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Registered:
December 2003
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 4AGE camshafts-HELP!!!!
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Sun, 03 October 2004 22:24
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How do I tell the difference between a bigport camshaft and a smallport camshaft if they are not installed in the head. Is there any distinguishing marks to tell the two apart. Can the cam lobe height be measured as I believe that the bigport has more lift so the cam lobe should be bigger (could measure its height with verniers). Does anybody know the cam lobe heights of these cams and would this be the correct way to identify them.
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Location:
Sunshine coast, QLD
Registered:
May 2004
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Re: 4AGE camshafts-HELP!!!!
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Sun, 03 October 2004 22:46
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As far as I know, cam duration ont he bigport motors have 240 inlet and 240 exhaust, when the smallport motors have 232 inlet and 232 exhaust... so measure the cam lobe height and see which is bigger... that will be the bigport one.
thats pretty much an educated guess, can anyone back me up or correct me?
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Location:
Menai area of Sydney
Registered:
June 2003
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Registered:
December 2003
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Re: 4AGE camshafts-HELP!!!!
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Mon, 04 October 2004 03:15
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Scorpion, I am planning to use bigport cams in AE92 MAP GZE. Is it worth the effort?
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I supported Toymods
Location:
sydney.au
Registered:
August 2002
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Re: 4AGE camshafts-HELP!!!!
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Mon, 04 October 2004 07:26
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nope
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: 4AGE camshafts-HELP!!!!
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Mon, 04 October 2004 09:29
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I don't have any personal experience with the GZEs but in the forums I've seen it's not uncommon to use bigport cams in small port engines, particularly for turbo conversions. Any improvement may be marginal but I guess any improvement helps.
I'd check the duration of the stock GZE cams first though.
If the bigport duration is longer than the stock GZE then if you have the opportunity, you may as well use them.
You could try posting some more questions in the technical forum and also try the technical forums in www.twincam.org - there are plenty of GZE owners in there.
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: 4AGE camshafts-HELP!!!!
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Mon, 04 October 2004 10:08
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make sure you are looking at the early bigport 4age cams and not just bigport 4agze cams, as the 4agze bigport cams are the same as the smallport 4agze ones.
the early 4age (blue writing on inlet cam cover) has the 7.56mm lift and 240 degree duration cams compared to 7.1mm lift and 232 degree duration the 4agze's have.
i have a set of both in my shed, but am still not sure how to measure the difference properly.
people put them in their 4agze's (mainly bigport AW11 guys that i know of) and report a butt dyno improvement.
i dont know if anyone has tried the difference on a actual dyno?
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Location:
brisvegas
Registered:
August 2004
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Re: 4AGE camshafts-HELP!!!!
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Mon, 04 October 2004 10:54
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i have spent ages on this doing the maths..and found that a bigport inlet cam and a smallport ex cam..both timed with 114 deg Lobe centres..(in relation to TDC) they work out to be perfect for the job with only 8 deg of overlap...i'll post up a dig that i drew up for it..detailing this issue
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