[Al_R]

So I'm putting the finishing touches on my little 355 sbc rebuild and I noticed something. I'm using a new Cloyes timing set and when I first put it on and while I was checking/diaing in the cam it seemed perfect, I had vitually no crank movement without the cam coming along. So now I've installed all the valvetrain parts, rolled the motor over multiple times to preset the valve lash then installed the balancer and arbor drive system and while rolling the motor to preset the crank trigger I feel crank movement without cam movement.

I checked this real close and I have 1 full degree of crank movement (back and forth) worth of cam chain play. Granted, when it seemed perfect there was no valvetrain load but I didn't expect this. I haven't bolted on the intake and pan yet so if I have a problem now is the time to go back in after it.

Is 1 crankshaft degree of cam chain play unusual for a new chain under load? Did I push all the oil film out of the crank and cam bearings and create this play that way? Am I being way to picky?

I can live with the idea of finishing up, running it and monitoring chain stretch if this initial play isn't way outside the norm.

What do you think guys?

Thanks, Al.

p.s. Here's a pic of my 355 as it sits right now.

 

[Billyman]

So I'm putting the finishing touches on my little 355 sbc rebuild and I noticed something. I'm using a new Cloyes timing set and when I first put it on and while I was checking/diaing in the cam it seemed perfect, I had vitually no crank movement without the cam coming along. So now I've installed all the valvetrain parts, rolled the motor over multiple times to preset the valve lash then installed the balancer and arbor drive system and while rolling the motor to preset the crank trigger I feel crank movement without cam movement.

I checked this real close and I have 1 full degree of crank movement (back and forth) worth of cam chain play. Granted, when it seemed perfect there was no valvetrain load but I didn't expect this. I haven't bolted on the intake and pan yet so if I have a problem now is the time to go back in after it.

Is 1 crankshaft degree of cam chain play unusual for a new chain under load? Did I push all the oil film out of the crank and cam bearings and create this play that way? Am I being way to picky?

I can live with the idea of finishing up, running it and monitoring chain stretch if this initial play isn't way outside the norm.

What do you think guys?

Thanks, Al.

I'd be plenty nervous if I didn't have at least a degree of play in the chain. Much tighter and the chain will stretch prematurely.

When I degree a cam with a chain, I always leave room for a full degree of hot stretch while running. If you're desired centerline is 106 and you're setting it up on 106 then while it's running, that ain't where it's at. Advance it one more degree.

 

[Horndog]

I'd be plenty nervous if I didn't have at least a degree of play in the chain. Much tighter and the chain will stretch prematurely.

When I degree a cam with a chain, I always leave room for a full degree of hot stretch while running. If you're desired centerline is 106 and you're setting it up on 106 then while it's running, that ain't where it's at. Advance it one more degree.

X2

 

[Al_R]

Thank you Billyman and Jim for your confirmation that my cam chain play is normal.

As far as bumping another degree into the cam, I'll go ahead and collect some time slips with it where it is (with the newfound knowledge that I'm probably as much as a degree back from where I set it) before I start playing with cam timing. I need to make sure I have my carb and ignition timing sorted out before I pass judgement on the cam timing. I've read here, and agree, that you can't know during setup exactly what the combination will want. How the car leaves and the incrementals on the time slips will tell the story.

Jim, I see your out of Terre Haute. I'm on the SW side of Indy, Plainfield area. It wouldn't be out of the question for me to make the tow over to your neck of the woods for some racing. You spend any time at your local track?

Thanks again, YB rocks!

Al.

 

[Horndog]

Thank you Billyman and Jim for your confirmation that my cam chain play is normal.

As far as bumping another degree into the cam, I'll go ahead and collect some time slips with it where it is (with the newfound knowledge that I'm probably as much as a degree back from where I set it) before I start playing with cam timing. I need to make sure I have my carb and ignition timing sorted out before I pass judgement on the cam timing. I've read here, and agree, that you can't know during setup exactly what the combination will want. How the car leaves and the incrementals on the time slips will tell the story.

Jim, I see your out of Terre Haute. I'm on the SW side of Indy, Plainfield area. It wouldn't be out of the question for me to make the tow over to your neck of the woods for some racing. You spend any time at your local track?

Thanks again, YB rocks!

Al.

I get down there from time to time. I sold my race car a couple years back so I'm not there as much anymore. I go usually to help my nephew with his Camaro that we built.

Had a tube chassis Beretta that I bracket raced. Injected 406, glide, 4-link etc.
Wanting to go heads-up racing - stock suspension stuff. Looking around for the right car to build up.

Don't have the car count we used to but it is still a decent place to race.