ToManyProjects
ToManyProjects Reader
10/20/23 5:54 p.m.

I've never owned a 'vette, nor have I spent much time driving one. Tell me what I need to know about the cars.

I'm not needing another project, but a close friend may be offering me his '93 40th anniversary edition. 1 owner, 6 speed manual with under 40K miles. It's never been parked outside, but also hasn't been driven in at least 10 years.

What kind of issues would I be looking at, besides the obvious stuff for any car that hasn't been driven in a decade?

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
10/20/23 6:08 p.m.

Clean and secure grounds

?

Profit

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
10/20/23 7:49 p.m.

The 6-speed is a corvette-only ZF unit only used for a couple years, and parts don't exist anymore.  Conversions are nearly impossible since the tailhousing is basically a stressed frame member.

So, yeah... flip for profit before it starts grinding 2nd and 5th.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
10/20/23 7:52 p.m.

.... Or, park it for another 10 years and take it to a Corvette show and wait for someone with more money than sense and sell it for a bigger profit.

Cousin_Eddie (Forum Supporter)
Cousin_Eddie (Forum Supporter) SuperDork
10/20/23 8:17 p.m.

Insert obligatory water pump / optispark comment.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
10/21/23 4:32 a.m.

In reply to Curtis73 (Forum Supporter) :

There's got to be a way.  Mazda also uses that setup in the FD RX-7, RX-8, and Miatas, and people have figured out how to do trans swaps.

 

The bigger issue in my mind is that the shifter boot is not only part of the transmission, it's part of the floor. 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
10/21/23 12:19 p.m.

In reply to Pete. (l33t FS) :

According to the intarwebs, the only things common to the corvette ZF are the bearings and a couple of the gears.  The rest seems to be proprietary stuff made to adapt the ZF into the Y-body.  A deeper search might turn up something, but it looks like the going rate is $3500 in parts to rebuild a ZF if it needs synchros... and if you can find the parts.

I should also add that the ZF is not as apocalyptically bad as one might think, in fact in many ways it's stronger than the T56, it's just that getting parts if it does fail is pretty awful.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
10/21/23 12:40 p.m.

In reply to Curtis73 (Forum Supporter) :

I meant in terms of swapping another trans into the shell.

The ZF is really weird! The shift tower is sealed to the shift boot and as far as I can tell the shift boot is part of the floor.  I had to do a clutch in one last summer and decided to stick a long length of hose on the shifter to guide it through the boot so as to not risk tearing it.

 

I do think it shifts a heck of a lot better than any T56.

buzzboy
buzzboy UltraDork
10/21/23 12:50 p.m.

Looks like people are putting other transmissions in them. A kit even exists to mount a T56 to the "C Beam."

Anything shifts better than a T56...

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
10/21/23 3:03 p.m.
Pete. (l33t FS) said:

In reply to Curtis73 (Forum Supporter) :

I meant in terms of swapping another trans into the shell.

Plenty.... all of them costing about $3500 and requiring pretty intense machining/fab skills.  GM kept it close to the hip because "corvette."  They maintained proprietary rights to parts and then dropped them like a hot potato.  Last time I looked (circa 2000) there were two individuals who found some ZF parts to distribute to people for the cost of a solid gold Rolex.

The ZF is a stressed member of the frame.  There is no trans mount or crossmember in those C4s. 

Swapping a ZF to something else in a C4 is probably slightly easier than converting a Lambo to front-engine... unless the aftermarket has really stepped up it's game.  Again... a game which I have been out of for a while.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
10/21/23 3:12 p.m.

I should also add that I'm not pooing the idea of the OP buying a 40th anniversary vette.  I think it's a great investment, and the ZF is a fine transmission, just a bit of warning.

I give the same advice for buying a E38 750i.  The catalysts in those are perfectly fine pieces and not prone to problems, but they are proprietary, and $1400 each to buy.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
10/21/23 3:29 p.m.

In reply to Curtis73 (Forum Supporter) :

It is the same setup that Mazda calls a "power plant frame".  There is no trans mount or front diff mount in an FD, RX-8, or at least three generations of Miata (and probably the ND, too), they are mutually supporting with a truss that has no contact with the chassis.  People swap all sorts of things into those all the time.

dj06482 (Forum Supporter)
dj06482 (Forum Supporter) GRM+ Memberand UberDork
10/22/23 8:32 p.m.

My parents have a '94 LT1 / ZF 6speed.  It's a fun car, consumables like brakes are cheap (tires not so much). And insurance was about 1/2 of their '02 Mustang GT when both were worth a comparable amount of money.  The gearing is really high (even with the 3.08 performance rear end), but the motor has a ton of torque.  Theirs has required very minimal work over the 20 years they've owned it.

What are you going for, a fun cruiser, track/auto-x car, etc?

EDT (Forum Supporter)
EDT (Forum Supporter) Reader
10/22/23 9:22 p.m.

I had a '92 ZR-1 for a bit that was also very low mileage, kept indoors, but sat for many years before I acquired it. It needed new fuel pumps and injectors, but I believe the latter would be a ZR-1 only issue. Everything was beginning to get brittle both inside the car and rubber parts in the engine bay, but nothing seemed too awful. I loved the ergonomics and if it's the same trans it was great, it just oozed a feeling of strength. 

Overall, a fun car that definitely felt like a small event to get in and drive. Not awesome to daily but was fun to cruise around and romp on occasionally. Also possibly ZR-1 specific, but the gearing was so long it was comical, like it would go 300mph and it felt like it could given a long enough road. 

ToManyProjects
ToManyProjects Reader
10/22/23 10:20 p.m.

Thanks guys!

The words of caution are well heeded. I would expect the car to gather mileage at only a lightly faster rate while under my care, with occasional weekend usage and the odd trip to the cigar shop.

Any other gotcha's with the C4 design? I was reading something about the C5's ABS system and it's issues, anything like that to worry about?

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