WEBER 48 IDA quality issue

[EGLITOM]

Dear all

i´m in the process of collecting parts for changing my induction system from Holley to a WEBER IDA 48 setup.

I already have purchased a very nice pair of NOS IDA´s from a VW guy in germany. Don´t know where they have been made, because the embossed field after "made in" is kept blank. Nevertheless they are very nice and all tolerances which i can measure are ok.

Additionaly i did purchase a pair of brandnew spanish IDA´s.
They did look very nice from the outside ( although the casting surface is slightly rougher than on my NOS pair). Also from the inside they looked ok on the first sight. They dont feature the brass fuel float anymore .
In closer inspection i found the following.
The bore of the venturi choke is app 1 - 1,5mm bored offset to the bore of the the throttle blade. This is consistently wron on every bore on each of the new carbs. The venturi bore of the NOS pair is exactly centered towards the throttle blade bore.
The dealer i purchased the carbs from checked his stock and also asked back at WEBER UK. According to his answer every of the carbs of this production run shows this issue. WEBER UK thanked me for the notation of this issue but also answered that they will continue to sell this stock givven the numbers of this already sold without complaints. They will inform the factory about this issue in order to correct it for the next batch ( good luck).
here are some pics.

As my engine needs a lot of air (331 with RPM up to 7800) i will have the need to optimise the flow through the carbs as good as possible to keep low rpm driveability ok and still moving enough air for the high RPMS without the need to go to the biggest venturi choke. To achieve this i have planned to remachine the Venturi choke by CNC to have no step on the transition from venturi to throttle blade bore and do flow optimisation on every other part as well which could be done without loosing signal strength on the main circuit. As this is not possible with this carbs i will send them back and look around for good ones.
THe dealer is taking the carbs back without any discussion and he has been very helpful and quick in getting answers.

So if you are in the processe of purchasing IDA´s look exactly what you get.

If anyone of you has a nice ( even used ) spare pair of 48 IDA´s which he would be willing to sell, please inform me.

Thanks
TOM

 

[Chuck]

It is sad that the manufacturer, where ever it is located, would permit those carbs into the market with such an apparent flaw.

 

[Keith]

Not good Tom, not good. Perhaps you should have opted for Chinese IDA's - they are a lot cheaper..

 

[EGLITOM]

Not good Tom, not good. Perhaps you should have opted for Chinese IDA's - they are a lot cheaper..

SOURCE ???:lipsrsealed: to my knowledge there is no IDA produced in china except the EMPI IDA 48 (51,5) which i´m not sure where it is produced. All what i have red about them , they should not be a bad carburator. Givven the issues with the WEBERS it may be a viable solution.

TBH i look around for those unused sets from the times where manufacturers still cared somehow and a bit for what they sell.

Also hope to give Weber a wake up call with that post in the way that the comments of their main customers ( beside VW, MAZDA and COBRA guys) will likely not appreciate such attitude.

TOM

 

[Randy V]

I haven't looked up the throttle bores of my IDAs but suspect they may be the same way.
Is this really a bad thing?
I think you need to take the intended use into consideration.
I've spent much of my life working with various carburetors and metering systems and can offer two explanations for why there is a step there:

1) that step will aid in halting any reversion effect coming back up the intake runner
2) that step will aid in tripping up the boundary air layer which will tumble the fuel/air mixture therefore entraining the atomized fuel more completely with the airstream.

In the case of #2 above, I have removed this ledge on a number of carburetors in the thought that I was assisting the airflow. When checked on an airflow bench I found that this modification did not yield any improvement in the airflow whatsoever. In the dyno tests though, the carb actually flattened out the torque curve in the low/midrange IE it actually decreased the torque in that range, but yielded no discernable change in the torque peak. After those tests, I called someone who I really trusted a lot while he was alive. He confirmed what my suspicions were and congratulated me. He also added that the step would aid in the negative pressure seen at the fuel idle transfer slot and would aid in low speed driveability.
I have since stopped worrying about that step and have concentrated my efforts instead on aligning booster venturis properly and removing casting flash from the bores of the carbs along with sealing throttle shafts and streamlining the shafts and throttle plate screws. This has always shown a positive result.

Take this for what it's worth, but I would simply give them a thorough cleanup and try them.

 

[EGLITOM]

Dear Randy

Agree to what you said but that doesn´t change the fact that they are messed up in manufacturing.

would completly agree to your argumentation if the older NOS pair would show the same excentric step , but they defenitely do not. they show a small, 0,5mm step equally around the circumfence of the transition from venturi to throttleblade bore.

If a step is necessary why not do it on the whole circumfence in the same dimension or if excentric on the same location.
If the bores of venturi chokes and throttleplates would be aligned ( Like on my old NOS pair) the step could be easily controlled, changed and or mantained by the design and dimension of the venturi choke.
Exactly this is my plan. In CNC age this venturi chokes are easily produced in every desired shape and alternative concepts could be tested. For this i want the best and perfect base i can get and which already was available if it would not be for some sloppy spaniards messing it up.

If my engine would only rev to 6500 max i would agree to you, but this is not the case.

Also agree to you, that all the other optimisations will have an effect, and they are in the build plan as well.

Ever heard of those?

More custom designed products from JPM

[ame="http://www.youtube.com/watch?v=XzomjALtdeE"]Raptor venturi 48 IDA - YouTube[/ame]

According to the aircooled VW bunch they work just great and i´m considerung this modification, also for those i would like to have a perfect base carb. They are out there and i´m not in hurry ( my Holleay performs perfect, just lacks the look and sound of Webers).

BTW could you PM me your spec sheet of your set up ( jets, venturi size and so on)

Also to all of you. May be one of you have a set of original italian ones laying around ( either the early sandcast ones or the later massproduced pressure casted ones) . If so just take a picture of them the same way as above and show us how they have been made in the past.

look at these.
http://www.flickr.com/photos/8423892@N04/sets/72157622406807891/
This are early sandcasted ones ( they dont have the cast on triangles with the bolt hole on the side of each barrel). Just look at that surface quality. Of course the sandcast body is not as strong as the later pressure casted ones, but nicer he he. Watch the last picture with the same view as mine above. It shows a equaly distance step all around.

TOM

 

[Dave Hood]

Tom:

Have you considered switching to an EFI system? Eight Stack Injection is an excellent product and looks very similar to the Weber IDA 48 set-up.

Eight Stack Injection- home

 

[EGLITOM]

Dave

yes i did consider it. The 8 Stack system is nice, but the more i thought about it, the more i got drawn to challenge of setting up a real IDA intake system. I realy want the car to be the same as in the past. Currently i perceive EFI as cheating.

If everything goes wrong i still can machine a straight venturi without the aux venturis, machine some injector bungs into the intake and only use the IDAs as trottle body and convert to EFI.

There is one thing i particularely don´t like on the 8 stack. it is the placement of the injectors above the trottle blade. especially in low engine loads they will squirt on the almost closed blade. It may not be an real issue, but i just don´t like the idea.

TOM

 

[Tom]

Hello Tom,
FWIW, the Borla/Roush system's injectors are placed below the throttle plate, as you can see from my pic below.

In my opinion, your car is quite 'modernized' as it sits now, and I think some would argue that this is also 'cheating'. So a good EFI system that controls fuel (and ignition), would complement your car's modern look and performance expectations better than the Webers would.

I went EFI due to all the elevation changes you can go through where I live outside of Denver. The EFI systems work very well there. We can go from less than 5000 feet to over 12k within a 1.5 hours drive and the car runs and idles pretty much the same except your power drops.

Besides what German would not appreciate the precision and adjustability of fuel injection. :thumbsup:

 

[EGLITOM]

Interesting TOM

Tell me what on my car is modernized !
15", no power brake, servo steering , also all my ductings are like on orginal cars. front and rear frame are as well, so besides a almost perfect bodyfit, don´t see anything modernised. Just nice and tidy.

The challenge for a german like me is, to get this Webers running so it makes you think its EFI. BORLA and all the other likes defenitely look to modern.

Taste changes the longer you are with this cars. I realy like the plain race style of all the Gelscoe cars.

Anyhow, the topic is not WEBER or EFI ?
The topic is bad quality control and a severe lack of quality consiouness once a mistake is detected at WEBER.

would appreciate to go back to this topic.

TOM

 

[Cliff Beer]

Tom,

Are you sure it's a given that the offset to the venturi is an accidental flaw? Perhaps this is a designed-in feature of newer webers?

Is the atomized fuel perhaps less disrupted by the throttle plate and shaft with an eccentric venturi placement?

In my (limited) experience it would be very strange for this to be a casting mistake. A sand cast is made from a very specific mold, and changing the position of the venturi would require a number of changes to the mold as well as some changes to finishing machining. Just a thought.

 

[Keith]

Tom,

Are you sure it's a given that the offset to the venturi is an accidental flaw? Perhaps this is a designed-in feature of newer webers?

Is the atomized fuel perhaps less disrupted by the throttle plate and shaft with an eccentric venturi placement?

In my (limited) experience it would be very strange for this to be a casting mistake. A sand cast is made from a very specific mold, and changing the position of the venturi would require a number of changes to the mold as well as some changes to finishing machining. Just a thought.

Don't think that it's eccentric Cliff, just not centered or symmetric.

 

[EGLITOM]

Hi Cliff

yes quite sure about the fact that it is not a designed offset.

This webers are die cast. Only the first ones where sandcast.
After casting the barrels are machined. So any offset or centered placement is just question of correct or as in this case uncorrect machining. No changes of mould necesarry to correct this, only good machining.

this is how it should be. I could take a picture of my other pair of IDA´s both of them look like this. So defenitely bad quality of the "made in spain" stuff.

TOM

 

[Tom]

Taste changes the longer you are with this cars. I realy like the plain race style of all the Gelscoe cars.

I agree, that goes with just about any car for that matter.

I have had good results with older with dual 45 DCOE style Webers and decided only to upgrade to a Grose needle and seat assemblies, then left them alone. There was some lack of attention to detail but it appeared to be only cosmetic and did not seem to affect its performance. They were quite reliable, just suffered from carb icing during certain weather conditions.

Hopefully you will find a good set of IDA's that are matched and require minimal cleanup.

Tom

 

[Randy V]

Tom - for some ideas on jetting your IDAs check out this thread. I document my jetting here as do others:

http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/26034-weber-ida-jetting.html

 

[Rick]

In an effort to locate Italian made Webers, short of finding an NOS set and paying a ransom you can buy used set and can learn a lot while rebuilding them and make some useful small modifications during the rebuild.
When I was on the hunt for mine a few years ago, I ended up getting them from 3 different sources, (2 singles and a pair). I focused on the VW crowd, many of whom are in the midst of changing over to Fuel Injection and are selling their carbs in pairs, ocasionally singles. Just be careful of getting some that have been used heavily on a sand rail because there will be a lot of wear in various areas. Ebay & Samba are good spots to look.

 

[EGLITOM]

Rick

exactly my plan. I´m in contact with one VW guy in US already . lets see if we can agree on the price. In the meantime if any knows of a good rebuildable set of italian Weber IDA 48´s. please send me a pm

THanks
TOM

 

[Chuck]

Rick

Is that yours? Stunning recreation. Excellent attention to detail. I really like seeing those 289 set ups.

In an effort to locate Italian made Webers, short of finding an NOS set and paying a ransom you can buy used set and can learn a lot while rebuilding them and make some useful small modifications during the rebuild.
When I was on the hunt for mine a few years ago, I ended up getting them from 3 different sources, (2 singles and a pair). I focused on the VW crowd, many of whom are in the midst of changing over to Fuel Injection and are selling their carbs in pairs, ocasionally singles. Just be careful of getting some that have been used heavily on a sand rail because there will be a lot of wear in various areas. Ebay & Samba are good spots to look.

 

[Rick]

Yep thats mine. 289 NAF that's received a lot of TLC to get it to where it is.

 

[EGLITOM]

Did manage to buy another pair of used IDA´s. They only have beend installed for 1000km on a VW beetle and are in realy good condition and most important, they are corectly bored. This is how it looks like when the bores are aligned

Nice and even all around the venturi choke

Also got my intake plenum, fit the gaskets to my ported intake channels , put a little of "the right stuff" on their plenum side, mounted the plenum, aligned the gasket with my intake channels again and bolted the plenum down a bit. Will let it cure for two days and take the intake of than, hopefully with the gaskets sticking to it. This will show me where to port the intake plenum to match the heads ports.

TOM