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Old 12-28-02, 04:04 PM
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Building Peripheral Port housings

This kind of goes with my resurfacing rotor housing project. Does anyone here have first hand experience or knowledge of the best way to bore the approximately 2" hole in the housing. I have a mill and a lathe and the positioning of the housing is not the question. The question is more the cutter tooling used.
Since tooling for mills is expensive I would like to know what has worked for others and avoid as much trial and error as possible.
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Old 12-28-02, 05:58 PM
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I've never done bridge porting, but I do have some machining experience, I would suggest using a boring tool in ur mill with a carbide insert.
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Old 12-28-02, 07:24 PM
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I'm no machinist but the aluminum cuts nicely with a drill bit! One day I took a fresh battery in my cordless and chucked a big ole 1/2" bit in there and drilled a starter port. The metal shaved away nice and clean. After I did that, I was told that if I'd have used ethylene glycol coolant as a cutting fluid it would have cut even nicer.

The metal insert was a bit tougher, but it's chrome-moly steel so it kinda should be

No pics, and if I had any they'd not be worth seeing, just a 1/2" hole vaguely where an intake port should go while I finally decide on a port configuration.
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Old 12-28-02, 08:26 PM
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A 2" drill bit would not be as practical as you may think. A bi-metal holesaw may work but I have a feeling the hole may look as primitive as the tool.
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Old 12-28-02, 08:33 PM
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A starter hole is a no brainer, he's talking bout a 2" hole. U need something that will cut a smooth, round, straight hole that size. Just like if u were making a carb adapter plate.
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Old 12-28-02, 08:36 PM
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You might consider a flycutter in the mill. They are not very expensive at places like Kennemetal. You might have to start with a pilot hole and make multiple cuts, but it really shouldn't take long.

Just a thought...........

db
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Old 12-28-02, 08:38 PM
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Fly cutters r for milling the surface, not boring a hole.
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Old 12-29-02, 09:08 PM
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Actually a hole saw seems to work pretty well. The only bi-metal one I could find in my garage was just 7/8" but I was looking more for how the teeth cut the material more than the size since it is all relative.
Just in case any of you want to try this. I will not go into setting up the lathe jig so this is after the housing is mounted in position to bore.
Since the hole saw used a 1/4" pilot bit I used a bare bit and drilled a 1/4" hole the entire way through.
Most of you can figure out that if you get a hole saw on an uneven surface that it is going to try to "walk" on you and leave a pretty rough looking hole. Since the surface where the bit enters the housing is awkward this is how I kept it from walking.
I took the 1/4" drill bit out of the hole saw and put a smooth piece of 1/4" round stainless rod in its place.
This forced the saw to stay true to the pilot hole. If I would have left the drillbit in it would have had a tendency to side cut the hole. Since the side of the rod was smooth it could not cut change the shape of the original pilot hole.
I know that is a long explanation but it is real important that anyone who tries this method adhere to that step. Otherwise you might end up with a oval hole.

I am milling a set for Ken Sheepers. This port is based on what he currently uses which is very similar to factory peripheral ports as opposed to the Racing Beat that comes in at a different angle than what he is wanting. He has ran both types and prefers this from experience.
Just in case you have not looked at a housing in a while remember where I drilled this is a little below center of an existing hole. The second picture from the bottom would appear to be screwed up if you don't keep that in mind.
I will post a pic after I do an actual pport ready housing and if I run into any surprises. So far this is a pretty inexpensive way to tool up for a job











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Old 12-29-02, 11:36 PM
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hmm interesting, Im also thinking of building up a PP for myself, so just a few quick questions

when you have the 2" hole bored, are you going to use an insert of some kind and then seal the water galleries off?

and also the final port shape on the ionside of the housing? is this just going to be a round hole, as I am thinking of stopping just short of the insert and doing final port shaping using a die grinder or something to control the port timing a bit better.

any help, thanks.
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Old 12-30-02, 12:56 AM
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Yes. The insert is actually just a tube. Since you drill through a water jacket it is at least the easiest way to accomplish this. All the pports I have seen always used an epoxy like Devcon with the exception of Jesus Padilla that uses some kind of silicone. Or at least that is what it looks and feels like.
And after I measured Ken's the tubing was 2" ID with a 2 1/4" OD. He has a huge dual 55mm throttle body fuel injection setup.
I understand why people use epoxy just to be sure they don't get any leaks but if this was mine and not Ken's here is what I would do.
I would start off with a thicker walled tube. I would prep my hole saw. If you feel the outer edge of a hole saw you will be able to feel that the teeth slightly bend outward because these are not made for precise work and it allows clearance to reduce binding. Basically I would spin the holesaw on the lathe and file the hole saw so it was true. I would bore the holes and get a precised measurement.
After I had the measurement I would put the tubes on the lathe and make them a little oversized and put a small taper at one end.
The tubes would then go into the deep freezer to shrink them as much as possible. I would put the tapered end of the tube in the bore then press fit them in.
It should work like a freeze plug. You have to make sure the the tubes are longer than neccesary since it needs to be ground to follow the curvature of the inner wall of the housing.
To bench test it I would make to block off plates. (see picture) One would be tapped for an air fitting to tap into it. Laying the housing flat with the fitting pointing up I would fill it with a flourescent liquid and hook the air compressor to it. Look and see if there are any obvious leaks and if not hit the lights and fire up the blacklight and see if there is any sign of even slight leakage.
If it passed that test I would grind it back and to a finished state and test it again.
Obviously if I did this pport setup it would be for a race motor anyway so if it had to come back out it would not be the end of the world and it could still be epoxied later.
I will conceed that is more trouble than it is worth but I just like to do things sometimes to see if it will work


This would be two plates sandwiching the housing using 3 bolts and using sheet rubber between the plates to seal.

Last edited by Scalliwag; 12-30-02 at 01:07 AM.
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Old 12-30-02, 01:13 PM
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If you were really **** retentive you'd bolt a complete "empty" engine together (just housings, no internals) with the tension bolts torqued to spec, then heat everything up to operating temp (flow hot/boiling water through it) so all the stresses are the same.

Kinda like boring cylinders with a deck plate.

Some head porters bolt deck plates on the cylinder heads and flow hot water through them before doing a valve job! Every little bit of accuracy counts
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Old 12-30-02, 02:11 PM
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Dammit Peejay why you want to get me doing something like that?!?!?! I think a hot liquid under about 180 lbs. of pressure will have to do.
Then again if I drilled and tapped the plate that is opposite of the air fitting I would put a small heating element and a temperature gauge as well as a pressure gauge to keep it from getting ridiculously hot.... dammit Peejay, see what you got started?!?!?!
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Old 12-30-02, 04:07 PM
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At some point you have to shoot the engineers and make the damn product already!

That's why I said hell, I'll just pot the whole thing with Devcon and chew a port out of that. Not pretty, but pretty doesn't matter.
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Old 12-30-02, 05:10 PM
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No don't shoot the engineer! At least not while I'm the one wearing the hat that day!
Yes, theory can only get you so far and you have to put up or shut up eventually. You just want to do as much practical research as possible and look for any problems that may be avoidable.
My wife went to WW Grainger and picked up my holesaw and I have to run by a shop and pick up a piece of aluminum pipe after work. So by New Years day hopefully I will be doing a pport.
Right now I don't have anything to use on the tailstock of my lathe to turn the pipe on so I am trying to figure out how I am going to make due on that.
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Old 12-30-02, 10:55 PM
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Well I got home and I looked at the hole saw. Like a kid in a candy store I made a beeline for the garage! I popped another housing up on the lathe and ran the 1/4" pilot and ran the 2 1/4" hole saw. It worked great.
I can also tell looking at it without a tube epoxied in why they epoxy them. There is no place for the water to circulate past the tube.
I probably won't try to press fit it after all.
So like I mentioned earlier the only hurdle now is figuring out how to support the tailstock end of the tube on the lathe so I can turn it down to fit in the hole now.









Last edited by Scalliwag; 12-30-02 at 11:09 PM.
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Old 12-31-02, 12:17 AM
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that is a surprisingly clean cut the hole saw made...
though i have no experience with machining or cutting hard metals i remember trying to use a hole saw to install a new dead bolt onto my door...

let just say... ****! the cut wasn't the cleanest possible... thank good ness the dead bolt covers my sloppy hole.
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Old 12-31-02, 12:38 AM
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Originally posted by Cheers!
that is a surprisingly clean cut the hole saw made...
though i have no experience with machining or cutting hard metals i remember trying to use a hole saw to install a new dead bolt onto my door...

let just say... ****! the cut wasn't the cleanest possible... thank good ness the dead bolt covers my sloppy hole.
Hey, let's not be talking about "sloppy holes"! I used a Starrett holesaw and it is pretty nice. Before I made the cut I reversed the lathe and lightly ran a flat file against the side of the teeth. This trued the saw somewhat.
The main thing to remember is that I did not use a drillbit in the holesaw. The flutes on the side of the bit you have acted like a rotary file and distorted the 1/4" hole because there is a shitload of uneven side pressure. When you look at the picture be sure to take a good look at the smooth 1/4" shaft in the holesaw.
I am convince now that any time I ever use a holesaw for a door or anything else I will predrill the pilot hole and used the smooth shaft. It really is the ****.
If I did not have a lathe this would have been a lot harder.
Accurately positioning and keeping the housing still is the most critical part. The second part is how much "play" you have in what you use to drill with.
That is where the lathe really comes in.

Any machinist will read this thread and laugh to the point of tears. I am no machinist and my lathe is not much to brag about. But from a "tinkerer's" standpoint I am feeling pretty good about it. Especially since no machinist offered to give any advice and I just had to wing it.
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Old 12-31-02, 02:09 AM
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I showed this thread to my dad - he owns a machine shop. He laughed a little at your lathe, guessed at the brand and cost, then told me he would have used an end mill (I think that's the name) instead, but the cost is about $80 for a 2" one. Then he made this suggestion for turning that pipe on your lathe (The first sentance is word-for-word, the rest I summarized):

Your best bet would be to turn a plug for the end and put a live center in your morse taper. Or you could cut the tube into the short lengths that you need, then make a plug to fit inside the tube so you can tighten down the jaws without crushing it; then you wont need the tailstock for support.

Make sense?
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Old 12-31-02, 06:55 AM
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Thumbs up

Wow! Good thread... mainly due to the action photos!
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Old 12-31-02, 08:14 AM
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Originally posted by nimrodTT
I showed this thread to my dad - he owns a machine shop. He laughed a little at your lathe, guessed at the brand and cost, then told me he would have used an end mill (I think that's the name) instead, but the cost is about $80 for a 2" one. Then he made this suggestion for turning that pipe on your lathe (The first sentance is word-for-word, the rest I summarized):

Your best bet would be to turn a plug for the end and put a live center in your morse taper. Or you could cut the tube into the short lengths that you need, then make a plug to fit inside the tube so you can tighten down the jaws without crushing it; then you wont need the tailstock for support.

Make sense?
Tell your dad thanks for the advice and to quit laughing at my cheapass lathe! It's the best "new" lathe/mill combo that a poor white boy can buy!
Making the plugs is a great idea. I was looking through my J&L Industrial catalog and found a "bullhead" live center that has a big tapered end that is made for pipe. They cost around $100 so I think I will try your dad's idea.
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Old 12-31-02, 08:16 AM
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Originally posted by Bridgeported
Wow! Good thread... mainly due to the action photos!
What? The long winded explanations aren't the highlight?
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Old 12-31-02, 08:40 AM
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What 3 in one machine do you have Scalliwag?
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Old 12-31-02, 08:59 AM
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Question: Wouldn't you want the the "outer hole" to be the OD of the PP Tube and the housing hole to be the same diameter as the ID of the PP Tube; so that a lip is created to seat the PP Tube on. Of course this would require the housing end of the tube to be contoured to match the housing contour.
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Old 12-31-02, 10:47 AM
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That is a great idea that would require a little more work. I woill have to look to be sure but I think you would not have to cut the tube to follow the contour though.
You may be able to bore the OD of the tube until you are an 1/8" or so from cutting through the inner wall. You would then change out the OD bit for just under and ID bit and bore through. From the pictures it is hard to tell but there is enough solid aluminum to do this without the water passage exposed.
This way you could leave a 90 degree cut on the tube and push it in the bore.
If the cuts are true enough by the time you hone it you would hardly (if at all) be able to see a seam.
I might give this a shot. It will require more tooling.
If it involved making the tube seat on a contured surface that would be pretty difficult to obtain a nice seal.

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Old 12-31-02, 12:17 PM
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Originally posted by banzaitoyota
What 3 in one machine do you have Scalliwag?
Most of the stuff I need machined I have to get a machine shop to do it. This will only get you so far.
This is the one I have from Harbor Freight:


If I ever figure out how to use a real lathe I may buy a real one
I also found what I need to use to put the tube on the lathe for less than $20 It is a bullnose live center

Last edited by Scalliwag; 12-31-02 at 12:21 PM.
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