Insane Performa
15+ Year Contributor
- 91
- 2
- May 5, 2007
-
Murfreesboro,
Tennessee
Ok guys I'm in the finishing stages of building my motor. I've come upon a stumbling block.
2.4 (G4CS) Block
2g Head
BC280 cams
The old cam card was:
Intake- Open 7* BTDC ____________________ Duration : Intake 218*
Close 31* ABDC _____________________________Exhaust 216*
Exhaust- Open 38* BBDC
Close -2* BTDC
New cam card is:
Intake- Open 3* BTDC
Close 35* ABDC
Exhaust- Open 42* BBDC
Close -6* BTDC
I have uploaded the old and new cam card drawn out on a timing wheel. After days and days of reading about cam timing in particular the BC 280s, I was going to start with a happy setting of 2* retard on the intake and 2* advance on the exhaust to close the overlap some.
My problem starts at this first, the (-)negative BTDC.
I seen it post herehttp://www.dsmtuners.com/forums/cylinder-head-short-block/423220-find-my-cam-degreeing-error.html in # 6 that it is suppose to be a (+) positive ATDC. However the math doesnt come out right if you use it ATDC.
Example (going around a timing wheel)
38* BBDC + 180*(Back to TDC) + 2* ATDC = 220* (4* too much) or
38* BBDC + 180* - 2* BTDC = 216* (On the Money)
Same goes for the other one if you do the math or look at the pics.
Second problem is that I had lost the old card, just printed a new one and dialed them in this way:
Intake- Open 6* BTDC ___________224* Duration(longer than what's called for)
Close 38* ABDC
Exhaust- Open 40* BBDC _________216* Duration (On the Money)
Close 4.0* BTDC
First question: Is the way I'm looking at it right?
Second: Looking at the old card versus the new, Did BC take out over lap and/or should I? It looks like they went 4* on each cam. Posing the next question.
Third: Looking at the new card, did I go the right or wrong direction with each individual cam?
I'm looking at going with the new card, but what numbers are right for the exhaust cam.
I'm dialing them in on Sunday, so all the help given is much appreciated and will update after Sunday.
These are being dialed in with BLE solid lash adjusted and a pretty good set up. I will post pictures if any one would like to see.
Come on anybody, I really need the help before Sunday.
2.4 (G4CS) Block
2g Head
BC280 cams
The old cam card was:
Intake- Open 7* BTDC ____________________ Duration : Intake 218*
Close 31* ABDC _____________________________Exhaust 216*
Exhaust- Open 38* BBDC
Close -2* BTDC
New cam card is:
Intake- Open 3* BTDC
Close 35* ABDC
Exhaust- Open 42* BBDC
Close -6* BTDC
I have uploaded the old and new cam card drawn out on a timing wheel. After days and days of reading about cam timing in particular the BC 280s, I was going to start with a happy setting of 2* retard on the intake and 2* advance on the exhaust to close the overlap some.
My problem starts at this first, the (-)negative BTDC.
I seen it post herehttp://www.dsmtuners.com/forums/cylinder-head-short-block/423220-find-my-cam-degreeing-error.html in # 6 that it is suppose to be a (+) positive ATDC. However the math doesnt come out right if you use it ATDC.
Example (going around a timing wheel)
38* BBDC + 180*(Back to TDC) + 2* ATDC = 220* (4* too much) or
38* BBDC + 180* - 2* BTDC = 216* (On the Money)
Same goes for the other one if you do the math or look at the pics.
Second problem is that I had lost the old card, just printed a new one and dialed them in this way:
Intake- Open 6* BTDC ___________224* Duration(longer than what's called for)
Close 38* ABDC
Exhaust- Open 40* BBDC _________216* Duration (On the Money)
Close 4.0* BTDC
First question: Is the way I'm looking at it right?
Second: Looking at the old card versus the new, Did BC take out over lap and/or should I? It looks like they went 4* on each cam. Posing the next question.
Third: Looking at the new card, did I go the right or wrong direction with each individual cam?
I'm looking at going with the new card, but what numbers are right for the exhaust cam.
I'm dialing them in on Sunday, so all the help given is much appreciated and will update after Sunday.
These are being dialed in with BLE solid lash adjusted and a pretty good set up. I will post pictures if any one would like to see.
Come on anybody, I really need the help before Sunday.
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