Bad brakes

The bore size of the master cylinder may be too small. Did you change that or is it stock?

No, it is the same size, they did work fine once. I have changed booster and seal but nothing effects the brake performance...

the power brake booster relies upon vacuum to operate. The bigger cam = less intake manifold vacuum.

If you haven't already done these things, optimizing ignition timing and replacing a single plane intake manifold with a dual plane intake manifold will restore a lot of the vacuum your motor has lost.

-G

Low engine vacuum? Now there's a thought. You need around 12 inches minimum at idle to have vacuum assist to the brakes.'

However, if you don't, don't panic. You can install a vacuum reservoir kit in the car. An electric vacuum pump is also an option.

Measure the engine idle vacuum and see what you have.

Wilwood calipers are available with different size pistons.
So it does depend on what you fitted.
If the combined area of the Wilwood caliper pistons are greater than the stock Pantera calipers you will have a pedal that is softer & has more travel.
With this setup you should have better braking, but its possible to run out of pedal travel before the brakes bite.
In this instance you need to go to a larger master cylinder.
Smaller caliper piston area than stock, the pedal will have less travel & be much harder to push.
And as others have stated, lack of vacuum could also be the issue.
I used a vacuum bottle on my car, it helped a bit, but not enough.
So now I'm installing a Hella brake vacuum pump, (you can get these from Summit racing).

regards,
Tony.

I installed a vacuum pump after I determined that I was getting only 3" of vacuum. It makes a big difference.

Mark

The system I have is sorted out by Pantera Performance Center. Intake is a efi weber style with a small vacum block for the ecu. Electric pump?! Could a hose with smaller diameter make a diference?

Ahhh, so your running a similar system to what I have.
Because your manifold is individual runners there needs to be a vacuum port tapped into more than one intake runner.
Have a look & see how many intake runners are feeding the vacuum hose that in turn supplies the brake booster.
I tried one on my setup, (has a moderate cam) & that was not enough vacuum.
Now I have the vacuum supplied from 4 intakes & it still really needs more.
Brakes are OK, but could be much better.
(Difficult & time consuming to tap into more intake runners with the intake installed on the engine).
Hence the need for the electric vacuum pump.

regards,
Tony.

quote:

Because your manifold is individual runners there needs to be a vacuum port tapped into more than one intake runner.

If a carb is on top, it usually has a large vacuum port, and then put a plug in the hole in the manifold?

quote:

Originally posted by No Quarter:

quote:

Because your manifold is individual runners there needs to be a vacuum port tapped into more than one intake runner.

If a carb is on top, it usually has a large vacuum port, and then put a plug in the hole in the manifold?

I think the point is that there is not one carb on top on this setup. There are individual runners with 8 stacks. (Edge's avatar)

Got it. Yeah, need to find some vacuum "in the middle" somehow.

There is no "middle" like on a carbie manifold.
The 8 throttle body setup has 8 individual runners.
regards,
Tony.

Got it (too high tech for me)

How is this sorted on all other cars out there with this set up, Panteras and all? They all need vacuum, right?

I was thinking maybe some tubing to each runner, looking like a Nitrous injection but being just vacuum, 8 lines into one tube 3/8". Could be made good looking.

I would think that most IR setups will use Hall Pantera Weber intake manifolds? They don't lend themselves well to plumbing vacuum or nitrous under the manifold.

The 48ida's don't have vacuum ports, TWM 48ida throttle bodies do. I don't know about others like Clasic, which may.

Actually there is no rule that says a Pantera has to have power assisted brakes. I doubt the race cars do.

Plumbing all runners together for vacuum or even nitrous is not an esthetic delite. There are not going to be a lot of possible variations.

You could use 48ida carb spacers and put the plumbing nipple in them. That would save butchering up the manifold itself.

If that is too high of an assembly, you could mill down the mounting flange for the carbs on the manifold.

The Hall manifold is very thick there. The DT manifold wasn't and had the tendency to warp as a result.

As far as what size tubing to use for the plumbing to work, I don't know that.

With the Webers if you go too large it will affect interaction of the carbs since at some point you start to create a single plenum manifold and depending on the overlap of the cam, you are presurizing the tubing.

The Webers actually make enough vacuum for the brakes to take vacuum off of one cylinder. That's the way Halls manifold was sold new originally, with a vacuum port off of #8.

quote:

Actually there is no rule that says a Pantera has to have power assisted brakes. I doubt the race cars do.

I am working on such a setup right now...

In this picture you can see I'm pulling vacuum from cylinders 1 & 4, as well as cylinders 5 & 8 on the left side, (not visable).
This only just supplies enough vacuum for the brakes, it's the absolute minimum.
I find it difficult to imagine Halls system supplies enough vacuum from just one cylinder.
I tried that & it was hardly noticable, no brakes at all.
Maybe Halls setup may work with a stock cam?

regards,
Tony.

quote:

Originally posted by Edge:
In this picture you can see I'm pulling vacuum from cylinders 1 & 4, as well as cylinders 5 & 8 on the left side, (not visable).
This only just supplies enough vacuum for the brakes, it's the absolute minimum.
I find it difficult to imagine Halls system supplies enough vacuum from just one cylinder.
I tried that & it was hardly noticable, no brakes at all.
Maybe Halls setup may work with a stock cam?

regards,
Tony.

It takes a -10 hose. I suppose it depends on how much vacuum assist you want? I don't see where 8 1/4" hoses will do it either? I think it is volume rather then pressure itself?

The brakes are on the firm side, yes. Not at all like you would get slamming on those marshmallows that they call breaks in a Lincoln. Ford does need to build cars for your great grandmother and worse?

The Pantera was a "Luxury GT" sold at Lincol-Mercury dealers. I'm surprised that it was only built as a manual transmission and not an automatic as it is?

It isn't a perfect world that we live in now is it?

Seems like this thread wandered off track a little. . . .

My Hotrod truck:
wilwood fronts (came with a front suspension kit) and it would only lock the rears in the gravel.
added wilwood rear discs: it would only lock the rears in the gravel.
New master cyls: it would only lock the rears no matter how hard I pushed on the pedal.

At this point I was out of ideas - and mentioned to my fab man that it needed vacuum boost. Fab man says no.

(here is your possible answer)
So: I went and re-measured everything and did the math. (this is where you should find YOUR answer - doing the math on what you actually have)

Turns out the original front calipers were REAR calipers and the problems were all fixed by installing the correct FRONT calipers on the FRONT.

Sorry I don't have pictures of a wonderful carb setup or half nekkid girl to illustrate. - - - - make sure you have the appropriate sized calipers everywhere.

Done the math yet? Know exactly what you have? I didn't and spend a lot of $$$ until I did.

all the best,

quote:

Originally posted by SF:
Wilwood superlite brakes with balance bar brake effect is weak.
First installed they was great, 280 cam, then a turbocamshaft and now a Crower 292 cam. I have to push harder then hard to stop the car. No air in system soft brake pads.
Any thoughts?
Anders

Has not wandered off topic at all.
Anders has poor brakes, looks to be vacuum related & he is running an IR injection setup.

Looks like he had good braking, then changed the cam & now has poor braking, so more vacuum supply would be the obvious route to go down.

Yes alot has to do with caliper/master cylinder matching which was what I originally posted on this thread.
That all needs to be correct before you start chasing more vacuum.

PanteraDoug.
The 4 x manifold hoses I'm running are -8 which then feed into the original vacuum pipe to the front.

regards,
Tony

quote:

Originally posted by Edge:

PanteraDoug.
The 4 x manifold hoses I'm running are -8 which then feed into the original vacuum pipe to the front.

regards,
Tony

Tony how are the routed? Are they in line with t fittings tying them all together or do you have them running into a vacuum block individually until they reach the block?

When it comes to vacuum accessories and IR EFI, I recommend running an electric vacuum pump and plenum. Stock Panteras used vacuum for brake (majority of demand), ignition advance, carburetor secondaries, actuating the air cleaner door on inlet air warm up circuit, and a few other warm up and emissions gadgets.

The only thing left to talk about on an IR EFI converted engine are the vacuum assisted brakes. The brakes don’t need to be vacuum assisted. That’s just a choice. The problem with all the vacuum driven devices is they are all set up to work for a given engine combination, and changing the cam and induction systems usually means the vacuum condition is no longer sufficient nor reliably predictive of engine operating condition when it comes to driving things like ignition advance.

On subject of IR EFI, there is another recent thread (and many more) on useful sensors that discuss some of the reasons for separation of vacuum accessories and sensors and ECU control schemes. The short answer is that vacuum accessories can interfere with more important engine control and sensor schemes and vacuum is unreliable on high performance cam shafts.

http://pantera.infopop.cc/eve/...841081836#4841081836

Soooo, if you want to preserve vacuum brakes and simplify your life as far as engine tuning, a pump and plenum located as close to the brake booster/servo as possible is a good alternative. You’ll need a relay, fuse, to switched power and also to insure you have sufficient amperage available from your alternator system to run the pump.

Tony, on the matter of only using 4 of 8 cylinders for vacuum, do you find you are able to maintain uniform rich/lean conditions in all cylinders at idle? I’d be concerned about the potential for lean conditions over time. The other reason I suggest a separate vacuum pump for accessories is it takes big plumbing between the 8 cylinders to flow enough to achieve sufficient vacuum, and as mentioned, depending upon cam, sometimes never enough. At the same time it can foul up idle conditions and also if you are trying to run a MAP sensor off this vacuum circuit to do predictive enrichment routines (speed density approach), it can wreak havoc with this as well. -It can take some experimentation.

Best,
Kelly

Plumbing of the vacuum at the manifold are -8 Earl’s fittings.
90 degree at cylinders 4 & 8, both feed forward individually to a tee on top of cylinders 1 & 5, then across the front of the engine & tee into the original supply line.
Supply line goes up to the front area, into an Earls check valve, then a vacuum bottle, then into the twin diaphragm booster which has its original check valve.
(Ran this twin diaphragm booster when I had the Holly carbie & had heaps of vacuum & great brakes).
Now the intention is to fit a Hella vacuum pump which also draws on the vacuum bottle.
Fit a switch into the bottle which senses vacuum, switches the pump on at 15 hg & off at 22 hg.

Question: Both the vacuum pump & the engine drawing on the vacuum bottle.
When the pump is on it will draw close the engine supply check valve?
So with this setup, will it ever actually be using engine vacuum?

I am having issues with fouling plugs when idling for extended periods of time.
Then the engine starts to mis-fire.
This is I think more about getting the butterflies synchronized.
Last time I drove it I was fouling plugs, (NGK BCP5E S) on cylinders 5 & 6 which I believe these 2 butterflies must be slightly closed compared to the others, reducing air flow & thus running too rich on those cylinders.
I need to play with the air-bleed screws more for the idle, instead of relying so much on the idle screw on the butterflies.

New set of coil packs are on their way as originals are old & going to fit a set of Bosch Iridium plugs & see if I can get a better spark.

Regards,
Tony.

Hi

Ive been using this system on my car for years with weber carbs on hall pantera manifold. Brakes work great, have now upgraded to fuel injection and still works the same.

Joe

I know the system.

I think it works simply because each port comes individually to a common plenum.

The reversion pulse are therefore too small to play major havoc. If they were plumbed together in series. like Christmas lights, that would be a different story.

Obviously the volume of vacuum is sufficient to work the power brakes.

quote:

Originally posted by Edge: Plumbing of the vacuum at the manifold are -8 Earl’s fittings.
90 degree at cylinders 4 & 8, both feed forward individually to a tee on top of cylinders 1 & 5, then across the front of the engine & tee into the original supply line. Supply line goes up to the front area, into an Earls check valve, then a vacuum bottle, then into the twin diaphragm booster which has its original check valve.

Understood. It’s big plumbing compared to the 8-line set up in Joe’s post. I’m sure it flows well. One thing that does catch my attention is it appears 1 & 4 are plumbed in series, as are 5 & 8, then I presume the two pairs are plumbed in parallel at 1 & 4 and off to the check valve isolated vacuum plenum. If so, on a 1-3-7-2-6-5-4-8 firing order, it may induce some variation in the average vacuum each cylinder sees at idle because of their different relative positions in the firing order and the communication up and down the -8 line. This can be the case even if the vacuum has stabilized in your check valve isolated plenum (maybe even especially so). Not sure if this could be a contributing factor to the fouling issue but is would seem like it could create some anomalies when you try to vacuum sync the respective cylinders. -I’m sort of paranoid about plumbing symmetry in IR schemes.

quote:

(Ran this twin diaphragm booster when I had the Holly carbie & had heaps of vacuum & great brakes).

Even if it was the same cam, you had the benefit all eight cylinders sucking on the same plenum and butterflies.

quote:

Now the intention is to fit a Hella vacuum pump which also draws on the vacuum bottle.
Fit a switch into the bottle which senses vacuum, switches the pump on at 15 hg & off at 22 hg.

Sounds good.

quote:

Question: Both the vacuum pump & the engine drawing on the vacuum bottle. When the pump is on it will draw close the engine supply check valve? So with this setup, will it ever actually be using engine vacuum?

I would say if you need the pump to begin with, the engine vacuum may likely never get to draw air from your plenum. Sort of depends on the volume of the tank, the level of vacuum the engine can achieve, and displacement of pump and vacuum switch settings. The problem usually is when you need the vacuum most is when you have the least. If you are running WOT, you have no vacuum. If you need the mash on the brakes immediately after WOT, the booster servo needs to catch up. The plenum can at least can store enough for a few actuating cycles but can be drawn down with repeated application of pedal. The pump will likely be capable of higher vacuum than your engine. If you have a big enough reservoir/plenum, you may never draw it down enough to get into the region the engine helps you get there. The higher vacuum from the pump will likely mean crisp actuation of booster. I think you’ll like the pump approach and loose interest in engine vacuum.

What level of vacuum does the plenum stabilize at idle now?

quote:

I am having issues with fouling plugs when idling for extended periods of time. Then the engine starts to mis-fire. This is I think more about getting the butterflies synchronized.

If by misfire that’s backfiring or popping back through the throttle bodies this can be caused by one of the connected cylinders scavenging air from another it is connected to via the vacuum lines, then you have a lean condition which usually is consistent with backfire through carb, especially if you are running a fair amount of ignition advance. It’s a little more unusual for EFI but don’t know if you are running full sequential or different injector scheme.

quote:

Last time I drove it I was fouling plugs, (NGK BCP5E S) on cylinders 5 & 6 which I believe these 2 butterflies must be slightly closed compared to the others, reducing air flow & thus running too rich on those cylinders.

Are you setting the butterflies with feeler gauge then checking with synchrometer type vacuum gauge?

quote:

I need to play with the air-bleed screws more for the idle, instead of relying so much on the idle screw on the butterflies.

The challenge with setting the butterflies to control idle in IR scheme is they can be very position sensitive and a small change in position means a relatively large change in area thus idle speed or air fuel ratio variation cylinder to cylinder. This will be especially true for big throated throttle bodies trying to achieve low idle. It’s easy for the linkage to get out of tune too. I’ve seen lot’s of schemes. Some folks run the butterflies fully closed and drill a hole in each butterfly with diameter near enough to maintain idle and then trim with the idle air screws. On my next scheme, I’m going to try an idle air control valve on a common plenum plumbed to each cylinder and see if I can get decent closed loop response from a wideband O2 sensor.The Roush IR crate motor uses this scheme with reportedly decent success. It also works very well on the more typical plenum/runner/single throttle body set ups, most of which are massflow not speed density schemes.

Take care.

Best,
Kelly

Hmmm, I like the vacuum plumbing on Joes manifold, thanks for the pictures Joe.
I may take the time to drill & tap all runners & re-plumb in a similar way with smaller tubing.
At least that will potentially harmonize cylinder vacuum & may make it easier to tune.

Thanks for the info Kelly.
Yes I did synchronize the butterflies with a feeler gauge, but not with a vacuum gauge.

It’s been a learning curve, but I’m starting to come to grips with it & understand the setup better.
Sometimes it’s a good thing to have a few issues because you learn more during the process of sorting it out.
As well as people pointing out their ideas/solutions which helps greatly.

Vacuum pumps going in today.

Thanks all.
Regards,
Tony.

A little progres
I disconected that idle control valve, mechanical, and get a little better brakes. The brakes are moore instantley but when you apply the pedal at the first braking point but when you brake a second time the effects are weaker.

Thank you all!
Anders

It is not clear to me what you are referring to?
If you are saying that the brakes themselves work less and less and the car doesn't stop OR are you saying that the ASSIST is less and less as you pump the brakes?

If you are talking about the vacuum assist to the power brakes you need to verify that the brake vacuum booster is not ruptured and is working properly.

If it is, you most likely have low engine vacuum because of the camshaft profile. If that is so, the simplest remedy is to install a vacuum storage can plumbed into the vacuum system.

This usually adds enough stored vacuum to operate the car adequately.

Sorry, but you are not making yourself clear to me what the issue is.

Anders,

One of the benefits of all the electric cars now on the market is, it's created a demand for quiet electric vacuum pumps that are specifically designed to generate vacuum for power brakes.

This is the one I'm using:

http://www.metricmind.com/products/706e2/

... but I understand Hella makes a good one too:

http://www.summitracing.com/parts/HLA-009428087/

I'm sure there are others but these are two that I know of. Problem solved!

Anders,
My induction system is just about identical to yours.
This is what I finished fabricating & installed over the weekend.
Both the engine & an electric vacuum pump, (Hella) sucking on a vacuum bottle.
Both lines have check valves just before they enter the bottle.
Then the bottle is connected to the brake booster with the boosters standard check valve.
On the end of the bottle I have a Vacuum switch which is adjustable.
I adjusted it so the electric vacuum pump will suck up to 20hg, then switch off, when the vacuum drops to 15hg the pump switches back on again.
Tested over the weekend & the brakes are very progressive.
When you push the pedal right down the car nearly stands on its nose.
Made a huge difference to the braking performance.

Regards,
Tony.

I´m sorry if I missed something in my explination

It´s the ASSIST that is less and less as you pump the brakes.

I will go for a tank first, if I can find som space...
Regards
Anders

Do they have inboard regulaturs?
Anders

I have Wilwood dual master and IR intake. 1/2" ID hose plumbed to one port on Hall? intake. Cam is not that fat at .580' lift.
Brakes work flawlessly.
Hose in pic is connected to TB at cyl #2

How vacuum lines run on my manifold. There used to be a little alloy 2 to 1 manifold bolted on, but didn't like it, and will be replaced by a simple "T" piece to connect both sides.

"""A little progres
I disconected that idle control valve, mechanical, and get a little better brakes. The brakes are moore instantley but when you apply the pedal at the first braking point but when you brake a second time the effects are weaker.""""

I had this problem a few years ago. It turned out to be a defective seal between the master and the booster. It would work at the beginning and then there was little braking after I depressed the brake pedal the second time. I bought a vacuum reservoir and never mounted it because I found the defective seal. It too thought it was lack of vacuum but it didnt make sense because it had worked well for years.
Will

when I was wrighting about regulators I ment the Hella vacuum pump. My new motor has .650 lift, even less vacuum then that by the old motor. Think I have to add reservoir or pump or both.
Regards
Anders

4NHOTROD what kind of throttle bodies are you using, is that the low style from IPSCO?
Anders

My car has a fairly large can with lots of duration and lift. The brakes used to be unpredictable. Work well sometimes and sometimes not so well. I installed the vacuum pump that Scott at SACC sells and the brakes are very consistent now. The work well all of the time. The pump is a little loud but the sound of the 180's mask it out well enough.

quote:

Originally posted by SF:
4NHOTROD what kind of throttle bodies are you using, is that the low style from IPSCO?
Anders

Yes, they are.