M112 - 300 Build for the '56

clintonvillian

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This thing has stalled momentarily (Getting the Bronco in summer shape so me, wife, and kids can enjoy the warm weather). As such I have been doing some research.

Here is a picture of the actual lightning solenoid that operates the vacuum diaphragm on the M112. The diaphragm has two ports, one is a "manual" in which if vacuum is seen on the engine intake manifold, it will open the diaphragm allowing the air to bypass the rotors.

The second nipple connects to the solenoid in the picture. When the computer sends a signal to the solenoid it in turn opens up, allowing vacuum to be seen at the diaphragm and opening up the butterfly valve.

My question now becomes is the an all or nothing solenoid. I assume it is 5 volts? Would you guys think that is correct? Does it have to have a full 5 volts, or is it variable so that at 1 volt it lets some vacuum through and cracks the valve?

What do you guys think?

If I buy it is there any way to test it?

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MechRick

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Solenoids typically operate with 12 volts. There is usually a shared 12v connection with all solenoids in the vehicle, and the ground side is controlled by the PCM to turn it on or off. Partial operation would be pulse width control, but I don't think the supercharger bypass operates that way...
 

pmuller9

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Here is a picture of the actual lightning solenoid that operates the vacuum diaphragm on the M112. The diaphragm has two ports, one is a "manual" in which if vacuum is seen on the engine intake manifold, it will open the diaphragm allowing the air to bypass the rotors.

The second nipple connects to the solenoid in the picture. When the computer sends a signal to the solenoid it in turn opens up, allowing vacuum to be seen at the diaphragm and opening up the butterfly valve.

My question now becomes is the an all or nothing solenoid. I assume it is 5 volts? Would you guys think that is correct? Does it have to have a full 5 volts, or is it variable so that at 1 volt it lets some vacuum through and cracks the valve?
The solenoid is 12 volts and is either on or off.

The question is why do you need it?

The computer uses it to open the bypass valve to reduce boost under certain conditions.
When the throttle body is wide open and the supercharger is making full boost the bypass valve is not large enough to bypass all the airflow so some boost remains.
When the throttle body is partially open during cruise conditions the airflow is low enough where the bypass valve can bypass all of the airflow past the supercharger.
 
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bubba22349

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Those were the timing marks used on the early Carb engines with V belt drive front dress you would also need to use the early Crankshaft Dampeners for those marks to line up and work, or make a new mark at TDC on your Dampener. I think the timing covers are the one few parts that didn't change much if any from the 1965 240 & 300 six engines introduction to end of 4.9 / 300 six production so it should be interchangeable for any year engine, but I might be wrong. Best of luck
 

Frank

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Good Sunday afternoon gentlemen... The simple well known formula to calculate HP or torque can also be used to find the RPM at which a known HP @ known torque occur. Your first post, you were shooting for 300 HP with 400 lbs of torque. This power paring occurs at 3939 RPM. Your planned setup should produce this with ease. . Nice build! (RPM= HP x 5252 / torque.)
 

clintonvillian

Famous Member
I would mount everything on top which would block the heat from the exhaust.

You may need manifold vacuum/pressure for something later. Add two spare.

The air temp sensor uses a 3/8"-18 NPT thread size.
You may want to wait till you get one to finalize the hole
Getting ready to finish order my "add ons" from holley, wanted to make sure I am not missing anything as far as sensors and signals go....

Cam sensor (96 distributor with vanes ground off)
Crank Sensor and Wheel
IAC
TPS
Air Temp Sensor
MAP
PCV
Oil Pressure Sensor
Knock Sensor
Coolant Temp Sensor

Am I overlooking anything???
 

clintonvillian

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Talked to Molnar, They will have press fit rods available soon in the stock size.

Bushed rods are still up in the air. Which should I go with?

I'll have to have custom pistons made, I think you recommended racetek, is that correct?
 

pmuller9

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I would just go with the press fit rods since you don't plan on changing pistons and rods like you do on a race engine.
Plus you don't have to worry about a clip coming out of place.

Is Molnar making the rods as a catalog item?

Yes on Racetec pistons.
 

clintonvillian

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I would just go with the press fit rods since you don't plan on changing pistons and rods like you do on a race engine.
Plus you don't have to worry about a clip coming out of place.

Is Molnar making the rods as a catalog item?

Yes on Racetec pistons.
I think so.

Do I need to confirm that racetec can make the piston for the press fit pin, or is that a given?
 

pmuller9

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Do I need to confirm that racetec can make the piston for the press fit pin, or is that a given?
The RaceTec piston will have the grooves for the clips for a floating pin or you can use the piston without the clips for a press fit pin.

Did Molnar say what the price was going to be on their 300 six rods?
 
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