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Well, if it's GM, chances are it'll take a "banjo" type fitting on the caliper, and a 3/16" flared steel line on the other. Most of the differences in the seventies and most of the eighties GM stuff was just length, or extras like tabs or ends designed to clip into holders.

If you know what the caliper originally fit (for example, Chevy Impala, or GM 1/2-ton truck, etc) try getting a hose for that make/model.

Doc.

Good. Grizzly is an importer. Most of their machinery is pretty good (the Taiwanese-made is better than the Chinese made) but all their tooling is only mediocre to decent. It's not bad, but for the cost, I tend to recommend buying just a handful of the sizes you need- like 3/16", 1/4", 3/8", 1/2", and so on. Do you really need a 13/64ths?

I'm a machinist, and even I find I use only perhaps as many as a dozen sizes regularly, another three or four very infrequently (once or twice a year, tops) and the rest sit around gathering dust because they're either too big or too small.

Especially if you have a good supplier in town, and not too far away. I'm lucky in that there's an industrial supplier not three miles away, with a good selection of drills, including 6" and 12" in a few sizes. When I need a new drill in a size I don't have, I just run up and buy two or three at sometimes less than $2 each.

That way I have fewer oddball sizes just sitting round not being used.

Doc.

Go megasquirt and sort out the fuel side of things first.

This is the option I'm taking. Skin one cat at a time.

-I hear that!

Like I said, just building the manifold will be a trick in and of itself. My current ignition works fine, and can always be upgraded later.

Doc.

[Stude]

I found a reference earlier today that mentioned developing an EFI system, and having to work at keeping the fuel from puddling on a port wall due to the spray angle.

Interesting point on the spray cooling the valve though... that's an interesting bit of data.

I found a reference on the injector ports as well- the end cup dimensions are .530 to .535" ID. Doesn't give a depth, but from the diagram it looks like it could be anywhere from .250" to .500". The fuel rail pockets are the same. So it seems I can just use a 13.5mm endmill, which is easy enough.

Stude- I saw the M'Jolt on the 'Squirt site, but hadn't looked through it yet. At the moment I wanted to keep things simple- I already have an HEI on it, and that works fine. I just hadn't thought about the vac advance until just now. If necessary, I'll convert to the electronic advance HEI, but for the moment, I need to concentrate on the injection itself.

Sean- Interesting torch. One of my Richard Finch TIG books has a pic of one smaller still, though it might be hard-pressed to weld 3/4".

I still need to get the materials in and mock the thing up in realtime before I even know what sort of room I have. If it works the way I have in mind, I may be able to weld both ends of the runners from the inside, no external welds.

Doc.

Drill bits can be a books' worth of information all by themselves.

The first thing is, 90% of the time you're turning it too fast. I see guys with 1/8" bits in air-drills turning 2,000 RPM, or guys with a 1/2" in a HoleHawg doing 500 RPM.

Slow down some- most of the time you'll find the thing cuts better at a slower speed, and you'll be less likely to make a triangular hole. Of course, that means you need a variable-speed drill...

Second, use a pilot hole. The center of the drill moves the slowest and has the shallowest edge, so cuts the poorest. For anything over 1/4" or 3/8", it's useful to pilot drill with something about the diameter of the center web of the final-size drill.

Also, use lube. WD-40 in aluminum, any ol' motor oil in steel. If you're going any real depth in stainless, it can't hurt to get some of the black high-sulfur cutting oil. And remember that stainless can work-harden at the drop of a hat. Never let the drill "idle"- if it's turning, it should be cutting. If it's not cutting, it shouldn't be in contact with the surface.

If it work hardens, either by trying to go too fast or letting it idle, you can sometimes get through with a new, sharp drill, but I've seen it bad enough you'll have to bump up to a carbide or cobalt drill. You can also try coming through from the other side.

On that note, coatings are worthless. "Titanium", "Titanium Nitride", "cobalt coated" and all that... TiNitride- the gold-colored stuff- does add a small bit of surface hardness, but it's only a few microns thick, so it doesn't add much. It's mainly a lubricity thing- it keeps chips from "welding" to the cutting faces. Useful in a CNC production enviroment, but pretty much worthless in a home-shop. It's just bling-bling to get you to pay more for the bit.

Same with cobalt- if the bit is a real cobalt alloy (usually referred to as M2 HSS, or 10% Cobalt) then that's a good improvement over 'plain' high speed steel. Cobalt adds heat toughness- the metal doesn't soften as much as it gets hotter, as plain carbon steel does.

But cobalt coatings are as worthless as the Ti coatings. Might be useful in a production enviroment where you're making 5,000 pieces, but just an extra cost for the home-shop user.

Buy good quality American-made drills, NOT ones that come in bubble-packs at Wal-Mart or Home Despot. Those ones might be okay for woodworking, but I wouldn't use 'em for anything critical. Try and find a real live industrial supplier, or barring that, mail-order some from a machinery supplier.

Good drills are worth every penny.

Doc.

The valve is just a needle-and-seat; knob all the way out is less restriction, knob all the way in is more restriction, just like a carb idle-mixture adjustment.

The more restriction, the longer it takes that pair of brakes to come up to line pressure. If you try a panic stop with the knob wide open, and only the rears lock up, try it again with it full closed.

If you're lucky, you'll find a "happy medium" in between somewhere. Also, don't bother playing with it until the brakes are well adjusted and broken in. If you find out, for example, the fronts aren't being held in place by the residual valve, the extra puck travel will mess with the feel, and therefore how you set the P-valve.

Doc.

Start with it all the way out. The proportioning valve is just a needle-and-seat restriction; it doesn't limit the overall pressure that goes to the brakes, it can only slow the rate of pressure increase.

On mine, a Behr (WilWood copy) "increase" means "increase proportioning"- add time to the pressure curve, which simply means increase the restriction.

Setting it can only be done seat-of-the-pants; Find a quiet street or open, empty back corner of a parking lot and try hard braking runs, and experiment with the diffeetn settings. Easiest thing to do is try one run wide open (on the valve, that is) and another full closed. (Most P-valves only add about 40%.)

Now, I might be off on this, but I think you might have some problems with the setup because the 'Vette master cylinder is a disc/disc unit. Drums need less pressure and less volume to actuate (smaller cylinder and the self-energizing nature of drum brakes) so it's entirely possible you'll find that the rears are doing all the work, even at full proportioning.

Doc.

The three wires are a holdover from the points-ignition days.  Of the two smaller terminals, one is the solenoid-energize lead, and the other feeds full voltage to the coil to bypass the resistor wire, to improve starting.

In your car, you'll just need the main battery cable and the solenoid-energize wire (purple, as I recall.)

Assuming you're running an electronic ignition, unless I'm mistaken (a distinct possibility) you won't need the other wire.

Doc.

[GPster]

GPster- I have a partly-dismantled junkyard block that I plan on doing the fabricating on. It's a rebuildable core, but filthy- Won't have any problems dropping shavings or aluminum dust into it, it needs tearing down and rebuilding anyway.

If I were to build the thing to the block and heads directly- as in no gaskets- that would leave me some room to have the faces milled back to straight, wouldn't you think? Stock Olds intake gaskets are just pressed sheetmetal with a valley pan though... I wonder if I can get composite gaskets or a Fel-Pro with the rubber lines? The sheetmetal might only be ten or fifteen thou.

Doc.

I hadn't through about milling the injector pockets into the plates themselves... Interesting. Of course, I haven't picked up the injectors yet and  haven't even moved into the mocking-up-with-cardboard stage, but that's a great idea. Would you happen to know the correct dimensions for a GM injector pocket?

The Olds has a pretty wide runner spacing, wider than an SB Chevy, so the wall between runners will be fairly big- thankfully, I'm not sure how I'd weld 'em if they were any closer.

On the ignition, you have to realize I'm not an electonics whiz. I can get the batteries into a flashlight the right way two tries out of three if I'm given enough time to practice beforehand. As far as factory ECUs, I'd have little or no documentation, and no laptop support, besides needing additional sensors like knock and crank-position.

The two things I like about the M'Squirt setup is that it's well documented (you can even compile and flash your own code if you want) and has a built-in laptop interface for tuning on the fly and recording.

They're working on an add-on upgrade to run electronic ignitions (like the 7-pin HEI, or Ford's distributorless) but as I understand it, that system isn't ready for release yet. I'll probably upgrade to that when it's available (they're also working on a wideband O2 sensor interface) but for the moment I'd like to keep it relatively simple. Just fabricating the manifold will be farily involved undertaking.

Doc.

Well, I thought it was more a fabrication question than an application question, but on rereading I note I didn't even mention it was a V-8, so yeah, a few details couldn't hurt.

I have a '66 Toronado (that I've been working on for considerably longer than Jay Leno has been doing his, but I'm still gonna be called a "copycat" ) with a '68 455 that I want to convert to EFI. The problem is the car's very low hoodline- there's almost no room for a bolt-on TBI injector like a Pro-Jection, even the 2-barrel unit, since the stock intake is literally "sunk" in the middle.

Here's a pic- the hood insulation actually compresses a touch on the air cleaner hold-down knob. I have just under 3-1/2" from the peak if the valve covers to the hood.

Nobody makes a port-injector system for the Olds (not off-the-shelf anyway) and even if they did, it wouldn't fit under the hood.

What I plan to do is fabricate an intake that looks something like a wider, lower version of the Chevy LT-1 intake. (Pic stolen at random from Google image search.)

Mine will be a bit lower and almost 4" wider, simply due to the width of the 455. But the layout will be about the same- central plenum/doghouse, front-mounted twin-nostril LT-1/TPI type throttle body, runner-mounted injectors. I'll be using the MegaSquirt DIY controller to run it in closed-loop standalone, batchfire mode.

Due to the location of the throttlebody, I plan in moving the thermostat down and to the driver's side, in what will probably be a custom-made housing. I plan on using an aftermarket 52mm to 58mm throttlebody, and I found a couple of sources for both weld-in injector cups and extruded fuel rail. I can make both from scratch, but the prefab stuff is cheap enough to buy.

As far as the fabrication goes, I have in mind, at the moment, to make the cylinder head faces from 3/4" 6061 flatbar simply for the thickness and rigidity. It'll be a bear to weld, but considering the bar will be seriously reduced (port passages and bolt holes, etc) by welding time might make it a bit easier.

I wondered if 1/2" were thick enough to seal properly- it'd be easier to weld, definitely, but also more likely to warp either during welding or later in use. Some of the photos of pro-stock type intakes I've seen online appear to have 1/2" or even 3/8" faces, but then again, they're racers, regularly rebuilt and serviced, while mine will be a long-term daily driver.

The runners will be 1/8" wall extruded 1-1/2" by 2-1/2" rectangular tubing, which internally almost perfectly matches the dimensions of the stock ports. The base valley cover, most of the plenum and other parts will be 3/16" sheet 5052, with a few 'billet' 6061 pieces, like the TB face, threaded water temp bungs and other bits.

I'm worried about making sure I allow for gasket clearance, and/or leaving enough room that I can have the faces surfaced after all the welding's done to take care of any warpage. I'm worried about placing the injectors at the proper angle, and wondering how much volume I should give the plenum. I know it's "dry" air, but should I minimize volume? Will it matter? Will a smaller plenum give me a better vacuum signal?  (Power brakes, trans modulator, etc.)

For that matter, where can I pull "ported" vacuum for the distributor advance? Just thought of that one, lemme write that down...

So actually I guess it's a two part question; manifold theory and design, and actual fabrication techniques.

Doc.

Newly delurked guy with a question:

Does anyone have some good info on the whys and wherefores of fabbing sheetmetal intakes? I'm a decent machinist and I'm learning/relearning the TIG under some professional guidance, but I'd like to find out some more info, preferably from someone who has already done it.

The application is an EFI manifold for a daily driver, so things like plenum volumes and runner sizes aren't quite as critical as they'd be for a pro-stockers' tunnel ram, but I'm still sweating things like building in proper clearance for gaskets, should I bother with a heat crossover, and will I have corrosion problems from the coolant? (Iron block, copper radiator.)

As well as things like how thick should I make the gasket faces? 1/2"? Will 1/4" flex too much to seal well? Is 3/4" too thick? (I know it'll be a pain to weld...) Is injector angle critical? Should they spray right at the valve, or is "pretty much anywhere into the runner, heading in that general direction" okay?

Thanks for any and all replies.
Doc.