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MP 528 cam went flat, good time to make a few changes.....

Started by Kern Dog, June 06, 2022, 07:21:04 PM

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70 sublime

Just use what ever name you want for your picture but then ad the current date to the photo also will fix most of your name problem on the picture file
next project 70 Charger FJ5 green

Kern Dog

Thank you. This is very frustrating.
I made a specific file for pictures to post on THIS site, trying to make it easier by making them small enough and to categorize them with somewhat unique titles and STILL they bounced back. What the hell? Maybe sometime over my ten year membership, I had the same idea for a name that I had last week and this system refused it. That is simply a shitty operating system.
I know that the site is FREE to members and costs money for the owner to maintain but the man should either upgrade the site or sell it to someone who will. THIS is the only forum that I know of that has such a weird glitch like this.

Kern Dog

In summary.....
In May of this year, I installed the Borgeson steering box. Within 10 days, the cam went flat in the 440-493 and I pulled the engine to go through it.
While the engine was out, I decided to upgrade the brakes.
THAT turned out to be the biggest hurdle of the whole project.
The car  weighed 3940 lbs and has a Tremec 5 speed transmission.
Before the engine removal, I had 11.75" Cordoba front disc brakes with 2.75" single piston calipers, the Dr Diff 11.7" rear disc brake kit with 1.5" single piston calipers and a 1975 Dart power booster and 15/16" master cylinder. Braking was decent but not excellent.
I wanted to improve the braking to a level on par with newer cars so I ordered a 13" front brake kit with drilled and slotted rotors from Dr Diff and while I was at it, matching rear rotors. He also sent me an experimental hydroboost unit to install, test and report about.
I formed the hydraulic lines for the hydroboost, sourced a Saginaw P/S reservoir with 2 return line nipples, the suggested 79-93 Dodge D-150 2 bolt 1 1/8" master cylinder and screwed it all together.
Right away, the HB provided no boost while the steering worked normally. I bled the brakes and still, the HB was inop but soon, the steering assist began to fail. I put in another pump and the same thing happened again. A 3rd pump started going bad so I removed the HB and boxed it up to return it. I tried a number of bleeding attempts with the HB system with no success so I felt that I gave it a fair shot.
I installed a 15/16" master cylinder in an attempt to make a manual brake system work. I've driven and owned several manual disc-drum A bodies and the braking is excellent with them. I expected similar results from this car but was disappointed in the feel and performance. Pedal effort was very high and brake force was very low. I don't have gauges to test the pressures.
Yesterday I noticed that when I bench bled a master cylinder, that the front port (which is supposed to serve the rear brakes) got fluid and bubbles first. This surprised me because with the front brakes assuming the majority of the braking force on street cars, I'd have expected the rear port (which is supposed to serve the front brakes) to get the fluid first.

Today I lined up all the master cylinders that I have gathered....

Three are cast iron 4 bolt units. One at 1" and two of them 15/16".....They all had 9/16" front ports, 1/2" rear ports and when bench bled, pushed fluid equally in time front and rear.

Two of the aluminum units were 1.03" and had 9/16" front, 1/2" rear ports and pushed fluid equally.
One aluminum one was 15/16" and had weird 3/8" ports. The front reservoir was longer but the whole reservoir was sloped.

It pushed fluid to the front first.

The final two MCs are the ones I've been working with lately. Both 15/16" and 1 1/8" units have identical ports and push fluid to the front reservoir first.

Kern Dog

As I closed up the shop tonight, I can say that I may have the brakes at a point where I am satisfied.

I first had the 1 1/8" MC with the '75 Dart vacuum booster and a vacuum pump mounted behind the left headlights up in the wheelwell.
The pedal was too firm and the brake force was too high.
I switched to the 15/16" master cylinder that I had previously used in the attempt to run a manual based setup.
This resulted in a much better feel and better braking. Low speed braking is excellent, higher speed braking is better than before I started this whole project but not as good as I had hoped. I really wanted to be amazed at the performance like I am with newer cars. Again, it is very good and it will serve me well.


So you use a Mopar type front disk/rear drum master, boosted, for all wheel 13" disk? Got pics?

Kern Dog

I used aluminum master cylinders with large reservoirs based on the advice of Dr Diff.
As soon as I resize some pictures, I'll gladly post them up.

Kern Dog

Quote from: b5blue on November 24, 2022, 08:17:55 AM
So you use a Mopar type front disk/rear drum master, boosted, for all wheel 13" disk? Got pics?

Dr Diff sells a Ford based 13" front disc brake kit that fits the 73-76 A body disc spindle/knuckle. He includes adapter brackets to fit the aluminum calipers. They use 2 pistons, sized 1.59" each.
The entire front brake kit shed 14 lbs over the 11.75" Cordoba rotors and 2.75" iron calipers and brackets.

Kern Dog

The '528 cam had a wide lobe center which delivered decent idle vacuum. The Lunati cam I have now is ground on a tighter lobe center so the vacuum is under 10" at idle. To run a vacuum booster, I needed a vacuum pump.
I ran this pump before the last time I used this cam. It worked great then.
I cleaned it up before installing it despite the fact that it is in a place where it will get dirty. I just can't bring myself to install grungy parts.

Kern Dog

It has been awhile since the last update.....
The vacuum pump puts out 22" of vacuum but the brakes still didn't feel tip top. I changed the rear brake pads and drove it. Stopping power is great but inconsistent. I can stop a few times with great confidence and then randomly it will feel like there is no assist. I don't know if this is a matter of a finicky booster or what. I have a vacuum cannister that I might plumb between the pump and the booster. The added reserve may be all that is needed. If not, maybe the 47 year old booster needs to be rebuilt or replaced.
I still need to align the front wheels.
I installed an FBO ignition box and Flamethrower coil. This resulted in a bouncing tachometer needle. I'm told this does happen in some cases so thanks to Wayne in Canada, I have a diode that I will solder in the wire leading from the coil to the tachometer.
The engine runs great and makes plenty of power. The tighter valve lash (Compared to the '528 cam) results in quieter running. The Tremec shifts great.


Always thought about getting one of the FBO boxes mainly for the REV limiter but also for the plug and play.

Are you running a stock Tach? Or any idea why the bouncing problem?

Kern Dog

The gauge cluster is a Dakota Digital unit. I've read that some tachometers work fine while others react like mine.