SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: bac Tahiti on May 08, 2015, 06:56:47 PM
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Help please!
Have a new curved HEI on a 460 ford jet 21' tahiti. Person who curved the HEI on a machine said to set run the motor to 3000 rpm and set HEI between 32-34 degrees. Don't worry about the idle. Does this sound right?
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Yes it does, the idle will be adjustment with the carb.
Sent from my garage drinking a cold PBR
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Thank you! :-)
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ive heard that method before many times. its been explained to me that the engine spends more time somewhere in the advance curve or at full advance than it does at idle. most of us arent asking much from our engines at idle...other than to stay idling. engine should work better if allowed to fully advance when its supposed to. :beer:
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ive heard that method before many times. its been explained to me that the engine spends more time somewhere in the advance curve or at full advance than it does at idle. most of us arent asking much from our engines at idle...other than to stay idling. engine should work better if allowed to fully advance when its supposed to. :beer:
This is close but wanted to clarify a couple of things.
The engine will idle better with more initial advance. It will create more vacuum also. Making the idle circuits on the carburetor more effective. It can potentially take away some of the lumpiness out of the idle.
The reason for being able to do this is because the jet pump requires almost no torque at lower rpm, so the engine does not have to "pull a gear". The timing can ramp up virtually immediately off idle.
GT
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Thaks GT you have always been helpful!
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Too much advance during starting (like a locked out dist), especially with high compression will reek havoc on a starter and make the engine difficult to start.
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This is close but wanted to clarify a couple of things.
The engine will idle better with more initial advance. It will create more vacuum also. Making the idle circuits on the carburetor more effective. It can potentially take away some of the lumpiness out of the idle.
The reason for being able to do this is because the jet pump requires almost no torque at lower rpm, so the engine does not have to "pull a gear". The timing can ramp up virtually immediately off idle.
GT
makes sense. so what ive been told was implied to street cars.... they didnt mention idling better or making carb more efficient. hmm....if you smell smoke, its me....im thinking. ;D
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The spec I didn't see in the first post is how much mechanical advance will the distributor give?
The idea is to get as much initial advance as the engine will allow without becoming hard to start or dieseling on shut down, and then use mechanical advance to get you to your desired 32-34 degrees above 3000rpm.
You get what I'm saying?
So if your distributor is set up with 20 degrees mechanical advance your static will fall around 12-14 initial.