'79 930 - Finally Running Great!
 

Hi everyone. In reading a lot of the threads here, I was in the same position as a lot of you guys with a 930 not running well. I purchased a '79 930 almost a year ago from one of the popular auction sites. When I got it, it had some tuning and electrical issues and a bunch of oil leaks. It has taken a while to sort everything but my shop was able to get it running 100%. It would have been a much quicker process but in the midst of doing some shakedown testing, I broke a rocker arm and bent a couple valves so it was down for a few months and the second time the engine was removed. Anyway I got it back early January and was finally able to stretch its long legs in 2nd and 3rd gear (quick video below). Fearful of revving too high (from the broken rocker arm experience), I am keeping the RPMs under 6,000 if doing a (rare) WOT pull. Also I'm definitely granny shifting as I want to keep the clutch happy.

This isn't the fastest car in the world (like it was 45 years ago lol) but still is a blast and takes your breath away when full boost kicks in at 4,000 RPM. It has Brian's headers and modular Hoonigan muffler with a catalyst added + a K27-7006 seeing about about 1 bar of boost on the gauge.

Now that I'm comfortable with the reliability, looking forward to taking some longer drives.

Cheers.

https://www.youtube.com/watch?v=1dZgRh-StHQ

Cool, enjoy it and don't break it.
They are a piece of motoring history, and a work of art.
Alan

video looks and sounds great..
how do you like those Rarly8 headers? i am itching to get those...

Broken rocker arms and bent valves? Ughhh...must have been messing with your cam chain tensioners and kinda-sorta screwed up the valve timing. I'll admit, ive been there many many (did I say many) moons ago on my first 911. Luckily for me just one exhaust valve took the hit and if my aging brain cells recall it was about a $75 sodium filled piece.

Yes agreed. But as you know (looking at your sig), they are a blast to drive hard so I guess sometimes we will break some things. Just hope nothing catastrophic.

Thanks. The RarelyL8 headers are paired with the Hoonigan modular catless muffler. When I first got it, it was crazy loud and really hollow sounding while both cruising and also in the upper RPMs. But I neutered the sound by putting a catalytic converter on it and that really chilled it out but I'm sure my neighbors are a lot happier lol. Because the Hoonigan is modular, the catalytic converter is easily removable if I want to go back to having that amazing (and loud) sound.

In this case, I was doing some higher RPM WOT testing. I took it up to near 7K RPMs in second gear and when I pushed in the clutch to shift, the car backfired and lost power. My distributor cap actually popped off and so I was hoping it would be fixed by just snapping it back on...but no luck. I realize that it could have been a freak thing as the engine was designed to rev that high. But even being R&R'd about 15 years ago (receipts from prior owner), it's still a 45-year old engine and probably shouldn't be pushed to the limit all that often.

Your Vid showed a nice car powering up like they should. But if you are going to run it near the limits regularly you might need to expect stuff to fail. 1 bar is a decent amount of boost. At that point timing, fuel etc all become critical. 7k is pushing it without some more internal mods.
For a road car, do you need to stress it that hard?
I don't race mine at 1 bar all the time. Yes it will go quicker. But I don't want to be dealing with a bunch of broken bits either. I don't push it to 7k either. Max torque is around 5600, so I gear everything around that. I prefer the quiet life of putting it back in the shed in 1 piece.
Not sure you are gaining much by going into the high rev zone. Pull another gear and sit back and let the torque and those long gears do the job.
Alan

I have BB single outlet exhaust so i am guessing with Rarly8 would work ok.... just worried about those stock header bolts removal :(

Do you have an AFR?
If not, it would be a very strong recommendation to fit one - esp if you run 1 bar and high rpm.
plenty of stories of damaged engines on here. I have come to the conclusion these are tough engines. But stray outside the limits and problems will find you.
Alan

Do you have an AFR?
If not, it would be a very strong recommendation to fit one - esp if you run 1 bar and high rpm.
plenty of stories of damaged engines on here. I have come to the conclusion these are tough engines. But stray outside the limits and problems will find you.
Alan

Good points. I don't ever plan to take it much past 6k rpm again since it's just a road car and not racing it. And the engine has already been out twice in my 11 months of ownership - once to address the myriad of oil leaks and then to address the broken rocker arm/bent valves. So I'm certainly not looking for a third.

I don't have any AFR data yet, but I am bringing it back to my shop at some point soon to address a few remaining items (minor electrical and suspension). My shop has a nice mustang dyno so we can check the vitals including AFRs.

What a transformation—sounds like you've really been through it to get that '79 930 running perfectly! The fact that it’s back to full health after the rocker arm issue and some serious tuning is impressive. It’s great to hear you’re getting those pulls in 2nd and 3rd gear now—there's nothing quite like that feeling when the boost kicks in at 4,000 RPM. Definitely a breath-stealing experience.
A Few Thoughts on the Build:

K27-7006 Turbo with SC cams and RarelyL8 headers + Hoonigan muffler—this is an amazing setup for a street-oriented 930. The turbo should spool pretty quickly with those mods, and the sound of that exhaust is probably insane. That low-end torque must feel like a freight train when the boost hits, and the SC cams give it a nice balance of top-end pull too.

Clutch and Granny Shifting: I totally get why you’re taking it easy on the clutch for now—it's a good strategy while you're building confidence. The 930's clutch can be a bear, and it's always smart to not rush things after major engine work. Once you get used to the new engine setup and everything is fully bedded in, you might feel more comfortable giving it a bit more of a spirited shift. But for now, better safe than sorry.

Boost at 4,000 RPM: That’s where the magic happens. You’re already getting solid boost by then, so it must feel like the car really comes alive. The low-end punch combined with the turbo spool just creates such a great driving experience. Keeping your pulls under 6k RPM right now is a good plan—let things settle in nicely.

It looks like the shop has done a nice job setting your car up, and would undoubtedly been setting AFRs.
Just that things can get out of whack for a number of reasons. You don't want your AFRs straying lean when running high boost and rpms. They tend to lean out at the top end - depending on the health of your fuel system. Also they can get pig rich - which you don't need from a performance aspect or engine wear. So it is very useful to have a permanent AFR set up. You can do your own tuning at that point too.
Alan