jbwetzels Posted January 17, 2005 Share Posted January 17, 2005 ok has anyone here tried this DIY? http://www.sa-motorsports.com/diyport.htm if so how hard is it? Quote Link to comment Share on other sites More sharing options...
Guest magnadyne Posted January 17, 2005 Share Posted January 17, 2005 Eh, I am not a big fan of manual porting. The big reason is it is very inconsistant. To expect a human to open up an intake/exhaust port evenly though out the part is pretty hard to imagine. I have also see people grind away objects that they thought were "obstrustions", but were really there to aid in some aspect other than exhaust flow. Like turbo spool. There is more to intake/exhaust flow than most people think. Simply gutting an intake/exhaust manifold isn't always the answer. Porting is another story. Simply smothing out the material that is already there can help, and is fairly easy to do. If you want to open a manifold by porting, I would highly suggest Extrude Hone. You will get a consistant smooth path for air/gas to travel. Their prices are actually very resonable too. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 17, 2005 Share Posted January 17, 2005 I gotta disagree here. I think that even a person with little or no experience who has patience and a good idea of what they're doing can make some pretty decent improvements on an L head. As far as consistency goes, when I did my head the chambers were up to 2.5 cc different from the factory (and no it wasn't from previously cutting a warped head - #2 and #6 were the biggest IIRC), and the shapes of the chambers and casting in the ports wasn't anything remotely close to "uniform". I didn't open my ports up huge, just cleaned up the casting in the runners, and cc'd the chambers and unshrouded the valves. If that's jbwetzel's goal, then I think he can do a hell of a lot better than the factory. If you're trying to make the ports a lot bigger than stock then I still think it can be done with a reasonable amount of accuracy with a few simple tricks like sticking a valve into the port to measure the diameter, but obviously having a shop with a flow bench would be the preferred way to go. Regardless of your goal, READ as much as you can from as many different sources as you can before you start cutting. Quote Link to comment Share on other sites More sharing options...
jbwetzels Posted January 18, 2005 Author Share Posted January 18, 2005 hmmm i am not convinced to start it my self but if i do what should i not do Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 18, 2005 Share Posted January 18, 2005 Just start reading as much as you can. Online articles, books on cylinder heads, etc. Then at least you will have enough info to make a decision as to whether to take on the project or not. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted January 18, 2005 Share Posted January 18, 2005 Two excellent books: “Theory and Practice of Cylinder Head Modification” by David Vizard. and: “Practical Gas Flow” (subtitled: “Techniques for Performance Porting” ) by John Dalton. Quote Link to comment Share on other sites More sharing options...
Guest magnadyne Posted January 18, 2005 Share Posted January 18, 2005 I suppose you are correct when it comes to an L6. The differences you found in your combustion chambers is proof that standards were pretty low back then. Most of the stuff I have ever worked on or been around and seen ported is something no older '90. For instance, I would be VERY reluctant to touch the cumbustion chamber of an RB26. Today places like JUN & Toda use CNC machins to duplicate a design they have found through R&D to produce gains. You can't go wrong there. I suppose I figured the L6's tolerances to be a little tighter than that. Given this info, I would feel a lot better about porting myself. Just do what was mentioned above. Read, and go slow, and be patient. No need to take off all the material in one swipe. Quote Link to comment Share on other sites More sharing options...
EZ-E Posted January 19, 2005 Share Posted January 19, 2005 I looked at the Extrude Hone page, 600 for porting an intake! WOW, costs more then what I had thought. Quote Link to comment Share on other sites More sharing options...
Guest magnadyne Posted January 19, 2005 Share Posted January 19, 2005 Price list...... I suppose it can add up. Especially for 6cyl motors, but to me, it is totally worth it. Quote Link to comment Share on other sites More sharing options...
Kazuya1274 Posted February 16, 2005 Share Posted February 16, 2005 Speaking of porting, I have a burning question. I have my intake ported now, which we did as much as we could up the runners. We were able to get about half way up all 6. I am going to replace the head gasket, and was thinking about porting the exhaust manifold (turbo), the cylinder head (P90), and possibly cutting open the intake to port the rest of the runners. Question is, am I hurting the air flow by only porting out the runners half way? I am thinking that maybe the air is slowing down by going through a small opening inside the intake, but getting bigger right before the head. Of course, my car is running pretty good with the halfway-up porting job on it now, but I changed a lot of other things when I put it on too. Is it worth it for me to cut open the intake to get at the front of the runners, or is the porting I have on their now sufficient to support the future porting of the head and exhaust manifold? Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted February 16, 2005 Share Posted February 16, 2005 I've been hand porting and polishing heads for years. The last set of heads was my LT1 heads on my Z28. I've learned SOOO much over the last 15 years. These heads are my greatest porting and polishing acheivement to date. I'm going to be P & P'ing my RB26 head as well as massaging the combustion chamber to prevent detonation, which the RB is known for due to a "notch" in the chamber. I get that information from a well known RB26 tuner in Jp. I look forward to digging in to it. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 16, 2005 Share Posted February 16, 2005 Speaking of porting, I have a burning question. I have my intake ported now, which we did as much as we could up the runners. We were able to get about half way up all 6. I am going to replace the head gasket, and was thinking about porting the exhaust manifold (turbo), the cylinder head (P90), and possibly cutting open the intake to port the rest of the runners. Question is, am I hurting the air flow by only porting out the runners half way? I am thinking that maybe the air is slowing down by going through a small opening inside the intake, but getting bigger right before the head. Of course, my car is running pretty good with the halfway-up porting job on it now, but I changed a lot of other things when I put it on too. Is it worth it for me to cut open the intake to get at the front of the runners, or is the porting I have on their now sufficient to support the future porting of the head and exhaust manifold? A simple port match just removes the lip between the runner and the port and this is a good thing, but it kinda sounds like you really opened up the runner, which is not a good thing if you have only opened up the bottom half. In general terms you want the opening to constantly taper down from the plenum to the head. If you've opened up the ports in the head, and matched the runners to them, then your plenum end of the runners are going to be too restrictive. The idea is to get the velocity to increase all the way into the chamber. You might want to look for a die grinder with a long shaft http://shop.store.yahoo.com/bradystools/diegr14inexs.html or cut the plenum open and weld it back together. The Z ports might not be big enough to fit the long shaft of the die grinder in there. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted February 17, 2005 Share Posted February 17, 2005 FWIW, you can get 6" long shank burs and cartridge roll mandrels for deep porting. They will become you most used bur. I have multiple "flame" tipped and straight 3/8" diam and 1/4" diam. burs. Plus, an endless supply of cartridge rolls in varying grits. I also like to use a very fine grit flap wheel when the port or chamber is about done. I mirror polish the cumbustion chambers. The exhaust ports get 180 grit flap wheeled and the intake ports depend on the application. On all heads I 180 grit flap wheel the "pocket" or "Bowl" area. The intake port will get done to a 120 grit or finer depending on the application. I tend to polish more when the head is for a turbo engine and no so much with NA. Don't be afraid of doing it. Your first time, you will not even come close to optimizing the port or bowl. And, remember, on the intake side you can use epoxies to build up the floor and port the roof to raise the port for a straighter path to the valve. Also on the intake side, you can use the same epoxies to seal cracks that may have occured during the porting. I have actually been told by Air Flow Research(formerly Brownfield) to make the port the shape you need it and just fill back in were you go into a waterjacket or push rod hole. This takes experiance and nice aluminum welding equipment or epoxies to make it work. If you screw up an aluminum head during porting, I'll bet you I can fix it. Quote Link to comment Share on other sites More sharing options...
Kazuya1274 Posted February 17, 2005 Share Posted February 17, 2005 jmortensen, What we did is actually matched the port to the gasket on the intake manifold. Sorry I didn't clarify that. I got an old screwdriver and cut the handle off to make a longer shank for the rolls. But, #1 and #6 runners have an angle in them, so even if I could reach all the way back in there, it might not work on those 2 runners. Or, if I start at the end of the runners and move back toward the plenum, I might take off just enough to reach every angle inside?? I was also wondering if there was some sort of flexible shank I could put the rolls on, that way it could bend a little bit. (This could be a bad idea though) If I have to cut open the intake plenum, which would be the best way: plasma cutter or cutting disk? I'll have to have a machine shop grind the threads in the screwdriver handle to match the porting kit shank, as the rolls just fly off when I test it out Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted February 17, 2005 Share Posted February 17, 2005 You can buy 6" mandrels for cartridge rolls. That is enough to get you just about anywhere. Cut you manifold with a band saw. You can even use a sawzall if you are comfortable with it. Quote Link to comment Share on other sites More sharing options...
midnightzxt Posted February 17, 2005 Share Posted February 17, 2005 I've been thinking about this too. I was also warned that you "shouldn't mess with years of nissan research" (stealthz and others). What are your views on this? Quote Link to comment Share on other sites More sharing options...
Kazuya1274 Posted February 18, 2005 Share Posted February 18, 2005 midnightzxt, IMO, years of Nissan research went into making the 280ZX a great car with plenty of power to move from a standstill, and a good useable powerband throughout all gears. But, when you start putting a bigger turbo on it, and wanting to go well beyond the 85 Mph speedometer reading, then a porting job can only help for this. Porting the intake and head will shift the powerband more towards the top end, but in my case I can loose some of that tire spinning low torque. Unless you are somebody like Ferrari, you have to make some compromises in the design of the car to sell to a mass market. Plus, if you look inside the intake ports, you can see the line where the casting marks were left. Taking that out right there will definately improve airflow. For me, I'm just trying to get the most hp out of what I have, and porting the intake, head and exhaust manifold will surely help some. Quote Link to comment Share on other sites More sharing options...
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