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Mark Roby (aka robymarks) [ View ] [ mroby@coatesfieldservice.com ] [ Car Ads ] [ Blogs ] Houston, Texas (281) 728-1824

I am full of questions tonight. I am running disc/disc. Any reason not to run the solid block type proportioning valve or should you still use the adjustable type? Thanks again

Comments

Posted by trorie  -  08/05/2008 10:09 PM I like the adjustables so it can be tuned to your car's weight. That's the advice I got from a guy that knows his stuff on this site. trorie [ View ] [ Email ] [ Blogs ] [ Car Ads ] Pleasant View, Tennessee   Posted by 41 Kustom  -  08/06/2008 07:28 AM I called to buy one from a well known supplyer out west. He told me to go to my local speed shop and buy an adjustable one. He also told me to try my system first and if work with out one, it would be fine. Do'nt know, but thats what he said. He said that I could put it in the rear line anywhere. 41 Kustom [ View ] [ Email ] [ Blogs ] [ Car Ads ] Essex, Vermont   Posted by aosborn  -  08/06/2008 10:23 AM This topic comes up quite frequently and there is alot of misinformation regarding what the different brake valves actually do. Proportioning valves allow full brake preassure to the rear brakes up to a certain preassure point, (medium brake preassure) and then reduces preassure increase in proportion to system preassure to the rear brakes if that point is exceeded up to maximum brake preassure. Doing this helps to control rear brake lockup as vehicle weight is transfered forward under hard braking. Factory style valves are excellent for doing this unless you made major modifications to your vehicle in either mass,(big block for example, more front end weight) tire size, wheelbase, suspension changes, etc which alter the weight transfer characteristics, tire contact patch etc. If the factory style valve is not set up for your vehicle combination then the chances of it working well are a crap shoot. That is why with vehicles I build that aren't restorations, I use an adjustable valve to custom tune the rear brake preassure limit for each specific car. Inresponse to 41 kustom, I would not run a car without some type of rear proportioning valve. I begin setting up my brake balance in smooth gravel parking lots before going out on the pavement, it is easy to see when the rears begin to lock up. Im sorry if I am rambling, but this is a major safety issue and folks need to understand what will happen with their vehicle when it is time for a panic stop. If you haven't driven your car at highway speeds and attempted a panic stop, I advise that you do it, but make sure you are in a safe place, and hang on tight!!! aosborn [ View ] [ Email ] [ Blogs ] [ Car Ads ] Olympia, Washington   Posted by trorie  -  08/06/2008 10:30 AM Good write Andy trorie [ View ] [ Email ] [ Blogs ] [ Car Ads ] Pleasant View, Tennessee   Posted by aosborn  -  08/06/2008 11:47 AM The post is regarding a disc/disc system. Testing lockup in the gravel is so an indication of rear lock up is obvious and can be adjusted out with the adjustable proportioning valve at lower speeds and then move on to testing rear lockup on a higher friction surface, ie pavement and at higher speeds. I then keep testing at higher preassures and speeds and adjusting it out of the rears until you get to the point where the fronts lock up first, which is what you are after for braking stability. At that point is when you go for the full on highway speed panic stop and see how the car reacts. I want to know how the car is going to react before I turn my customer loose on the world. aosborn [ View ] [ Email ] [ Blogs ] [ Car Ads ] Olympia, Washington   Posted by drpepper  -  08/06/2008 03:27 PM i attended a seminar last week at the nsra nationals by ralph licenia (probably mispelled) owner of eci. that question came up during the q and a. eci's typical brake diagram shows an adjustable proportioning valve. ralph said while their diagram shows one they don't sell them or even suggest that you use one if you have a street rod with larger rear tires than the front. he asked if anyone had ever adjusted one where it actually made a difference on a street rod and no one answered that they had. he added that only roundy round cars need them. i've installed them but i have never seen any difference in the braking no matter how their adjusted personally. i always buy from eci. in my latest car which is disc/disc. they suggested a combination valve in the front and no proportioning in the rear. only residual valves at both ends because the m-cylinder is lower than the calipers. drpepper [ View ] [ Email ] [ Blogs ] [ Car Ads ] henderson, Kentucky   Posted by hotrodgene  -  08/06/2008 03:44 PM I run a adjustable one but don't really know proper way to adjust.I messed around with mine because I felt I needed more rear brakes so I opened up the valve by turning countrclock wise and was later told I did it wrong.The person said I should have turned clockwise to get more rear brake and that don't seem right to me unless clockwise opens the valve.Anyone have help or advise for proper way.On hard braking car does not stop like it should.It has 4 wheel disc. Gene Riffe [ View ] [ Email ] [ Blogs ] [ Car Ads ] Saint Petersburg, Florida   Posted by drpepper  -  08/06/2008 04:14 PM i had the same problem with a disc/ disc set up and found the problem to be metric calipers on the rear and large gm on the front. (91 camaro on heidt's dropped spindles) the rears were ford explored 8.8. i called eci about the problem and the 1st question they asked was "do you have explorer disc on the rear?". i bought their 8.8/9 inch rear disc and it corrected my problem. eci says they gets lots of calls with the same symptom when explorer rears are used. call them and they'll help. they're good people. i most always ask for mark. p.s. they have a band aid fix which is a stepped pressure multiplyer that goes in the rear line. drpepper [ View ] [ Email ] [ Blogs ] [ Car Ads ] henderson, Kentucky   Posted by hotrodgene  -  08/06/2008 04:19 PM Mine are matched and are Wilwood Brakes. Gene Riffe [ View ] [ Email ] [ Blogs ] [ Car Ads ] Saint Petersburg, Florida   Posted by drpepper  -  08/06/2008 04:26 PM ralph answered questions last week in louisville and some concerned wilwood. he seeme very familiar with them. talked about several different piston sizes in wilwood. he said that most of his day is spent on the phone trying to correct brake problems. engineered components inc. drpepper [ View ] [ Email ] [ Blogs ] [ Car Ads ] henderson, Kentucky   Posted by APLUS  -  08/06/2008 06:46 PM drpepper, I also attended Ralph's (ECI) seminar and I thought that he said on a disc/disc system you didn't need a hold-off/metering valve (Ralph uses only part of the combination valve, machines the proportioning part off). On a disc/drum system he said to install the metering valve. Of course if your master cylinder is below your calipers you need 2 psi. residual valves in both front and rear lines with a disc/disc system and 2 psi. valve in front and 10 psi. valve in the rear with a disc/drum system. A combination valve is a two parter: metering/proportioning. On my '37 I have his Mustang II big brake system along with his master cylinder/power brake booster system. When I ordered my system he didn't have the machined metering valve in stock so I used the complete combination valve and it works perfectly. Sorry that this in so long but brake sytems are a very important subject. APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by drpepper  -  08/06/2008 08:43 PM that's correct. he uses the combo valve in just the front. i believe he said his valve is like 1/2 the oem. i bought his combo for my disc/disc on my 40. it's a small brass piece that gets plumbed between the front calipers. i don't remember if he called it a hold off but i do remember him saing that if it wasn't plumbed close to the center the left would engage slightly before the right. your also correct on the 2 psi residuals.over the years i've gotten combo valves and proportioning valves confused. i've only used disc/disc on the last cars i've done. i just go to mark and tell him what i'm working on and he sells me the right stuff. drpepper [ View ] [ Email ] [ Blogs ] [ Car Ads ] henderson, Kentucky   Posted by aosborn  -  08/06/2008 09:34 PM Disc/disc doesn't need a metering valve, that is for a disc/drum application to overcome return spring preassure. To hotrodgene, typically turning the valve clockwise allows more preassure to the rear brakes. Read my comment above on how to adjust it. Keep in mind for those folks who have had problems with adjusting manual valves, it could be a situation where the brake system is so out of balance that the range of adjustment might not be capable of overcoming a badly engineered system. I have had much success with manual adjustable valves. aosborn [ View ] [ Email ] [ Blogs ] [ Car Ads ] Olympia, Washington   Posted by 41 Kustom  -  08/07/2008 08:05 AM I have members in my club that have adjustable porpotioning valves. They don'nt know if they are working or not. The gravel test would be a good indication. I'm going to try that when the time comes. A smooth dirt road in the boonys would work for a higher speed test. 41 Kustom [ View ] [ Email ] [ Blogs ] [ Car Ads ] Essex, Vermont   Posted by db32  -  08/07/2008 03:15 PM I've got a similar question on my 32 roadster I've got about 250 miles now running 4 wheel wilwood disc brakes. It doesn't want to stop! I mean it will stop but I can't lock up the wheels even when I stand on it. I've played with the proportioning valve and see very little if any change. I heard from another vendor saying something about the pistons in the Wilwood being so small. I'm wondering if it's just my car or does anyone else have this problem. I've got an MP master cyl (#1001mz) 2lb residual valves on both front and rear but it doesn't seem to make enough pressure in the lines. Any answers would be appreciated. db32 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Spanaway, Washington   Posted by APLUS  -  08/07/2008 06:27 PM Ralph (ECI) did lightly go over some problems with Wilwood brakes in the seminar at the Nat's, something about piston size and master cylinder size. My best advice is call ECI and run it by him. The man knows about brakes---that's all he does. (860) 872-7046 APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by hotrodgene  -  08/07/2008 07:36 PM aosborn you are second person to say clockwise gives more rear brake and I believe you since I don't know,it would seem that would close off fluid flow so what is it I am not understanding.I really appreciate all's advise and help.I did check mine and it was turned counterwise as far as it would go so I went other way but haven't driven it yet. Gene Riffe [ View ] [ Email ] [ Blogs ] [ Car Ads ] Saint Petersburg, Florida   Posted by jimmothershead  -  08/07/2008 08:17 PM Going road racing thru the Blue Ridge Mountains, then use adjustable prop valve. Going cruizin', then use the block. Don't forget the 2 & 10 pound residual valves if master cylinder is under floor. Jim [ View ] [ Email ] [ Blogs ] [ Car Ads ] Huntingtown, Maryland   Posted by prost56  -  08/07/2008 09:13 PM so what about a 70 chevelle with disc/drum set up?..was wondering.since the pedel is lowwww,,power brakes dont seam to be that powerfull..humm prost56 [ View ] [ Email ] [ Blogs ] [ Car Ads ] west seneca, New York   Posted by robymarks  -  08/07/2008 11:23 PM 2 and 10 pound residual is on disc/drum isn't it? 2 qnd 2 on disc/disc? robymarks [ View ] [ Email ] [ Blogs ] [ Car Ads ] Houston, Texas Charter Member since October 2005   Posted by APLUS  -  08/07/2008 11:25 PM That is correct.......... APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by aosborn  -  08/07/2008 11:43 PM To DB32---How does the pedal feel? For example is the pedal hard to push and doesn't travel far, or is it just the opposite, soft with lots of travel? When you pump the pedal, does it pump up, or stay at the same level? When you push and hold the pedal hard, does it sink to the floor or stay put? To prost56---does the pedal on your chevelle pump up? If you hold your foot down on the brake pedal with the engine not running, and then start the car what does the pedal do, drop some and stay put or no real change? aosborn [ View ] [ Email ] [ Blogs ] [ Car Ads ] Olympia, Washington   Posted by prost56  -  08/08/2008 07:36 AM ill let ya know.. prost56 [ View ] [ Email ] [ Blogs ] [ Car Ads ] west seneca, New York   Posted by db32  -  08/08/2008 03:43 PM my pedal is solid, travels down 2-3 inches and stops, it doesn't move from there. I've tried pumping it up but it stays solid. I wouldn't say it hard or easy to push.......just normal. db32 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Spanaway, Washington   Posted by aosborn  -  08/08/2008 10:43 PM db32, if you have pedal travel to spare, you can up the brake system preassure by replacing the master cylinder with one with a smaller bore. Even a 1/16" dia change will make a noticeable difference. The potential downside is the increase in pedal travel. For manual brakes, 7/8" to 1" bore should be good, for power 1 1/16" to 1 1/8" would be what I would start with. aosborn [ View ] [ Email ] [ Blogs ] [ Car Ads ] Olympia, Washington

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