ICL for Isky?

ole4

ole4

#2
#2
Depends on Lisa. He grinds them straight up so depending how accurate the gear is pressed on the crank icl will equal Lsa. Here is my degree results from a 108 lsa black mamba.
 
TheDullCarbide

TheDullCarbide

Active Member
#4
#4
ole4 said:
Depends on Lisa. He grinds them straight up so depending how accurate the gear is pressed on the crank icl will equal Lsa. Here is my degree results from a 108 lsa black mamba.
Click to expand...
Tell me if I have this correct:

Your specific Black Mamba has a 109.5* ATDC intake centerline and a 106* BTDC exhaust centerline. The ICL is 109.5* and the LSA is 107.75*.

The Black Mamba should be 108* ICL and 108 LSA.

The Black Mamba Jr. has a 104* ICL and 104* LSA.

The actual ICL varies from cam to cam because of small errors in the pressing of the cam gear. LSA errors are made in the grinding alone before the gear is pressed on.
 
ole4

ole4

#5
#5
Pretty much sums it up. I checked it with .003 lash. If I had waited till .050 it may have been closer to the spec sheet. I needed the total duration and intake closing point to input into pipemax software.
 
TheDullCarbide

TheDullCarbide

Active Member
#8
#8
Another question:

I've been doing a ton of research on cams for my Greyhound and set my eyes for a 252 0207. Then I took a look at the CM cam...

Question being, since the CM is half the price of the 252 0207 and it is closer to the cam I'm looking for in all ways but one, could I re-press the cam gear to bring the ICL from 110 back to about 103-104? Is it worth my time?
 
ole4

ole4

#9
#9
It is difficult to move the gear, some guys have posted pics of tools they made which go on the gear with a long lever and clamp crank in a big vice but still just a little turn may be too much. I would not attempt it myself. I think if you do a search on bobs there are some threads on it there.
 
TheDullCarbide

TheDullCarbide

Active Member
#11
#11
ole4 said:
It is difficult to move the gear, some guys have posted pics of tools they made which go on the gear with a long lever and clamp crank in a big vice but still just a little turn may be too much. I would not attempt it myself. I think if you do a search on bobs there are some threads on it there.
Click to expand...
I took a look at bob's and it seems like turning the crank gear is easier than the cam gear. At least that would give me two options.

Also, being the camshaft gearing is 24/48, advancing a tooth would subtract 15* from ICL?
 
ole4

ole4

#12
#12
Yes it is the crank gear you move, cam gear is not movable unless you get a billet cam with the adjustable gear but then no decompressor so hand starting becomes a problem. One tooth is too much.
 
TheDullCarbide

TheDullCarbide

Active Member
#13
#13
I've heard other people say "re-press the cam gear" so naturally I started saying that too. Did they really mean the gear on the crank and not the cam itself? Would that mean the small ICL error on your cam is due to the gear on the crank and not the cam itself?

Sorry for all the questions but you're really setting me straight on all of this. Thanks.
 
ole4

ole4

#14
#14
Cams have been known to be off as well as the gear but when I degree the various cams I have used Isky, Dyno, NR they have always been within a degree or so. No idea if something is off or its me. I find TDC on the degree wheel with a piston stop but still its easy to be off even reading the degree wheel.
 
You must log in or register to reply here.
Top