LA964RS

Is anyone running different cams w/your set up. I hear you can run n/a 3.6 cams and they work very well. I also understand you can switch to mechanical lifters for better response and more accurate cam timing.

This is asked knowing that there are a lot of combinations out there, ecu, turbos, fuel systems, etc. etc. So just trying to get a better handle on this subject, not necessarily a "one cam fits all" type of answer.

Anyone comment on this....

ScottMellor

I have hydraulic RS 993 cams on Andi. pn 993 105 247 41 and pn 993 105 246 41

Scott (Bradford) has mechanical cams on his FVD 3.8. I gather it's a bit of a bugger to adjust the mechanical ones.

LA964RS

Thanks Scott...I see you have one of the very desirable Andial 3.8....I wonder if I've seen your car at VCR or elsewhere around town????

LAT

I have mechanical GT2 lifters in mine and it was a $1,200 touch to set them but you only have to do it every 20,000 Km or 12,000 miles.. For me that is every two years.

ScottMellor

Yes we met at VCR a coupla times. Steve (OFE) used to make me get up early to go down there, but now he's in Norcal I sleep in.

LA964RS

LAT...what cams do you run?....stock?

LAT

They are 993 GT2 cams and lifters.

JBL930

I have the solid lifters in my engine too, i'm told that they are only really necessary when wanting to raise the RPM limit and/or when using really high lift cams. My car has niether, standard RPM limit and not sure on the cam profile but it isn't radical, not really sure why the PO fitted them TBH

A pic

LAT

Jean: time for your input on the pros and cons of mechanical lifter.

Spartan

Isn't the only "con" of the mechanical lifters the maintenance?

I'm going to put EVO cams and mechanical lifters in my engine and don't mind spending the $1k a year on the valve adjustment. When you spend that in tires for a weekend that put's it in perspective

LA964RS - From my research a mild cam like the RS can work with the hydraulic lifters which can actually rev as high as you need to in these motors. Factory 993RS rev'd them higher than our tt motors without issue. Aggressive cams such as the EVO require mechanical lifters. Mechanical lifters will allow better protection against an slight overrev and you don't have to worry about a lifter failing. Don't know if you get better response with them over the hydraulic but I do think you get more accurate timing (with the updated sprockets)

LA964RS

I think if you get too radical on the cam timing it screws your ability to pass smog. I think I did the n/a cam gears when it was apart, I need to ask my guy. He also told me that n/a 3.6 cams worked well w/my set up....16/24's and ecu. The mechanical lifters are more accurate, but like you said if your not revving the sh*t out of it...do you "need" them? I'd like to get a bit more aggressive cams and try and get a bit more HP /TQ out of the car. I understand if your going to get 500hp out of the thing you're going to have to do cams....just trying to get the fact separate from the fiction....hope Jean chimes in is right, he knows his stuff and has facts to back it all up....like a few of the other very smart guys here.

budge96

Robert ,I've recently purchased a set of GT2 EVO mech lifted cams off ebay, a buddy
that has a turbo shop in whittier said he could convert the original rockers to mechanical for not to much .
I've read the 95 NA cams are similar to RS for the
993TT,like SC or 964 for 930's..
I have read it's worth investing in titanium rods should you try and step up the revs..
Bert

NineMeister

993 hydraulic lifters theoretically run at zero clearance, but in practise this is not the case and they are reknown for "pumping down" at sustained high rpm use (5000-7000rpm range) even with standard cams. It's a situation made worse with the higher lift of the RS cam or pretty much any aftermarket profile, so the fact that mechanical lifters are fitted to all Porsche race cars sums up what Weissach think of the hydraulics. We have one 993GT2 customer who exclusively tracks his GT2 Clubsport and we are now fitting the third set of hydraulics in four year simply because he wants to keep the engine absolutely standard.

The stock 964/930/911 follower is a direct replacement fit although in some cases the 993 cam carrier is a little narrow across the bearing and may need to be clearanced, however if you use this follower unmodified you will have to restrict the oil supply through the stock 993 rocker shaft otherwise the oil will squirt out of the hole in the follower. We make replacement shafts with smaller holes for this purpose, I guess that others do the same.

Jean

Sorry but I certainly am not qualified to answer this, the little I know is that the GT2 race cars revved to 7600-7800 RPMs in many instances and were primarily built to sustain 24 hour races on the other hand.

But I am not sure if the problem with the hydraulic lifters was directly related to RPMs (whereas springs and retainers were) but rather with minimizing moving parts, increasing reliability, and lightening the assembly. The GT2 parts are not the same as the 964 ones, they were adjusted via shims, and did not have an adjustment nut.

As to cams, the type of car usage is what dictates the cam profile choice, the ones that are most discussed in this forum are the proven solutions (964, RS, EVO, etc..), but there are so many others.

LAT

Then I stand corrected as I have GT2 cams with 964 style adjustment nut.

I replaced one bank of rockers as they were leaking and the replacement part numbers started with #964 etc. We used the O ring remedy to prevent leaking in the future.