Master Cylinder for a Race only car

[turbodave231]

This question is strictly Race car related so I figured I'd post it here:

Has anyone replaced their Power Master with a manual master cylinder (no vacuum)? What brand did you use? What bore size? I've heard good things about Tilton Master Cylinders. I'm still set up with stock front calipers and rear drum setup.

Your Opinions and Experiences please..........

Dave

 

[bruce]

Originally posted by turbodave231
This question is strictly Race car related so I figured I'd post it here:

Has anyone replaced their Power Master with a manual master cylinder (no vacuum)? What brand did you use? What bore size? I've heard good things about Tilton Master Cylinders. I'm still set up with stock front calipers and rear drum setup.

Your Opinions and Experiences please..........

Dave

The one I was using was off a 81 El Camino, and used the flate adapter plate mounting.
Some use the P/M adapter, and a mopar brake master.

Tilton makes great stuff, but, it'd take alot of fab'ing to use one of his.

Remember to set things up so the push rod can NEVER come loose and fall out. ie, add a return spring.

 

[KendallF]

Dave,

I used a Mopar one straight outta the 'yard. If you buy one from Wilwood you basically get a Mopar m/cyl with an adapter kit. I took a stock powermaster mount plate, welded a flat plate on it, and drilled it for the Mopar unit.

As far as bore size, I think I ended up with a 7/8" piece; I also have a 15/16" one around here somewhere if I feel like I could put up with more effort/less stroke. The smaller the bore, the more pressure, but the longer stroke.

 

[turbodave231]

Kendall,

Does the Mopar unit have a captured pushrod? I'd like a Master Cylinder that the pushrod can't disengage the piston. I nearly lost a friend late last year (Cecil County) when his pushrod had a problem.

His accident really has me looking close at the safety stuff in my car.

My PM pressure switch is acting wierd and is causing the motor to try to cycle when the pressure hasn't dropped. I can probably replace the whole darn PM with a new Tilton or Wilwood unit for what a PM switch costs these days. Plus replacing the PM unit will take some weight and complexity off the car.

Bruce: Your advice on a positive stop and return spring is good advice!!!!!!

Dave

 

[bruce]

Originally posted by turbodave231

Does the Mopar unit have a captured pushrod? I'd like a Master Cylinder that the pushrod can't disengage the piston. I nearly lost a friend late last year (Cecil County) when his pushrod had a problem.

His accident really has me looking close at the safety stuff in my car.

Bruce: Your advice on a positive stop and return spring is good advice!!!!!!

Dave

No on the mopar, at least on the one I have here.

I also, plugged, and soldered up the combination valve so that both sides were fully independent, and also eliminated it as a possible leak.

Yep, brakes are not to be taken lightly.

FWIW, after years of running the manuals, and never being really satisfied with the geometry of things, went back to a vacuum booster set up.
FWIW II, I just went to the 02 Camaro front brakes, and they're terrific. I thought the 12" B Spindle set up was neat, but the dual piston calipers, and thicker (1.25") rotors really can let you shut down in a hurry.

 

[KendallF]

Originally posted by turbodave231
Kendall,

Does the Mopar unit have a captured pushrod? I'd like a Master Cylinder that the pushrod can't disengage the piston.

Dave,

It has the deeper hole (3/4" maybe?) for the pushrod. I used a stock pushrod, cut and shortened with some hex stock in the middle (basically like how we used to shorten wastegate rods). I have it adjusted so that it is captured and can't be removed without loosening the master cylinder mount.

 

[turbodave231]

Thanks Kendall,

I'm gonna look at the Mopar M/C as a strong possibility. What model cars/trucks make good donors? I wonder if the rear piston could be machined to accept an internal snap ring to capture the pushrod.

I've heard about the pushrod disengaging the Master Cylinder from more than one racer....and that's one problem I plan NEVER to have!

Dave

 

[Wheeler]

Master Cylinder

So, the bigger the bore the better?

Would the Wilwood 1"master cylinder sold under Summit P/N WIL-260-6766 be good to run?

Thanks for any help and info,

 

[drturbo69]

Re: Master Cylinder

SAW ONE ON TR WAS TOLD 70 CORVETTE MANUAL DISC BRAKES AND WAS A BOLT UP WITH P-MASTER PLATE HAD TO MAKE ROD .
HOPE THIS HELPS

 

[Nashty]

Re: Master Cylinder

Originally posted by Wheeler
So, the bigger the bore the better?

Would the Wilwood 1"master cylinder sold under Summit P/N WIL-260-6766 be good to run?

Thanks for any help and info,

A bigger bore requires more pedal effort but is a shorter stroke. If you are going full manual, anything under an inch is a good idea. I have a Strange M/C on the Metro. It was under $100 new and came with fittings. I used a Wilwood prop valve on the rear brakes. I have 4 piston strange front brakes and explorer rear discs also.

 

[HighPSI]

I have the 1 1/16 Wilwood MC on my car. I used the larger bore since I had disc's on all 4 corners and was considering dual calipers in the rear. I abandoned the dual caliper idea once I saw how well my current set up worked. If I were to do it over, I would probably use one of the smaller bore MC's.

 

[turbolou]

reply

I too have used the willwood/mopar set up with good results. The only problem that I could anticipate would be the diff. in the pressure that the power master has over the manual. This could be a problem if your foot brake launching. But if your useing a trans brake then the manual will work fine.

 

[Wheeler]

Thanks for the info.

So, far it seems the 15/16" Wilwood master cylinder is the way to go for my application.

Another question that has come up is their a need to change the brake peddle?

When I switched from a PM system to a vacuum system I changed the brake peddle too. Will this peddle work with a manual master cylinder too or will I need to change it?

As the car sits I'm running stock discs in the front and 11" drums on my 9" in the rear with an adjustable proportioning valve. I have a trans brake so building boost on a foot brake really isn't a concern.

 

[Quick Turbo V6]

Re: reply

Originally posted by turbolou
I too have used the willwood/mopar set up with good results. The only problem that I could anticipate would be the diff. in the pressure that the power master has over the manual. This could be a problem if your foot brake launching. But if your useing a trans brake then the manual will work fine.

Lou,

How did you mount the M/C to the firewall? The 2 studs on the firewall are to far apart to mount it.

Thanks,
Scott

 

[turbolou]

Re: Re: reply

Originally posted by Quick Turbo V6
Lou,

How did you mount the M/C to the firewall? The 2 studs on the firewall are to far apart to mount it.

Thanks,
Scott

Its been awhile but I seem to remember elongating the bolt holes to get it to fit.

 

[Scott Atk]

This guy has a nice setup. Pretty much complete. Although I'm sure it could be done cheaper.

http://www.smithperformance.com/catalogue_fbstock.html