Improving my SC's Driveability

[Nickshu]

I need some advice on how to improve the overall driveability of my 82 SC. I have had the car since 2000, but have put very few miles on it. The car has about 80,000 original miles and is in generally good shape and runs well.

I have always found that the car is hard to drive (I know it's a 30 year old 911, but I remember my other/previous 1982-era cars being easier to drive). Clutch is very heavy, shifting from 1-2 is difficult, and sometimes uncooperative going into first gear. The car does have an OEM short-shifter in place, installed by PO. Also the car seems "sluggish" to rev during acceleration.

I did adjust the throttle linkage (which had alot of slop) and this improved things alot.
I do know that the PO had rebuilt the transmission around 70-75K and replaced the clutch. I don't think the clutch cable was replaced at that time. I did drain and install Swepco oil in the transmission in 2001. Engine is original except for Carrera tensioners and pop off valve. A/C compressor has been removed.

I am thinking of doing the following to try to improve driveability:
-Pedal cluster rebuild
-Replacing shift coupling (However I have inspected and adjusted it and it appears to be in good condition)
-Replace clutch cable and helper spring (have already tried adjusting)
-Replace rear shocks - they're pretty bouncy compared to the front.
-Valve adjustment -- I know it's been over 10K and >10 years since this was done.
-Bump steer kit install -- PO lowered it to euro height (25" on the front) but never installed the kit.

I guess overall I just find that the car makes me drive in a "jerky" manner despite my best efforts to be smooth and "fluid" in braking, shifting, turning and accelerating.

Any other suggestions or input anyone can offer from experience?

[javadog]

When you checked the clutch free play, did you also check the preload and travel? In other words, a "basic" adjustment?

Do you have the records from the clutch replacement? Any chance a non-stock pressure plate was installed?

Replace the short shifter with a standard shifter. While you're at it, replace the bushings below the shifter and the one just aft of it, in the tunnel. Adjust the play in the new shifter to your liking.

Go ahead an do a full service. Valve adjustment, check and set CO, distributor service, verify all of the CIS stuff is working correctly, set the ignition timing, etc. Verify that the rest of the accelerator linkage is good and adjusted properly.

If you change the shocks, consider replacing the suspension bushings and other wear parts and doing a complete alignment, including corner balance. Bleed the brakes with new fluid.

Go from there...

JR

[Bob Kontak]

TRAND FLUID

Change fluid in trans. Even if no miles since 2001. Hot gear oil now is Kendall. This one specifically.

Pelican Parts - Product Information: KEN-LSD-7745

I just put it in mine and don't have enough driving time to comment on touted improved shifting characteristics.

CLUTCH

I have the Sachs "Power Clutch" in mine and it is no problem. Not Camry like - but no where near heavy. Others can comment on what may cause this. Bushings in the shaft the moves the TO bearing fork? Omega spring may be a good search term. Do they get tired?

LOWERED

I over lowered mine a few years back and recently brought it back to Euro spec (do have the spacers) and there is a MARKED difference in the predictability of where the car is going now.

If you put bump steer spacers in you will need an alignment. Double check the factory setting using the correct method. Not the fender lip height.

SLUGGISH

Replace injector o-rings and associated parts (see pic)
Replace plug wires - Love me some Clewitt Engineering wires
Make sure mechanical and vacuum advance functions are working properly.
Put in new cheep-o NGK copper plugs - factory gap
Check fuel pressures and CO. This is important and you can buy the tools for about 175. $125 for pressure tester and $50 for a dwell meter (if US model with an O2 sensor)
Eliminate vacuum leaks.

[Bob Kontak]

Originally Posted by javadog

Replace the short shifter with a standard shifter. While you're at it, replace the bushings below the shifter and the one just aft of it, in the tunnel. Adjust the play in the new shifter to your liking.

+1. Rear coupler may need replacement if original.

I got a small boat load of crap from Mayo (rebuilt my trans in 08) about using a short shift kit. I have the SCRS factory shifter and they were kind of ok with it but still like the factory shifter better because it does not beat the synchros as hard.

Also - SWEPCO 201 not 210. Don't ask me how I know.

[Nickshu]

Originally Posted by Bob Kontak

+1. Rear coupler may need replacement if original.

I got a small boat load of crap from Mayo (rebuilt my trans in 08) about using a short shift kit. I have the SCRS factory shifter and they were kind of ok with it but still like the factory shifter better because it does not beat the synchros as hard.

Also - SWEPCO 201 not 210. Don't ask me how I know.

Thanks for all the replies. So how to I backdate to the regular shifter? Is there a "regular shifter kit" available or do I have to buy individual parts to piece it back together? Unfortunately I don't have the original shifter as the short shift was installed by the PO.

[Bob Kontak]

The original shifters pops on on Ebay frequently. Pretty cheap. I have mine in my attic and am tempted to re-install it over the weekend. I can send a pic. There is not much to it once you separate it from the aluminum tower.

I do know the shifter shaft is a different length at the knob install point. It's longer (on my SS shaft) and the knob does not sit flush with the base like the original. The throw is way different so if you do it, prepare for the old school feel.

[bsimonson]

You can also consider installing a Seine gate shift kit for an improved shift feel.

[javadog]

Porsche made a change to the 915 shifter nearly every year but you can break them down into roughly 4 groups, not counting the one used in '72.

73-76
77-84
85-86 standard
85-86 optional

The first group and the second group are largely the same, except that the free play/preload of the shifter lever in the left/right plane can be adjusted on the second group. There are several different parts involved in this change, along with a modifcation to the housing.

The 85-86 standard shifter is similar to the previous version but the throw is reduced about 10%. The 85-86 optional shifter has a throw reduced another 10% (total of about 20% then) and is usually what is referred to as the "factory short shifter".

Any of them can be changed from one to the other with the replacement of the appropriate parts. The cheapest way to accomplish this is just by buying a complete used shifter.

Porsche also changed the lever several times, both in length and shape. Some of these can be swapped around, although you have to be carefull of the pivot hole-lower ball length in the case of either of the shorter shifter throws. Certain parts must match and some of them are hard to differentiate from one version to another.

JR

[Nickshu]

Originally Posted by Bob Kontak

The original shifters pops on on Ebay frequently. Pretty cheap. I have mine in my attic and am tempted to re-install it over the weekend. I can send a pic. There is not much to it once you separate it from the aluminum tower.

I do know the shifter shaft is a different length at the knob install point. It's longer (on my SS shaft) and the knob does not sit flush with the base like the original. The throw is way different so if you do it, prepare for the old school feel.

Yes that's how my SS is, the shift knob sits high and is not flush with the ring "base" a couple inches down the shaft. I'm going to replace my coupler and shaft bushing, then see how it drives before I decide on the SS backdate.

[E Sully]

Here is a good thread on adjusting the clutch cable. The pedal should not be heavy if it is adjusted properly. If not set correctly it would also make shifting the gears difficult.
Clutch Adjustment and Pedal Question

[GaryR]

Don't forget todays gasoline starts breaking down after just a couple weeks, how old is what is in that tank? I would drain it and put a heavily treated (Sta-bil for Ethanol or similar) 5 gallons in there if you will continue your light use..

[Dr J]

You'll have to replace every plastic bushing. You covered two main areas as you examined the shift coupler bushings and work on the pedal rebuild. If your steering wheel shakes up and down, the one on the steering column will need to be replaced. If it doesn't do that yet, give it a year or two. The bushings in the engine for accelerator linkage (one in the tranny and one in the engine bell crank). Just whenever you have access, replace any plastic bearing with bronze bushings. Pelican sells these and you won't have to revisit them again.

You may also want to check/replace your motor mounts. If you drop the engine/tranny at all, check the transmission mounts as well.

[Roby466]

I found that my SC was very jerky also after being worked on by the mechanic. I found way too much advance and too rich to compensate. Once the timing is set properly, set the mixture at idle by hooking up a voltmeter on your o2 sensor and measuring between 0.45 and 0.7 volts. It will fluctuate a fair bit but within these it should give you proper mixture without the control system hooked up and then try hooking up the sensor back in and see if it works good. If your system does not work, adjust it a bit on the high side (close to 0.8 - 0.9 volts) and leave it unplugged. When I did this, the car started driving like a modern car and very smooth. For the rest, exactly what was said above for clutch and get new fuel in there and fuel treatment to clean the system. Sorry, before doing the mixture, your WUR pressures need to be within specs. Bentley manual has good specs.

[mpetry]

If the OP reported that "the clutch is very heavy" - do you have an omega spring ? these do break. A working omega spring makes a HUGE difference in clutch effort and freeplay adjustment.

[Bob Kontak]

Originally Posted by Nickshu

I'm going to replace my coupler and shaft bushing, then see how it drives before I decide on the SS backdate.

Here is some info on couplers.

Question on shift coupler

On the SS kit I do not hear a lot of "OMG YOU ARE GOING TO WEAR YOUR SYNCHROS OUT IN NO TIME" There must be some cost related to the faster speed at which the synchros engage but I don't know what that is and it must not be monumental.

[javadog]

Porsche used what is called a balk ring syncromesh. The faster you make the shift, the more wear you put on the parts. There is a slight pause that is beneficial to a shift in one of these cars. It's described in an article in the back of this month's excellence, so I won't repeat it all here. You can wear out the synchros in 30-40,000 miles, or run the transmission for well over 100,000 miles, depending on how you shift it. Most people that use a short shifter shift too fast. A short shifter also reduces the feedback you get when you make a shift, so even more finesse is required.

JR