Stab-n-Steer
08-27-2005, 08:38 AM
Hey Guys,
Need some help! I race Crackerboxes and at Long Beach 2 weeks ago the motor started loosing RPM. Let me give you a little background on the motor... Due to the rules we are limited to 314 CUI and a 650 Holley. We are direct drive (no overdrive) and build the motors to rev very high. We run a large bore, short stroke configuration, 4.155 x 2.82. The motor has always run up to 9200 on the shoots. At Long Beach we were only able to pull about 8200...
Motor is a Bow-Tie small block, 23 degree CNC ported Brodix Track I heads with Ti valves. Crower springs are new... 13 to 1 compression and we run VP 114 octane. Mag is a Mallory Sprint Mag that was just serviced at Mallory.
The motor is fresh with maybe 12 heats on it. It runs great, pulls real hard off of the corners just doesn't pull the top RPM we're use to. We moniter air with a weather station so we are pretty sure jetting was very close. It's hard to do a good plug check because we have to idle in to the ramp but the plugs looked good.
On the Dyno it made the most power with 40 degrees of timing. Thinking that much timing may be hurting us on the big end we went down to 38 with no results.
The cam has been in the motor awhile. It's a roller and when we freshened up the motor I noticed the rollers were leaving a "whitness" mark on some of the lobes. It wasn't a deep groove or anything and was told that was pretty normal for a roller... I'm thinking the cam may be going away. Any thoughts or suggestions would be very much appreciated!
S&S
Need some help! I race Crackerboxes and at Long Beach 2 weeks ago the motor started loosing RPM. Let me give you a little background on the motor... Due to the rules we are limited to 314 CUI and a 650 Holley. We are direct drive (no overdrive) and build the motors to rev very high. We run a large bore, short stroke configuration, 4.155 x 2.82. The motor has always run up to 9200 on the shoots. At Long Beach we were only able to pull about 8200...
Motor is a Bow-Tie small block, 23 degree CNC ported Brodix Track I heads with Ti valves. Crower springs are new... 13 to 1 compression and we run VP 114 octane. Mag is a Mallory Sprint Mag that was just serviced at Mallory.
The motor is fresh with maybe 12 heats on it. It runs great, pulls real hard off of the corners just doesn't pull the top RPM we're use to. We moniter air with a weather station so we are pretty sure jetting was very close. It's hard to do a good plug check because we have to idle in to the ramp but the plugs looked good.
On the Dyno it made the most power with 40 degrees of timing. Thinking that much timing may be hurting us on the big end we went down to 38 with no results.
The cam has been in the motor awhile. It's a roller and when we freshened up the motor I noticed the rollers were leaving a "whitness" mark on some of the lobes. It wasn't a deep groove or anything and was told that was pretty normal for a roller... I'm thinking the cam may be going away. Any thoughts or suggestions would be very much appreciated!
S&S