Mystery cam grind - Logicam?

[stownsen914]

I posted this over on the Technical forum, but didn't get much response there, so figured I'd try here ...

I am trying to ID a set of race cams that came out of my engine that I am rebuilding this winter. I would like to see if anyone recognizes the grind designation. I believe they may have been done by a grinder called Logicam which closed up shop years ago (Logicam was run by Bob Walter, who also owned Dial-in Cam). The stampings on the end of the two camshafts show “3188”. They also show “10 93” which I believe is a date code that matches when this engine was originally assembled, and “APC”. It’s an aggressive grind with lift and duration specs similar to GE100 (I degreed the cam and measured lift while they were still in the motor). No markings aside from the stock Porsche ones are evident elsewhere on the cams.

This designation doesn’t look like ones from the usual cam grinders like Web, Dougherty, Elgin, Newman, or even Crane which used to do Porsche cams. See pics below. Any ideas?

Scott

[racing97]

I can't tell you anything about the company but I can tell you they have a hard-face overlay to build the lift off the base circle instead of cutting down the base circle to create a different profile.
This process has been eradicated in light of the loss of zzdp in oils in favor of new billet cores.
You can see the overlay by the contrast in the top pic o side the lobe.

[stownsen914]

They are definitely weld-ups, if that is what you mean. Back then new billets were scarce, so building up the lobes on stock cams by welding was common practice.

[MBruns]

Megacycle has done several 911 grinds as well, give them a shout
Mike Bruns

[Neil Harvey]

Timely post for the service we are about to offer.

After many calls regarding cam choices, we now will offer a full Camshaft analysis service to the DIY community as well as to our existing trade partners.

[stownsen914]

Thanks Neil. At this point I'd just like to know who ground these cams.

Not sure if it will help, but here are the cam timing specs (I measured them with a degree wheel and dial indicator for lift before I disassembled the motor). Read the asterisks as "degrees" in case that's not obvious.

Intake: open 45* BTDC, close 53* ABDC, which makes 278* duration (measured at .050" lift). Max lift is .510"

Exhaust: open 61* BBDC, close 35* ATDC, which makes 276* duration (measured at .050" lift). Max lift is .500"

[faapgar]

I built this motor and I believe these were from Garretson because of the weld ups.Looks like they held up well.I always liked the GE-80 Cam better than GE-100.Mid range was more responsive and revved quicker.They had their own billets back then but there were some issues with lobe deterioration with the stiffer Aase valve springs.Also could not use adjustable forged rockers as the pad was not large enough.Fred

[Tom_in_NH]

Fred, you had mentioned in another thread that you have always used stock valve springs, but cryo'd them. Would that also had been the case with GE60, GE80, GE100 class of cams? My concern is lobe wear with the EBS or Aase springs.

Sorry if I have hijacked !

[lvporschepilot]

re springs: my springs are stronger than stock but not as stiff as Aasco, EBS, or Aase springs. 80-85lbs at the seat and 250-260lbs at 13mm lift. Install at 34mm and you're done. I still have a few sets remaining. Fits stock retainers. PM me if you'd like a set.

[stownsen914]

Not to hijack my own thread, but if these are Garretson cams, wouldn't they be marked as such? There isn't any GExx designation anywhere that I can find. Did Garretson stamp their cam designations on the end of the cams like other grinders do?

[racing97]

Aasco springs are 70lbs on the seat @ 34mm and 270full open 13mm 1.25 from coil bind