Thanks for the feedback. I did some more work last night raising the roof. I didn't bring home a camera, or I would post more pics. I ordered up a couple more bits yesterday, so I'm guessing there will be a lot more progress this weekend.
Thanks for the feedback. I did some more work last night raising the roof. I didn't bring home a camera, or I would post more pics. I ordered up a couple more bits yesterday, so I'm guessing there will be a lot more progress this weekend.
I think the easiest way to think of porting is somewhat the same as choosing a cam;
According to valve size, where do you want your power to be? Do you want a head that has great out of boost drivability and low end power (velocity over volume) or do you want a top end screamer that makes max power at max lift and max rpm? (volume over velocity) Or something in the middle?
Bottom line is, just like a cam with a set profile, once the head is done, it's going to have a preferred operating range that can't be altered. An all out head that has max flow @ .600 lift would be waisted running a stock cam, just as a stock head running a .600 lift cam would be. This is where I've found the G-heads to be the best to work with for the novice, and I still consider myself a novice porter.
Port configuration is better right from the git go. Chamber is better as well for flow and higher rpm power, and you really can't go wrong with anything from a clean up to a fairly significant port job with +1mm valves. (just not much that can go wrong vs going any bigger)
Having said that, I have done a few 782's now and they are doable, just more work AFAIC.
Looking forward to you progress
Robert Mclellan
http://www.youtube.com/watch?v=wambNdfnu5M
10.04 @ 143.28mph (144.82 highest mph)
Worlds fastest 8v MTX Shelby Charger
Manitoba's Fastest 4cyl!
8 valve, No Nitrous!
New clutch combo is the SH!T!
Lookin Good!
Robert Mclellan
http://www.youtube.com/watch?v=wambNdfnu5M
10.04 @ 143.28mph (144.82 highest mph)
Worlds fastest 8v MTX Shelby Charger
Manitoba's Fastest 4cyl!
8 valve, No Nitrous!
New clutch combo is the SH!T!
Check out headgames motorworks YouTube page. They have some nice porting videos.
google cross buff pads.
work great for polishing.
A little more progress today. I got a couple new bits in the mail and thought I would try them out. They're longer, but they were really too long to grind without crazy chatter. I'm not sure if I need a grinder that'll go slower, or if I need to go faster. Either way, I cut them down some and they're perfect now. The small ball end piece that's about 1/4" diameter is awesome for working in the bowls. Thanks to Shadow for that suggestion. You can see that I've eaten up the valve guide pretty good. I think I'm going to knock the guide back into the head when I do the next runner.
I also attempted to deshroud the valves. I tried to mimic what I've seen on other heads. I'm not sure if this is too aggressive or not, but I thought it looked decent. It may not be entirely noticeable, but I also laid back the portion near the spark plug. I think I'm achieving a better result than the chamber next to it that I attempted to grind with whatever I had laying around approximately 20 years ago now.
If you look at the picture I posted that 5digits noted on, he basically suggested turning a swirl head into a g head lol.
Actually, I remember the conclusion coming to be that the ideal head has characteristics from both. I think a pic of Warren Stramer's head was posted and his chambers are basically a hybrid of the swirl and the bathtub styles.
The problem with with the swirl head, I think (per conversation with 5DIGITS), is that it is too efficient per say. The higher the boost (ie more fuel/air charge) the faster the burn seems to be, and you run out of timing to pull out for pump gas. So the mods you do on the swirl head chamber are to slow that down. Bathtub chamber is sort of the opposite. The one 2.5 G-head cal I have done so far ended up working great with a lot of timing added in down low, indicating it is less efficient.
Port work theory is fairly similar though between the two though, I think.
Yes, Much better looking chamber than the one next to it!
Don't have to go crazy around the plug area. I'd just smooth some of the hard edges for better transition.
You are entering what I would consider stage 2 porting now. Most would be fine with the last set of pics where you don't move the guides, but you get around them decently, removing all casting flash and generally having a smooth slightly enlarged port from flange to seat. (stage 1)
Knocking back the guides so you can raise the roof and work the area above the valve significantly more is starting to go a step beyond the beginner porter and once you get comfortable with it, the sky's the limit
You may want to consider your intake at this point, picturing the complete runner tract, from intake all the way to seat. Understanding that you are trying to achieve a gradual taper all the way.
Robert Mclellan
http://www.youtube.com/watch?v=wambNdfnu5M
10.04 @ 143.28mph (144.82 highest mph)
Worlds fastest 8v MTX Shelby Charger
Manitoba's Fastest 4cyl!
8 valve, No Nitrous!
New clutch combo is the SH!T!
Thanks again for the notes everyone. I'll keep working on this and posting pictures as I progress. I've learned a ton by doing this so far, and I'd like to continue in that direction.
In regard to the intake, I think I've got a very good base there from what I can tell. I'll need to have the hole I put in the upper half of the plenum welded up. I'll have the lower portion welded at the same time so I can port the rest of the lower, and that should be good to go.
http://www.turbo-mopar.com/forums/sh...=1#post1143609
Brian,
Are you using any grease on your carbide bits? It helps keep them clean and helps with chatter. Quickest way to kill a carbide bit is letting it chatter or overheat. BTW are you using ferrous or non-ferrous burrs? I use a Amsoil grease with a very high melting point, but any high temp all purpose grease will do. Some people use tallow. You made a comment earlier about speed of your tool. Isn't the speed variable on your tool?
Didn't see any pics of the short turn area? This area is very flow sensitive and important. The factory short turn isn't very good IMO. Lots to improve there. Your making progress for sure. Attempted any exhaust work yet? Lots of work to do on those.
Todd
I've been using bits such as these:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
I'm spraying WD-40 on them while I'm porting. I have a variable speed Metabo die grinder which I run at its lowest speed. It can be seen here:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
I have attempted to smooth out the short turn. I'll try to get some pictures of that. It feels pretty good to my finger, but I know little to nothing of the subject at hand. In regard to the exhaust, I've opened it up to the gasket on the sides and top, while smoothing that back toward the bowl. I've just started on the bowl, but it seems to me that I'll need to knock the valve stems back to get in there at all. I'll try to get more pictures of this and post up.
Your link is showing a ferrous burr. Yes you can use them on aluminum, but the non ferrous burrs work a lot better and faster on aluminum. I use an oval burr like pictured for the vast majority of my porting. Probably do 85% or more with this one burr (albeit a slightly longer shank one).
Probably the best thing I ever did to improve my porting skills was to build device so I can mount the cylinder head (or whatever I'm porting) and rotate it anywhere I need. No longer standing on my head (or knees) to port. I can sit comfortably on a chair or stand and port without much fatigue. Can rotate whatever your porting quickly and effortlessly wherever you want. Can't stress how much this helped me.
Just skimmed through this thread but I'm not hearing too much about straightening ports. That is important. If your not going to buy an internal dial caliper gauge or inside dividers to measure the ports, at least make up some sheet metal plates that you stick into ports to check your pinch points. I never use flat files like John suggested, but only rotary files (carbide rotary files or burrs), but the point is well taken as inexperienced porters can get that wave thing happening easily in ports. That is the beauty of practicing on junk heads.
So my biggest ? is going to be, are you going to flowbench anything to measure improvements or setbacks?
Todd
Last edited by 4 l-bodies; 02-24-2019 at 04:41 PM. Reason: typo
Thanks for the tips on the burrs. I'll be on the lookout for some non ferrous burrs in the future. That's a pretty sweet fixture you built to move the head around. Do you bolt the AC bracket area to that?
I have an internal divider to use, along with a compass.
In regard to flowbenching the head, I'm not aware of any place around here which does that. I could ask around, but it would probably be an hour drive one way if I had to guess. Shipping would most likely make it cost prohibitive. I've read of guys making them years ago. Is that a viable option?
Yes in the case of 2.2/2.5 heads I bolt to the AC boss. I've been porting some LT5 (90-95 ZR1) heads, injector housings, and intake manifolds lately. LS heads too. They all can bolt up in a minute or two. I also made another fixture to easily fasten a Masi 16V head. I can just rotate it around to port intake, exhaust or chambers w/o moving fixture. I have another complete fixture I bolt to the end of a stainless bench I have on wheels. All my porting equipment is self contained in the drawers, so I can move outdoors or wherever I want to port. I use that one a bunch outdoors when the weather is nice. Natural light is always nice. Cleanup is a breeze too.
Another thing I recommend if you start doing more porting is to buy a burette so you can measure port volumes of chambers and ports. Some of the more sophisticated ECU's can detect chamber volume mismatches and start throwing codes if off by a single cc or so (one chamber to another). We obviously don't need to worry about that, but it is good to have chambers and runners balanced.
BTW- Most definitely need to knock guides out (or up) to port roofs on the exhaust side if you want to get good flow from exhaust. I knock them all the way out so I can use the guide hole to measure how much material I've removed. That entire machined area around guide can then be removed on the exhaust side. Then aero the guide in lathe or drill press before install. Be careful of the small waterjacket about 1/2" downstream of the guide on the roof of the exhaust (on a head you care about). My suggestion since you are working on junk heads at the moment, is to intentionally break through to the waterjacket on one cylinder you don't care about so you know how far down waterjacket is and where it is located.
Keep up the good work!
Todd
Thanks for all the tips Todd. I'll look into a burette. It would be pretty sweet to make a nice rotation device too. Looks like I really need to get some welding skills.
OK, I've ordered up a burette, but I'll probably just use the ones at work anyway...
Here are some more pictures. I did a tad more porting in the intake today. I have a lot of contour work to go to say the least IMO. I was surprised that everything seems to be going fairly smoothly though. I think with a few more hours of work this might at least look decent. The flow would be nice too though.
I also checked the internet to see what a flowbench costs. I now realize why guys want to charge $40-$50 to put anything on them. All of the homemade jobs I've seen so far don't look like they would produce repeatable results IMO.
Sorry to go off topic, but that would be neat to see some LT5 ZR1 heads. Are they at all like the TIII? Both Lotus designed from about the same era?
As a kid, I drooled over those, but I have never even seen one personally.