i spent the afternoon degreeing in a cam, shooting for 108° straight up ICL

Crower 15261
0.545"/0.545" lift
284°/284° adv dur
224°/224° @ 0.050
108° Lobe Separation Angle
Intake Center Line = 104° ATDC

@ .050"
IO 8* BTDC
IC 36 ABDC
EO 44 BBDC
EC 0* TDC

first i set up a stock replacement set, ICL almost 112°, or 4° retarded from manufacturers specs

then i set up the double row 3-key set that came in the engine, in the O position the ICL about 104°, bingo right on but not where i want it

next i get boloxed up somehow trying to set up -4° and the readings are making no sense, i'm like 20° off at least. so i tear it down & compare all my other 3-key crank sprocket keyway to tooth relationships... interesting, and not all the same either

so give it another shot i set the double row in the -4 position, back to 112°, same as the stock replacement set

How did 4° make 8°, wtf?
duh, crank degrees are double cam degrees. advancing the cam 4° retards the crank 8°... also interesting

and skipping a tooth on the cam sprocket is 10°, probably what happened when i came up out of the ballpark earlier, must have slipped a few teeth somehow?

ok, what if i skip a tooth and set at 4°, should net 2° at the cam and 4° at the crank i figger?

so with some fiddling around i come up with skip the cam a tooth back and set the crank sprocket at +4°

108° ICL! or thereabouts close enough

here's 3 sprockets all in the 0 position, whoops! the different one may be the same as an early non-retarded set?



here's the stock replacement crank key position



a -4° key position



and a retarded tooth skip & +4° key position, the black marker is just because the stamped mark is very light. this is the set that was 'off' in the comparison pic and has other issues so i decided to use the same set that came in the engine. the actual key/tooth relationship is between the stock replacement set and the -4° set above, but this pic shows the tooth skip and -4° position that got me my 108° ICL. i guess those marks are for 'other people'



there'll be phantoms, there'll be fires on the road... and the white man dancing

That's why I only use the 9 way FRPP sets. I have less issues dialing one in with those than anything else. I tried a 3 way on the last motor I built, never could get it where I wanted.

1967 Falcon 4 door 351C-4V
1970 Mustang 351C-2V
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

possible you may never get it where you want it with only a 3-way gear. Try a offset crank key with the needed # of degree offset and it'll get you close(r). Mr. Gasket makes 2, 4 and of course, straight-up keys.

http://www.autopartsnetwork.com/shop/engine_crankshaft_woodruff_key_Ford-submodel_Base-make_Ford.html

On some sets the 4 degree position actually sticks you 8 degrees out...

I like using the Ford Racing sets as they have a gazillion crank keyways and you can adjust the cam timing by 2 degrees at a time. For $65, they don't break the bank either.

You'll find as you do more that timing chains sometimes are not what they're supposed to be....and cams are not ground like they're supposed to be. At least you did the right thing and degreed it from the get-go. Don't take anything for granted when putting an engine together.

Brent Lykins
B2 Motorsports, LLC

[email protected]
502.759.1431

that's what had me spun around for a minute, it's been a while since i degreed

4* at the cam is 8* at the crank, where the ICL is measured

when i said skipping a tooth is 10*, that's for a stock set with 36/18 sprockets. the set i used has 48/24 teeth so each tooth is 7.5* at the cam

but yeah, look at my pic showing the one sprocket that doesn't match the others, timing sets are like a 'box of chocolates'... the keys are bad enough, then there's the dowel hole to wonder where it's at!

mostly i did this just as a refresher course and out of curiosity. for this install the stock set or the 0 position of the 3-key would've been fine but when they came up different i wanted to know why

now i'm so spun around from trying to figure out how it worked i'll have to go double check it because now i can't understand it OMG


there'll be phantoms, there'll be fires on the road... and the white man dancing