3.0 web cam questions

[Mark Henry]

I've been collecting for my 914 3.0 build and a friend wants to trade some parts I have for a set of new webcams.
I'm pretty sure he said they are these ones the 464/465:
http://www.webcamshafts.com/pages/automobile/porsche/install_data/tc_000452_003771.html

My 3.0 big port (1979) is going into a 914 with 40 webers, MSD, 1-1/2" headers and stock size malhe 9.7cr RSR pistons. other than that it will be stock.
I'm not after major horsepower, on a narrow body 914 200hp would be plenty, 6k redline, I do want street drivableity. Some day I may switch to SDS fuel injection as I've used this on my type 4 engine and really like the system.

The questions are would this be good cams for me?
And these are 3 bearing cams any problem with those in a engine that would of had 4 bearings cams?
I know they fit, just looking for opinions on this combo.
Thanks

[Mark Henry]

My slugs

[Mark Henry]

I'm thinking about it and it might be these cams...I'll have to call him and confirm

Web Cam Inc. - Performance and Racing Camshafts / Porsche 911 SOHC 12v Timing Card

The big thing is I don't want to "hot" of a cam, this car will be a street car 99% of the time.

[Steve@Rennsport]

Mark,

If they are 120/104's, you may not like those if you are looking for max torque & smoothness below 6K. Those do best between 5K and 7400 in a 3.0.

4-bearing cams cannot be used in 3 bearing cam housings but 3 bearing cams can be used (in a pinch) in 4 bearing housings.

I would recommend getting the right cams for your engine and type of use.

[Mark Henry]

Yes it would be 3 bearing cam in 4 bearing housings.
That's kind of what I thought about running this. "In a pinch" isn't really what I want, I do want longevity as well as good smooth power.
I love "deals", but I don't want to be stupid.

I'm on the fence about running my carbs or going to PEFI so the 120/104's would be a bad choice.
If I did go SDS fuel injection (and crankfire for MSD) what would be a good choice? My experinance (type 4's) is the SDS likes more of a FI cam better than a carb cam.
I also have perfect stock 3.0SC cams, almost a shame to use them as cores.

My ultimate goal is I want close to stock drivability with a bit more balls.
I want my wife to be comfortable driving this car, but she is used to driving high powered carbed bugs. (The '67 in my sig will be her summer DD)

[Steve@Rennsport]

I have no clue about the capabilities of SDS EFI so I cannot offer specific recommendations, but if the system doesn't tolerate cam profiles with some duration and narrow lobe centers, I'd stick with something thats docile such as the 964 grind. Those have excellent drivability.

[KTL]

My opinion is you're really not doing those pistons justice with 6K rev limit and SC/Carrera-like cams. Those domes are ideal for getting the rpms up there. But to each his own.

I have a pair of Carrera cams (bolt-end) that are perfect to use as regrind cores if you're looking for some.

[Flat6pac]

The cam bearings are different sizes between 3 bearing and 4 bearing. I think it would be easier for the machine shop to open the 3 bearing carrier to carry the 4 bearing cam then shrink metal onto the 3 bearing cam to get it to fill the mm needed to fit the cam in the 4 bearing carrier.

Bruce

[Mark Henry]

I don't mind having a spirited engine with a higher than 6k redline, but it should pull nice from 3K.
I do NOT want a car that that is an undrivable, over cammed, PITA on the street.
I may one day do an DE/AX, but that said I've owned it for ten years and I still have never wanted to do one. I drive mostly country roads, rarely get stuck in traffic and I don't go faster than 100mph. I would like to be able to go 75-85mph all day long if I go to a show. It will be my summer DD, but I only drive about 5k/per year.

The car: 914 narrow body with 205/60-15, 5 bolt 6" fuchs, brembo (alfa) calipers w/ SC size pads, vented rotors, stock sways, stock 914/901 trans w/ 911 cv's, other than that a pretty stock car.

Engine (so far): 40 webers, stock rebuilt 3.0 bottom end, 95mm 9.7cr pistons (above pic), stock big port '79 SC heads, new head studs, MSD 6al and coil, /6 conversion clutch, 1-1/2" 914 headers with a 2 into 1 freeflow muffler.

I may one day switch to PEFI, so I don't want a whole lot of overlap in the cam. I'm totally aware that PEFI doesn't add HP, that is a sum of the parts. I would either build a single TB system or gut 40 zeniths (sell the webers) for TB's. I'd really only do this for drivability and gas milage, plus the programable ignition curve.
I don't care about originality. I've also thought about twin plugging the heads and doing the extra gasket trick, but most likely will just be running the single plug.

Debating cam choice.
I also have 2.7 3 bearing towers, if that helps in my decision about my buddies new, 3 bearing 464/465 WEB cams. If it's a bad choice I'll pass and get my 4 bearing SC cams reground by Drcam.
Willing to upgrade my springs if required.

I also have new stock rod bolts should I upgrade to ARP?

My background is I owned an aircooled VW shop, I've built countless stock and performance Type 1 and 4 engines. I do most of my own work. I rebuilt a couple of stock /6 engines in the 90's, I have Wayne's book, but I don't have much more experience than that with 911's.

[KTL]

Stock SC/Carrera overlap/lobe separation is 113 deg. Your cams you're looking at have 101 deg. The 911S cams have 98 deg. Point being, is you're a lot closer to an S cam than you are stock. S engines are known to be a bit lacking in low end grunt but really come on strong when you get up in the revs. I believe the S redlined at 7300?

Timing card from Web Cam also indicates a fairly high lift spec at TDC overlap of 4.2-4.4mm. Stock cam is 1.1mm I believe? Not saying that cam won't work, as your pistons have sizeable valve reliefs in them.

As far as the rod bolts, for your intended use the factory rod bolts are suitable.

[Mark Henry]

I'm just seriously getting back into this project after life ((poop) happening...Can't believe it's almost 3 years.

I don't plan to be driving this quite as much but I still want it to be a streetable county road car. I don't do cities often and even when I do it's a mile off the freeway and then back on and I never get stuck in traffic.

My 901 (914) is being re-geared A, F, O, X, HB

Any ways I've got twin plug done to the heads, I should get just about 10 to 1CR now, plus I'm doing some more headwork, the clutch conversion done, bunch of stuff gathered and some bits to get yet. Most likely just going to stick with the 40IDA's and use 34 ventuies.

I need a set of cams, Camgrinder seems to be MIA, I'd like to be build this engine at the beginning of the summer and have it done this year...

Any thoughts on this set of RSR cams for sale and my combo?
RSR Cams

[Mark Henry]

I'm going to pass on that one, too much cam .....so what would be a good cam for me

...and who to use is the question...

[KTL]

Yep I agree the RSR cam is too narrow a powerband for you. It has a lot of duration so I suspect that profile is rather peaky.

You can't go wrong with Elgin for a cam. Call them up and let them know your specs and intended usage and i'm sure they can suggest an applicable cam that will get you what you want.

I've got a pair of decent cam housings you could have if the 4 bearing thing is still throwing you. I honestly don't know where the model year interchange begins for 3-bearing vs. 4-bearing housings. So i'm not saying my 4-bearing units will certainly fit.

[Flat6pac]

76/77 Carrera 3 was a 4 bearing and all went that way in 78 but carried the 901 part number on the outside casting for another year or more.
Bruce

[KTL]

Bruce,

Are the cam towers all interchangeable, regardless of engine year? I don't know if the earlier cylinder spacing affects cam housing fitment. Also, the earliest cars with the center-lubed cams would have some things to adjust in terms of oil supply fittings, no?

[Mark Henry]

Originally Posted by KTL

My opinion is you're really not doing those pistons justice with 6K rev limit and SC/Carrera-like cams. Those domes are ideal for getting the rpms up there. But to each his own.

I have a pair of Carrera cams (bolt-end) that are perfect to use as regrind cores if you're looking for some.

I think you are right.

Plans have changed, this is going to be more my baby and a sunny day car, plus I live in the country so open roads. And the fact that I've twin plugged my heads etc...

I just made a good deal for NIB hardwelded WEB 120/104 4 bearing cams.
I guess the next question is "Do I need to upgrade the springs and should I be thinking of ARP rod bolts?"
So much for the mild torque motor.

[KTL]

Those 120/104 cams are nice. Myself and owner of MotoDelta cstreit have them in our 3.2SS & 3.3SS carbed racecar engines. They make good mid and top end power. But on the low end they are pretty doggy. Below 4000 my engine struggles a bit.

I don't think the stiffer springs are a must for the 120/104, as it's not an extremely high lift cam. Not much more intake lift than a 964 cam. However, the 120/104 has a lot more duration which means the valves stay open longer and therein lies the opportunity for valve contact should they float.

ARP rod bolts are typically recommended for the 3.2 or 3.3 Turbo rods with the smaller odd-sized 9mm rod bolts. Stock SC 10mm rod bolts are pretty reliable. I would tend to think the ARPs for street use are overkill. For regular track use, they're "cheap" insurance.

[Mark Henry]

Originally Posted by KTL

Those 120/104 cams are nice. Myself and owner of MotoDelta cstreit have them in our 3.2SS & 3.3SS carbed racecar engines. They make good mid and top end power. But on the low end they are pretty doggy. Below 4000 my engine struggles a bit.

I don't think the stiffer springs are a must for the 120/104, as it's not an extremely high lift cam. Not much more intake lift than a 964 cam. However, the 120/104 has a lot more duration which means the valves stay open longer and therein lies the opportunity for valve contact should they float.

ARP rod bolts are typically recommended for the 3.2 or 3.3 Turbo rods with the smaller odd-sized 9mm rod bolts. Stock SC 10mm rod bolts are pretty reliable. I would tend to think the ARPs for street use are overkill. For regular track use, they're "cheap" insurance.

When you say "struggles a bit" will this cam still highway cruse at say 3200RPM?
I have no problem down shifting if I need power.
Worst case on the cam is I would have to swap it out one winter.

Thanks, seeing as I have new stock bolts already I guess I'll stick with them. So stockish springs and lighten up the valvetrain?

[KTL]

Oh yeah my car will motor along at 3200 rpm no problem. I cruise around the pits and my neighborhood at part throttle all the time. It just has no nuts. Mash the gas and it hardly wants to get out of its own way.

I think your easiest way to lighten up the valvetrain is some Ti retainers. Rebel Racing/Pelican sells them for $225 I think. Other Ti stuff like forged rockers, valves & keepers get expensive in a hurry.

If you want new springs and don't want to pay a mint for them, Eibach recently came out with their EVS line of valve springs. I believe the street/std. springs are just over $200 too. Just have to check the spring specs and make sure the cams don't introduce coil bind/clearance issues for your cam's lift specs.

[Mark Henry]

Cool that's what I thought.

Head work...well I'm an old school bug (aircooled VW) machinist and engine builder

Below is what I have done so far, I still have to do a light flycut.
The heads actually have decent guides but need new valves. I could toss in new valves, TI retainers and be done.

But....I've cheated a bit and have totally spec'ed out a set of Xtreme heads. I totally know what they use for springs, retainers, valves etc.
I wouldn't do as "xtreme" but I could easily step up to SS valves with 8mm stems, clean up the ports a bit and so forth.
Yes, it would cost a bit more, but not much, my labour is free and I have the tools.

Just wondering if it would be worth it? The 8mm stem valves alone is a greater weight reduction than just TI retainers.
Because I'm a bug/type 4 guy I don't have much faith in sodium filled valves.