Porting the heads now...

[Paul Workman]

Porting my heads is NOT a project I had intended to be doing now. But, the bad valve made pulling the heads a necessity. Danged if I want to do it again anytime soon. Sooooo.....!

Had a problem on my first hole and ended up perforating the water jacket in one spot. (Gonna need some of Al's magic welding again!) The problem was not knowing how to index the axis of the hole, ended up blindly following the 35mm ball guide ever so carefully...right into the side if the water jacket...Dayam!

Marc Hiabeck told me I could safely cut .030 at the point directly adjacent to the cutout for the valve spring. So, to establish a reference for the (new) bore axis, I set my snap gauge for .030 bigger than the port diameter at the spot adjacent to the valve spring cut (located directly on the other side of the port wall - about 1-1/4" 'north' of the tip of the valve guide), and dished out a spot .030 deep. That point became the bottom reference point of the circle which would be the new port diameter.

The reference seemed to work like a charm! Best I could tell, the center of the port was a bullseye to the valve bowl. No more holes either (and that's a goooood thing!).

Looking down the runner of the head from the injector housing port you can see the centerline seems to be poifect!



The diameter of the top of the ports are (now) a shade over 37mm, and that's all I can tell ya less Pete breaks my arms or something! (JK) That is a 37mm ball (below), and ya kin see it goes down a bit more than "flush" too. (So much for the ol 36mm rule, huh?)



And, some smoothing and shaping of the inlet to the bowl (according to recipe), a little valve relief here and there, some minor exhaust work, and voila!



I'm on a quest to be ready for the Crown Point Corvette Challenge on Sept 26th. 500 ponies, give or take, would be a nice "perk" against the C5&6 crowd, wouldn't ya say? Wish me luck in getting it together in time!

P.

P.

[limey]

Paul,

What are you actually using to port these? Do you have a picture of the tool?

[Pete]

Originally Posted by limey

Paul,

What are you actually using to port these? Do you have a picture of the tool?

He is using a pneumatic Snap On grinder,i don't have Model #.
I'm sure Paul will post up Model.


I prefer Elecrtic with speed controler i think you get more control this way i don't have to worry about speed control or running low on air.

I also prefer oval steel cutting carbide.

Limey,looking to do some porting.

Pete

Rick,yeap that's it.







.

[Paul Workman]

Originally Posted by limey

Paul,

What are you actually using to port these? Do you have a picture of the tool?

I use a couple pneumatic grinders. Some (like Pete) like the electrics, but I like the torque and the speed control in my palm.

Some may prefer the electrics, and true enough some pneumatics are junk - making it easy to see why electrics are favored by some. But, this Snap-On PT200LR is a real Cadillac! The speed control is by far the best I've ever experienced - smooth, linear, very easy to control, good torque at low speeds, and "wide open" it cuts aluminum a lot faster than you may want to!

With the Snap-On, I like to drape the air hose over my shoulder, and with both hands on the tool - one controls the throttle, and the other grabbing the barrel of the grinder - in a fist grip, I have terrific control of the cutting and the burr almost never gets away from me. But! When it does, I can instantly be off the throttle and the tool stops just that quick. (I'd venture to say that most of the gang that think they like electrics, if they test drove this Snap-On for a while, might change their minds!)



On the other little grinder I install the sanding drum. Having both tools makes it very convenient to switch between cutting an sanding and back to cutting again: I cut a little and sand a little...easy does it! (The sanding drum keeps everything straightened out. Otherwise it is pretty hard to keep the direction of the bore going in one direction; the bore can tend to wander without some calibration. The sanding drum, I find, does a nice job.)

The (60 grit) flap wheel (mounted on the little grinder) puts a final finish on the work.

As for air supply, I use a 5.5hp Craftsman oil-less with a 20(?) gal. tank. It keeps up with me as long as I'm not rushing it. With time to blow out the chips and take a measurement and resume, the compressor does a pretty fair job of keeping up.

The snap gauge and dial caliper comes in pretty handy as a survey tool set. With it you can take measurements, or establish a reference "benchmark", which seems to be working well for me (to keep it all going in the right direction.)

The two burs: One is a 2" shank, 5/8" diameter does the yeoman's work. The 6" bur (shortened to 4") is 1/2" in diameter and at low speeds is agile enough to get into most tight spots or spots out of reach for the shorter burr.

The ball gauges; one happens to be a 35mm and the other (Rick made) is aluminum(?) and measures 37mm. In using them, I find it best to establish some touch points along the route. Combined with the sanding rolls, boring a straight or curved (if that is needed) hole is really made a lot more precise.

If you're interested in porting, let me know and I can round up a "kit" for ya.

P.

[rhipsher]

The 37mm ball is made of Nitronic 50 which has twice the tensil strength and corrosion resistants of 316 stainless steal. The nice thing about the ball gage is when it won't go down any further you can just put some preasure on it and swivel it around a little and it will leave marks on the inside of the bore to show you where the high spots are without wearing the ball gage out.

[Paul Workman]

Originally Posted by rhipsher

The 37mm ball is made of Nitronic 50 which has twice the tensil strength and corrosion resistants of 316 stainless steal. The nice thing about the ball gage is when it won't go down any further you can just put some preasure on it and swivel it around a little and it will leave marks on the inside of the bore to show you where the high spots are without wearing the ball gage out.

Hadn't thought of that trick. I use a small LED "flash light" shined in from the other end. But, that doesn't leave a reference mark(s) when resuming the cut. Thanks 4 the tip!

P.

[rhipsher]

Originally Posted by Paul Workman

Porting my heads is NOT a project I had intended to be doing now. But, the bad valve made pulling the heads a necessity. Danged if I want to do it again anytime soon. Sooooo.....!

Had a problem on my first hole and ended up perforating the water jacket in one spot. (Gonna need some of Al's magic welding again!) The problem was not knowing how to index the axis of the hole, ended up blindly following the 35mm ball guide ever so carefully...right into the side if the water jacket...Dayam!

Marc Hiabeck told me I could safely cut .030 at the point directly adjacent to the cutout for the valve spring. So, to establish a reference for the (new) bore axis, I set my snap gauge for .030 bigger than the port diameter at the spot adjacent to the valve spring cut (located directly on the other side of the port wall - about 1-1/4" 'north' of the tip of the valve guide), and dished out a spot .030 deep. That point became the bottom reference point of the circle which would be the new port diameter.

The reference seemed to work like a charm! Best I could tell, the center of the port was a bullseye to the valve bowl. No more holes either (and that's a goooood thing!).

Looking down the runner of the head from the injector housing port you can see the centerline seems to be poifect!



The diameter of the top of the ports are (now) a shade over 37mm, and that's all I can tell ya less Pete breaks my arms or something! (JK) That is a 37mm ball (below), and ya kin see it goes down a bit more than "flush" too. (So much for the ol 36mm rule, huh?)



And, some smoothing and shaping of the inlet to the bowl (according to recipe), a little valve relief here and there, some minor exhaust work, and voila!



I'm on a quest to be ready for the Crown Point Corvette Challenge on Sept 26th. 500 ponies, give or take, would be a nice "perk" against the C5&6 crowd, wouldn't ya say? Wish me luck in getting it together in time!

P.

P.

Damn Paul! That ball gage looks awfully familiar. Hehe!

[rhipsher]

Glad to see it's being put to good use. Excellent!