pistons and other 4000 series high silicon pistons are not recommended for alcohol competition drag race engines. Coated piston skirts can help minimize wear in alcohol engines.
A vacuum pump system is recommended to minimize dilution of oil.
Gapless rings are also popular in blown alcohol truck and tractor pulling and so are stainless top rings.
A vacuum pump system is recommended to minimize dilution of oil.
Gapless rings are also popular in blown alcohol truck and tractor pulling and so are stainless top rings.
04-15-2011, 05:37 PM
#6
Senior Member
EXPERT BUILDER
Join Date: Nov 2009
Posts: 267
I am a dirt modified guy, and just switched back this season to VP113 race gas instead of methanol. The biggest, and mainly only reason to run methanol, is for heat control. Methanol engines run cool and clean, but the negative reasons FAR outweigh any good reasons to do so for circle track racing.
The biggest factor in methanol engines is to have as much compression as possible with tight closed chamber heads, and a lot of advance distributor timing. Methanol burns much slower than gas, so you have to put a lot of advance timing in it as well as an MSD type fire source to keep it lit good. The fame front is much slower and harder to ignite so you really need compression ratio of at least 12 to 1 to help complete combustion. Methanol engines can be difficult to start sometimes if everything is not just right.
You also need to run really tight wall to piston clearances, with preferably forged pistons, and really good rings (moly or better) to help reduce oil washdown from the cylinder walls.
You will need to change the oil at least twice as much as a gaser engine, as well as freshen the motor with new bearings and rings at least every season start. We will not even get into all the damage and maintinance on your fuel system parts that are a pain in the azz reason ro not run alky.
There has been much debate over any power or torque benfits, or not, running alky, with no apparent real hardcore facts to prove either way for circle track use. The numbers of people still using alky in circle track is dwindling very fast due to the vast improvments in available racing gas.
The biggest factor in methanol engines is to have as much compression as possible with tight closed chamber heads, and a lot of advance distributor timing. Methanol burns much slower than gas, so you have to put a lot of advance timing in it as well as an MSD type fire source to keep it lit good. The fame front is much slower and harder to ignite so you really need compression ratio of at least 12 to 1 to help complete combustion. Methanol engines can be difficult to start sometimes if everything is not just right.
You also need to run really tight wall to piston clearances, with preferably forged pistons, and really good rings (moly or better) to help reduce oil washdown from the cylinder walls.
You will need to change the oil at least twice as much as a gaser engine, as well as freshen the motor with new bearings and rings at least every season start. We will not even get into all the damage and maintinance on your fuel system parts that are a pain in the azz reason ro not run alky.
There has been much debate over any power or torque benfits, or not, running alky, with no apparent real hardcore facts to prove either way for circle track use. The numbers of people still using alky in circle track is dwindling very fast due to the vast improvments in available racing gas.
