81 5-speed trans question
 

I'm looking at buying a 1981 928s that's a 5speed. The owner says that shifting a bit clunky, due to the fact that the trans is in the back instead of off the engine. I'm familiar iwth engines and how htey work and all, i've never seen a car that had that sort of set-up, but i'm not to familiar with this specific car. He said hte linkage was recently replaced along iwth the clutch. I'm trying to see if it's an issue with the trans, or just how it is. the 5-speed car's i've owned in the past have all shifted very smoothly. I haven't driven it myself, but i'm going to look at it tomorrow. If you guys could provide some feedback it would be appricated. THanks.

Could possibly be the syncros, the are weak in the pre-85 928s. Replacement requires removing tranny and disassembly, shops charge $1000-1500 for this.

So I should expect it to shift similar to a 5speed 350z or 5speed maxima?

Nope, Porsche isn't known for smooth shifters until much more recent models. Typical "feel" on a good working early transmission is "notchy" an increase in resistance, a bit of delay, and its in gear. If the syncros are good you should be able to maybe a bit slower than some car, but still shift into any gear except 1st and reverse which I don't think have syncros. If you can't down shift into second or third with no grind etc., it needs a rebuild (assuming the clutch and linkage were done properly). The early clutch sometimes gets two trips to the shop, expensive and worse depending on if the intermediate plate is still good (if the clutch won't stay adjusted, you need a new one for $1k).

I bought a 83 4 months ago with bit of noise that seemed related to the clutch. New clutch, new torque tube, now waiting on new transmission for about $6k total on that part of the car, $2k of that is labor, $4k parts.

Don't buy a 928 without a professional detailed inspection by somebody that knows the 928 well. The cheaper the car is the more inspecting needs to be done. Most people can't afford a cheap Porsche. ;)

A fresh 5 spd should feel solid, not sloppy!

It could be something as simple as a shifter lever bushing to bad syncros, like Rixter described!

Early boxes have a weak syncrnizer design. Additionally, if the clutch isn't adjusted properly, you can put more strain on the syncros. Most 928s of this vintage have bad syncros or have had gearbox work.

Thanks for the advise. There is a local 928 specialist that I've been in contact with and he plans to help me out.

One thing that wasn't touched on is the clutch hydraulics.

My PO had assumed the clutch was gone, first- second- and third gear sycros were shot, etc......

Turns out the original hydraulic (actually brake fluid-the 928 uses brake fluid for clutch hydraulic fluid) fluid was still in the clutch hyd system. I bled the clutch (lots of air and very black fluid came out). This helped for a little while, but eventually it went back to its very bad behavour.

Remedy: REPLACED ALL CLUTCH HYDRAULIC COMPONENTS (the "blue hose", clutch master cylinder, rubber clutch hose, and clutch slave cylinder), new super blue racing brake fluid. This would also be a good time to completely flush, refill, and re-bleed the braking system as well.

Yes, as stated above, Porsche trannys are "notchy" shifting items.

Just make sure your hydraulics are up to the task as well, and don't just replace one piece, replace them all. You'll thank me for it.

There are numerous posts about shift linkage and its woes, clutch adjustment (particularly on the early dual disc units), and the early trannies are prone to early syncro failure, but not much about hydraulics......

Hopefully this will add to your knowledge base.

regards---rhjames



http://forums.pelicanparts.com/uploa...1172380313.jpg

Wonder if this'll fit in a 928.......665 cu inches, 1150 hp, 975 ftlbs torque.

Finding something that fits isn't as hard as finding something thats fitting. Interesting bit on the R list comparing the GT and S4 (with a 5 spd), hp is only 10 or 20 different, torque curve is shifted up a bit on the GT. What the GT guys say is that it wants to be driven hard more than the other models. Sounds like a quality worth pursuing to me.

Something else I noticed, I haven't seen anybody sell a car with a hybrid motor in it, and quite a few forum people have them.

It'll fit, just like the Renegade/Chebbie thing.

One big difference. Hords of hp and torque from a very lightweight package.

As for the hybrid parts, they are there for the asking. It just takes $$$ (about 5K for the parts, including short block).

regards---rhjameshttp://forums.pelicanparts.com/uploa...1172734967.jpg

With a 928 a thousand here, a thousand there, pretty soon it adds up to real money. Feb was a $3k month for me, Jan was a $5k month, Mar looks like a pass, but April looks like record setting time. So $5k for easy to get, vs $2500 that takes some shopping is worth some exploring. I've barely missed buying two complete running Euro S cars at $3k each, so it makes me reluctant to pay over $3k for just the top end parts of the motor in used as pulled condition.

I wouldnt really bother putting that engine in a 928 even if it did fit under the bonnet. That thing is like $35k and the 928 gearbox wont be able to handle the hp and if you could adjust it to handle the power it would be costly.

But imagine putting that engine in an ultima gtr then twin turboing it. That would be the fastest street car in the world

As I get older (now 45), mods like putting Chevy engines and Trany's in Jags and MB don't appeal to me anymore! BTDT, and glade I did when I was younger! Now all I want to do is get in, drive and Enjoy.

It was mostly a joke, putting a big block Dodge in a 928.

As I am an old Mopar fan (I've owned a dozen or so in the past thirty years), I just thought I'd have a fun putting that picture on......

It is a great product, though not something that's very streetable (the 665 is a 16:1 compression ratio motor).

Menace does point out that the cost (actually $30K for the 665) is pricey, but you'd spend that much "properly" prepping a 928 motor to handle the miriad of turbo and supercharger kits that are now on the market, blower kit included.

One could start out with the 'tamer' 605 ci motor (10:1 CR and only 750 hp), and then twin turbo it for a much easier on the wallet package.

Will the 928's trans and rear handle this much? I suspect it will. Porsche "over builds" everything including the drivetrains. Ask Herr-Kuhn how long he thinks his drive train is going to last behind his 800hp twin hairdryer 32V motor? (He'll tell you he expects it to be "no problem".) The Indy 605 starts at 750 hp (near Herr-Kuhn's ending point) and with twin turbo's you might go as high as 1000 hp.

Of course, if anyone wanted to argue the merits of putting a small block Chebbie (renegade kit) in a 928, what's to stop a guy from dumping any other US made muscle car iron in one? While at a DE event last month, I saw a Carrera with a Chebbie in the back end, to which I asked, "Why?" He replied that it costs more to build the Porsche motor, as opposed to doing the Chebbie swap.

May be so, but my hybrid build is going to be expensive as well...... And I wouldn't be doing that if my 4.5 wasn't broke.

regards---rhjames

I'm sure they spec'd it out, but Porsche didn't build the trany, MB did :)

RH, are you saying "your" 4.5 is broken?

Well darn, and I thought MB only did the slush boxes.......

Yeah, the 4.5 has bad hole, I suspect a broke piston ring or http://www.pelicanparts.com/support/smileys/puke.gifcracked piston. Who knows, maybe it's a bad headgasket, but if it is, it's blowing a lot air in to the crankcase.....

Anyway, it's coming out as soon as I can get the parts together for a new one.

regards---rhjameshttp://www.pelicanparts.com/support/smileys/pc2.gif

With the slushbox if you put in the AMG parts what I have heard is that its good for a LOT, like 1000 hp. What protects it is the traction even a 315 tire gets on a 928.

700 hp is what I hear the 5 spd is good for, but 3rd gear does seem to have a lower limit.

Either one a sticky tire hooks up and you break axles.

I have heard the same thing!

I have a 85 500 SEC with a trans that look almost like the one in my S4. I bought a filter kit from pelican once for the S4 trany and it listed more MB cars that it would fit than Porsche's :)

BTW RH, I might know of someone in Houston that has a 4.5/4.7 that he may want to unload. It would be cheaper than building one and get you running down the road sooner as well.

T-Max---thanks for the heads up on the early motors.....send me a PM about them, if you can?

I had just located a nearly complete 5.0/euro 16V hybrid in parts, but just didn't have the cash to get it done now......A month and a half off work with a cracked leg will do that to ya.

Maybe sometime this summer......

It's still driveable, but the intake fills with oil and it looks like a mosquito truck if you stand on it hard (ON SECOND THOUGHT, more like Bond in Goldfinger!!!!). Lots of blowby, and like I said, #8 is down about 25 psi from the rest.

Will keep the 4.7L in mind, but really want to go the hybrid route eventually.


(And now that I'm thinking about it.....)

Why hasn't anyone fab'd up a sheetmetal intake to put K-Jet on a 32V motor? These 928 intakes are basically tunnel ram units, so it seems to me that folks in my position should be able to use a 32V motor in an early 928 without the hassle of wiring harness swaps and electronic injection headaches (2 computers----?)

I know there's knock sensors and such on the later ones, but damn, if you're going to modify one anyway, where are the fabricators? The inventors? Hot rodders?

Threshie had Mark Anderson running a carbon fiber unit on his race 928, but $6 G's for a CF unit is way beyond what I was thinking about. More like something along the lines of a ProStock sheetmetal tunnel ram/cross ram unit, one that had bungs to plug in the injectors just above the intake ports, and would incorporate the throttle body and fuel distributor in their original positions.

Surely it can't be that difficult?

Thoughts?

regards---rhjameshttp://www.pelicanparts.com/support/smileys/pc2.gif

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I will give him a call today and see if he still has one.

Well, if I was to do a 5.0 liter in an early 928, I would do a 5.0 complete, with intake and all.

Either rewire the car to use the 90 or up fuse panel and harnesses or I would do a Motronic unit to handle the fire and gas. If a person would do a nice clean factory looking job, the car would at least retain it’s value.

JM .928 cents worth!