Could be because the Cam rotates 1:2 of the crank DJ?
93.37ABDC + 180ATDC =173.37 ATDC?
http://www.gmh-toran...e-2#entry893135
Camshaft change, performance difference
Started by
_rb3torana_
, Jul 26 2014 02:28 PM
58 replies to this topic
#51
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Posted 29 March 2015 - 07:27 PM
#52
_Bomber Watson_
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Posted 29 March 2015 - 07:44 PM
I have always measured camshafts in crankshaft degrees..........
I know i've missed something simple, will likely come to me tomorrow...
#53
S pack
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Posted 29 March 2015 - 08:28 PM
93.37ABDC + 180ATDC =173.37 ATDC?
What am i missing OJ?
TDC to BDC = 180 crankshaft deg (1/2turn)
Inlet closes 93.37 crankshaft deg ABDC
Therefore 180 deg + 93.37 deg = 237.37deg ATDC.
Edited by S pack, 29 March 2015 - 08:29 PM.
#54
_oldjohnno_
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Posted 29 March 2015 - 08:36 PM
Jeez I fukd that up didn't I? Let's see, Daves cam has IVC of 83 degrees ABDC. That means it's 97 degrees from TDC. So 97 is the number that should be plugged in. Not 83.
Unless of course I've fukd it up again 
ps. remember that the torquesoft tool is meant for two strokes and everything is stated as ATDC. But whether it's ATDC or BTDC, the distance will be the same.
Edited by oldjohnno, 29 March 2015 - 08:38 PM.
#55
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Posted 29 March 2015 - 08:39 PM
I shouldnt try doing maths in my head after i've had a few refreshing beverages should i?
i think all of us #@$^%& it up, I have my excuse 
#56
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Posted 29 March 2015 - 08:47 PM
As OJ said before,
after lash and rocker ratio, wouldn't it be:-
180 - 83 abdc = 97 degrees left before TDC
then 180 - 97 = the remainder of 180 degrees is 83 atdc
so this is the same?
but as you have just pointed out now OJ, 97 would be a better figure to raise the volume,
which gives me 2156 cc / 132 ci. 
Edited by NA-PWR, 29 March 2015 - 09:01 PM.
#57
_oldjohnno_
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Posted 29 March 2015 - 09:03 PM
As OJ said before,
after lash and rocker ratio, wouldn't it be:-
180 - 83 abdc = 97 degrees left before TDC
then 180 - 97 = the remainder of 180 degrees is 83 atdc
so this is the same?
but as you have just pointed out now OJ, 97 would be a better figure to raise the volume,
which gives me 2156 cc / 132 ci.
83 ABDC is 97 from TDC - 97 is the number to use.
#58
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Posted 29 March 2015 - 09:05 PM
Thank-you very much OJ. 
#59
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Posted 29 March 2015 - 10:51 PM
That's great to hear Coupe.
found some more of your info here:-
http://www.gmh-toran...-6/#entry303601
I've used a Wade 259a and a Crow 5651 with success with both cams on a draw through with a quadrajet carby on Holden 6
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