Reply With QuoteI don't know what you can get away with on today's pump gas. But you will want an advance and not locked out. I'm thinking maybe 15 initial and 20 curve in the mag.
We are about ready to install the mag on our Hondo project and I'm looking for some timing advice. What we have is a 427 roller with 10to1, carbs and a tunnel ram. I have a Vertex mag locked out and would like to run pump gas. Thanks in advance
I don't know what you can get away with on today's pump gas. But you will want an advance and not locked out. I'm thinking maybe 15 initial and 20 curve in the mag.
Thanks for the reply Fiat48, but why can't we run our mag locked out like we do on our blown motor? Not second guessing you, just curious why it works on blower motors and not NA motors. Also how do we change that, do we have to send it to Don Zig
Pump gas and 10 to 1 compression is the reason why. Advance weights are a little tricky to put in those Vertex's so Zig should do it.
My 10.5:1 632" BBC tunnel ram motor likes 32 degrees on 93 Octane. Solid roller helps bleed down the cylinder pressures. (155 cranking) Timing locked in.....Only thing timing curve is really for is start-up. If you need it in the mid range something else is not set up correctly.
With a 10:1 427 I would start with 34, but it's probably going to like 36. What cam are you running and do you know your cylinder cranking pressures?
Not even sure what cylinder cranking presure is. But I know the gross lift is .620 on both sides, 110 lobe seperation, and 246 at .050. We set it at 32 degrees just to see if it would fire and it did, but it needs a good charge or the motor sounds like it's hydraulicing which I'm assuming is from the timing being locked out and the starter being stock? So what are our options here? We have been working day and night the last couple weeks trying to get this thing together so we could use it this weekend. I don't want to send the mag to Don Zig, because it took him nearly three months to get our last one back to us, and I would rather not run race gas if I don't have to. Can we run an additive with 91, or mix some race fuel with 91?
Stop trying to start the motor with that much timing before you hurt something (starter, flwheel, or bend a rod.)
If you must use it this way then do this:
Time the mag in the motor to start (16 to 20 degrees should work.) Make a mark on the distributor base/manifold.
Put a timing light on the motor. Start the motor and while it is running advance the timing to your desired timing (36 to 40). Make a mark on the base.
Now..carrying a 9/16 with you at all times. Move the mag back to the first mark for starting..then when running move it to the 2nd mark and go make a run. And I would use a gas additive for sure.
Or put another distributor in the thing till you can get some advance weights in the mag.
I have the weight set. $100.
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Thanks for the advice fiat, I won't start it that way again. For this weekend we'll just start it at 18 and then advance it once it's running. What kind of additive do you recomend?
I can't help you much on additives. That's why I run alcohol and never worry about such things.
Moroso used to be good..not sure if they still make it.
Is the reason that you can start a blown engine with locked out advance/ because of the lower compression ratio?
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