steel inserts in aluminum heads

Discussion in 'PSI Superchargers Tech Questions' started by blownmudrail, Jul 19, 2010.

  1. blownmudrail

    blownmudrail New Member

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    i know this has been asked before. but i have steel inserts in brodix aluminum heads, have burned the cadium of the face of plug and down to first thread. how does the steel inserts affect the heat going into the plug? is this too rich or to lean or just right. and how much timing has anyone ran in a sbc 10-71 hi helix, 406, 12.3:1 compression, mag 4? have 36 degrees timing in it now but spud miller said it would lose 4 degrees at 4000 rpm. was wondering how far to push the timing seems to just keep running better with the more i add. just dont want to go to far. thanks jeremy
     
    #1
    blownmudrail, Jul 19, 2010
  2. Mike Canter

    Mike Canter Top Dragster
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    The steel inserts are meant to be OK for heat transfer so it will be pretty close. When you say you have burned off all the cadium is the base circle dark gray/black or is it frosty looking after one run on new plugs. How much are you wanting to push this motor?
     
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    Mike Canter, Jul 19, 2010
  3. blownmudrail

    blownmudrail New Member

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    they are turning slight gray/black. blower is 51 percent over makes 38 to 40 pounds boost. only run 200 ft so want to lean on the moter, timing make on plugs is just on the begining of the bend.
     
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    blownmudrail, Jul 20, 2010
  4. Mike Canter

    Mike Canter Top Dragster
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    The problem is that you will not correctly color the plugs or the blue line in 200ft. My guess is if the plugs are like that in 200 ft you are probably lean. 12.3:1 is a lot of CR. You need to pay real close attention to the sharp corners of the ground strap using a magnifying glass and a light. When you start seeing the corners/points start rounding off then you are just starting to detonate. Compare them to a new plug so you have a comparison. The more advance you put in the more fuel you need.
     
    #4
    Mike Canter, Jul 20, 2010
  5. Ken Sitko

    Ken Sitko Super Comp

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    We run a tafc, and have had one hole with a steel insert in it for the past while. It doesn't seem to hurt the piston, but while the other 7 plugs still have all the cad on them, this cylinder is burnt down to 1 thread. I would estimate that the motor is still 0.5 gpm rich, but this cylinder is showing lean. I have used the time serts as well, and while they are a bit better, the plug still shows leaner on the steel inserted cylinder. I think it is best if you fix the stripped hole with an aluminum insert.
     
    #5
    Ken Sitko, Jul 20, 2010
  6. blownmudrail

    blownmudrail New Member

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    so did you lean out the motor more? i have inserts in all eight holes. and the car will never run over 200 ft so im happy with the fuel but not if i can lean it out more. was mainly just wondering about the timing. thanks for your responses
     
    #6
    blownmudrail, Jul 21, 2010

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