Cam timing
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Cam timing
I have a a 78 Corvette I'm playing with. I can't seem to get it timed right, when I hook up a timing light the marks don't even come close so I time it by ear but it is never quite right. Today I did a compression test to see if the engine was even worth working on and all cylinders came out beetween 135 and 140. A friend if mine says the engine was built about 5 years ago and the guy that built it put In the cam to retard the cam timing because he was not sure of his drive train and this was supposedly a high performance engine. Does this make sense could this be my problem
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
I will bring the number one cylinder up to TDC this weekend and see where the timing marks land. I remember doing this before by pulling all the plugs and rotating it by hand. I don't remeber how far behind the marks were but I remeber them being quite a bit. The car idles well, if I don't jump on it it accelerates ok and if I put my foot into it the ignition falls flat around 3500, I feel a slight surge when holding around 3200 rpm.
I have never heard of someone retarding the cam If someone did that would it still run?
I have never heard of someone retarding the cam If someone did that would it still run?
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
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I will bring the number one cylinder up to TDC this weekend and see where the timing marks land. I remember doing this before by pulling all the plugs and rotating it by hand. I don't remeber how far behind the marks were but I remeber them being quite a bit. The car idles well, if I don't jump on it it accelerates ok and if I put my foot into it the ignition falls flat around 3500, I feel a slight surge when holding around 3200 rpm.
I have never heard of someone retarding the cam If someone did that would it still run?
I have never heard of someone retarding the cam If someone did that would it still run?
http://www.compcams.com/Pages/413/ca...ion-angle.aspx
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Retarding the cam it will still run. My opinion is if you need to change cam timing you picked the wrong cam. Retarding cam timing closes the intake valve later, reducing cranking pressure and moving the powerband up. I would go straight up on cam timing, change out the balancer, check for vacuum leaks, set up a performance timing curve and do a good tuneup and carb setup, and see where your at. Sounds like you might have an issue with your secondaries not kicking in. Check your accelerator linkage for full throttle engagement with no binding or interference.
http://www.compcams.com/Pages/413/ca...ion-angle.aspx
http://www.compcams.com/Pages/413/ca...ion-angle.aspx
