Intake runner polishing/smoothing

[AxemanZZ]

I recently bought a GT-40 intake and I am in the process of smoothing the outside of the lower to clean up it's appearance a bit. My question is this...
Inside the lower intake ports it is very rough and I was wondering if it is ok to smooth that out a bit just to remove the bumps. I don't intend on changing the size of the ports or anything like that until I get some aftermarket heads and then I'll gasket match it to those.

What would I gain by doing this if anything at all? Also, would this cause puddling of the fuel, or is it just in the heads where this can occur with too smooth of an intake port? Thanks.

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90 Mustang LX 5.0
My Ride*My Site

On a 5.0 fuel injected engine, smoothing the runners will not cause fuel puddling because the fuel is not injected until right before the cylinder head. On carburated engines, a polished runner would cause this condition. You are correct about not polishing the heads because they move wet flow (both fuel and air) rather than just air. I think that you would gain a few HP by smoothing the runners.

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67 Fastback - Arctic White Pearl paint
351W 415 hp, Trick Flow Alum. Heads, C-4 Trans, 3.55 gears, Front Disc Brakes, 1-1/8" Fr. 3/4" rear sway bars.

[AxemanZZ]

Cool. Thanks. Anyone else have anything to add?

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90 Mustang LX 5.0
My Ride*My Site

Ever think about having your lower intake extrude honed?
www.extrudehone.com has some useful info.I myself am going to send my lower GT-40 manifold to them to have it extrude honed just for "cleaning up" the inside for better flow.

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Paxton Blown 87GT
Mustang..it's not just a car,it's an attitude

[AxemanZZ]

Yeah, I will have that done, but I am going to wait until I get some aftermarket heads before sending the intake out for any work as cash flow right now is at an all time low, and I am trying to save up for a TB, MAS, and injectors. Not to mention a cam and rockers =P

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90 Mustang LX 5.0
My Ride*My Site

[n20lx]

if yoyr using a die grinder, make sure you get bits specically for aluminum or they will only last 2 minutes.

[89LXNB]

Hey Axeman
On another note.
Can you square up a block 6 sides within .005 using only a flycutter?
LOL,
Sometimes, I really miss cutting chips.
Good Luck,
Dan

[AxemanZZ]

Funny you should mention that 89LXNB. That is exactly what I had to do last night at work, only I used a shaper and a shell cutter. Are you spying on me?

The bits I am using are lasting about 20 minutes each, but I have enough to last me about 10 years so no worries.

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90 Mustang LX 5.0
My Ride*My Site

[89LXNB]

No spying here, just a lucky guess. Anyway, it's a technique that seperates the men from the boys in a machine shop environment.

A shaper huh,
that's a machine I have not seen utilized for some time. Is it an old unit? I remember that thing was pretty damned impressive, taking BIG chunks at a time. You had to grind the tool just right to get that chip to break nice.

You will NEVER be out of work with those skills dude.

Dan

[AxemanZZ]

Yeah, I believe it's a pretty old machine. But it'll take a .200 cut through 718 Inconel without a glitch, so it's still pulling it's weight =)

If you've never cut that material it compares to Rene 41 or a Waspalloy somewhat. You sound like you know your chit though so I'm sure you're familiar with it.

You should come to work at the shop where I'm working now. We make parts for jet engines and do a ton of developmental stuff. And to make it even better - they don't like buying new tooling so we have to make a lot of our own stuff. It makes for great experience though!

Anyway, back to the topic... I have the outside nearly completed and will be taking it for sandblasting Monday. I haven't started on the ports yet, but should have them done tomorrow. I want to spray a clear over the outside of the intake after I have it sandblasted so it doesn't dull up on me after I install it. Anyone have any suggestions as to what brand of clear to use? Or any ideas about pros and cons on clear coating a lower intake? I was wondering if that would hold in too much heat, but for the record - I'm not building a flat out race engine so much as I am a good looking one. Thanks.

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90 Mustang LX 5.0
My Ride*My Site

[fiveohpatrol]

hey Kevin, Drew here, what kind of machining do you do in your shop? i had 3 years of machining in highschool and i worked in a maintenence shop at Lilly as a machinist-trainee, i never knew you were a machinist, would you know if your shop is in need of a little part time help (in school) or if they ever use summer help? i miss it too and dont want to forget everything

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88 Notchback 5.0, 3.73's, pulleys, BBK headers, off-road H-pipe, flowmasters, subframe connectors, 65mm TB, shift kit, March ram air kit, motorsport wires, MSD coil, upper and lower control arms, 155lph fuel pump, cheap 2800 stall, Crane Adj.FPR, best time- 13.99@99.75, not yet tested times after 1.7RR install

[Mach 1]

My friend just sprayed his 300ZX t/turbo intake that he polished to a nice shine with clear, and it turned out like chit. It had runs where he tried to make it an even coat, and it got all "pasty" looking after having it on the car. He ended up polishing all of the clear off, and leaving it as is. Something to consider. Just keep it relatively clean(wipe it off occasionally)

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1993 GT/AOD
'93 Mustang GT

[Rick 91GT]

Oops..don't know what happened here

[This message has been edited by Rick 91GT (edited 01-05-2001).]

[Rick 91GT]

If you plan on keeping the GT-40 upper have it powder coated it will look sweet. As for using clear the only clear I have foeund that works well is the Hi-Temp clear avaiable for The Eastwood Company (www.eastwoodcompany.com)a lot of people glass bead then clear it turns out nice, but you have to put it on nice and smooth and not to thick, multiple coats.

Kevin- just got a battery box welded up after I get it polished up I'll drop you some pic's if your still intrested

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My Ride Check Out My Site 91GT, Holley SysteMAX II Kit-Heads 2.02" x 1.60",Full MAC exhaust 1-5/8" Long tubes, 2-1/2" O.R H-Pipe, 2 1/2" cat back, 12" K&N Filter, RNH PERFORMANCE Ram Air, Ron Davis Radiator, Full Suspension,3:73's, Welds, Best on new motor-12.60 @ 108, no traction 1.98

[LX XLR8R]

yea i would suggest porting and polishing the lower intake..i prolly put about a good 8 hours into mine to make it perfect..even the guy at the machine shop asked who did it and was impressed when i told him i did it..i did another one after that but me and my buddy knocked it off in like 2-3 hours..

hey i think im ganna have mine powercoated..the only thing is what color so my car doesnt look ricey..my car is black(for now)

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1987 black notch(ex 4 banger)
DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one..

[NOS_Notch]

They say that an intake swap is only worth about 8 hp.
When i put a GT-40 w/ ported lower on my old GT it picked up about 1 1/2 tenths.
So it definitely helped out.
I have a cobra upper and lower both extrude honed, waiting to put them on til heads but it is beautiful...like a mirror



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4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

[AxemanZZ]

When you port a lower intake, what all is involved? Do you match it to the gasket and just try to blend it all together? I don't want to screw it up and was just thinking of polishing the runners up while leaving them the same size. I'll be running this intake on stock heads for the time being, but was wanting to port on them a bit too so the intake ports on the heads aren't smaller than the ones on the intake.

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90 Mustang LX 5.0
My Ride*My Site