Modifying a phenolic carb spacer.

[Loves302Chevy]

I bought a used 3/4" thick phenolic Quadrajet 4 hole spacer on flea-bay.
The secondary holes are too small to match my 1904 Edelbrock 795 cfm QJet.
I was planning to modify it to look like the spacer below, except for keeping
the center divided to maintain the dual plane of the intake manifold.

With the new Ram Air hood, I now have the clearance to use a spacer. I have access to a Bridgeport milling machine.
What is the easiest way to machine or grind/sand this to work the way I wish?

Grumpy,

The photos in your post here show that the dividers between the intake runners where the intake runners depart the plenum are thick and appear to present an obstacle to laminar air flow into the runners. I have seem similar castings in 2-stroke motorcycle jugs. Is that because casting thin dividers that help air flow more smoothly into the runners would be a problem in manufacturing?

It seems that putting a knife edge on these dividers could be beneficial to air flow, both in intake manifolds and motorcycle jugs. Is that correct?

Ray W

yes the stock as cast intake manifold plenum and runner entrances require some clean-up work if you want to maximize air flow
matching the lower edges of the spacer too the plenum entrances is the best way to reduce turbulence, and flow restrictions, of the air flow exiting the spacer

a few hours with a grinder and some reasonable care taken during the process will increase air flow rates

http://garage.grumpysperformance.co...ing-tools-abrasives-sources.10683/#post-46209

http://forum.grumpysperformance.com...=462&p=7593&hilit=gasket+porting+intake#p7593

http://www.harborfreight.com/air-die-grinder-with-3-inch-extension-99698.html

http://garage.grumpysperformance.com/index.php?threads/epoxy.14058/

 

[87vette81big]

I think using Sanding Drum Rolls will work best Mike.
I have never Reshaped a Phelonic Plastic Spacer.
See what Grumpy thinks.
I know many plastics are Deep Frozen prior to machining in a Hand operated Lathe.

 

[Grumpy]

If your trying to match the carbs throttle bore or venturie base size to the carb spacer you intend to use you want a smooth transition, from the carb to the intake plenum, keep in mind what the object of the modification is to begin with,
and what your trying to accomplish,
the idea here is to add plenum volume
(effectively making the carb on that intake act as though it was a bit larger)
and increasing the distance from the carb base too the plenum runner entrances,
(this tends to reduce the effective air flow angle of change in direction so the air can hold and transport micro droplets of fuel it contains more efficiently) what your trying to avoid is edges and rapid abrupt changes in flow direction as this tends to cause un-even fuel distribution from runner to runner, which a more common plenum feed to runner entrance angle , and distance the spacers addition allows from each carb venturie to each individual intake runner tends to help even out.
I generally start with a carb gasket matching your intended carb to be used!
measure its secondary size accurately.
the material used in the spacer can be selected to reduce heat transfer rates to the carb base (like wood or various plastics, and man made composites) or aluminum which has a good heat transfer rate
CLOSELY RELATED INFO THREADS
http://garage.grumpysperformance.co...spacers-and-related-intake-modification.1038/

http://garage.grumpysperformance.com/index.php?threads/holley-annular-vs-down-leg-boosters.5229/

http://garage.grumpysperformance.com/index.php?threads/carb-intake-test.58/

place the spacer in a vise on the mill, or drill press, accurately index the hole saw

line up the carb ,mounting bolt holes, spray the spacer with bright red paint and use a properly sized hole saw ,on a mill or drill press to open the rear section venturies and a die grinder to contour the remainder

BTW, I occasionally find I'm working with some guys who either lack experience or are clueless as to their options, when bolting an intake manifold down on an engine.
Ive watched guys fight for 20 minutes trying to tighten the standard 9/16" hex head machine bolts on some intakes where access was very limited

Coarse-Thread Socket-Head Bolts - 3/8in.-16 (thread) x 1 1/4inch (length).

most guys are familiar with use of standard HEX HEAD BOLTS

when used on a chevy aluminum intake manifold you'll frequently find, the required room,for easy access with a box or open end wrench is very limited due to the intake runner proximity to the threaded holes center line,
and that after some time standard bolt heads tend to rust and dis-color aluminum intakes.

now ideally youll use a lock washer, under the bolt head and ANTI SEIZE on the bolt threads

that prevents vibration and heat cycles from allowing the bolts to back out of the threaded holes.
there are both 6 and 12 point, reduced bolt head size , stainless bolt sets available that allow increased clearance

STAINLESS STEEL socket head cap screws make a much neater look ,
are less likely to rust,and allow far more clearance around the bolt heads, both standard and TORX versions and several head designs are available
BUTTON HEAD VERSIONS MAKE FOR A CLEAN APPEARANCE

Id like to point out that if your going to port match or port heads , take the time and effort to buy and USE some safety equipment like a face shield, clear glasses and use a decent vacuum cleaner to limit flying trash, I recently had a guy I know spend several hours in the local hospital with an optical surgeon who removed an aluminum splinter from a guys eye because he was porting a set of heads without any safety equipment, that bit of lack of sense cost over $4300 , so spending less than $150 on everything you might need to do that job and dozens of similar jobs makes a great deal of economic sense and it can avoid a great deal of pain and might save your eye sight

http://www.summitracing.com/parts/PRO-66483/

a decent cylinder head stand helps

http://www.harborfreight.com/air-die-gr ... 99698.html

read these threads
viewtopic.php?f=52&t=462&st=0&sk=t&sd=a&hilit=porting+help

viewtopic.php?f=52&t=3143&p=8387&hilit=porting+help#p8387

viewtopic.php?f=55&t=2773&p=7802&hilit=+porting+help#p7802

viewtopic.php?f=52&t=2630&p=6788&hilit=+porting+help#p6788

viewtopic.php?f=27&t=1831&p=4763&hilit=+porting+help#p4763

https://www.homedepot.com/p/RIDGID-14-Gal-6-0-Peak-HP-Wet-Dry-Vac-WD1450/100081216?cm_mmc=Shopping|THD|G|0|G-VF-PLA-D25T-Vacs-Ridgid|&gclid=EAIaIQobChMI04eNrujh1wIVErXACh0_hgYoEAYYCSABEgLzOfD_BwE&gclsrc=aw.ds&dclid=CO7ihrro4dcCFQ_ZwAodWkUDiw

https://www.harborfreight.com/adjustable-face-shield-46526.html

https://www.harborfreight.com/safety-glasses-clear-99762.html

https://www.harborfreight.com/headlamp-with-swivel-lens-45807.html

 

[Loves302Chevy]

Thanks. I just did not want jump right in with both feet, screw it up, and then
find out there is some special way to do this.
And I found your dual plane picture.

 

[NOT A TA]

You'll probably find that bits for the die grinder used for wood or aluminum will work better on the plastic than carbide bits used for porting iron. The fine bits used for steel/iron will probably melt the plastic and clog up.

 

[Loves302Chevy]

You'll probably find that bits for the die grinder used for wood or aluminum will work better on the plastic than carbide bits used for porting iron. The fine bits used for steel/iron will probably melt the plastic and clog up.

Good point.

 

[chromebumpers]

Phenolic describes "things" made from Phenol, an organic compound not a plastic. Phenolic objects are easy to mass produce because Phenol sets or binds together hard when subjected to high pressure and heat such as in the process called "injection molding." Car parts made with Phenolic parts goes back mare than 100 years, you know them as "Bakelite." Other Phenolic items, Billiard Balls, old telephones and radio cases ( getting the idea of hardness?)
Any tools with approval to use with plastics is preferable. "Not A TA" is correct in regards to using tools for wood or Aluminum is best when you can't find a cutting or grinding tool/s that are not easily identified as for use cutting plastics.
Since not a plastic Phenolics won't melt so easily. Remember those fuel pump bases on old VWs? They were made of Bakelite and when it got old it dried out and became brittle (but could take the heat and chemical resistant.
I hope this gives some education for someone

 

[Loves302Chevy]

Now that is what I call a complete answer. Thanks.

 

[NOT A TA]

Phenolic describes "things" made from Phenol, an organic compound not a plastic. Phenolic objects are easy to mass produce because Phenol sets or binds together hard when subjected to high pressure and heat such as in the process called "injection molding." Car parts made with Phenolic parts goes back mare than 100 years, you know them as "Bakelite." Other Phenolic items, Billiard Balls, old telephones and radio cases ( getting the idea of hardness?)
Any tools with approval to use with plastics is preferable. "Not A TA" is correct in regards to using tools for wood or Aluminum is best when you can't find a cutting or grinding tool/s that are not easily identified as for use cutting plastics.
Since not a plastic Phenolics won't melt so easily. Remember those fuel pump bases on old VWs? They were made of Bakelite and when it got old it dried out and became brittle (but could take the heat and chemical resistant.
I hope this gives some education for someone

Thanks! I learned something. I've always thought it was a special type of hard plastic.