HELP !!! QUICK CAM QUESTION!!!
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 3,376
Likes: 4
From: Hershey, PA, USA
Cruise-In VI Veteran
St. Jude Donor '12
HELP !!! QUICK CAM QUESTION!!!
Ok I installed a new cam and heads on my car. I go and start the car up and it runs like poopie, needs almost half throttle to keep it goin. Could I have put the cam in 180 degrees off. I install it according to the instructions, the 2 dots closets to each other but could have I flipped the cam gear backwards and put it 180 off? This is really maken me sick and I know someone in here can help me. :U :cry :cry
Drifting
Joined: Oct 2000
Posts: 1,823
Likes: 52
From: Shawano WI
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
The cam can not be installed 180° off. The cam turns at 1/2 of crank speed so for every turn of the crankshaft the cam only turns 180°.
The first thing I would check it the timing to be sure it is correct along with the firing order to be sure that you didn't get any of the plug wires on wrong.
Then I would check to be sure you do not have a valve with the lash set to tight. That would require a higher RPM to keep running.
The first thing I would check it the timing to be sure it is correct along with the firing order to be sure that you didn't get any of the plug wires on wrong.
Then I would check to be sure you do not have a valve with the lash set to tight. That would require a higher RPM to keep running.
Instructor
Joined: Nov 2001
Posts: 231
Likes: 0
From: Burlington NC
Re: HELP !!! QUICK CAM QUESTION!!! (Pete79L82)
The cam can not be installed 180° off. The cam turns at 1/2 of crank speed so for every turn of the crankshaft the cam only turns 180°.
The first thing I would check it the timing to be sure it is correct along with the firing order to be sure that you didn't get any of the plug wires on wrong.
Then I would check to be sure you do not have a valve with the lash set to tight. That would require a higher RPM to keep running.
The first thing I would check it the timing to be sure it is correct along with the firing order to be sure that you didn't get any of the plug wires on wrong.
Then I would check to be sure you do not have a valve with the lash set to tight. That would require a higher RPM to keep running.
Careful I flattened a cam lobe because I set my lash to tight. Same symptoms as you've described
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 3,376
Likes: 4
From: Hershey, PA, USA
Cruise-In VI Veteran
St. Jude Donor '12
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
Would having the valve lash too tight make it back fire and make it extremly too hard to start? Cause this whole setting the valves is givin me a head ache, any one have tips on setting the start up valve lash? It is a hydralic (sorry 4 spelling) cam.
Drifting
Joined: Oct 2000
Posts: 1,823
Likes: 52
From: Shawano WI
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
Having an intake valve set too tight will cause it to backfire throught the carb because the valve may not be closing completely. Having any valve too tight will cause hard starting and a very poor idle.
[Modified by Pete79L82, 10:30 PM 6/4/2002]
[Modified by Pete79L82, 10:30 PM 6/4/2002]
Race Director
Joined: Sep 1999
Posts: 11,358
Likes: 379
From: Plano TX
Re: HELP !!! QUICK CAM QUESTION!!! (Pete79L82)
I recommend you set the valves the **** way:
With both valve covers off, rotate the crank and watch the rocker arms on cyl 1 and 6. As you come close to TDC you will see the rockers of cyl 1 OR 6 move. The other cylinders rocker pair will not move. If #1 moves, rotate the crank one full turn. If #6 moves, you're set. With the timing mark aligned with zero on the tab, adjust both rockers on #1.
To adjust, loosen the nut until you can wiggle the rocker up/down. The "spin the pushrod" method is unreliable. Once you can wiggle it up/down, tighten slowly until the play is just gone. Now tighten an additional 3/4 turn.
Rotate the crank 90 degrees (1/4 turn) clockwise. I recommend putting a dab of paint on the front of the pulley as it makes it easier to turn the 1/4 turn.
Adjust the next rocker pair in the firing order, #8. Turn crank another 90 dgr and adjust #4 etc. Firing order: 1-8-4-3-6-5-7-2.
This takes longer to do than the method in the manual, but your chances of success are far greater...
With both valve covers off, rotate the crank and watch the rocker arms on cyl 1 and 6. As you come close to TDC you will see the rockers of cyl 1 OR 6 move. The other cylinders rocker pair will not move. If #1 moves, rotate the crank one full turn. If #6 moves, you're set. With the timing mark aligned with zero on the tab, adjust both rockers on #1.
To adjust, loosen the nut until you can wiggle the rocker up/down. The "spin the pushrod" method is unreliable. Once you can wiggle it up/down, tighten slowly until the play is just gone. Now tighten an additional 3/4 turn.
Rotate the crank 90 degrees (1/4 turn) clockwise. I recommend putting a dab of paint on the front of the pulley as it makes it easier to turn the 1/4 turn.
Adjust the next rocker pair in the firing order, #8. Turn crank another 90 dgr and adjust #4 etc. Firing order: 1-8-4-3-6-5-7-2.
This takes longer to do than the method in the manual, but your chances of success are far greater...
Instructor
Joined: Nov 2001
Posts: 231
Likes: 0
From: Burlington NC
Re: HELP !!! QUICK CAM QUESTION!!! (zwede)
zwede,
My stupid question for the day. If the cam is an aftermarket cam, which I am assuming it is - is this method still valid?
I'm not a cam expert by any means, however won't the charactistics of the cam be different possibly causing problems when rotating the the crank 90 degrees.
When I set mine, the second go around, I followed CompCams instructions. Which were to crank the engine and watch for movement on the exhaust. When the exhaust begans to move set the intake. They also recomend the "spin the pushrod" and I agree the up/down is better. Then continue cranking the engine until the intake has almost completed a full up/down stroke and set the exhaust.
The method you recommended should put you on the compression stroke, correct? But depending on the cam - would this always be true?
Just trying to understand the vast world of cams - life was much simplier with my pontiac 400's - you simply torque the rockers to spec and walk away.
-david
My stupid question for the day. If the cam is an aftermarket cam, which I am assuming it is - is this method still valid?
I'm not a cam expert by any means, however won't the charactistics of the cam be different possibly causing problems when rotating the the crank 90 degrees.
When I set mine, the second go around, I followed CompCams instructions. Which were to crank the engine and watch for movement on the exhaust. When the exhaust begans to move set the intake. They also recomend the "spin the pushrod" and I agree the up/down is better. Then continue cranking the engine until the intake has almost completed a full up/down stroke and set the exhaust.
The method you recommended should put you on the compression stroke, correct? But depending on the cam - would this always be true?
Just trying to understand the vast world of cams - life was much simplier with my pontiac 400's - you simply torque the rockers to spec and walk away.
-david
Team Owner
Joined: May 2001
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
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CI-VIII Burnout Champ
St. Jude Donor '06-'10, '13
Re: HELP !!! QUICK CAM QUESTION!!! (DavidOrr)
no mater the cam, the firing order, and therefore the order of it opening and closing will always be the same (for the same engine).
It may be that you have the distributor 180 degrees off, or maybe even 1 tooth off.
You may want to make sure to get the #1 cylinder at TDC, and then pull the distributor cap and make sure the rotor is pointing to when #1 should be.
Hope this helps.
It may be that you have the distributor 180 degrees off, or maybe even 1 tooth off.
You may want to make sure to get the #1 cylinder at TDC, and then pull the distributor cap and make sure the rotor is pointing to when #1 should be.
Hope this helps.
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Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 3,376
Likes: 4
From: Hershey, PA, USA
Cruise-In VI Veteran
St. Jude Donor '12
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
Ok I re-adjusted the valves and now it seems to go better but you have to have the throttle help wide open to get it to idle and then it will just shut off even. WTF!!! I m getting really sick of this, I am goin to pull the distrubtor out and get it on TDC and make sure every thing is in perfect.
Safety Car
Joined: Feb 1999
Posts: 3,630
Likes: 14
From: Fountain Hills AZ
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
DCB, what is your timing set at? If it's close to where it should be, you can save yourself the trouble of r&ring the distributor and look elsewhere for a solution. If you can't get it close to where it needs to be, then the distributor has been installed wrong and needs to be redone.
Instructor
Joined: Jun 2002
Posts: 117
Likes: 0
From: epping nh
Re: HELP !!! QUICK CAM QUESTION!!! (DCBStingray)
By looking at all these post if it was carbed I would say rebuild or check the carb. But so many problems are related to the EFI units and if you installed the cam after the efi unit was running there may be a possibility you need to readjsut the program or in some systems get a new chip.