How to tell if cam was reground?

[bpu699]

Any easy way. My cams have a 930 serial number. Prior owner said there were sc cams... Torque curve really flat, not peaky...

How can I tell if the 930 cams were reground to sc? Or if it's just 930 cams?

[Flat6pac]

Some have a corporate stamp on them and defining numbers. Webcam comes to mind
I have seen the casting numbers ground off
Bruce

[Catorce]

Stamp on the head, copious black nitride coating on the whole cam

[bpu699]

Will check, but don't recall seeing any company stamp on it... Will try to post pics this weekend...

If it were reground, would the cam lobe base be measurably smaller?

It hasn't been rewelded, as I would think that would be obvious, right?

[Trackrash]

Stock SC cams have a 930 stamped on the end. Usually a reground cam will have other numbers stamped on the end.
Here is a stock SC cam.

[Walt Fricke]

Beat me to it.

[bpu699]

Originally Posted by Trackrash

Stock SC cams have a 930 stamped on the end. Usually a reground cam will have other numbers stamped on the end.
Here is a stock SC cam.

Seriously?! How does that make sense? No Porsche logic involved?

My cam towers are a 964xxx part number... No point asking about that...

Geesh. You just blew my mind...

Thanks!

[Matt Monson]

Originally Posted by bpu699

Seriously?! How does that make sense? No Porsche logic involved?

My cam towers are a 964xxx part number... No point asking about that...

Geesh. You just blew my mind...

Thanks!

There are a ton of 911 sc parts that use a 930 prefix.

[timmy2]

930 part numbers likely due to the 3.0 being a 930 engine for a little while?

[Catorce]

Originally Posted by timmy2

930 part numbers likely due to the 3.0 being a 930 engine for a little while?

It's not THAT 3.0 exactly.

[KTL]

If it's a regrind to the same existing profile, they may not stamp anything on the cam because it's sort of the same cam. Whereas if the cam has been re-profiled, you'll see the cam maker's markings on it. These cams I had were clearly re-profiled original SC cams. Take a look at the side of the lobes

S Cams for Carbs- Webcam 149S Hardweld

And speaking of hardwelded cams, anybody considering this should remember that the rocker followers should be hardwelded too. The harder face of the cam will wear the original face of the rocker much faster

Regarding the 964 part number on the cam housings, the '89 3.2 engines started to have these 964 castings. They're not the same as the 964 3.6 N/A engine, as that cam housing used a redesigned oil feed system for the chain tensioners. But they're the same housings that are used in the '91-'93 3.3L turbo and the '94 3.6L turbo which used the older style of chains and tensioners.

[cgarr]

Bo, Clear your messages so I can send you one.

Craig

[Steve@Rennsport]

Just a reminder that reground cams LOOK identical to factory ones so the only real way to know precisely what you have is by putting them into a Cam Doctor to read the profile. Anything else is just guesswork & conjecture.

Hardwelded cams be used without any further rocker arm modifcations, however they MUST be reconditioned to ensure the pads are parallel with the cam lobes (OEM ones are almost never are). Done this for 35+ years without any issues. Naturally, this is predicated on using the proper oils and having clean spray bars.

[bpu699]

Originally Posted by Steve@Rennsport

Just a reminder that reground cams LOOK identical to factory ones so the only real way to know precisely what you have is by putting them into a Cam Doctor to read the profile. Anything else is just guesswork & conjecture.

Hardwelded cams be used without any further rocker arm modifcations, however they MUST be reconditioned to ensure the pads are parallel with the cam lobes (OEM ones are almost never are). Done this for 35+ years without any issues. Naturally, this is predicated on using the proper oils and having clean spray bars.

Any input on doing one cam vs both? Webcams said you can go either way... I think they take .005 off during a re grind...

Of course doing both is optimal, but then your grinding the rockers on that side too... I hate fixing stuff that ain't broke...

If it effects running, then it has to be done right...

[Steve@Rennsport]

Originally Posted by bpu699

Any input on doing one cam vs both? Webcams said you can go either way... I think they take .005 off during a re grind...

The base circle will be affected by a regrind, but .005 is accommodated by the adjusting screw without a problem.

Properly done, you can do one cam without any running issues.

[bpu699]

Originally Posted by Steve@Rennsport

The base circle will be affected by a regrind, but .005 is accommodated by the adjusting screw without a problem.

Properly done, you can do one cam without any running issues.

Thanks Steve, appreciate the info...