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Join Date: Oct 2001
Location: Redondo Beach, CA, USA
Posts: 78
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To Port or not to Port?
Okay I have a 2.4L (73') engine that originally was a "T", but Im upgrading the motor with "S" pistons and Solex cams. The heads are still "T" heads, should I port them out to "S" size or should I leave them alone. Any thoughts would be great, seeing how I dont want to waste the money or be dissapointed.
Thanks Eric |
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08-15-2002, 08:43 AM
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Any porting would be OK if you're going to increase the size of the valves at the same time.
If not...the money spent on porting would be better spent on a good exhaust system. Remember...what goes in must come out! Bob
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Bob Hutson |
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08-15-2002, 10:35 AM
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Location: Redondo Beach, CA, USA
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Vlave sizes are going to stay the same.
The guy who wants to port the heads said Im probably losing a lot of bottom end power. Eric |
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08-15-2002, 10:40 AM
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Location: TX USA
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Eric,
That disclaimer sounds like a 'warning' light to me! The Solex cams are only slightly 'hotter' than the 2.4E cams ... and the 'E' ports were only 32 mm. What are your ports now? 30 mm or 32 mm? If your 'porting' guy is suggesting going to 36 mm 'S-spec' ports ... that would be a mistake with Solex cams! Use 'S' cams with 'S' ports, and 'E' ports with Solex/'E' cams! You can even use 'S' cams with 'T' ports ... for more torque across the rev range, and only about 10 hp loss at the top end over an 'S' engine! The type 901/30 rally engine did just that with carbs in 1968! ps ... Hawg ALL 2.2, 2.4, 2.7 engines used the SAME 46 mm/40 mm valve sizes!!!
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' Last edited by Early_S_Man; 08-15-2002 at 11:46 AM.. |
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08-15-2002, 11:42 AM
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Location: Kent, CT
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Depends on the Vintage. I personally like the Sandeman's 20 Yr.
Cheers, James
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You will never know the feeling of a driver when winning a race. The helmet hides feelings that cannot be understood. Ayrton Senna 1993 964 RS |
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08-15-2002, 12:29 PM
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Location: Santa Clara, CA
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T, E and S have the same size valves. Only the port sizes are different.
But as Warren says, don't mismatch the cam. Port to the proper size for the cam, no bigger. Why not go for the S cam?
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Chuck Moreland - elephantracing.com - vonnen.com |
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08-15-2002, 12:45 PM
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Join Date: Mar 1999
Location: Vancouver,Wa.
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Assuming that you have 2.4L heads, port em'.......34 or 35 mm would be good, me thinks.
Solex cams love to rev. Tho they have a very similar profile compared to the E cams, their lobe centers are the same as the S cams. .....lots of overlap (over 4mm) for scavenging at elevated rpms......in practice. Making them run smoothly at low revs is....or was, my biggest problem. The 35mm ports on my 2.7 (smoothed out to a bit over, actually) probably didn't help here, but it pulls hard from 4k to over 7k. Driveability is good down to 2500 or so. According to my research (while building this motor), the combo of S cams and Webers bring another set of problems. Want low end? Go with T cams & leave the ports alone.....but that's no fun 
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JPIII Early Boxster |
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08-15-2002, 01:00 PM
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Harley
