Another Porting Thread

[turbofabricator]

Widening the port near the head bolt will only take 10 minutes (unless you are using a sanding roll). Do it once......do it right. If you need verbal assistance pm me my number. I really don't want to port another Buick head and if you will take over for me I will send everyone to you. I have taught a hand full of guys how to port heads and everyone of them said (after doing their own set SBC, BBC, SBF, SBMP).,...........OH Hell no! Ain't never gonna do that again!!!

 

[34blazer]

Ok. You talked me into it. About how much material will need to be removed? There's no way I'm ever going to port another one of these heads after this lol. I'll take a conical carbide to it and smooth it with an 80 grit cartridge.

Thanks!

 

[turbofabricator]

Just make the port wall straight from intake flange all the way to the radius of the bowl. Air does not like to make twists and turns. Every bump can make the air lift off the wall causing turbulence. Knife edging the leading edge of the guide will help the air navigate around it. The intake guides inside the bowl can be cut down approx. 3/16-1/4", too.

 

[34blazer]

Just received the .530" guide cutter today. I need a rough WAG on how much to remove off the top of the guides to accommodate a higher lift cam. The comp posi seals will add about .150" to the top of the guides.

 

[ek02]

Probably the best way to go about cutting the guides is to cut a guide enough to get a seal on it. Then install a valve with the retainers you are going to use and measure from the retainer to the seal. The lift of the cam plus .060 is the dimension I use. Measure the hight of the finished guide with a dial caliper and then cut them all the same. Cut them enough so if you go to a cam with more lift, there will be enough clearance. Go a little at a time and measure often until you get the hang of it.

 

[earlbrown]

Yep. Mock up what you got and set it for the biggest lift you think you'll ever run.

 

[34blazer]

OK great, works for me. A couple more questions; still using the original valves with the oil table on the exhaust valve, looks like I will be able to cut the guide low enough so the table doesn't wipe out the seal at max lift. Well, actually, I have no idea cam is stock or modified, but will check once the valve covers are removed. But if the table clears the seals, will there still be an issue with the table causing oil starvation of the seal? And can I remove the table(or lip) without any consequence?

Thanks!

 

[ek02]

You can not use the stock exhaust valves when you cut guides for seals. You need smooth stem exhaust valves. The step in the valves will tear up the seals. I would cut all the guides .525+.060 for .585 total. That should be enough for most any turbo cam.

 

[34blazer]

Awesome thanks!

 

[ek02]

Sealed Power V4168 exhaust valves have straight stems and are about $10.00 each from Summit. You can also get Ferrea stainless intake ( 1.775 ) and exhaust valve sets on E Bay pretty cheap. Manley also makes stainless valves for the V6. You would have to have your intake seats opened up for the stainless valves. Easy to do when the seats are being cut.

 

[34blazer]

Yeah I priced some out from rockauto.com and can buy the SP V4168 valves for just under 60 shipped. This was supposed to be a budget oriented project, so if a valve job is required, this project will be placed on the back burner indefinitely. New edition to the family due by Christmas, so time and $$$ will be gone.

After work this morning I cut about .350" off one of the exhaust guides, then performed a dirty measurement between the oil table and top of the seal, and came up with about .430" until the oil table is at the top of the seal. So depending on the cam installed in the engine, it may work as long as I cut another .050" or so off the top and still have plenty of guide left.

 

[earlbrown]

You're logic and measurements are only half the battle.

If you lower the guide enough so the step doesn't physically tear up the seal, it won't matter. That step is there to minimize the oil running down the valve. The seal will get smoked from lack of oil. On the upside, it won't matter as a seal failure there will have you just like stock. (keep in mine our exhaust ports are pressurized so there's no negative pressure pulses in the port to pull oil down like a N/A with tuned headers).

Since you're down this far, I would go with Ferrea oversized valves and be done with it. When cutting the valve seats it's just as hard to cut them at 1.770 as it is 1.700. There should be no difference in price. It will also give the machinest an extra .035 of meat to work with. Going with a O/S valve is cheaper than seats and with more material, he can set the valve height correctly on the cheep.

If the cost of a valve job is holding you up, I'd hand pocket port the heads while stockpiling another check or two. Putting the car back together without a good valve job is like pissing in the wind. And head/intake gaskets are way to expensive to pull the heads later to do it right.

 

[34blazer]

Even if I had the $$$ for the ferrea valves, and machine work to put it all together, Im halfway or better to champion irons. This is a budget project, I wanted it to be that way from the get go. Fortunately, I don't have very much money invested in these heads so I could walk away from the project now before I lose too much. I may even sell the heads if needed. All the pocket porting is complete, chambers polished, and guides cut. Stuff left now is some 980 valve springs, and possibly new valves. I spent about 5 minutes and removed the oil table, but that was just to figure out what would happen. Also lapped in the valves and the seats cleaned up nice, even the exhaust, these heads were in really good shape. You think I would lose a lot if I forgo the valve job?

This is it, military pay isn't much and we are expecting another new brat by Christmas. Once I sell the engine from my turbo blazer project I need to invest in a good trans. Alky kit is going in this weekend. My first born is at the age to start Jr. Dragster racing so we will be saving for a 1/2 scale car. I was hoping to install these heads for a few seasons, I don't drive the car much as it is anyway. A trans/converter/alky/6262jb set up should get this car into the 11's, I wanted mid 11's without needing to throw too much boost at it, but will be happy with high 11's without the heads.

 

[earlbrown]

If you've got a nice lap line and the valve faces didn't get convexed doing it, you should be fine.

 

[34blazer]

Yeah, the valve faces are convex, oh well. This project has now been placed on the back burner.

 

[34blazer]

Wait. The valve faces are concave, or curved inward. Is that satisfactory?

They all look like this after lapping...

 

[turbofabricator]

IMO the exhaust valve seat has way more contact than what is needed. That is good, in that it gives you room to use a stainless exhaust valve or buy a set of Turbo Trans Am exhaust valves with smooth valves stems and k3p your seals alive.

 

[34blazer]

Not ideal I know, but the face is still in decent shape? If it will work OK for a little while, that will keep this project within budget and off the back burner. Just for the hell of it, chucked up one of the exhaust valves in the drill and took a file to the shelf, theres a nice radius there now, cleaned up with sandpaper.

 

[turbofabricator]

Buy just a six smooth stem exhaust valves and let it eat. I get the low budget deal. That will force you to learn how to make these cars run good. You are in the same boat I was back in '88 when I first got involved. I read and read everything I could on making power. (Prior to building these tiny engines I was building 2,240 cid racing engines and had a decent background of what makes power). I had been building winning race engines/components since I was 14. That didn't mean I knew how to make this new fangled EFI/turbo Buick purr. With the help of a good friend I was running 11.7's @112 with a stock turbo, intercooler, and stock injectors.(OK.......they were 30 lb Tomco's). I had young kids and not a lot of play money. The car was also my wife's Dailey driver and she drove it about 50 miles a day. If I blew a head gasket on Saturday, (which happened ALOT back then) I was thrashing on the car all day Sunday to get her to work. I've even had to change head gaskets on the side of the road. Good luck with your project.

 

[34blazer]

Well, the good part is, it's not a DD. I haven't even driven 75 miles in the car yet LOL, which that doesn't really help my case. I totally understand the concept of building it right the first time, that's why I'm back and forth on the idea. The engine in the car now has been gone through within the last 5 years but it's still a big question mark. I want the car to run but I'm not going to dump a lot of cash into a big unknown and have it self destruct. If I could I'd take it all apart and build it the way I want. The idea now is to get it running well, and once their is a larger budget, build something sacrilegious(60v6 GenIII) or a stout 600+hp 109, or SII if I strike oil. Also, I like to learn how to do stuff like this on my own, takes my mind away from the ops tempo of work, and if I break something, it's an excuse to build something better, and a good selling point to finance dept.