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I got the bottom end of the 403 assembled this weekend and decided to degree the cam. Your typical sealed power/wolverine/Edelbrock 214/224 474 /496. (Yes I know it is not optimal but it's better than what was in it and has been on my garage for years). Anyhow compared to the cam card it came out 6 degrees retarded when installed straight up. I have never had a chevy cam come up more than a couple degrees off. Each crank tooth is 10 deg, and by moving to the advanced gear position I got it to come out dead on. I have heard about olds came being off, guess it is true. Will be way better than the stock cam and chain with almost an inch of play that came out. degree that cam!
I had to set the cam in my 394 eight degrees retarded to get it " straight up " .
Turns out , the crankshaft keyway was off by more than five degrees alone .
Yes , if you have an " adjustable " timing set , it is well worth degreeing the cam .
I used the Comp Cams 2113. I have used the Edelbrock 7813 set in the past and found it to be way off as well as more expensive. What would you recommend? It would probably be worth $20 extra bucks to have a set that is right the first time, or has more adjustment, but if the crank or cam is off, it doesn't help a lot. This one seems nice and tight, and this double roller set doesn't require clearancing the fuel pump arm or slot like the Edelbrock set did. The set that came out of the engine was a generic replacement chain that didn't have a nylon cam gear, but was not adjustable and was super sloppy.
Just an FYI, most all of the three keyway sets are made by one of two companies, and they’re all not worth the box they come in. I had a Comp cams set that was 11* off on the +4 setting.
CJ I’m curious as to how you determined the crank was off 5*.
Thanks.
CJ I’m curious as to how you determined the crank was off 5*.
Thanks.
I had already determined that the whole works was off by eight degrees when I degreed the cam .
When I installed the balancer , which had just been re-built by The Damper Doctor , it was off by five and a half degrees on the timing marks . .
I figured the error was in the crank keyway and not the balancer .
I will probably have to use a " dial back " timing light to set the timing .
“I will probably have to use a " dial back " timing light to set the timing “
What does that have to do with cam timing? You would use the dial back timing light to check total advance for ignition not the Cam. I’m confused here.
“I will probably have to use a " dial back " timing light to set the timing “
What does that have to do with cam timing? You would use the dial back timing light to check total advance for ignition not the Cam. I’m confused here.
The balancer was just rebuilt by Damper Dr. They take great care to make sure the timing mark is in the correct relationship to the keyway .
When I installed the balancer I checked it against " true top dead center " (as found with a dial indicator ) and at true TDC the timing mark was at five degrees advanced .
My ignition is supposed to be set at 10 degrees advanced . With a five degree error that's a total of fifteen degrees , which is off the timing scale in "guess territory " .
Hence the need for a dial back timing light .
You are right about the cam timing having nothing to do with the ignition timing or the timing mark on the balancer . Except that an error in indexing the keyway to the center of the #1 rod journal will affect both .
Perhaps my crankshaft guy didn't get the crank journals indexed properly to the keyway ?
Last edited by Charlie Jones; April 9th, 2019 at 10:45 PM.
I used a Cloyes stock replacement set on the 307 from my Wife's Buick last year. I used a Crane hydraulic roller that was ground very close to stock specs and it came in right on the money.
Also .... good tip on the damper. I check them on every engine I build. I actually have found very few that are not correct.
April 7th, 2019, 06:30 PM
