Porting Heads - And so it begins.......
12-11-2006, 02:23 PM
#21
Here are the pics from yesterdays porting on the exhaust and chamber.
.
Comparison between the stocker and the ported version.............
Shot of the chamber with both runners finished up.....
Shrouding of the valve before port work.....
After unshrouding the valve.......
That is all for now. I dropped off the head and should have numbers back later this week. He's going to flow them as is with the small stock valves, then rough-in the larger valves and play with seat angles. I'm stoked!!!
Mike
.
Comparison between the stocker and the ported version.............
Shot of the chamber with both runners finished up.....
Shrouding of the valve before port work.....
After unshrouding the valve.......
That is all for now. I dropped off the head and should have numbers back later this week. He's going to flow them as is with the small stock valves, then rough-in the larger valves and play with seat angles. I'm stoked!!!
Mike
12-15-2006, 08:16 PM
#28
Well, I got my new flow numbers today. I guess I'm fairly happy with them, even though I didn't quite meet my goal of 290/.550 lift. These are my first set of LSx heads afterall.... They still flow decent, and I'm not done yet. After talking to Dennis, it's clear that after the throat cut for the larger valve, it left a nice "ridge" on the throat all the way around the seat, that causes a nice disturbance in flow. He didn't have time to **** with it much today and I needed to take the head with me this evening to finish porting over this weekend. He said he'd re-test it after I smooth and blend the ridge down in the throat. I took took some pics of it the ridge I'm talking about and I'll post the pics later tonight or tomorrow. Notice the exhaust #'s are pretty strong, especially at the higher lift ranges. This will be good for my nitrous plans. 
Dennis had more to say, and I'll post that up later also. Also, the intake short-side-radius didn't become turbulant at all!!!
Here they are:
lift........./ int../ exh
.200...... 131.... 111
.250...... 160.... 131
.300...... 190.... 149
.350...... 217.... 168
.400...... 240.... 183
.450...... 257.... 201
.500...... 273.... 217
.550...... 283.... 228
.600...... 289.... 235
.650...... 295.... 241
.700...... 298.... xxx
I'll post more info later. I also edited/posted these numbers in my very first post of this thread, for a direct comparison with the "before" numbers......
Mike
Dennis had more to say, and I'll post that up later also. Also, the intake short-side-radius didn't become turbulant at all!!!
Here they are:
lift........./ int../ exh
.200...... 131.... 111
.250...... 160.... 131
.300...... 190.... 149
.350...... 217.... 168
.400...... 240.... 183
.450...... 257.... 201
.500...... 273.... 217
.550...... 283.... 228
.600...... 289.... 235
.650...... 295.... 241
.700...... 298.... xxx
I'll post more info later. I also edited/posted these numbers in my very first post of this thread, for a direct comparison with the "before" numbers......
Mike
12-15-2006, 11:52 PM
#30
Originally Posted by Robert56@NitrousDirect
What do you suppose you can gain by getting rid of the ridge?
Robert
Robert
Ironically, he wants to leave the exhaust at 1.55" instead of the larger 1.60". He seems to think the 1.6's would just start shrouding the chamber and he wasn't even "for sure" if all the stock seats would be large enough for them.
Mike
12-16-2006, 02:43 PM
#31
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Nice numbers! You made it look pretty easy to do for some very substantial gains, hopefully I can work something similar out, I took my head apart and dropped it off for a bath yesterday 
Did you use the stock angles for the valve job?
Did you use the stock angles for the valve job?
12-16-2006, 03:31 PM
#32
Thanks Eric. I'm not positive on the valve angles, I'll have to ask Dennis when I drop off the head again on Monday or Tuesday. I do, however, know he didn't do a backcut on either valve. I'd like to improve the low/midlift numbers as well, and I have another post in the LS1 section asking for advice/pointers in case I end up porting another set down the road.
Are you porting the Volvo head then? If so, good luck with it. Most gains in flow are determined in the bowl area and valve seat angles, depending how restrictive the runners are.
Mike
Are you porting the Volvo head then? If so, good luck with it. Most gains in flow are determined in the bowl area and valve seat angles, depending how restrictive the runners are.
Mike
12-16-2006, 08:05 PM
#33
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Yeah the 4 valve one. I'm just going to port match the intake and smooth everything and make the short side radii a little smoother. I'll be keeping stock valves because I guess they are good for ~600+. Should any machine shop be able to back cut the valves? I have a bunch of spares, just want to get some done for when I test it. The stock angles are 15, 45 (seat), 70. I don't really know which way to go with the seats, so that's why I asked about your angles. Thanks 
12-16-2006, 08:24 PM
#34
Originally Posted by Poik
Yeah the 4 valve one. I'm just going to port match the intake and smooth everything and make the short side radii a little smoother. I'll be keeping stock valves because I guess they are good for ~600+. Should any machine shop be able to back cut the valves? I have a bunch of spares, just want to get some done for when I test it. The stock angles are 15, 45 (seat), 70. I don't really know which way to go with the seats, so that's why I asked about your angles. Thanks
Mike
12-17-2006, 12:07 AM
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Originally Posted by Mikey 97Z M6
Dennis seemed to think that 5-8cfm accross the entire lift range. That would put the intakes at 288-291cfm at .550 lift. If that is the case, I'll be very pleased. I'm going to blend in the ridge and have it re-tested next week.
Ironically, he wants to leave the exhaust at 1.55" instead of the larger 1.60". He seems to think the 1.6's would just start shrouding the chamber and he wasn't even "for sure" if all the stock seats would be large enough for them.
Mike
Ironically, he wants to leave the exhaust at 1.55" instead of the larger 1.60". He seems to think the 1.6's would just start shrouding the chamber and he wasn't even "for sure" if all the stock seats would be large enough for them.
Mike
Hey I think Nate tried to email you but your account didn't work for some reason. Anyway he was saying the exhaust valve sizing is usually tempermental of the header length and diameter and wouldn't go past a 1.57" exhaust valve on a 1-3/4 full length header. Email him at nktpolk401@hotmail.com he has a few other suggestions if you send him pics.
Mikey
12-17-2006, 11:41 AM
#36
Originally Posted by michael402z06
Hey I think Nate tried to email you but your account didn't work for some reason. Anyway he was saying the exhaust valve sizing is usually tempermental of the header length and diameter and wouldn't go past a 1.57" exhaust valve on a 1-3/4 full length header. Email him at nktpolk401@hotmail.com he has a few other suggestions if you send him pics.
Mikey
Mikey
Mike
12-30-2006, 04:40 PM
#37
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Results look good. You need to remember one thing, I went 10.82 with a little 224/224 .535 .535 lift cam with the first set of heads I ported (only about 275 or so cfm). It's not all about flow numbers. Don't open up the runners more just to chase numbers. I do recommend a back cut on the valves though as you should pickup 4-5cfm through out. Really depends on the valve you are using. The stock 241 intake valves have a backcut on them and they work well. I've swapped them out with Rev, ferrea, and manley without backcuts and you'll LOSE flow. You need the undercut stem with a backcut on the valve. Also, the tulliped exhaust valves work better vs. a straight neck like the ferrea's that I played with. I always liked the Rev valves. Think round radius from the throat to the seats. You don't want them abrupt and the throat straight to the bottom cut of the valve job.
