Port and Polish by Comiittee thread (Cool pics throughout)
02-27-2015, 02:56 PM
#286
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Now when you are going to install your .500" high lift camshaft and find out it will not rotate freely in the cylinder head - what to do? I made this simple tool to further cut the cam lobe cutouts at the lifter bores. As the tool was going to be sent to a Rennlister over there having no machines, I made the tool to be driven by an electric drill.
Åke
Åke
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dramis85 (06-27-2020)
02-27-2015, 04:28 PM
#287
Three Wheelin'
99.9% of 928 engines couldn't use these heads. What Ake is building is in the 0.01%! There aren't many 7.0L 928 engines around...
If you read some posts earlier in the thread, there are recipes by Ake on how to modify the 928 heads in a way that would be an improvement on a much broader set of motors. There's a budget porting recipe for a head that uses the stock 37mm valves. There's another budget porting recipe for a head that uses new 39mm valves and seats.
I think most people here who are thinking about getting some head work done on their 5.0L motor should take a look at the posts in this thread about budget porting with 37mm stock valves. In my personal opinion, beyond those changes to the head, the effort and money are better spent on improving the intake upstream of the head than more radical modifications of the cylinder head itself. This is just my personal opinion, caveat lector.
If you read some posts earlier in the thread, there are recipes by Ake on how to modify the 928 heads in a way that would be an improvement on a much broader set of motors. There's a budget porting recipe for a head that uses the stock 37mm valves. There's another budget porting recipe for a head that uses new 39mm valves and seats.
I think most people here who are thinking about getting some head work done on their 5.0L motor should take a look at the posts in this thread about budget porting with 37mm stock valves. In my personal opinion, beyond those changes to the head, the effort and money are better spent on improving the intake upstream of the head than more radical modifications of the cylinder head itself. This is just my personal opinion, caveat lector.
03-02-2015, 12:55 PM
#288
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When flow testing there is a never ending work of removal and installing valves and springs.
In order to ease the work I made this small tool to be used in combination with an ordinary universal valve spring compressor.
Åke
In order to ease the work I made this small tool to be used in combination with an ordinary universal valve spring compressor.
Åke
Last edited by Strosek Ultra; 03-04-2015 at 10:07 AM.
03-02-2015, 03:36 PM
#289
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Would you be willing to share that drawing? Very nice details in it.
03-03-2015, 08:28 PM
#291
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03-06-2015, 07:58 AM
#292
Nordschleife Master
I added the first 2x42mm port to the efficiency graph. This graph is entirely consistent with Ake's hypothesis that it's the shrouding between valves that is keeping the flow below the expectations for this valve size. At low lifts, the curtain height is small relative to the gap between the valves, so the gap between valves doesn't matter. When the lift is increased, the port efficiency drops as the valve to valve shrouding becomes a constraint. Then, as lift is increased to very high numbers, the port efficiency picks up again with less and less air actually having to flow to the side between the valves and more of more exiting from the front and back. Spreading the intake valves out should help increase the mid-lift efficiency.
item value units explanation
valve diameter 42 mm valve head diameter
alpha1 45 degrees seat angle
alpha2 65 degrees second angle into the port
alpha3 75 degrees thrid angle into the port
z1 1.00 mm seat width
z2 1.00 mm second angle width
z3 3.00 mm third angle width
x1 0.71 mm seat horizontal width
x2 0.42 mm second angle horizontal width
x3 0.78 mm third angle horizontal width
y1 0.71 mm seat vertical height
y2 0.91 mm second angle vertical height
y3 2.90 mm third angle vertical height
cut horizontal width 1.91 mm the horizontal width of all three cuts
cut vertical height 4.51 mm the vertical height of all three cuts
throat diameter 38.19 mm resulting throat diameter
throat to valve % 91% throat diameter to valve head diameter ratio
item value units explanation
valve diameter 42 mm valve head diameter
alpha1 45 degrees seat angle
alpha2 65 degrees second angle into the port
alpha3 75 degrees thrid angle into the port
z1 1.00 mm seat width
z2 1.00 mm second angle width
z3 3.00 mm third angle width
x1 0.71 mm seat horizontal width
x2 0.42 mm second angle horizontal width
x3 0.78 mm third angle horizontal width
y1 0.71 mm seat vertical height
y2 0.91 mm second angle vertical height
y3 2.90 mm third angle vertical height
cut horizontal width 1.91 mm the horizontal width of all three cuts
cut vertical height 4.51 mm the vertical height of all three cuts
throat diameter 38.19 mm resulting throat diameter
throat to valve % 91% throat diameter to valve head diameter ratio
03-07-2015, 09:20 AM
#293
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05-17-2015, 10:59 AM
#294
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Åke, no flow numbers. These were done by local Subaru guy. They are for 5.4L SC engine and have 39mm 968 intake valves. Your tool gets into use. Just need to make new piece to other end to push valve. Small bolt and washer plus some welding and cutting should do it. Original is lost somewhere in garage.
05-17-2015, 03:24 PM
#295
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Åke, no flow numbers. These were done by local Subaru guy. They are for 5.4L SC engine and have 39mm 968 intake valves. Your tool gets into use. Just need to make new piece to other end to push valve. Small bolt and washer plus some welding and cutting should do it. Original is lost somewhere in garage.
Åke
05-17-2015, 04:51 PM
#296
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39mm intake valves! You must have been forced to install oversize intake seat rings for the larger valves. Supercharged engine sounds interesting. Tell us more, please. I am sure the tool I made for you will work just fine. Will you be over here on the 27th of June?
First use of your tool will be Jarko's '89 S4 5sp. It needs full engine rebuild before end of June. He wants to come to your meet with it. Just hour ago we checked X-pipe setup for your ex MSDS set. It will also have S3 cam's with some tenths removed from base lobe. Should make it fly.
I don't know my work situation yet. One option is to come on ferry on Friday night and arrive before noon on Saturday. Have to see. Those ported heads can come along if you want to see them. Would be very interesting to hear your comments of them.
05-18-2015, 08:48 AM
#297
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Seats were changed. Engine will be build into early '87 squirter block. GTS crank, Wössner 100mm low compression pistons so stock bore can remain at least in this build. Colin's custom cams and Vortech SC with toothed belt drive. Aim is close to SC's capacity which is around 800hp. It will get four air-to-water IC's and custom radiator to give space for SC mouted at water pump. We have had all planned out for years already and build is finally going forward this year. Car is '87 S4 5sp which previously had Delta-P SC kit with their air-to-air IC. It had 537hp and 670Nm on unopened stock engine.
First use of your tool will be Jarko's '89 S4 5sp. It needs full engine rebuild before end of June. He wants to come to your meet with it. Just hour ago we checked X-pipe setup for your ex MSDS set. It will also have S3 cam's with some tenths removed from base lobe. Should make it fly. I don't know my work situation yet. One option is to come on ferry on Friday night and arrive before noon on Saturday. Have to see. Those ported heads can come along if you want to see them. Would be very interesting to hear your comments of them.
First use of your tool will be Jarko's '89 S4 5sp. It needs full engine rebuild before end of June. He wants to come to your meet with it. Just hour ago we checked X-pipe setup for your ex MSDS set. It will also have S3 cam's with some tenths removed from base lobe. Should make it fly.
I don't know my work situation yet. One option is to come on ferry on Friday night and arrive before noon on Saturday. Have to see. Those ported heads can come along if you want to see them. Would be very interesting to hear your comments of them.Arnoud said you guys should be here at around noon Saturday.
If you bring a head I think we can find time to flow test one intake port. Please prepare by having the exhaust valves and springs installed as well as the plug. Bring the intake valves, retainers and keepers uninstalled.
Regarding the Wössner pistons do they have a proper coating to be able to run in the alu-sil bores?
Åke
07-31-2015, 07:36 AM
#298
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Extended informations about my porting research. Measured volume of the different intake port.
- stock intake port 37mm valves 155cc
- budget ported intake 37mm valves 170cc
- maximum ported intake 39mm valves 186cc
- race ported intake 42mm valves 212cc
Pictures of the intake port molds.
Maximum intake port with 39mm valves. Port area at the flange unchanged (1700 mm2).
Race intake port with 42mm valves. Port at flange oval 40x55 mm slightly raised (1857 mm2).
Åke
- stock intake port 37mm valves 155cc
- budget ported intake 37mm valves 170cc
- maximum ported intake 39mm valves 186cc
- race ported intake 42mm valves 212cc
Pictures of the intake port molds.
Maximum intake port with 39mm valves. Port area at the flange unchanged (1700 mm2).
Race intake port with 42mm valves. Port at flange oval 40x55 mm slightly raised (1857 mm2).
Åke
Last edited by Strosek Ultra; 07-31-2015 at 07:56 AM.
07-31-2015, 02:17 PM
#300
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Port and Polish by Comiittee thread (Cool pics throughout)
Originally Posted by Strosek Ultra
Extended informations about my porting research. Measured volume of the different intake port.
- stock intake port 37mm valves 155cc
- budget ported intake 37mm valves 170cc
- maximum ported intake 39mm valves 186cc
- race ported intake 42mm valves 212cc
Pictures of the intake port molds.
Maximum intake port with 39mm valves. Port area at the flange unchanged (1700 mm2).
Race intake port with 42mm valves. Port at flange oval 40x55 mm slightly raised (1857 mm2).
Ã…ke
- stock intake port 37mm valves 155cc
- budget ported intake 37mm valves 170cc
- maximum ported intake 39mm valves 186cc
- race ported intake 42mm valves 212cc
Pictures of the intake port molds.
Maximum intake port with 39mm valves. Port area at the flange unchanged (1700 mm2).
Race intake port with 42mm valves. Port at flange oval 40x55 mm slightly raised (1857 mm2).
Ã…ke
