Is one tooth off (cam/crank) noticeable on daily driver?

[DaveMcLain]

Dave Mc,
I think you will find that '4*' is crank degrees. Example, If a cam is ground on 110 LSA with no advance ground into it, theoretically if the timing set was installed 'dot to dot' then the ICL would be 110*. If the the 4* adv slot is used on the crank sprocket, ICL becomes 106, ECL becomes 114. 106 & 114 are crank degrees, not cam degrees. The cam itself has only been advanced 2*, which translates to 4* crank..
A Cloyes timing chain set I have in front of me says: To advance cam 1*, use the 2* slot on the crank sprocket.

Put the pulley on there and check the cam timing with it on zero. Then take it off again and put it in the advance or retard position and check it again. I think you'll find that most of the three position sets do not move the cam timing four crank degrees but four cam degrees instead.

Cloyes directions are correct in that if you advance the cam one degree it is two crank degrees.

[Walter R. Malik]

Here is a scenario which is not presented very often.

A 4.9L Ford 300 L-six in a 1977 truck has a gear drive. As delivered the cam is about 2 degrees retarded. NOW, advancing that cam by simply moviing the crank gear one tooth, makes the cam 5 degrees advanced so, there is only about 7 crank degrees difference per tooth in that gear drive.

It stands to reason, for the late 1970's emission engines ... Ford simply had the "dot" on the crank gear moved one tooth because now being a tooth "off" makes the valve timing like a later fuel injected 4.9L vehicle using the same camshaft.

[Geoff2]

Dave Mc,
The Cloyes set is a 9 key way set like many on the market: 2,4,6.8, adv & 2,4,6,8 ret & 0. These are crank degrees. If they were cam degrees, it would mean that a cam on 110 LSA installed on the 8* slot, would be 16 crank degrees advanced & on 94 ICL/126 ECL!!
Isky sells offset cam bushings, 2,4,6,8 crank degrees.

Here is where it gets confusing. This is from a Hot Rod article on adv/ret cams: " If a cam with a 110 LSA is specified to be installed on a 106* ICL, the cam would be 4* advanced." In the strictest sense of the word this is wrong because the cam is only advances 2* of rotaion when the crank is rotated 4* further.
What the writer meant was that the timing events were advanced 4* [ crank ], not the actual cam rotated 4*. Confusing.

[Walter R. Malik]

Dave Mc,
The Cloyes set is a 9 key way set like many on the market: 2,4,6.8, adv & 2,4,6,8 ret & 0. These are crank degrees. If they were cam degrees, it would mean that a cam on 110 LSA installed on the 8* slot, would be 16 crank degrees advanced & on 94 ICL/126 ECL!!
Isky sells offset cam bushings, 2,4,6,8 crank degrees.

Here is where it gets confusing. This is from a Hot Rod article on adv/ret cams: " If a cam with a 110 LSA is specified to be installed on a 106* ICL, the cam would be 4* advanced." In the strictest sense of the word this is wrong because the cam is only advances 2* of rotaion when the crank is rotated 4* further.
What the writer meant was that the timing events were advanced 4* [ crank ], not the actual cam rotated 4*. Confusing.

Some manufacturers use CRANKSHAFT degrees and some use CAMSHAFT degrees. That is why it always needs to be checked.

Believing anything from a magazine article as gospel is your fault.

[Geoff2]

I checked the popular Rollmaster 9 keyway set instruction sheet. It states that the 2,4,6.8 slots are crank degrees & translate to 1,2,3,4 cam degrees, due to the 2:1 ratio.
The only only cam measurement I have seen in cam degrees is the LSA. All other measurements, ICL, ECL, IO, EO etc are in crank degrees.

[roc]

The only only cam measurement I have seen in cam degrees is the LSA. All other measurements, ICL, ECL, IO, EO etc are in crank degrees.

This has always been my understanding too.

[DaveMcLain]

I checked the popular Rollmaster 9 keyway set instruction sheet. It states that the 2,4,6.8 slots are crank degrees & translate to 1,2,3,4 cam degrees, due to the 2:1 ratio.
The only only cam measurement I have seen in cam degrees is the LSA. All other measurements, ICL, ECL, IO, EO etc are in crank degrees.

That's right but if you buy one of those even more popular three keyway sets and check it you'll find that it probably moves the cam timing 8 crank degrees not four.