Weber IDF questions...

[Rallygorgo]

O.k., I have my engine put together, time to get the carbs together. A few years ago I picked up a set of 44mm IDFs and a manifold and have started playing with them. They're missing a few parts but, for what I paid for them, I can buy all the parts I need and still be ahead vs buying them new.

Anyway, the ones I have currently have short emulsion tubes, they don't have the 2 tall tubes sticking up between the velocity stacks. Does the heights of them matter?

I need to buy/build a linkage for them. I've seen 3 out there and I'm lookin for advice on which to go with. Those of you who have Webers, what linkage do you have and how well does it work?

One issue with the IDFs on 289/302s is the accelerator pump pushrod hitting the valve covers. I've seen pics of dented covers and creative use of copper plumbing caps in the covers. What about a combination of spacers and trimming down the pushrods?

I also need air filters. Since I'm building a Coupe space under the nose is at a premium. How tall a filter generally fits on top of the IDFs and clears the nose? I want to go with K&N filters on top of each carb rather than the "tea strainer" types to keep the emulsion tubes from seeing different air pressure than the venturi sees. I suspect that the filters will be one of the things I figure out later.

Any other bits of advice? I'm sure I'm overlooking something. I'm also sure someone's going to say Webers aren't cheap and that at some point I just need to start beating it with a money bag.

Thanks in advance!

[dallas_]

I'd suggest contacting Jim Inglese (not Inglese Induction Systems).

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He has a wealth of knowledge in setting up webers, including different linkage setups for both the 289 and 327 cars.

[oldguy668]

Wayne Presley at Very Cool Parts is the resident Weber expert. Give him a shout first (he's a forum vendor)

[Bob Cowan]

For linkage, I ended up making a few of my own parts. The prefab kits were fairly expensive, had a lot of parts I didn't need, and didn't fit exactly the way I wanted them to. You order what you think you need, it comes in a week later, and it's not what you need. Then you have to order something else, and wait another week.

I bought alum hex rods from McMaster for the center stand and the cross bars. I bought drill bits, #10-32 taps (left and right), and rod ends from Grainger. The throttle cable attachment I fabbed out of some sheet metal. The bell cranks and arms I bought.

It was time consuming and exacting work. But now it works exactly the way I want it to.

One very important thing to remember about IR systems - the balance has to be perfect. And I do mean perfect. Before you do any tuning, you have to spend the time and get the balance exactly right. That can be really tedious and time consuming. Especially if the linkage isn't right. But if you don't do it, no amount of tuning will get it to run right.

I also had trouble fitting some of the linkage around the valve covers. I looked at the plumbing plug idea. But then I put spacers under the throttle bodies, and then everything fit much better. It also gives a little more room over the top of the distributer for the fuel line.

For air filters, that depends on how you set them up. Air horns will probably make a little more power. But filters for those are hard to find and expensive when you do. I'd like to have a set of these, but the price is more than I'm willing to spend.



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Do Not use the traditional "Tea Strainer" filters. They will cost you a lot of power. On my engine, I lost about 100hp on the dyno.

I had these made about 8-9 years ago. They use a standard K&N filter. I use these for the street, and open trumpets on the track.

[Derald Rice]

I have a set of 48 IDF's on a 302.

Originally Posted by Rallygorgo

I need to buy/build a linkage for them. I've seen 3 out there and I'm lookin for advice on which to go with. Those of you who have Webers, what linkage do you have and how well does it work?
Thanks in advance!

I use a throttle cable that pulls from the rear, between the 2 rear carbs. I made a plate that attaches to the inside carb bolts and works well. I can send you a tracing if you want. I also use 2 of the holley return springs as an extra assist. This linkage has worked flawlessly for about 4 years.

Originally Posted by Rallygorgo

One issue with the IDFs on 289/302s is the accelerator pump pushrod hitting the valve covers. I've seen pics of dented covers and creative use of copper plumbing caps in the covers. What about a combination of spacers and trimming down the pushrods?
Thanks in advance!

I use a machined aluminum 1 inch spacer from inglese under each of the carbs and there is no problem with my tall valve covers. Wayne Presley has a source for a 1/2 inch spacer that would probably work also. The other option is a "stack" of gaskets to meet your requirements. Denting or providing a "relief " in the valve cover was not an option for me with cast valve covers. See the photo below.

Originally Posted by Rallygorgo

I also need air filters. Since I'm building a Coupe space under the nose is at a premium. How tall a filter generally fits on top of the IDFs and clears the nose? I want to go with K&N filters on top of each carb rather than the "tea strainer" types to keep the emulsion tubes from seeing different air pressure than the venturi sees. I suspect that the filters will be one of the things I figure out later.

Just like Bob, I found out that the tea strainers are junk. The air flow was so restricted that the engine would run blubbering rich. I am using a set of Redline filters, that are clones of the K&N's. The velicity stacks are still under the filter, and the HP loss has been measured at 8hp. They are 3.25 inches tall, and before I added the bolt-on hood scoop, one of the air filters was just barely kissing the underside of the hood. After the scoop change, there is no problem, but I am at a minimum of clearance.

I initially installed my webers 4 years ago, and I have not had any need to retune. I do have a LM-2 that I can check them with.

Derald.

[Rallygorgo]

Thanks for the advice guys. I think I'm at the point of pricing out having Wayne rebuild and set them up for me vs ditching them and going with a 4-barrel carb. I dug into them a bit deeper last night and found I need more parts, the linkage, and probably should have an expert go through them for me because they just don't feel right when I tighten the shaft nuts down. I'll try to give Wayne a call but I know any experts don't come inexpensively. Maybe it's good that I haven't gotten rid of the stock 1989 5.0 FI system.

Thanks again guys, I think I'm swimming in a pool that's too expensive for me...

[Rallygorgo]

I ordered a linkage from Inglese today, looks like the best one to me.

Also sent a note to Wayne yesterday, haven't heard anything yet. I saw another guy who rebuilds carbs but gets $275 each to do it. So, after the linkage shows up, I should be able to clean them up and bolt them on. I decided a 4-barrel is not an option.

[Rallygorgo]

Never heard from Wayne, I'm probably a bit too cheap but that's o.k., I'm almost done rebuilding the 3rd carb.

The linkage arrived from Inglese today, might be missing a part or 2. It has the 2 small needle bearings that get pressed into the bellcrank but what goes in the center of the bearing? I thought there would at least be some kind of shoulder bolt or sleeve but there's nothing like that. No instructions either. I'll try giving them a call tomorrow.

Update: Nothing missing from kit, supposed to buy a shoulder bolt for bearing to ride on, original levers on carbs work with their kit (gotta' buy new ones, were missing from my carbs), and no instructions are available...

'Nother update: Have all the Weber parts, carbs are all cleaned & reassembled, and now working on building a turkey pan. Looks like I'll need ~1/2-inch spacers to move the carbs up high enough for the accelerator pump push-rod to clear the valve covers and turkey pan. Will need to mount the body and nose for final fitting of turkey pan eventually. Leaning toward phenolic spacers to better insulate carbs from engine. Turkey pan should look like one offered by mastertouch327dotcom when I'm done (a replica of a replica).

[Rallygorgo]

I made som progress. The carbs are all back together, I have all the small parts that were missing, I bought a linkage, and I'm building the turkey pan.