Build me an engine...

[Jeff Higgins]

That's a solid, proven combination, Scott. I assume you stuck with the CIS, hence the 964 cams.

Going to carbs, MFI, or modern EFI really opens up the selection of camshafts. CIS limits cam timing in that it cannot tolerate any reversion into the airbox (also known as the plenum chamber). Any reversion confuses the MAF sensor. As a result, they need pretty mild cam timing. The 964's or Webcam 20/21's are the accepted "hot rod" cams for CIS, but they are very mild compared to what we can run with an induction change.

Since the OP has 46mm PMO's already, he can go with much more aggressive cam timing. The afore mentioned GE or DC 60's are about where we start talking about suitable 3.0 liter cams that are no longer constrained by CIS.

[red-beard]

Originally Posted by Jeff Higgins

Yeah, this would be better asked on the tech forum. But, since you asked...

I'll chime in against the 3.6 conversion for a couple of reasons. Number one, the torque of the 3.6 is a 915 killer. I've seen far too many 915's eaten up by 3.6's. Number two, the conversion is not as cheaply accomplished as some would think. Lots of things need to be altered or replaced altogether. There will be some clearance machine work required on the 915 bell housing, all of the engine tin is different, the wiring harness is completely different, and on and on. "The devil is in the details".

It would be far cheaper to to rebuild your current 3.0 into something with a bit more power, but power that is more "915 friendly". Go with 98mm P&C's and appropriate cams, like GE or DC 60's (and proper springs), maybe even bump the compression up to 10.5:1 and twin plug it. That would make for a very entertaining motor at about half the cost of a 3.6 conversion.

My own motor is much like that. I kept it at 3.0 liters, though. I'm running JE 10.5:1 pistons, Dougherty GT2-102 cams, and reworked MFI to run with that motor. Exhaust is SSI's and a Dansk RSR muffler. Ignition is Electromotive crank fire, twin plug. This combination made just under 220 hp and 215 ft lbs on a chassis dyno. My 2,200 pound '72 hot rod is a very fun car with this motor in it. Something similar to it would really wake up your SC, and you already have almost all of it already.

I took my 914/6 with a tired engine that was already upgraded to 2.2l. I had originally planned a high compression 2.4 by changing the crank and rods (from Wayne, no less!). When it went into the shop, the P&Cs were too far gone. I found some RS spec 2.7 Nikasils, added in S cams, changed the webbers out to a set with more flow and ported the heads. We estimated 210hp. Anything more and the 901 would have been destroyed. It maxed out at 136, gearing/rev limited. In a 2000 lb car, 210 was fine!

To the OP, you might consider some Cams and a 3.2 displacement change and a Megasquirt system. If I hadn't sold my /6, I was going that path. Along with air conditioning...

[KFC911]

Mebbe whatcha need is a Moosetang ?

[Jeff Higgins]

Originally Posted by red-beard

I took my 914/6 with a tired engine that was already upgraded to 2.2l. I had originally planned a high compression 2.4 by changing the crank and rods (from Wayne, no less!). When it went into the shop, the P&Cs were too far gone. I found some RS spec 2.7 Nikasils, added in S cams, changed the webbers out to a set with more flow and ported the heads. We estimated 210hp. Anything more and the 901 would have been destroyed. It maxed out at 136, gearing/rev limited. In a 2000 lb car, 210 was fine!

To the OP, you might consider some Cams and a 3.2 displacement change and a Megasquirt system. If I hadn't sold my /6, I was going that path. Along with air conditioning...

Yes, we have to understand the limitations inherent in the other pieces of the puzzle. You really were right at the limit of the 901. Not the horsepower, but the torque. I bet that thing was a lot of fun.

[red-beard]

Originally Posted by Jeff Higgins

Yes, we have to understand the limitations inherent in the other pieces of the puzzle. You really were right at the limit of the 901. Not the horsepower, but the torque. I bet that thing was a lot of fun.

It was! Some guy is still having fun with it in Germany!

[Jeff Higgins]

By way of contrast, a guy I used to see at the track all the time dropped a small block Chev into his 914 GT replica. One would think that would be "more fun". Only if you like fixing schitt all the time. Constantly breaking transmissions, over heating, twisted the tub enough to crack it, and on and on. Totally out of balance, out of sync. There is a synergistic "sweet spot" that cars like yours hit, that we can't really put our finger on.

The OP would be wise to keep this in mind. More isn't always better. SC's are really happy cars with hooped-up 3.0's or 3.2's. Anything more starts to tilt the scales towards too much money and work for the additional "reward".

[GH85Carrera]

Best bang for the buck, sell the SC and get a 964 or 993 if you want to stay with air cooled. A 996 is a great bargain. Newer cars have lots more power, working AC and other nice things like ABS more.

You can spend many 10s of thousands and still have a car slower than a 993.

[speeder]

Originally Posted by GH85Carrera

Best bang for the buck, sell the SC and get a 964 or 993 if you want to stay with air cooled. A 996 is a great bargain. Newer cars have lots more power, working AC and other nice things like ABS more.

You can spend many 10s of thousands and still have a car slower than a 993.

I was thinking the same thing and was going to post it. If a used 3.6 engine is that expensive, just sell the SC for the crazy current price, throw another $20k at the problem and buy a good 964 or 993. Or sell it and buy a nice 996 turbo for a lot less, put a few thousand, (very few), into it and have a serious rocket. We're talking *widow maker* power.

Spending big $$ to rebuild and massage a 3.0 doesn't make sense. You won't get more than 250hp out of it. A lightly breathed-on 996tt is 500hp easy.

[Geronimo]

There is a champ that the SC has, I love the way the 3L revs with little effort. I love the old classic feel of the car as well as the older look.

A 50-60K 964 or a 60-70K 993 is just out of my range. I bought my SC last year so I am at the top of the bell curve, and prices on the impact cars seems to have stabilized or ever cooled, besides I do love the car, its like a great song that you just want more of ya know.

I think moving toward what Jeff has suggested in the future would be the smart bet along with some TRE bumpers and light seats, getting me under 2300lbs.

I was planning on searching for a Cobra kit in a few years or so anyway to get my cheap hair on fire fix. So keeping the Porsche more inline with where it is now might make the most sense, and maybe learn to appreciate what I have a bit more

[javadog]

15 grand? That’s not enough budget. I would spend more than that on the stock rebuild, which leaves you no money for pistons, cams, headwork, etc.

[Geronimo]

Yea, that's kinda what I figured. These engines are crazy expensive for what you get.

[javadog]

You have two choices. Spend a lot more money than you expect, or change cars. It has never been cost-effective to make substantial horsepower gains on the air cooled engines. Back in the day, you did the math and then sold your car and bought a turbo. Now that turbo prices are beyond stupid, you look at other options.

If I were you, I’d strongly considered selling your car and taking that money, plus the money you would invest in the engine and gearbox rebuilds and putting it towards a 996 turbo.

Speaking of the gearbox rebuild, if your gearbox is in bad shape, a proper rebuild of that is going to scare you to death. You can easily spend four or five grand on a stock rebuild and add several thousand more for wholesale gearing changes.

Of course, you can do what a lot of people do and do a partial rebuild and never be happy with the gearbox in the entire time you own the car. That’s up to you.

[Jeff Higgins]

Originally Posted by javadog

15 grand? That’s not enough budget. I would spend more than that on the stock rebuild, which leaves you no money for pistons, cams, headwork, etc.

Are you kidding me? Starting with what he has, that motor can be built for maybe $5,000 to $8,000, tops. Unless you are talking about having someone else do it for you.

[javadog]

Originally Posted by Jeff Higgins

Are you kidding me? Starting with what he has, that motor can be built for maybe $5,000 to $8,000, tops. Unless you are talking about having someone else do it for you.

No, not kidding.

Your standards and mine might be a little different. I’m not going to go to the trouble of rebuilding a 911 engine without rebuilding the entire cotton-picking thing. I’m probably going to use a new set of pistons and cylinders, my choice would be Mahle, I’m not a fan of JE pistons, at all. There’s five grand, right there.

I’m also assuming that he would have someone else rebuild the motor. If he’s asking questions as to what components to use, I can safely assume he’s not capable of a proper rebuild of a 911 engine. Nothing personal against him, but it does take tools and skills that the average 911 owner does not have.

Then again, let’s not forget he’s got a gearbox that needs rebuilding. There’s no way I would rebuild a gearbox and an engine and then put a used clutch back in it. While I’m there, I probably won’t use stock clutch and flywheel components, as there are many games to be had in that area. More money.

One last point I will make, I’m not a fan of his muffler, so I would probably try to track down a Monty twin pipe sport muffler. I also don’t think the 46mm carbs are a good choice. They are far too large for the engine he has now, and two large for much of anything other than a pretty radical, large displacement motor.

[CalPersFatCat]

Originally Posted by speeder

This question should really be on the tech forum, half the people here haven't even owned a 911 in this life.

I don't like you Speeder (because I'm a brainwashed, low IQ, MAGA disciple who relies on Rush and Shapiro to shape my entire world outlook for me), but I concede that you make a lot of great points and have a great sense of humor. So my close mindedness mandates that I dislike you.

But, I have owned five 911's and 2 914's and completely agree with you about the 3.6 being the most direct route between two destinations.

I have a 3.8 that the experts say is prone to piston wall scoring. I only have 28k miles on my car but if and when this motor lets go, I will bump up to 4.0 or 4.1.

I don't care about originality or retaining value or any other purist rationalization. I'm going to die (maybe today, maybe 20 years from now) and I don't care how much the car sells for after I kick the bucket. My wife has zero interest in owning a 911 after I die and she will simply sell the car, collect the money and blow it on shoes. That is a Fact.

Very few of these cars are actually "special." They are to be consumed, not conserved.

Every person in this car hobby should do whatever they want to their car. This is why Magnus Walker is the envy of so many. The guy simply gives no credence to what anyone else thinks. More power to him and anyone like him.

DL

[Zeke]

No one mentioned a turbo. Ask Sammyg2. I think you can hook on up to a CIS with few problems. How much could a decent CIS cost?

[javadog]

They used to make turbo kits for the SC, back in the 80's. They ran okay, nothing to write home about. I knew a guy that had one.

They were quite different than the turbo installations on the factory turbos. Lots of little differences that the factory did, for a reason, that you didn't get in the aftermarket kits.

You can probably find a complete CIS system easily enough, but whether or not all the components would work properly... I'd wager that's pretty unlikely. By the point in time that someone yanks a CIS system, it's because it had running problems. Some of the parts are hard to find and most of the parts are not interchangeable, if you want the engine to run right, which is why a lot of them don't run well. People replace components with parts from another year or market and those mismatches often cause all sorts of running problems. Porsche changed something on the 911 CIS about every year. The system they used on the 82 SC is not one I'd probably choose for a turbo installation.

[speeder]

Originally Posted by CalPersFatCat

I don't like you Speeder (because I'm a brainwashed, low IQ, MAGA disciple who relies on Rush and Shapiro to shape my entire world outlook for me), but I concede that you make a lot of great points and have a great sense of humor. So my close mindedness mandates that I dislike you.

DL

I totally understand, it's all good.

I know a lot of smart guys here who don't visit PARF, ever, because they don't want to dislike their fellow Porsche enthusiasts with whom they get along just fine on the main/tech board.

I'm not that smart. But at least I can say that I don't dislike anyone for having different views than me, it's more about the delivery and the underlying motivations that sometimes shine through. I've never not liked you.

[pwd72s]

Originally Posted by KC911

Mebbe whatcha need is a Moosetang ?

Depends on whether or not you want a decent driver over being "inner circle" with an air cooled 911.

My choice was good for me...might not be good for somebody else.

[speeder]

Originally Posted by javadog

No, not kidding.

Your standards and mine might be a little different. I’m not going to go to the trouble of rebuilding a 911 engine without rebuilding the entire cotton-picking thing. I’m probably going to use a new set of pistons and cylinders, my choice would be Mahle, I’m not a fan of JE pistons, at all. There’s five grand, right there.

I’m also assuming that he would have someone else rebuild the motor. If he’s asking questions as to what components to use, I can safely assume he’s not capable of a proper rebuild of a 911 engine. Nothing personal against him, but it does take tools and skills that the average 911 owner does not have.

Then again, let’s not forget he’s got a gearbox that needs rebuilding. There’s no way I would rebuild a gearbox and an engine and then put a used clutch back in it. While I’m there, I probably won’t use stock clutch and flywheel components, as there are many games to be had in that area. More money.

One last point I will make, I’m not a fan of his muffler, so I would probably try to track down a Monty twin pipe sport muffler. I also don’t think the 46mm carbs are a good choice. They are far too large for the engine he has now, and two large for much of anything other than a pretty radical, large displacement motor.

When I rebuilt my 1982 3.0 SC motor back in 2002, it was 100% DIY w the exception of machine work on heads. I had some unfair advantages w my friend and neighbor Tyson Schmidt helping w all of the tough parts, (he's one of the best air-cooled techs in the USA), I also had an uncanny ability to find deals on parts and components in those days.

We reused the P/Cs and re-ringed the Alusils, (which showed zero wear @ 120k miles), many said that they wold not seal. They were wrong. There was some break-in technique and special prep involved but the car sealed better than new.

I went absolutely bananas replacing any part that even might fail on the CIS and everywhere else under the hood and I don't think I spent $5k including a very expensive, (and high quality), valve job from Competition Engineering.

Those were the days...sigh.

Typical "while you were in there" story: