Intake Spacer

[Lost_in_Kansas]

Interested in upgrading to a 38/38 but it appears to require modifications to the intake manifold.

In searching eBay, ran across several vendors selling machined spacers to mount a 38 to a stock manifold.

I am space challenged because I have a strut bar which goes over my 32/36 so I don't have the room to add a spacer like this without removing the strut bar. 

Curious if these work and if there are other low-tech solutions.

from

https://www.ebay.com/itm/38-38mm-Weber-DGAS-DGES-mounting-flange-or-spacer-1-2-thick-/352139735287?hash=item51fd29f0f7

 

Thanks

74

[Son of Marty]

Imho, your over estamating the work needed to the manifold, you just need to chamfer the openings on the manifold enough to clear the throttles, you could do it with a hand file although a dremmel tool would be way easier.

Edited May 5, 2021 by Son of Marty

[2002iii]

Air cleaner to hood clearance is already tight, a spacer will only make it tighter.

 

Use the gasket from the 38/38 to mark the part of the manifold you need to remove with permanent marker. Then use a dremel or die grinder to remove the metal and a vacuum cleaner to suck up all the metal shavings.

[Hans]

I'd be removing the manifold before doing the grinding just to be safe.

[Son of Marty]

Removing the manifold would be best but stuffing rags/paper towels down the runners and using the vacuum has been done many times.

[Mark92131]

It gets hot in Kansas, you might consider running a Phenolic spacer to avoid the vapor lock with that 38/38 in the summer.  Hans is right, don't be this guy, (me).  Ended up removing the manifold to clean up the mess I made.

 

Mark92131

 

 

[Mike Self]

When I did this to accommodate my 32/36 carb--which also needed some enlarging to flow properly--I lightly sprinkled oil on a shop rag until it was thoroughly damp, and poked it down the manifold opening.  When I was finished with the Dremel, I carefully pulled the rag out, with the aluminum shavings stuck to the oily rag.  A quick swipe with a clean rag to get the last little bits, and I was done.  That was in 1981, so I must have gotten 'em all...

 

+1 on the Phenolic spacer--one should be easy to find--you could once get 'em at your local Ford dealer as Pintos used a Holley Weber that was pretty much identical to the 32/36; jets interchanged too.

 

mike

['76mintgrün'02]

['76mintgrün'02]

Damn Glitch ate my words again.  At least I didn't type very much this time.

 

1 hour ago, Mark92131 said:

don't be this guy

 

 

 

I must be that guy, since I took that photo.  In my defense, it shows the work the previous owner had done to the manifold.  I wound up making a two hole gasket to replace the oval one that comes in the rebuild kit and tapered the holes to match it.  (as seen in the post above)

 

I did do it in place after stuffing the intake with rags and then vacuumed it, pulled the rags and vacuumed again.

 

That's only part of the mess though.  I cut a rectangular hole in a large sheet of cardboard, to fit over the intake because the aluminum shavings go EVERYWHERE and stick to everything oily.  That really helped contain the mess.

Tom

[e21m10]

[uai]

I built these for Weber 45DCOE in a thickness of 12mm, 15mm, 20mm and 25 mm.

 

 

 

Edited May 6, 2021 by uai

[mgben]

For my 38 38 I removed the intake to do the grinding. I have a peanut manifold and it still too a LOT of work to make a smooth transition for the 38 butterflies. 

I added a 6mm phenolic spacer  (debate on here about spacer but I wanted to add it). 

https://www.carburetion.com/Products/ProductDetails.aspx?Part=99900.624

or pay more on ebay

https://www.ebay.com/itm/CARB-SPACER-6MM-THICK-FITS-WEBER-38-38-DGS-DGAS-DGES-DGMS-FREE-SHIP-/192096681116?_trksid=p2385738.m4383.l4275.c10

 

It had flexoid gasket paper on both sides.

 

Edited May 6, 2021 by mgben
clarification

[jimk]

Talk to a gas dynamics guy and he will tell you that hogging out the manifold larger than the throats in the carb is a step backwards because is causes a pressure loss.

Spend lots of money to get more air thru the engine then take a step backwards ????

['76mintgrün'02]

3 hours ago, jimk said:

Talk to a gas dynamics guy and he will tell you that hogging out the manifold larger than the throats in the carb is a step backwards because is causes a pressure loss.

 

Would the gas dynamics guy suggest maintaining two separate ports under the 38-38?

(as you suggested for my 32-36)

 

Why did the factory add a peanut intake near the end of the run?

 

I'd like to talk to the gas dynamics guy about how air enters the carb.  The factory air silencer is a tight fit on top of a Weber, but it sure does give a nice smooth entrance.

 

 

Tom

 

[jimk]

20 hours ago, '76mintgrün'02 said:

Would the gas dynamics guy suggest maintaining two separate ports under the 38-38?

(as you suggested for my 32-36)

 

Why did the factory add a peanut intake near the end of the run?

 

I'd like to talk to the gas dynamics guy about how air enters the carb.  The factory air silencer is a tight fit on top of a Weber, but it sure does give a nice smooth entrance.

Yes  The equation for pressure loss is Pressure Loss = KfL/D.  An abrupt change in diameter of the flow duct has a lare K factor.

 

My guess is cheaper to produce.  It was probably a cast opening, I haven't seen it to be sure.  Let's face it, at the end of the production run for carbs, they were more interested in other stuff for FI systems.

 

The intake form you retained from the original configuration is the best.  It's a form of a bell mouth entrance.  A sharp entrance also has a big K factor.

Edited May 7, 2021 by jimk