Cam gear adjustment?
Thread Starter
Drifting
Joined: Sep 2006
Posts: 1,387
Likes: 30
Cam gear adjustment?
Can you change the cam gear independantly of the crank gear, or do you have to start over, taking off rockers, pushrods, and lifters in order to accurately do it.
The timing is off from a cam/head swap. I put the cam gear in at 12 and the crank at 12. Well now I realized that they should be at 6 (cam) and 12 (crank). I had the thought that I could turn the motor until the cam gear is at 6, then take off the timing chain, and turn the crank gear by itself til its at 12. then reinstall it all and then it would be right. At least thats what I'm hoping. I don't want to take off the rockers/pushrods again.
The timing is off from a cam/head swap. I put the cam gear in at 12 and the crank at 12. Well now I realized that they should be at 6 (cam) and 12 (crank). I had the thought that I could turn the motor until the cam gear is at 6, then take off the timing chain, and turn the crank gear by itself til its at 12. then reinstall it all and then it would be right. At least thats what I'm hoping. I don't want to take off the rockers/pushrods again.
Thread Starter
Drifting
Joined: Sep 2006
Posts: 1,387
Likes: 30
ok, so then I don't have to take off the push rods/rockers to do this right then??? I can just turn it over til the cam is at 6, then do the crank by itself and get that to 12, and we're good to go?
Thread Starter
Drifting
Joined: Sep 2006
Posts: 1,387
Likes: 30
well we just checked it out, and at TDC (both pointing at 12) is where we had it originally. So, its still not right obviously. (it would just die after a few secs of running and no matter what, never went above 400-600 rpm). The cam is a lunati grind, Duration @ .50" = 235/240, lift .490/.490. Maybe we should advance or retard it? Its a holley timing chain set so it has those square, circle (where we set it) and the triangle marks on the crank gear.
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
With both gear timing marks at 12:00, you should be right at TDC for #1 cylinder. Unless you are off by a tooth or you have your distributor WAY off, it should fire right up.
Did you happen to degree the cam to make sure you had everything lined up?
Elm
Did you happen to degree the cam to make sure you had everything lined up?
Elm
Thread Starter
Drifting
Joined: Sep 2006
Posts: 1,387
Likes: 30
It does fire right up, BUT, it dies very fast. If you hold the throttle all the way open, it'll stay on a little longer, but then it'll die again. It won't go past 4-600 rpm no matter what. we didn't degree the cam, we don't know how.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Two things, since I dont know exactly but there basic.
1] make sure the valves are not too tight
2[ try a little more lead
dont worry about the degree of the shaft. there all cut near perfect with today's technology
1] make sure the valves are not too tight
2[ try a little more lead
dont worry about the degree of the shaft. there all cut near perfect with today's technology
Instructor
Joined: Jun 2005
Posts: 156
Likes: 0
From: Liverpool NY
Read the instructions and then read them 9 more times.
When I installed mine I had the cam gear advanced but set to the crank incorrectly. I'm not dumb, but I actually did this twice
I think my installation instructions were a little vague.
When I installed mine I had the cam gear advanced but set to the crank incorrectly. I'm not dumb, but I actually did this twice
I think my installation instructions were a little vague.
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Race Director
Joined: Nov 2002
Posts: 12,142
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From: Taylor Michigan
If I said this once, I said it several times. BUY from your independent local auto parts store. They know what there doing. Help would have come forth with the purchase. Even buying parts would have its advantage at the locals. Valuable knowledge to install parts is right at your fingertips, plus no high priced freight or service charges. The mail order or chains are not very well schooled in auto parts. If you dont believe me just ask them some questions. You will probably get as many conflicting answers as to how many persons answer the phone's bUY local from experts and you wont be sorry or have to do it over
Advanced
Joined: Jan 2008
Posts: 90
Likes: 0
From: North Carolina
Did you set your distributor in with both dots straight up ? If you did, your 180* off . the crank turns one time to the cams 2 times. If you had turned the crank one more complete turn your dots would have faced each other. I would check and redo distributor before i tore it back down.
Race Director
Joined: Jun 2000
Posts: 10,029
Likes: 662
From: FL
Distributor installed 180 degrees out would be my bet. Pull the distributor, trun the crank one revolution (this will turn the cam 180 degrees) then reinstall the distributor. You can verify that you have the dist set so that it fires #1 at TDC by pulling the valve cover and watching the rockers.
Thread Starter
Drifting
Joined: Sep 2006
Posts: 1,387
Likes: 30
So we should install the distributor with the dots facing each other? Ok we can try that next. I'm pretty sure we put the gears on right. Its at the end of compression stroke when they're both at 12, and end of exhaust, beginning of compression when they're touching.
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Did you set your distributor in with both dots straight up ? If you did, your 180* off . the crank turns one time to the cams 2 times. If you had turned the crank one more complete turn your dots would have faced each other. I would check and redo distributor before i tore it back down.
Dots facing each other = #6 TDC compression stroke.
Ask the General (shop manual).