I know many do not see the importance of degreeing a cam! :-) line the marks up that's good enough right! I don't think so Tim!
There is 4 things that can be off affecting the true timing events! 1.The placement of the dowel pin in the cam (key in a small block).
2. The placement of the key in the crank.
3. The placement of the keyway in the lower sprocket
4. The placement of the dowel pin hole in the upper sprocket (keyway on small block).
Any one off or worse a stacking affect in the same direction (advanced or forward) may have the cam out in left field not a bad thing if i guess if your playing baseball with it. :-)
So today's story degreeing in a Mopar 509/292 duration 248/248 @.050 108 LSA.
It's a 383 ported 915 heads going in a 69 super bee 4 speed with 4.56 gears.
So mopar says intake centerline install 106 I like to put them in 2 to 4 degrees more advanced then that especially on a tight converter or smaller motor like a 383.
Timing gears are new Mancini brand 3 keyway 0, -4 and +4 so after finding true TDC and lining pointer up to my 18" degree wheel i decide to try +4 so in theory that would put me at 102.
well it comes out at 106.5?? so I recheck TDC and it is bang on and still 106.5???
Ok so lets try the 0 keyway and wow 114 in by the 0 marks this cam would have been 8 degree retarded from manufacturer install in the straight up positon.
so recheck TDC many times @.050 is 248 as it should be lift is .508/9 .339 lobe lift.
So now I think well I will move it a whole tooth and now I get 100 on O and 92 on + 4 a little over 14 degrees what one tooth should give?? Dang??
so I happen to have a lower 3 keyway sprocket in my degree kit so we slide it on and + 4 to + 4 don't line up but with it on 0 and installed on + 4 they are pretty dang close?? But for some reason chain will not fit it properly.
So now he says he's got another Mancini brand timing set so we get it out and it lines up exactly the same as the one installed even the poor location of the marks so that's no help.
So now just for giggles i say well lets install it on the -4 deg keyway and dam if it slid right on without moving the cam roll it and check it anyway and its 106.5 in the -4 114.5 in the 0 and 106.5 in the +4??
I don't know why but I move it back to the +4 and re chech to verify 106.5 put stop in and re verify TDC mark is O.
Now it has a slot in the top gear so no drilling it and using an offset bushing.
I'm going to have to get some offset crank keys to have with me?
I'm not as happy as I would have been if I could get it to 104 and even 102 :-) but it is in spec and with a 4 speed and 4.56 gears it should be fine.
In at 114.5 this thing would have been a real dog!
Without degreeing a cam in you have no idea where it is actually installed.
I'm just saying
There is 4 things that can be off affecting the true timing events! 1.The placement of the dowel pin in the cam (key in a small block).
2. The placement of the key in the crank.
3. The placement of the keyway in the lower sprocket
4. The placement of the dowel pin hole in the upper sprocket (keyway on small block).
Any one off or worse a stacking affect in the same direction (advanced or forward) may have the cam out in left field not a bad thing if i guess if your playing baseball with it. :-)
So today's story degreeing in a Mopar 509/292 duration 248/248 @.050 108 LSA.
It's a 383 ported 915 heads going in a 69 super bee 4 speed with 4.56 gears.
So mopar says intake centerline install 106 I like to put them in 2 to 4 degrees more advanced then that especially on a tight converter or smaller motor like a 383.
Timing gears are new Mancini brand 3 keyway 0, -4 and +4 so after finding true TDC and lining pointer up to my 18" degree wheel i decide to try +4 so in theory that would put me at 102.
well it comes out at 106.5?? so I recheck TDC and it is bang on and still 106.5???
Ok so lets try the 0 keyway and wow 114 in by the 0 marks this cam would have been 8 degree retarded from manufacturer install in the straight up positon.
so recheck TDC many times @.050 is 248 as it should be lift is .508/9 .339 lobe lift.
So now I think well I will move it a whole tooth and now I get 100 on O and 92 on + 4 a little over 14 degrees what one tooth should give?? Dang??
so I happen to have a lower 3 keyway sprocket in my degree kit so we slide it on and + 4 to + 4 don't line up but with it on 0 and installed on + 4 they are pretty dang close?? But for some reason chain will not fit it properly.
So now he says he's got another Mancini brand timing set so we get it out and it lines up exactly the same as the one installed even the poor location of the marks so that's no help.
So now just for giggles i say well lets install it on the -4 deg keyway and dam if it slid right on without moving the cam roll it and check it anyway and its 106.5 in the -4 114.5 in the 0 and 106.5 in the +4??
I don't know why but I move it back to the +4 and re chech to verify 106.5 put stop in and re verify TDC mark is O.
Now it has a slot in the top gear so no drilling it and using an offset bushing.
I'm going to have to get some offset crank keys to have with me?
I'm not as happy as I would have been if I could get it to 104 and even 102 :-) but it is in spec and with a 4 speed and 4.56 gears it should be fine.
In at 114.5 this thing would have been a real dog!
Without degreeing a cam in you have no idea where it is actually installed.
I'm just saying
