911SC - Very close to buying one.......

[hopkinskid]

I apologize for anybody who read this message on rennlist.

I've been looking for 911 SCs for the past four months now, and I think I've found the ONE. Great exterior, great interior, no problems (as far as I can tell when driving), looked over it for 1 hour, drove it for 1 hour, all the updates done, etc. Just a PPI next week and that's it.

But I do have some questions, if anyone can help me out.

1) Engine was "rebuilt" at only 78k miles. Owner is 2nd owner, and is currently trying to find out why the first owner had the rebuilt done at 78k miles. Car has 116k miles now, so it has just about 40k since then. Any concerns about the rebuilt at 78k?

2) I was looking over a 1996 work order for the "rebuilt", and the following is a summary:

Remove/install engine/tran
complete valve job
replace valve guides
replace oil return tubes
replace all 24 head studs
install timing chain update (both sides)
= $2200 parts, $1300 labor; total $3500

I've heard about rebuilds costing $5k, chain tensioners for $750-$1k, stud replacements for $2.5k, valve guide replacements for major $$, etc. So what gives? Was this just a case of good timing (labor costs down since everythiing was done at the same time)? Is $3500 a little low for all the work described in the work order? Does the above work constitute a "rebuilt" engine?

3) PPI done in April 2000 (of course I'm getting one next week also:
Compression - 180 on all 6 cylinders

PPI Repairs needed: Leak in oil return tubes, flywheel seal, oil hose from engine to thermostat, diff flange seals.

Anything serious about the leaks?

4) I've checked just about everything. Anything querky or weird that I would miss, and 3 years down the line, I'd be telling myself "darn, if I had known, I would have checked that out"? Again, I've read all the posts on rennlist and pelicanparts, read Used 911 Story, talked with owners, etc. I'm ready to become a Porsche owner (been planning this moment for the past 16 years)!

Regards,
Hopkinskid

[Superman]

It does sound like you've been doing your homework. You probably know that these engines have been having exhaust-side head stud problems. Mine has that problem and I need to do the work described in the work order above. An engine with this done at 78K miles would not need a pricy rebuild. $3500 seems like a pretty good price, perhaps too good. I know you'll check it out. I'd go and talk to the guy who rebuilt the engine. I'd go see him at his shop if at all possible.

[StuttgartDavid]

Based on both the invoice details and the price, it seems pretty clear that this was a top end overhaul only, and didn't split the case for bearings or replace p/c s or rings. Which is fine. The major (maybe only!) wear point on the 3.0 engines is the valve guides. For people that know to check, the p/c s usually are within spec even after 200k. If it checks out in the PPI, just drive the damn thing and don't worry yourself to death with "what-ifs?" If you simply change the oil and adjust the valves on schedule, the engine will probably outlive you!

[RarlyL8]

The SC I purchased a few years ago had a similar history.
The motor had only 78K on it and had been rebuilt.
Reason is not so much mileage as it is time.
Time kills hoses, gaskets, fuel lines....... you get the picture.
Everything was upgraded at the time and the bill was similar to the $3500 you spoke of.
Good owners overmaintain their cars.

If you really want to find out how this car was treated talk to the guys neighbor.

[Don Wohlfarth]

The PO "probably" had a couple of broken head studs. While the motor was out he redid the guides, valve job, and it sounds like maybe the Carrera tensioners. That something you may want to check. None of this is anything to be overly concerned about.

[hopkinskid]

Superman - Thanks for the reply. The good thing about this owner is that she kept every single record/work order, so I can easily locate the mechanic who worked on this engine. A person on Rennlist suggested that the previous owner may have suffered a broken stud (downshifting problems), which may explain the rebuild down at just 78k and the replacement of 24 studs. Hopefully this engine will last another 100k.

StuttgartDavid - yup, I'll be sure to take care of this car religiously. PPI is early next week, and I hope the compression/leak-down numbers are ok. 180 compression on all 6 cylinders just last year sounds good; I hope the numbers are comparable now. Just in case, I saved up a little more for a possible tranny job in the near future.

RarlyL8 - From what the 3rd owner told me, the 2nd owner (the owner who had the car for pretty much the car's entire life) was criticized for not driving the car hard enough! Friends kept telling the 2nd owner, "it's a Porsche, drive it like one" or "damn, you have to enjoy this thing!" But the owners did take very good care of the car (maintenance, repairs, etc).

thanks again,
hopkinskid

[Jdub]

You don't mention the year of the car. For the '78, as an example, the valve springs of some of these cars were suspect. My '78 had a total topend done at 68K due to bad shift that may or may not have been exacerbated by "bad" valve springs...hard to say.

Jw

[hopkinskid]

Sorry, the car is a 1983 911 SC Targa.

Jdub: how common is it to have a "bad shift". I have read countless posts and heard numerous stories about over-revving and the damage resulting from it. I have about 4 hours total driving time with the 915 transmission, and I am far from even
being a novice, daily driver. Any tips or advice?

Hopkinskid

[Jdub]

I don't think bad shifts are that common unless you are doing the classic downshift from 5th to...oops; 2nd!

Bad shifts come from bad drivers. Most new Porsche owners tend to be pretty careful with their new cars and so shift the 915 quite carefully. However, after time and frustration with the unique synchro setup in this trans some start forcing shifts as they expect the 915 to shift like their Toyota or equiv. The nature of the 915 is you can't hurry it, thus most damage when forced comes down to synchro rings and dog teeth which can get expensive over time.

As to bad shifting, that is a quality of hard driving and inexperience/frustration with the 915. Really most drivers won't perform damaging shifts unless it is DE/trackday or they are just hard-driving on the street and are not respecting the limits of the car (or more likely themselves). So in sum I'd say you don't need to worry, but I would note on this SC if you can ease it into 1st under 10mph coming up to a Stop sign. Also, how is it into 2nd gear: any grinding? Generally a 915 will give you 100K if well treated before showing signs of needing a repair, but this is optimistic and best case. Many 915s need rebuild work earlier than the 100K mark just to ensure that more damage won't occur: damage that would make the rebuild much, much more expensive.

Jw

[StuttgartDavid]

I concur with JW on most items above, but must disagree when he estimates "100k" from a 915 before needing work. This is highly optimistic!
Well, I guess it depends on what you mean by "needing work." 2nd gear synchros are a weak point on all early Porsches, and most will be gone well before 100k. That doesn't mean the rest of the tranny is worn out - just the synchros. As long as you change the transaxle lube every so often, the gears and mainshafts last forever. My old shop advised me not to bother rebuilding my 915 for synchros, because most of their customers wear out their new synchros again in as little as 20k. That was 100k ago on my '82 SC, and I've never regretted not doing the rebuild.
The solution is to simply learn the Zen of the car, and adapt your technique to its needs. This is one of the joys of Porsche ownership Most 911 drivers who are tuned into their machine have learned how to pause for a heartbeat after moving the gear lever 85% of its travel, but before actually engaging second. This takes care of everything, and makes synchros almost irrelevant. My 1st and 2nd gear synchros are shot, yet I can shift my car perfectly, with no noise, and pretty quickly to boot. However, others can barely get it in gear at first if I loan it out. My girlfriend used to hate driving the car because it demanded so much involvement; now that she has learned the tricks to being one with the machine, she complains that other cars are uncommunicative, unresponsive and like driving "big marshmallows."
Don't worry about the 'box. If you spend $1500 to rebuild for synchros, you'll just have to do it again soon, and that will piss you off and you will curse Porsche. If you can't adapt to the tranny, you probably will hate all the other quirks that make these cars interesting, and may be better off with a newer, less demanding car.

[Jdub]

Well I agree that 100K is probably overly optimistic, but I tried to couch my statement to show best case situation for the venerable 915.

However, I will say that SDave is probably a better driver than most. For me and maybe others, if you are experiencing bad shifting due to worn synchro rings you ignore them at your risk. Why? Because the friction they cause is what spins things up to like speeds. As they wear, they are not as good at doing this, and require more "wait time" for the shift. If you override the "tiredness" of your 'box by forcing shifts (i.e. not pausing) where once they were reasonable smooth, you risk broken dog teeth and bits and pieces floating in your oil as a result before the magnet grabs them. From there it is a matter of time before something more expen$ive breaks, I'd think.

So basically you either rebuild a box and use it in its ideal state or you don't rebuild and learn to shift craftily. Certainly the clutch is irrelevant to some experienced drivers, but speaking for myself the rebuild of my 915 with fresh synchros/stops/bands has resulted in a wonderful shifting experience that tells me what this box can do.

Jw

EDIT: Got this link from the "915 Rebuild" thread and it has some neat pics on blown dogteeth and worn synchros. Just to give context, note pics three, blown dogteeth, to pic four with the typical "off-pyramid" dogteeth look. You can clearly see how the teeth are gone in three and restored in pic four. Also, note the worn nature of the ring where it is shiny. It is now undersize and therefore cannot catch as it used to when new.

http://instant-g.com/Projects/915Trans/

[rscupper]

I have 71,400 miles on this car. I got it at about 65K. The PO massaged the engine slightly at 60K. Together, the PO & I have put on about 10K miles of track use (I don't know the PO's driving skills). No trans work yet and it shifts very well.

I agree there is something unique about 915 shifting technique, but once figured (never really mastered) performs very reliably. Embarrassing, but I must tell you - I have mis-shifted a couple of times on the track from 4th to 1st! Luckily no engine damage. Those mis-shifts were smooth and perfect in every way - except the location. I'm convinced the 915 is a work horse.

[hopkinskid]

Jdub: Thanks for your message. During my first initial test drives with the 911SC, I pretty much embarrassed myself....trouble getting into 1st gear, stalling most of the time, etc, etc. I'll try easing into 1st under 10mph tomorrow in another test drive. 2nd gear was smooth...no grinding at all. But since the car has over 115k miles and there doesn't seem to be a tranny job in any of the paperwork, I'm assuming it's still original. I have a budget of $17k, but I'm going to offer around $13.5k, so at least I have some $ left over for possible fixes in the near future. Would a PPI show how much life a tranny has left? I sure hope so.

StuttgartDavid: One thing I learned about the car (or all 911 SCs I have tested): not to insult any females owners out there, but this is truly a MAN's car. I absolutely loved the level of involvement and excitement driving these cars. Can you tell what the approximate cost of changing the transaxle lube? It doesn't sound too major, but again, I've got much to learn. But again, driving these cars is quite an experience.....my brother has an M3 coupe ('99), and that thing is way too "easy" to drive and even kind of wimpy.

Rscupper: Nothing is more embarrassing than this: sitting at a red light during one of my test drives, a beautiful woman in a 944 Turbo comes up next to me..."Nice car", she says with a wave. I wave back. Green light.....I stall going into first as she speeds off.
Ouch.

[StuttgartDavid]

Hopkinskid: Changing the transaxle lube normally costs $50-100 at a shop, depending on what they use and their labor rate. The factory recommends doing this every 30k. I believe that doing this more frequently is the key to making a freshly rebuilt box stay that way, and to keeping an old, worn box alive, because both are shedding metal particles from their synchros faster than a box in the middle of its lifecycle.
You can change the fluid yourself quite easily. You need the big (17mm?) allen wrench used to change VW transaxle oil, which is about $5-10, and about 3 quarts of gear oil. Jack the car up after the tranny is good and hot (so the oil will flow) and let it drain for up to an hour, 'til absolutely nothing comes out. It really helps to use one of the little oil pumps, either hand powered or bolted onto an electric drill,that are used to change the oil in a boat, etc., because getting the new stuff in there can be a major pain.
There is some good stuff like swepco, which costs big bucks, or plain old valvoline, etc. which is under $10 for the whole job. I think what you use matters less than that you simply do the job regularly in the first place. You must use the factory recommended grade - these boxes like the thick gooey stuff that will stick the the rotating pieces, not some of the thinner new synthetic low drag stuff.
I have kept both a 901 and a 915 with badly worn synchros alive for years this way, despite lots of heavy duty autocross and timetrial use and over 150k on each box. If you learn to heel and toe (which is key to smoothly matching rpm on a downshift anyway, so as not to jerkily upset the balance of the car on the track when you let the clutch out in the lower gear) and to double clutch into 2nd (which you typically need to do to simply get the damn thing into the lower gear at higher wheel rpms anyway, so you are well up in the powerband for corner exit - often synchros will keep you out of the gear unless you double clutch if the resulting clutch engagement speed will be over 4-5000rpm) Practice on the street at every stoplight. Soon it will be second nature and you will find that synchros are a somewhat redundant comfort item, not a reliability issue. Real race cars don't even use synchros at all!