OK, first, this is a mild work up.....porting, dual exhaust, elec fan. .040 over, 9.0:1 compression, for now the stock 1 bbl carb, stock size int/exh valves, automatic trans, 2.76 rear end.
THe cam I have is the late stock Volare cam.

After reading numerous posts, still not clear on some items:

1) was the late stock cam for hydraulic tappets?

2) when degreeing, is it not always necessary to advance cam?

3) with a mild build up like mine, and mild cam, is degreeing it really necessary? From what I gather usually the cam gets advance.

4) Could I advance by a tooth (or two) and probably do more good than harm?


5) Cam sprocket is slotted, not a dowel pin hole. Any suggestions as to
how to advance/ retard?

6) Do we generally advance a little extra to account for chain stretch as well?

7)When you guys say advance the cam, is it actually rotated clockwise?
I guess I never really heard for sure.

Thank you all.

If you put in a new cam and or timing gear/ chain set I would always degree it. When I assembled Ryan's current engine and installed the cam gear it was actually stamped 1 tooth off. I can't remember how many degrees that was but it was a lot. If I would have just lined up the marks it would probably have barely ran at all. One man's opinion.


Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

1. Hydraulic cam was new for 1981.
2. Sometimes the cam is right where you want it, but not always. With a performance cam more advance (than the cam grinder intended) is generally desired.
3. Do you want it to run right the 1st time? Do you like to gamble? Would you like to be unhappy with the performance of you engine because you skipped checking the cam to crank phasing?
4. Advancing a whole tooth is too much. Go divide 360° by the number of teeth on the cam sprocket and tell us how many degrees advance 1 tooth would be.
5. Get another cam sprocket with a round dowel pin hole and an offset bushing kit if the cam timing needs to be changed.
6. Maybe a degree.
7. Advancing the cam means turning the cam in the normal direction of rotation so the valves open sooner in relation to the crank and pistons. This is clockwise when viewed from the front.

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Joshua

All SL6 cams look the same and you don't know what you have unless you have a cam card &/or have measured it... and yes, "late" SL6 cams (after 1980) were hydraulic.
Sometimes the combo of parts needs cam advance, sometimes it needs retard... sometimes it is correct as bolted together... the degree wheel tells you what it needs.
Yes... most often, I end-up adding a little cam advance.
NO, that would do more harm then good. A one tooth move is 13 degrees and that is a lot... and way too much for most set-ups.
Install the gear and mark where the dowel pin is, in relation to the slot. Drill a 3/8 hole at that position. Use the off-set adjustment bushings to provide the needed amount of advance or retard.
Yes, I add 1 to 2 degrees for a new set of timing components. I do not add any extra advance when reusing "worn-in" parts.
Yes... the cam moves clockwise but that means that the cam gear moves counter-clockwise in order to give you cam advance.
DD

Ahhh, I (and probably others) are breathing easier! Couple more points to be clear:

So, if my intake center line says 106 deg. on the spec card, and I degree the thing, and get 106, I don't need to do any advancing, unless I choose to advance a degree or two for eventual slack?

and,

7)When you guys say advance the cam, is it actually rotated clockwise?


Yes... the cam moves clockwise but that means that the cam gear moves counter-clockwise in order to give you cam advance.


............so if a cam needs advancing, the position of the cam gear stays "dots lined up" with the crank gear, and the offset bushing allows some ccw movement of the cam only?

The off-set bushing will allow clock-wise movement of the cam so the intake valve opens and closes sooner.
DD

Beginning to make sense. THe cam card says

Lobe spread 109 deg
Intake center line 106
.050 intake open 8 deg ATC

THerefore,

1) the cam has been advanced by the manufacturer 3 deg. already?

2) If my degree wheel is set at 0 deg TDC, and I rotate the engine cw until
cam rotates .050 past the highest point on no. 1 cylinder intake lobe (fully open intake valve), and the pointer on degree wheel now says 8 degrees after TDC, the cam is properly installed?

The cam is ground 3° advance, yes. You can use the intake opening point to get a decent idea of the cam's installed centerline. That point is measured at .050" of tappet rise not .050" down from peak lift. You measure from the base circle of the #1 intake lobe as your zero point and stop at .050" lift. This is the intake opening point as indicated on the degree wheel

I prefer to use the intake centerline method when degreeing a cam. With that method you find the degree wheel numbers .050" down on the opening and closing side of the intake lobe and average them to find the intake centerline.

What are the specifications of the cam you are installing and the engine's static compression ratio?

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Joshua

I assume this is a mech cam, as it is specified for 1960-82 motors...it also lists intake and exh lash specs. But, I only assume.

Anyway,cam specs are

Int. cam lift 270 exh. cam lift 276

Int valve lift 406 exh valve lift 414


Adv. int duration 244 Adv exh duration 244

.050 int. duration 198 .050 exh duration 203

.050 int valve open 8 ATC closes at 26 ABC

.050 exh valve open 33 BBC closes at 10 BTC


Intake Lobe center line 106 exh lobe centerline 112

Lobe spread 109