timing chain set question
Thread Starter
Abby Normal
Joined: Dec 2001
Posts: 53,446
Likes: 92
From: Press "2" for English
timing chain set question
this may sound like a rookie question (and it probably is) but the billet set i bought for my build has me a bit confused. i think i understand it but i want to get a second opinion before i button it up.
the crank sprocket has a 9 way key for advance/retard. where i'm stumped is there is a set of numbers (A8,A6,A4,A2,0,B2,B4,B6,B8) surrounding the key ways. then above that series of numbers is the same numbers spaced off the teeth.
the instructions were week and it seems several of the suppliers i've used assume i do this all the time and know exactly what they mean.
my theory is the lower, or inside, set of numbers correspond to crank time. so if you want 4* advance, you can put the crank gear on at the A4 position and simply line up the cam sproket dot with the A4 on the upper, or outside series of numbers.
does that make sense?
so in my instance, where i'm going to be pretty happy with it "zeroed", i slid the crank sprocket on at '0' on the keyway, then lined up '0' with the cam dot.
i've checked my clearance, so if i'm wrong i won't be banging any parts. but i really just don't want to have to drop the pan and redo the timing after it's installed.
the crank sprocket has a 9 way key for advance/retard. where i'm stumped is there is a set of numbers (A8,A6,A4,A2,0,B2,B4,B6,B8) surrounding the key ways. then above that series of numbers is the same numbers spaced off the teeth.
the instructions were week and it seems several of the suppliers i've used assume i do this all the time and know exactly what they mean.
my theory is the lower, or inside, set of numbers correspond to crank time. so if you want 4* advance, you can put the crank gear on at the A4 position and simply line up the cam sproket dot with the A4 on the upper, or outside series of numbers.
does that make sense?
so in my instance, where i'm going to be pretty happy with it "zeroed", i slid the crank sprocket on at '0' on the keyway, then lined up '0' with the cam dot.
i've checked my clearance, so if i'm wrong i won't be banging any parts. but i really just don't want to have to drop the pan and redo the timing after it's installed.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Looking at the numbers you supplied, I'd say the numbers relate to degrees advanced or retarded the keyways are. The only way to tell for sure is degree the cam with a degree wheel. I think there are lots of cams out there that are 4 degrees advanced when they are made and installing them at the 0 mark is really at 4 degrees advance.
Thread Starter
Abby Normal
Joined: Dec 2001
Posts: 53,446
Likes: 92
From: Press "2" for English
ya, i know comp is ground 4* advanced. after checking comp, crane and lunati's site, i think i understand what it's doing so i'm good to go. i was just really surprised the instruction set said nothing about it.
i'm still open to input. i have been double, triple and quadruple checking things so all opinions are welcome.
except turtle's!
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J/K
i'm still open to input. i have been double, triple and quadruple checking things so all opinions are welcome.
except turtle's!
.
.
.
.
.
.
.
.
J/K
Safety Car
Joined: Aug 2001
Posts: 3,685
Likes: 202
From: Waterford Mi
[QUOTE=my theory is the lower, or inside, set of numbers correspond to crank time. so if you want 4* advance, you can put the crank gear on at the A4 position and simply line up the cam sproket dot with the A4 on the upper, or outside series of numbers.
: [/QUOTE]
That is correct. With each key way there is a different tooth on the gear that is used to match with it.
: [/QUOTE]
That is correct. With each key way there is a different tooth on the gear that is used to match with it.
Last edited by redwingvette; Dec 17, 2006 at 06:59 AM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
U need to degree the cam with a degree wheel.
If u had double checked everything then would have seen your adv or retard of cam timing on the degree wheel. Shift that crank gear one slot and u will know how much each slot advances or retards the cam. So if u truly want to know your cam timing then degree it and u will know more accuratly than what anyone here could tell you.
BTW i degreed my new cam and found it 5*-6* advance. Double checked before i called the company to verify 4* adv is ground in it. Don't know where the extra 1* or 2 degrees came from but i checked it enough times to see its there.
Had to verify my exh vlv event too and verify my lobe sep angle is ground correct so i needed to retard the cam a little - kinda unexpected but i had to get it right before reassembly (ain't gonn'a do it again).
So what i'm saying take nothing here for granted and verify for yourself. Yes u may have use a gear puller and remove the crank gear a few times but if u need to have the vlv timing u expect/want then u need to do this.
Good luck.
cardo0
BTW i degreed my new cam and found it 5*-6* advance. Double checked before i called the company to verify 4* adv is ground in it. Don't know where the extra 1* or 2 degrees came from but i checked it enough times to see its there.
Had to verify my exh vlv event too and verify my lobe sep angle is ground correct so i needed to retard the cam a little - kinda unexpected but i had to get it right before reassembly (ain't gonn'a do it again). So what i'm saying take nothing here for granted and verify for yourself. Yes u may have use a gear puller and remove the crank gear a few times but if u need to have the vlv timing u expect/want then u need to do this.
Good luck.
cardo0
