advice sought on 1978 SC engine upgrade options
 

This forum is really great! I have read it for some time and it helped me enormously to understand the 911.

I have recently acquired a 1978 euro SC 3.0 and want to make it my cool daily driver for next year.
The engine needs a rebuild and I would very much appreciate your input on the best engine upgrade options for this.
I have done as much homework as I can in order to waste as little of your time as possible, but I'm left with various scenarios.

For its intended use as a great daily driver it seems like a good idea to retain the CIS, heater blower and A/C. The car will run on good quality euro 95 RON fuel.

Furthermore, some upgrades seem obvious:
heads port matched to inlet and exhaust manifolds
SSI heat exchangers with 2 in 1 OEM muffler
Mallory coil, cd and Magnecor leads
964 cam profile
Carrera tensioners
ARP hardware
higher-spec valvetrain


Now I have worked it down to the following possibilities:

1. LN Engineering refurbishing of original cylinders 95mm with new Nikasil
plating, JE pistons CIS dome, CR 9.5:1


2. Cylinder upgrade, Nickies 95mm, JE pistons CIS dome, CR 9.5:1


3. Big bore to 3.2 with Nickies 98mm, JE pistons CIS dome, CR 9.5:1, heads camfered


4. Twin plug 3.2 with Nickies 98mm, JE pistons wedge dome, CR 10.5:1, heads camfered + machined for second plug, distributor converted to twinplug


I would love to have some advice on which option would give the most driveable, (fuel)efficient, cool running, enjoyable, powerful and sweet engine?
Now of course there is a price difference between these four options. Which option would be the best investment? Thanks!


PS: undoubtedly I failed to see other possibilities, such as going for Carrera 3.2 heads or backdate the heating etc., switch to EFI etc, please feel free to bring these to attention too.

Thanks very much!

I wouldn't look at these options as investments. The real question is how much do you want to spend?

Once you do the SSI's and set of 964 cams (or web cam 20-21, which is even a little more aggressive), the performance improvements start to get subtle unless you ditch the CIS.

Since you're starting from a '78 euro, you're starting from a good base (big port heads, decent fuel distributor, etc.). The big choice for you is the P/C - do you want to spend the extra $$$ and go for the 98mm, which will give you another 7% or so horsepower. This would be a lot more costly for you than reusing your cylinders (assuming they're Nikasil) with 9.5 JE pistons. If you have Alusil and need to replace cylinders anyway, 98's are a no-brainer.

Good luck - let us know how it goes!

Just curious. If he had decided to ditch the CIS, and go with natural aspiration, how would it have effected your comments on cam selection? Keeping in mind, "reliable daily driver". Thanks!

Thanks for your replies!

Perhaps a little more explanation is in order. At first I wanted to buy a new mid-size car but decided life's too short to drive in boring cars...
So I decided to buy and rebuild the 911 SC instead. I like the in-between look of the SC with the impact bumpers but still chrome and the ATS wheels.

So I have a good budget, it's just that I'm not sure how much I need to spend on the engine rebuild to get to the desired result, hence my post.
It's easy to spend as much as possible but I just want a great daily driver. And I'm a perfectionist so I want to be sure I picked the right configuartion, with your help...

The rest of the car will be great, brakes and suspension upped to Carrera 3.2 spec, rebuild 915 transaxle, nice new interior etc.

So, do I need twin plugging? Do I need the larger displacement? The car will be driven both in slow commuting traffic as on fast weekend trips to more desirable locations.

Again thanks for your input!

Jon, regarding the cams. I'm certainly no expert in that area; so, take what I say with a grain of salt. If you're ditching CIS in favor of carbs, you can run much hotter cams. However, hotter cams bring more power up high in the RPM range, but you'll suffer down low, which is where you want your power in a daily driver. Unless you're going for all-out, no-compromise horsepower, CIS is just fine.

In doing mine, I've opted to keep the CIS and have a set of 20-21 cams ready to go in. It's not a daily driver, but I didn't want to lose the flexibility that comes with the SC motor.

daddycool, if you haven't already done so, I'd go drive an '84 to '86 carrera and see how you like the speed. An SC with minor mods (SSI's and cam) will be as fast or a little faster than a stock carrera. If that's not enough for you, then you know you need to think about more displacement, carbs, etc.

Think EFI conversion + nice used (K27?) Turbo......;) You'll need pistons, wastegate, turbo headers instead of SSI's, and oil line plumbing...All the rest of your engine can pretty much be used with the turbo. Should get you well over 300 hp without a problem.

BUT, if you really want to stay N/A and keep it simple:
SSIs, 2 in 1 out muffler, 964 cams, standard valve springs (it sounds like it's not going to have the poop revved out of it every 10 seconds so I would try to minimize wear/pressure within the valve train by using stock springs)

Good luck! Scott

How about the SSI's and 2 in 1 out muffler, 964 cams, along with the stock '80 up P/C's. That extra point in CR was good for 25 HP, wasn't it? Would that be worth the bucks?

If you were to spend on the 80-83 P&Cs, might as well go to 98mm.

hey!
4 years ago i was in a simlar state..well kinda...anyways...

i had a mag 2.7L, i added a set of JE P&C's to take it up to 3L, with a CR of 9.81:1. I was told this is as high as u can go without twin plugging. if u go more displacment, or higher CR, twin plugging is nessecary. the car also ran with SSI's and a magnaflow two in 1 out muffle, and my fuel distributer was upgarded (flowed?) up to euro specs (yours)..... i also upped the valve springs and had a custom grind cam.. (longer lift S), believe they were called evo 2 S's...w/e....anyways...it makes really good power...though kidna high up...and it is very very loud.


now....on the other hand...there is no replacement for displacement, ( forced induction has reliablity problems) and upping to 98mm P&C's will have a nice effect, and removed the chance of poor re-finished of your current nikkies.

anyways...make sure to post a bunch of pictures. that what we like

Can you do that and keep CIS or is the swap to carbs / EFI then a neccessity?

3.2 P&C can be run with stock CIS no problem. Some machining is necessary if you use stock. If you use Henry's QSC/JE setup, for example, they will bolt right on without chamfering the heads.

Thanks, Brian!

Can someone please tell me more about "Henry's QSC/JE setup?"

Really interested since I have a 79 Euro 3.0 and like daddycool am also considering upgrading to later (e.g., 95mm or 3.2/ 98mm) pistons, while retaining stock CIS (ala Euro fuel dizzy, larger airbox, etc.). Would I have to obtain new cylinders, rings, etc., with this setup?

BTW, I already have John Dougherty''s 964 Cams, 1.75" headers, and Ben's (mb911) 2 in 2 out SS 911R style muffler.

Just search for "supertec qsc" and you'll find info on pics on his setup. Henry offers an aftermarket piston, cylinder, ring setup in multiple displacements and compression ratios - pretty much anything you could want to tailor to your needs.

Can someone tell me what difference there will be between a 2 IN,1 OUT and a 2 IN,2 OUT exhaust system?Need to replace the muffler and got some performance headers I want to install on a 79Sc.