Fixed or adjustable proportioning valve

[luvmyclassics]

Getting ready to start on the brake lines soon.

I have an f1 and am putting disc brakes on the front and staying with drums on the back.

Any suggestions as to whether to use a fixed or adjustable proportioning valve?

I like the idea of the fixed so I do not have to try and adjust the ratio myself. However, if I am better off with an adjustable valve, that is what I will purchase.

Thanks in advance.

[V8 Bob]

You want an adjustable proportioning valve on any non-stock/custom disc/drum or disc/disc system to allow tailoring the front/rear bias. Fixed value OE valves were designed for a particular vehicle, CG, weight, wheel base, tire size, brake system etc etc.

[woodiewagon46]

I would give both Master Power Brakes or Godman Performance a call. Both my cars have fixed, preset, proportioning (combination) valves as advised by them. Both my cars stop on a dime and could not be different in weight. My Deuce roadster weighs about 2700 lbs and my '46 Woodie weighs about 4000 lbs. and both use the same components. A combination valve has fluid metering, pressure proportioning and a system failure indicator built in. If you do use an adjustable valve you need a metering valve to balance the system. Adjustable valves are fine if conditions change such as on different race tracks. I'm sure you are going to get nothing but conflicting answers on this subject.

[V8 Bob]

Originally Posted by woodiewagon46

I would give both Master Power Brakes or Godman Performance a call. Both my cars have fixed, preset, proportioning (combination) valves as advised by them. Both my cars stop on a dime and could not be different in weight. My Deuce roadster weighs about 2700 lbs and my '46 Woodie weighs about 4000 lbs. and both use the same components. A combination valve has fluid metering, pressure proportioning and a system failure indicator built in. If you do use an adjustable valve you need a metering valve to balance the system. Adjustable valves are fine if conditions change such as on different race tracks. I'm sure you are going to get nothing but conflicting answers on this subject.

One reason there are conflicting answers or knowledge is the incorrect info put out by some brake suppliers. Most of the FAQ from MPB are good, while some is not. They don't understand the operation of residual and metering valves, and they are wrong about needing metering with proportioning. It was not used on all disc/drum systems. Metering had more to do with pedal and front suspension response on some vehicles, and nothing to do with proportioning.

[mrtexas]

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Originally Posted by woodiewagon46

I would give both Master Power Brakes or Godman Performance a call. Both my cars have fixed, preset, proportioning (combination) valves as advised by them. Both my cars stop on a dime and could not be different in weight. My Deuce roadster weighs about 2700 lbs and my '46 Woodie weighs about 4000 lbs. and both use the same components. A combination valve has fluid metering, pressure proportioning and a system failure indicator built in. If you do use an adjustable valve you need a metering valve to balance the system. Adjustable valves are fine if conditions change such as on different race tracks. I'm sure you are going to get nothing but conflicting answers on this subject.

Are you using corvette or mustang MC? Both work just fine.

Here is the proportioning valve I used twice both on my 36 and 41 also having space for the brake light switch, very high quality unit, never had to adjust the PV:
http://www.ebay.com/itm/CPP-HOT-ROD-...5UTsnE&vxp=mtr

And the metering valve makes sure the rear brakes come on first:http://www.speedwaymotors.com/Brake-...SABEgKvGPD_BwE

You also need some residual valves 2psi and 10psi because your MC is below the brakes:
http://www.speedwaymotors.com/Wilwoo...gs,233815.html