2004 3.8l Intake Machining Inquiry

[NoisyNewEdge]

Hey Everyone,

Several questions about the 3.8/3.9l intakes

I pulled a lower and upper intake from a 3.8l from a junkyard to try and gasket match them for fun. Inside and out they were caked in oil and dirt, so I cleaned them up using oven cleaner, with decent results. I brought the intakes to a machine shop to have them hot tanked and resurfaced. I've never had anything hot tanked before and had no idea what to expect, but I was surprised with what I got back. The lower intake still had decent spots of oil on the IMRC butterflies, loose dirt near the bolt holes, and crusty white build up in the coolant passages. Should I expect there to still be such residue after being in the hot tank? Like I said, I have no prior experience with having parts like this cleaned, but there is a part of me that doubts the lower intake got tanked at all.



The upper had less issues, although it is covered in a chalky substance. Any suggestions on how to remove it? A wire brush takes it off pretty well but if there's an easier way to do it, I'm all ears.



Also, I've asked a couple machine shops about boring out the throttle body opening in the intake to 65mm. The issue is that the intake is very difficult/impossible to mount onto any machine to be able to get at the opening. Has anyone had theirs bored before? How can I set it up so that it's machinable? Will taking it out to 65mm be cutting it close or interfere with the IAC passage? Do I just go to town on it with a burr?



My final question is about gasket sealing. The lower intake had some pitting around the coolant tunnel holes. Will I have issues with blowing a gasket if I try to use this intake still?



Any suggestions would be great, thank you!

 

[08GT500]

Hi, Like what you’re trying to do. This is a long one.....The Machine Shops were likely telling you they couldn’t do that as setup time would cost more than the intake, itself. If you get another that says “We can’t”- Print this description off, hand it to them- and ask them again- K? Looking at it, sitting on the Mustang- on Top there is a Flat below the Flange, using standard Bridgeport T Slot Clamps, Studs and a Stand-off, if needed (A piece of Scrap, square or Rectangular Tubing) the Width of such less than or equal to the space between the Manifold Flange, and the Protruding runners below. (Again, the TOP of it, as you have it Pictured sitting on the Pony- goes to the FRONT RIGHT of the Bridgeport Table). If their Bridgeport is small, they can also Bolt it to the INSIDE of the Table..- T Slot there, too.
It would be simple to be clamped to the front, extreme right side of the Table of a Bridgeport, Table positioned to extreme IN towards Machine & RIGHT (X+, Y-). (For Jobs just like this, there are the same T slots that run across the TableTop, across the FRONT (And BACK) of a Bridgeport’s Table, surface Machined as precise as the Tabletop) to slide the T Nuts across and anchor the long Studs that will hold the Part to the Table FRONT using either long Toe Clamps, or MUCH BETTER- a Beefy piece of 1/2” x 2” Carbon Steel Stock with 2 Holes hastily Drilled out to Clearance Studs & go right over the Front. Studs can be as long as needed (they Couple together with long Hex Nuts) and then the Manifold Tightened to the Table with 2 Nuts, any Shims needed to get it dead square will slip underneath (I doubt that’s even required, looks like a Squared surface).
Then, the head needs to be extended out & to the same direction (RIGHT) to reach the piece, a Dial indicator in a Collet in the Spindle will verify its square in all Axes, X, Y & Z, with the piece, then indicating the Bore would establish centerline, Boring Bar inserted- 10 Minutes later you’re at 65mm. Long as you have Threads, 1/4”, you’re OK with the IAC. Put the actual TB Butterfly on & verify it’s matched.. Have them Skimm the Flange, Flycutter in, Take it until flat. 15 Minutes...
As you can see, it’s a lot of Steps to an Automotive Machine Shop, or one who likes to keep the setup simple, make a lot of production parts $$ & dislike breaking their Setups. Part you don't see is afterwards, they have to slide the Head back and on center, Tram the Head back in (Indicate it w/a Dial indicator to verify perpendicularly) to the Table once that Job is done, so, it doesn’t end, there. Then the Vise, etc..
I’d seek out a Shop that isn’t so Automotive specific, or stuck in “No Brainer mode”, if you want that done.. even try a proximal Vocational High School. Worst they can do is say “No”. They may even fill in the Coolant Seal surface with a TIG, the Machine Shop would touch it off, Boring out the TB opening would seem fun, they’d likely WELCOME the challenge! Instructors and Students alike are always looking for Projects that are not typical, keep them thinking and ready for anything.
You will be fine with that as it is, however. If it was a Head to Block surface- it would be an issue. But not a Coolant passage. You can just use the Gasket, and add a bit of Permatex around the Port- it’ll Seal fine. Seen much worse that lasted many years with no issues, pulling apart Motors that were being modified.
If you wanted extra assurance, DEVCON, an Aluminum 2 Part Epoxy paste, Drillable, Machinable, etc- has Sealed Robotic Subs I’d Prototyped for many years, on O-ring Surfaces that have seen 7 Atmospheres (14.7PSI/33Feet= 1 Atm.) So- 14.7x 7,= over 100PSI per Sq.Inch... The Permatex will be fine, lol!
As for the Hot Tanking, I’ve done several things that required more than one night in the Tank, Bleach and Water in a 10% Bleach/90% Water Solution works well, Spray and keep it soaked, a Small Wire Brush will remove the rest
easy, then. You may get away with a Scrub Brush if you soak it long enough- wear Glasses, Gloves & Mask- throw it all in a Bag when done- pitch it.
Have you heard of Honing Runners with Abrasive Clay media? Done with high pressure and works for many Aluminum passage Intakes. Check it out- Google it, not super expensive.
You need a series of Burrs to do it, traditionally, and if you blow through- even with a TIG, heliarcing a Plate over a blowout is a mess, and can turn a piece into Scrap- quick. If someone knows them well, they will Heliarc a Plate on BEFORE they reach for a Die grinder. Easier to do that before an accident occurs, if they are close. If you can see it, sure- you can open it up, just KNOW how much Wall thickness you have- no guessing. Read a bit about doing it, it’s almost worth 200$ to have someone with a Flowbench do it, they’re equipped for it, and can tell you what you can expect, and give you the numbers of improvement, afterwards.
Porting isn’t only about enlarging, it’s reshaping- sometimes adding material and knowing optimal methods- time tested. Polishing rough Casting, however- is something you will most always free up some Ponies with. Find the real weak areas, and what’s already known- do that. Sometimes, it’s only a port or 2 that are restrictive, rest are ok.
GT40P’s lowers, for instance- passages #1 +#5 are something that should absolutely be done if going on a Mustang, the rest are better. So, watch YouTube with some Guys who do it all day and you’ll save Time, Money, Blood. Mostly Blood, lol.
Anyhow, I hope this helps. Feel free to ask if you have anything else!
P.S. Get your Intake Anodized Clear once it’s done, it will go through an Acid Bath, first- and remove most anything. Or, you can get it Anodized just about any Color you want! Just call on a local Anodizing Shop, Metal Treatment, Irridite, Rechroming Shop. They are usually pretty cool about doing a few pieces for little Coin.
Good luck! Cheers, John