Everytime I have installed a cam and degreed it the thing has been right on the money using the dots. Im getting ready to put in my newest beast and was wondering if anyone has experienced differently?

------------------
87z 383,afr 190's, comp hyd roller(242/248-.540/.562,114 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, tremec 5spd, , 1,3/4" slp headers, speed pro bank to bank-wb02.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

Man,,, any manufacturer can make mistakes and you can have tolerence stacking. For the most part I've seen very few "mistakes" and tolerence stacking when using quality parts. However, I've had a few custom grinds that were messed up,, some with the recommended advancement "built in",, others without it,, and some requested spreads were different than requested,, and the card was wrong also. So,,, long story short,, I degree all cam installs,, if nothing more for peace of mind,,, and to be able to discard cam timing as a potential tuning problem,,, if one developes. This is just being me though.

 

Yes, always degree in the cam. My LT4 HOT cam is supposed to be 218/228, its actually 219/228. Its supposed to be installed straight up at 108º center. With a 2º advance key it was 109º. I had to put in a 4º advance key. If I hadnt degreed the cam I wouldnt have known this.

------------------
West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Well Kevin, if you used products from a reputable manufacturer you wouldn't have quality control problems like that.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

Considering most cam chains get more than 4 degrees of stretch, I don't think it makes too much difference on a street motor. Especially something that is going to see 20K miles or more before you go inside it again. I think it is more logical to change the cam timing after you have determined what you need to accomplish. Does the thing have a little too much low end and is blowing the tires away, retard a little.

It should be used for fine-tuning not much else IMO.

 

I totally agree.
ODB

 

I want to make sure I understand this. How does the chain tension impact cam degree? Whether the chain is tight or not so tight, the crank and cam gears are still the in the same position relative to each other, or are they not?

 

No, not necessarily... if the chain is strteched, the cam will be behind where it should be because of the slack. The slack can be significant on a used chain, that is, one with more than a few thousand miles on it. So, no matter how carefully you set up the cam, you can rest assured that its timing will change over time, usually in the retard direction. And since the distributor is driven by the cam, the ignition timing will gradually retard itself as well.

Just to give you some idea how much uncertainty there is in the whole system, next time you're doing something where it's convenient, turn your crank backwards by hand while you watch the rotor, and see how much slack it has. I'd bet it would surprise you.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

NOT

expect camshaft retard under load for any amount of play in a timing chain.

If you want to observe this for yourself, simply disable the advance on your distributor and use a timing light to watch your timing mark move as you rev the engine up and down. The distributor is driven directly off the camshaft.



[This message has been edited by The ODB (edited February 22, 2001).]

 

considering it doesn't cost anything to do i can't think of a reason not to. of all the cams i've done in the last few years i've not saw any that were off, but you never know unless you check. way back in the dark ages when i first started fooling with cars it wasn't uncommon to find most cams off a little.

------------------
ICON Motorsports

1st & 3rd

 

Hey!! ODB hit it right on with the timing light method. With your vacuum advace hose disconnected or ECM connector unpluged on the distributer, use the light on your balancer mark. If it pretty much stays still and doesn't "hunt up and down" , then that pretty much tells you that the chain is fairly tight. If the mark "hunts" or "jumps around", then it's probably time to replace your timing chain. There's no need to rev up the engine or anything - check it while it's idling.

BTW - As far as Degreeing a cam, I know many people say it isn't needed on a mildly built street engine if you purchase your camshaft from a respectable manufacturer. I tend to agree. They are extremly accure when they're made at the factory with computerized equipment.

------------------
Freshly rebuilt 1983 Camaro Z28 305 H.O. (L69) 3:73 Gears, BW T-5, Duel Snorkle, Rhino Clutch, 2040 Compu-cam, LS1 valve springs, porting, PST front end kit, K&N Filter and runs great but ain't streetable yet!!....Future Mods: JUNK IT if this keeps up!!



[This message has been edited by Confuzed1 (edited February 22, 2001).]

 

What do you think about replacing the regular timing chains with gear drives to prevent the changing of cam timing? Are they worth it? Usually, they say minor machining required. Wht kind are they talking about?

------------------
82 Camaro:
350, Erson cam, ported heads, Crane Hi-6 ignition, Accel supercoil, Comp Cams 1.6:1 rocker arms, Turbo 350 tranny with 2500 stall.

 

GMPP isnt a reputable manufacturer?? It was a used cam, tho...

 

No serious racers use gear drives anymore. Belt-drives are much better.

ODB

 

It could also signal the knock sensor and kill power, although I saw it done and it didn't affect the sensor.... Another possible prob.