Notmyvette

iTrader: (1)

Looking at the timing chain set I got (double roller) I see there are two sets of degree marks on the crank sprocket. one on a top row and one below it. On the stock crank sprocket/oil pump drive one is on the sprocket and the lower one is on the oil pump drive.....Which dot do I use to time to the cam sprocket?? upper one? whats the lower one for then?

vettenuts

iTrader: (4)

Need a photo. How many keyways are milled into the crank sprocket? Some sets have multiple keys that allow for advancing/retarding the cam and each key will use a different timing mark.

Notmyvette

iTrader: (1)

It's got the "0" and to the left of it has R2, R4, R6 and to the right has A2, A4, A6...or whatever but it's got TWO of these one right below the other about a keyway apart...

Here's a pic of the stock crank sprocket/oil pump drive. The dots are in the same spot as the 0's on my new set except and obviously the aftermarket sprocket is seperate from the oil pump drive.

Why is there two dots? It's not like the oil pump is timed....and do I use the top row of timing marks to time with the cam sprocket right?

vettenuts

iTrader: (4)

It looks to me like the dot that lines up with the keyway is the "0" position based on the relative placement of the two dots. The A2, etc. is "advance" and the number is degrees. Conversely the R2, etc. is "retard" and the number of degrees. However, there typically are marks corresponing to each position. If I had to guess, and this is a guess, it appears that each key moves two teeth such that the timing mark would move accordingly but you really need to verify this to avoid any damage.

Did it come with any instructions? Who is the manufacturer?

Notmyvette

iTrader: (1)

I really need to get a pic of the sprocket so you know what I mean, It's a S.A. gear set I believe. Sprocket is made in good ol USA surprisingly too. The above pic is the STOCK sprocket/oil pump drive, what purpose did GM put 2 timing dots on there for? and the aftermarket sprocket has 2 rows of timing marks on it, in the same position as the stock sprocket so it's not like it's a mystery setup since it's mocking what GM did.

The instructions just say aligh the keyway with 0 if you want stock cam timing, A2 if you want it advanced 2 degrees, R2 if wanted retarded degrees, etc etc but what 0 do I align it to? the top or bottom, I would have to assume the top one...why are there 2 rows of timing marks even on the stock piece??

vettenuts

iTrader: (4)

That is not the stock piece in the photo.

Notmyvette

iTrader: (1)

Hmmm forgot this kid had gotten a cam swap done sometime during it's life. I heard the stock piece was a dual purpose crank sprocket/oil pump drive in one so it got me thinking it was stock anyway The cam sprocket said rollmaster on it. But either way both have 2 rows of timing marks or "0's".....What row of timing marks should I use to align with the cam sprocket marking? I assume the top one

vettenuts

iTrader: (4)

Do you have a photo of the new part that you can post?

Usually there is a keyway for the zero position (no advance or retard of the cam) and a corresponding tooth on the sprocket.

Notmyvette

iTrader: (1)

K here's a pic of the EXACT same set I got....exact mine was like 40 bucks cheaper go figure comp is higher....check out the bottom pic...



http://cgi.ebay.com/ebaymotors/LS1-L...Q5fAccessories

Notmyvette

iTrader: (1)

anyone?

MadIceV8

iTrader: (12)

I'm not sure you should be doing this build if you don't even know what the dots mean. But anyways I had some time at work.

vettenuts

iTrader: (4)

Per the link, each timing mark is associated with the corresponding keyway mark. So if you install so the "0" keyway is used, then the tooth with the "0" is your alignment mark. Hope this makes sense, if not I can download the photo and mark it.

Notmyvette

iTrader: (1)

Thanks for the pic, I've machined and built plenty of engines, just new to the LS motors....Every other motor I seen has one dot on the crank gear (crank keyway directly below the crank gear dot) and one on the cam gear....The offsetness just confused me.

So double checking here, line the bottom 0 to the keyway on the crank and the top 0 to the dot on the cam gear...right??

vettenuts

iTrader: (4)

Based on the photo in your link, yes that should be correct. The keyway usually ends up at around the 2 o'clock position when the timing mark is at 12 o'clock.

Doesn't the new set have instructions? I would think you could download them from Comp.

Notmyvette

iTrader: (1)

It had instructions but it just said use 0 for no advance, A to advance, R to retard etc...

I knew that just was confused with the 2 sets of timing marks....anyone know the reason they made that like that?

Thanks for the help tho

Scoggin Dickey

iTrader: (34)

Because the keyway doesn't like up with the corresponding 0, 2, 4 degree marks on the outside of the gear. Obviously, you have to have two sets of numbers since it's offset in order to time it correctly. If there was only one keyway on the crank gear you wouldn't need it either

Notmyvette

iTrader: (1)

Yeah I got that, I know that's how it's made but just curious why it came out to be like that as in engineering wise. Something with the firing order I would guess

vettenuts

iTrader: (4)

Not sure why the keyway in the crank is offset from the zero mark. I can't think of a reason but there likely is one.

Notmyvette

iTrader: (1)

Not like it's needed now but here's a pic for anyone that might need one in the future looking in a search....








Anyone know what the 2 threaded holes are for right above the crank gear? I dont remember anything screwing in there

LS1MCSS

iTrader: (18)

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They are for a timing chain dampener.