What is the best bit to use when porting a plenum. I was using a bit that came with a dremmel tool set and it keeps getting clogged easily from the aluminum. also any other tips would be greatly appreciated. thanks alot

 

cobrakiller1989 wrote:
What is the best bit to use when porting a plenum. I was using a bit that came with a dremmel tool set and it keeps getting clogged easily from the aluminum. also any other tips would be greatly appreciated. thanks alot

I bought Dremel 115 and 196 high speed cutting bits, and the eat right through the
aluminum. Took me about 10 minutes to port out to my plenum to 58 mm.

..What suprised me was that since this TB was on the engine when I bought it, it wasn't already done. The guy spent ~$300 for a SLP TB and it probably didn't make a bit of difference without doing the plenum side.


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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms Lakewood panhard rod
Corvette 2/4 servo, kevlar band
full poly rear.

 

Thats weird. Aluminum never has clogged my dremel, only plastic once.

Just pile up 5 or 6 cut off discs at a time. it will grind right through

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91 Formula
305 TPI 5speed
1LE/G92/WS6
Cold air ind. w/K&N, SLP airfoil, ported/polished plenum, March pulleys, TB coolant bypass,Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL, Holley 9mm wires, fastchip, Bosch O2sensor, SLP headers & catback,short shifter,3:73s w/Auburn posi,160* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

If you have access to a diegrinder(one with a 1/4" collet), use a single cut carbide bur. This thing will flat cut thru aluminum. I used one that had a extended reach, which made it easier to reach the inside parts of the plenum.

 

Use some WD-40 while using the bit, this will keep it from clogging.



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1990 Roadster

 

I suggest a carbide cutter that is designed for aluminum. These cutters cost about $15 to $20 apiece, and are great for aluminum. I have short-shank, (as pictured here) and long-shank, for reaching the insides of the plenum. I bought my long-shank cutters from Summit Racing equipment.

I'm also doing plenums on the side. One thing I've wondered: LeeH: How can you port your plenum in 10 minutes?? I spend 90 minutes on each plenum that I do. Have you just hogged it out, or did you actually radius and blend the opening? Did you clean up and radius the openings to each runner? Did you gasket match anything?




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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.

 

how do you gasket match something, i have seen it offered by people who port plenums, but I can't figure out how to gasket match anything.

If you want, you can send me a big email to j_hougnon@hotmail.com or just post it here.

Thanks,
Jesse

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85 Z28, 305 TPI A4
pretty stock with MSD and a few other toys
15.2@91mph
http://photos.yahoo.com/j_hougnon

 

ws6transam wrote:

One thing I've wondered: LeeH: How can you port your plenum in 10 minutes? I spend 90 minutes on each plenum that I do. Have you just hogged it out, or did you actually radius and blend the opening? Did you clean up and radius the openings to each runner? Did you gasket match anything?

It only took me 10 minutes to port out the tb intake holes with the metal cutting bits. Once I scribed by max diameter lines from the gasket as a template, getting the correct size was cake. The polishing
and blending takes a bit longer

I also have the advantage of having 3 years
experience as an machinist and apprentice tool & die maker - there's lots of little tricks you learn when you've worked with a bunch of old guys who have done this kind of
stuff for 40 years...
Plus I have a Fordam #30 industrial dremel too

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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials

 

I just used some of the bits that are used "for soft metals" and the dremel at 30,000 RPM cut through my plenum like a hot knife through butter!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

hey guys,
Thanks alot for your advice, you all helped me tremendously on my first plenum porting and it went well. I spent about 3 hours on it getting to my perfection. It is at a powder coating shop right now being coated siler. I am getting my runners done in red and I am getting the Edelbrock intake. It is all going to be topped off eith stainless steel bolts. So it should look pretty good. Thanks again, i appreciate it.

 

Cool! I'm glad it worked out well for you!
----------------

One high-speed steel grinding bit says to another one day while hanging out together in the tool crib:

"I dunno, ever since these new carbide-tipped guys showed up, I feel kind of like I've lost my edge."
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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.

 

It's really pretty simple.

First you use Dykem Blue or a Magic marker to color the area you want to grind on.

Then you use the gasket as a template. Put the gasket in place and use something sharp, like an ice pick or something else with a sharp point and scribe the inside diameter of the gasket.

That will highlight the area where metal needs to be removed. All that's left now is to use your grinder and remove the metal up to the line you scribed. Smooth and blend everything you ground on, clean away the metal shaving and you're done.

Working aluminum's a breeze; cast iron's another story altogether.

Hope this helps.

Jake



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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9