225 Porting

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circlepilot

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225 Cylinder head...Only three intake ports left to do. 1.70 intake and 1.44 exhaust. Hardened seats. Head milled .100, 44cc combustion chamber, block .025, cylinder .060.
Norm

Ported valves225.jpg
 
Looks nice, can you lay the headgasket on top to show the clearance. I am building a 170 with stock valves and hope the bowls and runners look like yours. You gonna dull down the perimeters sharp edges also?
 
Looks good Norm.
Having done a couple myself and found water, they are not easy to do.
I found going up was safer than going on the side walls in the ports.
Any tips you found?
Stan
 
I have a peanut head most of the way done, at least as far as I dare... considering how many who know more than me talk about hitting water jackets. mostly, I cleaned up right under the valve seat area, and cleaning up the big lumps at the top of the valve guide area (meaning, as head sits on bench for the work I am doing, I know is upside down from being on engine.... but gotta reference somehow) have 2 cylinders' worth to go. I see that you opened up the exhaust valve side of chamber too. I, too, want to do the o/s valves. there's another member that is on both here and on the /6.org site that I have talked to about "finishing it up" for me, as he has (at least access to) a flow bench. I think he actually has his own. Mine (at least this engine) will never be a race engine.... rather, it's gonna be a truck engine. but the flow bench thing is more for giggles than anything. I think that in my case either O/S valves and/or seat inserts are gonna be a must to be able to use this head.... had a few "oops's with the burr bit accidentally meeting existing valve seats.
I have a porting question for those who have done more of it than me (probably most here if I had to guess) When going to O/S valves is it mandatory to replace the seats with seat inserts?
I mean, I know there was a point in the early to mid 70s, where they started hardening the seat areas, when leaded gas began to be "watered down" so to speak, as lead in gas started going away. I'm thinking that if the virgin head material is simply ground away to fit O/S valves, that the hardened layer will be ground away, and valvs will sink into the head. I'm looking for 100K+ mile durability out of this engine, 3 season daily driver kind of thing. NOT a "weekend warrior" that just goes to swaps and car shows a few times a year.
 
Looks nice, can you lay the headgasket on top to show the clearance. I am building a 170 with stock valves and hope the bowls and runners look like yours. You gonna dull down the perimeters sharp edges also?
can I, "2nd" that request?
 
I'll try and answer some of the questions. First of all, my experience with porting has been limited to some Chevy 283 heads I butchered back in the 70s, however I'm a fabricator and metal worker by trade.
When I decided to do this, I made sure of some things before I started. You must have the right equipment and tools. I read several "how to" publications. I spent a lot of time on "Uncle Tony's page on Youtube. You do have to be careful and go slow, yes it would be easy to grind through a water jacket. Exhaust ports need the most attention. Get rid of "casting edges" and flat surfaces. Imagine blowing air up against a flat, rough wall, as it will act like a dam and defector. Smooth (blend) those edges out, giving the exhaust gases a "slide board" to the outside. The intake ports can be opened up somewhat like the exhaust ports, but smoothness is not as critical, in fact the little bit of turbulence caused by a a small amount of roughness, actually helps mix the fuel and air prior to entering the combustion chamber. The exhaust ports, being smaller, requires a little more control of you tool, as not to accidently nick the valve seat. I found that can be avoided by using a good quality tape applied to the valve seat.
Addressing the valve seats...I did not have harden intake seats installed, but I did have harden exhaust seats installed. Why? Because I was told (by a slant guru) it wasn't necessary for the intakes, the exhaust valves are the ones that take the biggest beating. I plan on running "a little" nitrous also. I would recommend that if you are going to overhaul an engine made prior to the late 70s to install hardened exhaust valve seats. My machinist's invoice listed the valve job and install the seats at 325.00. The seats cost 6.00 each. Yes, I will be breaking all the edges on the combustion chamber and dressing it up some what. I still have some work to do on the manifold side of the head. Uncle Tony will show you how to gage the amount of material to remove, by using the manifold gasket as a template. Again, you have to be careful also, not to grind through a water jacket. On all of the grinding, you need to use lay out dye. I found that it soaks into the pores and when you grind away the dye (especially on the sides of the port) you have went far enough. I can't stress enough that you need lights, bright lights, lights in the ports, lights over head, lights everywhere. I still have 3 ports and some manifold side work to do, so screwing up is still possible. Do your home work, visit Uncle Tony on Youtube, and take your time. Go for it.
Norm

225 head gasket.jpg


225 head gasket1.jpg


225 head porting stand.jpg


225 head porting stand1.jpg


225 head porting tools.jpg
 
when you grind thru the dye... wow that can't be that much grinding.....
 
I mean, I know there was a point in the early to mid 70s, where they started hardening the seat areas, when leaded gas began to be "watered down" so to speak, as lead in gas started going away. I'm thinking that if the virgin head material is simply ground away to fit O/S valves, that the hardened layer will be ground away, and valvs will sink into the head. I'm looking for 100K+ mile durability out of this engine, 3 season daily driver kind of thing. NOT a "weekend warrior" that just goes to swaps and car shows a few times a year.

If you want durability, spend money NOW and have hardened exhaust seats installed.

My machinist didn't want to do it but I insisted cause I wanted another 50 yrs service..
When I got the rebuilt milled head back and looked it over, I just couldn"t throw it on the fresh block so I did some pocket porting and gasket matching. I also ported the intake and exhsust manifolds a little, nothing outrageous. This was 4 yrs ago and yeah, I hogged out the exhaust outlet.
 
If you want durability, spend money NOW and have hardened exhaust seats installed.

My machinist didn't want to do it but I insisted cause I wanted another 50 yrs service..
When I got the rebuilt milled head back and looked it over, I just couldn"t throw it on the fresh block so I did some pocket porting and gasket matching. I also ported the intake and exhsust manifolds a little, nothing outrageous. This was 4 yrs ago and yeah, I hogged out the exhaust outlet.
I didn't screw the seats on this one up quite as bad as the last heads I tried to port, but once it hits the machine shop for a shave and the rest of the "valve job" it's going straight onto the block. So any and all porting will be finished before then.
I had a set of 318 heads done once and then decided to take them apart and clean them up a bit and had to take them back to the machine shop for rework since I oops'ed a few seats.
 
What is the max RPM power goal of this mill?
 
Ok, the intake needs opened up where the floor & guide-boss are close, namely shorten the guide about .200" with a 5/8" dia. spot-face/counterbore. Then remove the boss on the roof up to the guide, leave a square edge if these are the guides to be used. Next, blend the ORIGINAL spot-face out to the pocket, only put a radius on the new spot-face, short of the original on the long side, do not try opening it anywhere near the orig dia. or you'll get wet! Then get the port as wide as you can safely there, l've done 1.5" there on a peanut head, walls about .380 in, & .750 out from the stem. The valve-job, & short-side (keep as much as poss.) should roll into the floor, with about a .550" rad. Lay the floor down from there towards the intake. Nice & smooth....
 
Valve on the right is a 1.88" MaxWedge exhaust valve, there is more flow left to find, but that's where l stopped on it 2 decades ago....a bit large to deshroud unless You don't mind lots of bore/bore relieving...
 
The exhaust l don't shorten as much, & just blend/bullet-nose the guide, to keep the heat transfer factor up. On a drag-only job, l'd take it out tho'. The port CA on the intake above is 1.65"sq., which is enough to pull that .060" over mill to 6K, 1.110"H x 1.49"W at that crucial point. Again, there's more there l'm sure, l think l could manage 1.85"sq & avoid "blowout" happy port walls.
 
BTW, the stock "447" peanut head port on the left is about 1.25"sq CA there, lol! Embarrassing, & will start starving Your eng at 4500, more cam just more time to inhale through the same straw.
 
If it were to take to 4800 to start starving I won't ever hit that number in my truck so if that's the worst of it then it'll never be a factor.
I just finished rough out of my peanut head, waiting til time to go get the wife from work so I can get some more dremel pilots to finish it up. Lots of work with a 1/4" air die grinder and various burrs to this point. I wish the sandpaper rolls I have that fit the air tool were smaller diameter. Hope I don't burn up the dremel in finishing it up
 
Yeah, in a truck app, port CA doesn't need to be much over stock. Larger valves, a bump in compression & the right cam will do You best. Larger valves will get the port moving sooner & longer at a higher rate, kind of like roller-cam perks, no change in valve timing that kills low-end/idle/vacuum.
 
2481076924411677.jpeg

here You can see why it's impossible to shorten the guide by just deepening the origional spot-face.
 
As circlepilot has pointed out, & many times by others, these ports have more leeway in the vertical. My experiences have been that larger amounts of core-shift have been lateral, which is probably no surprise, but nonetheless...sidewalls & the "longside" of the pockets usually present the greatest risks..on ANY head.
 
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