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I do not use air cleaners on my Webers as they really destroy the looks, and I don't believe extensive harm will come to the motor with a couple hundred miles a month (I hope). Lately I started to put the Velocity stack caps on the carbs when parking it for a few days. Today I noticed oil on the underside of two connected caps on the carb that sits above cylinders 3 and 4. Could this to be from off gassing as I'm not burning oil? If so, why on two stacks only? Valve position? The inside of the stacks had a very slight oily film on them. I'm stumped and a little worried.

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All the Ford v8's I've had will siphon oil from the valve covers through the pcv system  into the intake if the mounting point into the intake is lower then the top of the valve cover. Some are worse then others.

Small amounts of oil are ok as they tend to lube the valve stems beneath the seals but will eventually cause a large build up of oil on the reverse side of the valves which could crumble and get into the cylinder.

I prefer to install an oil sepereator in the line since it is virtually impossible to get the entry point into the intake manifold high enough to stop the siphoning.

The worst I've seen was my parents '76 Granada with a 2v 302. It was completely stock and untouched by me. They took it on a 500 mile trip new and when they came back there was no oil in the engine at all.  So personally I learned to always check the dipstick everytime I stop for gas.

My Webers are plumbed for vacuum on all 8 cylinders and I don't see any evidence of the oil siphoning with the separator but the contents of that catch tank is usually a slimy mix of water mixed with oil.

Most people running a 48ida system are venting the valve covers to the atmosphere with vented caps so you don't hear much about this scenario but within recent years it has been documented that the engine will benefit with better ring sealing with a closed pcv system and there are dyno tests around that show about a 25hp gain using it.

To my knowledge that was NEVER a consideration in the '60s when the ida's were originally applied to US V8's for racing purposes.

Part of that black residue accumulation that you see with ida's in the exhaust is oil blow by in the cylinder and anything you can do to get a negative pressure in the crankcase will reduce the cylinder washing caused by the fuel shot from the accelerator jetting.

Cylinder washing, in this case, is the fuel mixture washing the oil off of the cylinder walls that is there to lubricate the piston rings.

To reduce some of the cylinder washing, you can reduce the pump shot jets  down from the stock 2.0's to .5's but that makes starting the engine cold difficult. You can compromise at 1.0's without any noticeable difference power or starting wise but some experimentation on your particular application is necessary.

Ride behind a 48ida equipped engine and watch the exhausts when the driver WOT. There will be a cloud of black smoke and that is largely oil.

Last edited by panteradoug

Thank you for that helpfully reply. I'll add an oil separator to reduce chances for a fowling problem, but don't know how I might reduce the pump shots. I assume the jets can be sized?

On given weekends a few of us engage in what we call 'warmup laps' on a lonely road. They can get quite spirited when we take turns passing each other and everybody loves it when I come by because Panteras have that unequaled sound, but they also mention that they'd be afraid to light a cigarette at that moment. I have yet found jetting that covers all the bases.  I have two progression hole Webers that came with the car when I bought it in 1979, and a new set of 3 progression hole carbs that purchased about three years ago, as well as a wheelbarrow full of jets that Jim Inglesi talked me into.


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Well the pump jets are not as simple to do as the a/f jets are. There is a single barrel jet sitting in the bottom of the fuel bowl that just unscrews. So you need to take the top of the carbs off.

Theoretically the carbs come stock with 2.0's. That means a 2mm orifice.

I've dialed them down to .5's but couldn't start the car the following morning when the engine was cold.

With the  .5's there was absolutely no loss of power driving the car. Strange, I know, but this is where I'd get "lectured" by Jim that this was as close to a fuel injection system as you could get with carbs and that's why it worked with the pumps almost locked out.

In my view, the ONLY value of the "stock" 2.0's is for cold starting.

As far as jetting goes, I've run mains all the way down to 125 fuel and up to 175 fuel with the corresponding air corrector for each fuel jet change.

That ratio that still holds true. It is the proportion of 140f to 160a. You have to chart those to see what it means. The proportion is the critical factor.

When I came to that conclusion it was Jim's opinion that it is WAY to heavy. I disagree. The plugs are a nice dark rust brown color.

I do not see the difference between F5 and F7 tubes. MAYBE the F5's are cleaner? They seem to be more important in a 289 set up. The Cleveland doesn't seem to care.

My driving is street driving. Perhaps it is more important under full racing conditions to get these exact? That I don't know.

The plugs were cleaner with 125f but power did drop off.

Testing 170f on the street, there was an immediate increase of power.

Now I did this all without an a/f meter years ago so I do not know what the a/f numbers actually read but I do know what works since I've been running the carbs, on and off to be honest, since 1978 and it was INGLESE that helped me set these up.

The ENTIRE issue with the IDA's is that the idle is next to impossible to lean out successfully. That's what pisses me on the set up and I will keep trying.

You can actually measure the crankcase pressure if you want to go to that hassle. You don't want to excede 12 inches of vacuum. That can be read as a negative number on a pressure gauge if you have one that can show plus and minus.

The racers that would talk to me on this seemed to be happy with 10 inches. Some stated they were still using the exhausts to create it and that number was around 6 inches.

So what a good number is, I can't answer that but I'd speculate that with Webers on this engine, you want the highest number you can get without sucking in the oil seals on the crank. That appears to be the 12 inch number which would explain the 10 being more desirable because of the safety factor.

IF by some chance you are at 12 inches now, you can bleed some of that off by provide a vacuum loss (drilling a hole) at some point in the pcv system. With this Weber set up you have to provide one somewhere. If you were a plumber, you would call it a vent and you could compare that to needing a vent on the gas tank.

For you, since you are already plumbed into the crankcase, a simple pump jet change to 1.0 will probably be helpful.

I had the thought, but never tried it, that you could use one carb as the starting carb with 2.0's and drop the others to .5. I get lots of weird thoughts so like the Warren Commission having to come to a decision after interviewing hundreds of witnesses pick a number on how many assassins there were that day in Dallas?

1.0's are working for me still. Oh, don't be surprised if the pump jet in all the carbs don't match. I've seen that a lot out of new stock carbs, and it doesn't effect anything but I'm running 42mm "chokes". 37's will show richer with the same jetting.

Oh...the progression holes. All the third hole does is theoretically eliminate that flat spot that you feel in the 2800 to 3200 rpm range.

There is a brass screw plug in the side of the carb. If you take the carb off, remove the plug and hold it to the light, you will see them at the end of the "tunnel".

They correspond to the notch that you see in the throttle plate. I think they are #72 drill size but you need a numbered drill set to measure them. All you do is "about" in the middle between the two existing holes, use a "pin vise" and put a third hole in between them. That roughly corresponds to the 3000rpm transfer point.

The "transfer point " is when the mains start coming in. Up until that point you were running on the idle system.

It is easy to do. Anyone can. No need to replace your two hole carbs. Just add the third. It does help a lot.

Totally confused yet? I did try my best! I have to rest now. My fingers hurt from typing.

Last edited by panteradoug

The carbs themselves are not complicated. What is complicated is how to apply them to an individual runner intake on an American V8.

IF all that you had to "adjust" them for was constant WOT applications, that is simple.

Attempting to apply an analog system (carbs) to get the results of a digital EFI on a car that needs to be street driven is another story all together.

EFI essentially is tuned to every single rpm by having a ECU match a pre-determined a/f ratio/rpm. Carburetors can only be tuned to certain points of the rpm and everything in the induction system is part of that.

Weber IDA's are not unique to that. You can clearly see the methods used on Holley carbs as well although generally speaking with only a few exceptions, you don't need to deal with reversion with them.

The intake manifold originally "designed" and built for Detomaso by Ford through Hoolman-Moody is really one of the best ever produced for a V8 but that may actually be more co-incidental then intended due to the fitment of the carbs on the manifold.

The distance from the intake manifold to the edge of the throttle plate was thought to be optimum at the time and is probably as correct as you can make it to be.

With EFI, the manifold ALMOST doesn't matter as long as it doesn't restrict maximum flow to the cylinder.

Going to EFI is the only way to make it better and eliminate the "Weber exhaust cloud" and heavy idle.

There you can optimize WOT at a predetermined a/f ratio, probably 12.5:1 and idle it down to 14.6:1, run a more radical cam profile, without the engine going into a revolt.

Frankly, since these cars are no longer everyday drivers the Weber issues are part of the fun of owning and using them. We love to complain but wouldn't give them up for anything else. They are pure old-fashioned power and beauty and provide me with much tinkering time.  However, it's a good thing that they are not found on many cars, global warming would be much further advanced.

You sync them at idle with the vacuum sync tool that sits on the stacks.

You usually can only sync one of the throats on each carb.  They have a common throttle shaft and normally even new are a hair off from the factory.

Original Weber 48ida's have soft brass throttle shafts and will twist with time so at some point they will need to be changed out IF you use too much return spring pressure on the linkage system.

You should be able to operate the entire linkage system with one finger, with little tension on it. That's what you need to aim for. Otherwise you will twist the carb shafts.

You also need to remove the solid tube located in the stock throttle cable assembly so it is flexible to bend to the connection point on your linkage otherwise the linkage will constantly hang up open. Any throttle cable has to be snaked through from the firewall and it has to be very flexible.

There are lines on the clear tube on the gauge. Three if I recall correctly? You need to get the carbs within one bar/line for each.

More importantly though, you have to have the linkage zeroed. If you don't you will have constant trouble getting the engine to idle down after a WOT run. It will idle at a higher rpm then you set it at since there is at least one carb throttle that is out of sync and holding the others open.

THAT can be the difficult part. It isn't like setting up a multiple Holley carb system at all. Those open progressively. The IDA's are tied together and all open as one.

I've got 12 inches at idle. The Pantera booster needs more then that. Somewhere around 18 inches. A Ford Bendix can get by with about 14.

What happens with the brakes is that the booster provides something like 150 to 200 psi more pressure to the brake hydraulic system. If you measure the pressure to the brakes, the fronts will show around 350 psi without any boost and the engine off. It will make the pedal feel artificially harder then it normally is.

With this brake system you want at least 550 if not more. 18 inches is what it is designed for and with that will give you something like 700 psi in the front.

The rear on the other hand will show 150 ish without any vacuum boost and if you do ANY kind of rear upgrades then needs to be restricted down to 80 to 100 depending on your car. So an in line pressure reducer needs to be installed AND the front pressure reducer needs to be removed.

This gets tricky and you run the risk of locking up the rears first before the fronts and the rear will come around faster then you can react to in any kind of a panic stop. In fact, you should never be able to lock up the rears at all even if you hit the brakes by standing on them. They are ALMOST just along for the ride.

The factory set up was done like that for a reason. The "average" Pantera buyer would not be able otherwise to handle the car safely.

I am running the Compcams vacuum pump. The only drawback is that it is noisy almost like a "construction air compressor" for a nail gun, BUT with a solid lifter cam and 180° headers on the car already, the noise just gets lost in the crowd and you don't hear it in the cabin.

Last edited by panteradoug

panteradoug said it all, so no need to repeat anything. I also use a vacuum pump as well to eliminate distracting plumbing from the engine compartment, those Webers need to stand alone. The pump which sits in the front trunk compartment is noisy, but I can only hear it until the engine starts up. It only runs when starting up or when the vacuum level drops slightly by applying the brakes. 


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My pump is about four years old. About six months ago a realized that the pump was not shutting down after building up the vacuum. I checked for leaks, found nothing, so I checked if a pressure sensor part was available for my pump. It was, so I bought one for about $75 (guess) and that did the trick. It shuts off and stays off when the needed vacuum is achieved.


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@tomkuester posted:

My pump is about four years old. About six months ago a realized that the pump was not shutting down after building up the vacuum. I checked for leaks, found nothing, so I checked if a pressure sensor part was available for my pump. It was, so I bought one for about $75 (guess) and that did the trick. It shuts off and stays off when the needed vacuum is achieved.

You bought the replacement pressure sensor from Compcams?

I'm thinking of putting a vacuum gauge in line so I know what the pump and reservoir are doing?

So now you are confident that the booster isn't leaking?

Doug thanks for the detailed writeup on how to use the Syncrometer!

You ever try any other method?

I’ve been running weber’s since ’87 after Gary Hall talked me into it after giving me a ride in a 1937(?) Chev Coupe with weber’s that he had. I’m also not running any vacuum from my manifold; I use a Wildwood peddle/master cylinders for both brake & clutch.

-No Sir. Do you know of another method?

I don't know of running just full mechanical brakes in my Pantera. At one point I had converted to them on my GT350. The end result is that the mechanical system was providing about the same amount off pressure to the calipers as the stock power brake system was.

The mechanical system was easier to deal with as far as avoiding locking up the brakes.

I talked to and dealt with Gary on many occasions. I miss the bugger. He would always say in the end, "do what you want. Don't listen to me. I'm just 'peckerwood'!

His solution to 48 IDA's was to reduce the size of the auxiliary venturi (aka chokes) to 32 mm. Simply stated, with that change it simply isn't the same system any more.

Jim Inglese "suckered me into Webers) in 1978. He knew I would become addicted to them. SOB.

Last edited by panteradoug
@tomkuester posted:

I removed all ID from the pump and can't find the receipt, so I don't know the make. Maybe you can tell from the photo I posted if it matches yours. I bought the 'vacuum switch' from Summit for $59.99 07/22. I don't appear to have a leak.

I think that the answer to your question is that the pump is one of those Chinese products, made with no i.d.'s or visible part numbers. That way they can be sold to multiple vendors that can put their own id lable and part numbers on them.

I have seen the same pump from different sellers. I think that they are all the same.

It probably is an industrial part sourced (idea stolen) from another application that just happens to work. That's just how the Chinese roll.

They are definitely not victims of the "not invented here syndrome". They will steal anything and you can't stop them.

The main source of "Weber's" now is China. They are quite good. They just reverse engineered them and make their own at like $250 each retail. Everything interchanges with the Italian carbs.

They probably make good reverse engineered "Alien " flying saucers to .I don't know where they get there element 135 from though?

Last edited by panteradoug
@tomkuester posted:

You are so right about Chinese parts, and they are unashamed about producing junk. I've had my share of associated issues. The problem is for the consumer, as there is no telling where the product was produced before you buy it.

I remember the '50s when so many toys came from Japan. Those were cheap junk. I would say that immage has changed quite a bit now?

Not everything from China is junk. They produce many high quality items.

The problem is that their prices are so low by comparison to the rest of the world. You can blame that on politics if you like and I won't object.

I know that we were having an issue with US produced structural steel for buildings. It seems that no matter how competitive the US companies tried to be, the Chinese would in effect, price dump in an attempt to put everyone else out of the market.

You, as a customer, need to know what you are looking at. Almost all of these "industrial products" are unmarked as to their origin. Right there stop and suspect they are out of China.

Incidentally, India is running the same swindle. Some of these "Australian" items are sold in Australia but manufactured "to their specs" in India. No ID's on them either.

Let me point out that they aren't necessarily junk either.

When the Borla's hit the market, there were plenty of quality complaints. First and foremost, folks need to know what they are talking about to begin with. Being disappointed is not the same thing as the product actually lacking quality.

I am used to complaints and complaining. I'm a New Yorker. WE complain about everything here. Everything. However, people should work harder to make it more of a sophisticated art form? It would reduce the stress level.

The "Spanish" ida's were criticized as well as are the current Holley carbs. Still are. Basically, I don't see it but I always consider the credibility of the critic.

It is a fact, a clear and present danger, that corporations have reduced the quality of labor assembling virtually anything these days, seemingly no matter where it's origin is.

I remember Sony having issues with the quality of capacitors around 1990. It turned out that for cost reasons, they were no longer quality testing them before they went to market and were experiencing failure rates of around 50%.

Recently, I had a Compcam with a broken distributor gear tooth right out of the box. Turns out Compcams only checks one out of four cam blanks that they load onto the machines. Costs too much to check them all. They're from Mississippi.

It's not about the country the product comes from, more the conscientiousness of the company to produce a quality product. That definitely can be lacking.

I don't want to say any more on this subject. In many cases it is just turning into out and out racism. That is unfortunate byproduct.

Last edited by panteradoug

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