Cam Questions

[Havok1105]

Hey I have a 2011 l99 (LT’s and CAI coming soon) and I was in the process of picking options for a cam. I got to a part that needed you to select a push rod length. What does the length of a pushrod do to the engine, does it make the lope sound more aggressive, does it make it softer, does it hurt the engine, will it make it harder to daily drive?

[TheFlyingBananaSS]

I went with 7.425 length and 5/16 hardened. Which was the recommended option for my cam. The length is important because it keeps he preload and lift in spec.
The lope has a few factors which impact it. Even the tune can change the lope. I went with a 3200-3400 stall converter for decent street drivabilities. I belive most stage 1 cams can be used with the stock converter. I'm sure others will pop in who have more information than I do. Some really great advice around here.

[Chris49066SS]

Your cam choice will affect the pushrod length you should be using. The best thing is to call your shop and make sure they have the cam and pushrod matched in the combo, as long as its a reputable shop and they know what they are doing. The last thing you want is for a valve to kiss a piston

[InFiD3ViL]

What Chris said is the best solution. The vendor selling the cam or your installer should be able to help you out, so contacting them is in your best interest. They will either recommend the best size based on your build or tell you to measure.

Best bet is to always measure for pushrod length and proper preload. Many of us do not measure though, especially if few other changes are made during installation. If you are not measuring then you/they need to know some things. For example, is the new cam ground with a smaller base circle than stock cam? Are you using aftermarket lifters? If you are removing heads for any reason, will you use OEM thickness head gaskets or will any head work, such as milling be done? All these things will affect the length of pushrod required.

Generally, most aftermarket LS cams are ground with a smaller base circle then the stock cam. Assuming you are going to run with stock lifters and stock thickness head gasket - you would likely be around 7.425" pushrod length as Banana said. My heads were milled .015" so my tuner/cam vendor recommended I go with a slightly shorter 7.4" pushrod, which I did, although I likely could have used the 7.425 with such a small amount of material being removed from the heads.

Too long of a pushrod can cause the lifter plunger to bottom out, leaving a valve open when it should be closed. Too short a pushrod will not let the valve open far enough. Either one of these scenarios can cause misfires and loss of power at a minimum, and at worst, excessive wear, valve train damage, or engine damage if the length is very far out of spec.

[wasthatacop?]

Originally Posted by Havok1105

Hey I have a 2011 l99 (LT’s and CAI coming soon) and I was in the process of picking options for a cam. I got to a part that needed you to select a push rod length. What does the length of a pushrod do to the engine, does it make the lope sound more aggressive, does it make it softer, does it hurt the engine, will it make it harder to daily drive?

You're camshaft installer should recommend new pushrods if needed. The camshaft manufacturer often identifies the pushrod length needed. My camshaft did not need new pushrods, but required different springs which help regulate the valves while opening and closing.
What camshaft are you thinking? There's a lot of great ones out there for Camaros.