Rebuild 915 costs, or eBay 915?

[Geronimo]

I have the car in the shop right now getting a trans diagnosis... for giggles I looked on eBay and see several "rebuilt" 915's for $4k give or take...

I really want to mitigate the costs as I want to go turbo and add a 930 SBH trans later.

I am in the early freak out stage of cost anticipation I think.

[racer]

Problem is, how much do you trust your "ebay rebuild"... could be junk.. could be great.. or somewhere in the middle imho.

[javadog]

Wait and see until you get a diagnosis of the damage to your gearbox.

I would only consider buying a rebuilt gearbox, if I knew exactly what was done to it and it was rebuilt by someone that I trusted using parts that I could verify. There are probably very few people who I would allow to rebuild a 915 gearbox, and a great number of people who might rebuild one that I would consider inadequate.

As for installing a 930 gearbox and your car, you may wish to take a harder look at that. I think it’s a lousy idea, as I have expressed before, but it’s not a simple bolt-in operation.

[Baz]

My 915 rebuild cost about $1K, but that was almost 20 years ago. Costs probably have gone up since. But still cheaper to have mine rebuilt then buy a rebuilt one.

I'd wait until you get an estimate.

Also, as has been pointed out - helps to know who did the work.

[Geronimo]

Yea, I know Java. Seems there are quite a few in the 4spd swaps in the turbo forums here. If you want more than 300HP I don't see a better option.

Yea, I'll wait to see what they find. I just hate to eat my entire "oh ***** fund I set aside when I bought the car... it's only 9K and that can go fast on these cars. LOL

[red-beard]

Originally Posted by javadog

Wait and see until you get a diagnosis of the damage to your gearbox.

I would only consider buying a rebuilt gearbox, if I knew exactly what was done to it and it was rebuilt by someone that I trusted using parts that I could verify. There are probably very few people who I would allow to rebuild a 915 gearbox, and a great number of people who might rebuild one that I would consider inadequate.

As for installing a 930 gearbox and your car, you may wish to take a harder look at that. I think it’s a lousy idea, as I have expressed before, but it’s not a simple bolt-in operation.

What would you consider "adequate"?

For a while, I was rebuilding 901s as a "hobby". Mike aka Dr.Evil, took over the franchise when I left San Diego and he has continued in his spare time (Evilworks).

Rebuilding a 901 or 915 is not that difficult. I could disassemble, replace parts, and re-assemble in about 5 hours. I used to sell them for $750 plus a core return. I used old 901 transmissions for the parts. 4th/5th gear sliders, dog teeth and sync bands were usually in very good shape. This was about 18 years ago.

If I had wanted to do an all new parts re-build (which I did on my 914-6, while the engine was rebuilt), it was about $1000 worth of parts. Today, that number would be well over $2000. And the hardest part to get is the bearings. I had considered having a machine shop modify standard bearings so that I could put a giant circlip on them in place of the flanged housing.

[javadog]

Given the age and uncertain history of most 915 gearboxes at this point, a rebuild for me would go far beyond synchros and sliders. Read Pete Zimmerman’s series on rebuilding a 915. If you do all of the steps and consider all of the parts that he discusses in his tutorials, that would be an adequate rebuild for me. I only want to be in there one time.

The fact is, doing that is insanely expensive on a 915 gearbox. That’s why almost nobody ever does it. They end up with when I call a half assed rebuild.

Then, there is the judgment that comes with experience. There are some things that wear over time and Porsche doesn’t have a published wear limit for the part. One such example is the pinion shaft bearing plate. I would wager that the average rebuilder does not even look at that part, but if he does, at what point do you change it?

The OP does not have enough budget to do all of the things he wants to do, so I would expect some pressure to cut corners here and there. That’s pretty normal, when most people rebuild either a 911 engine or 911 gearbox.

[GH85Carrera]

A used unit from EBay is just a pig in a poke. You might get lucky and get a decent one, or be screwed with a box of crap. Get into your transmission. At least see what the issues are. Old 911s are not a cheap car to own. Get an old 70s Chevy if you want cheap parts and lots of torque and horsepower.

[jwasbury]

I had the 915 in my race car rebuilt. It was thoroughly trashed. Main case where bearings press in was hammered and cracked, so a good used case was sourced. Original ZF limited slip diff clutch was worn to the point it was nearly an open diff. New GT diff installed. Used the reinforced side plate and inner bearing plate. Of course new bearing, dog rings and operating sleeves as required. All in all, a rather extensive rebuild. Cost was in the 7k range. Probably have 30-40 hours of wheel to wheel racing on it since the rebuild and its been great. I would expect the typical street 911 will not have been subjected to the thrashing that a race car gets, so a gearbox refresh probably won’t include replacement of the main ca$e (or differential unit).

[onewhippedpuppy]

I’m with JR, I would never buy a rebuilt anything without knowing who rebuilt it. eBay is the Wild West, good luck....

[Geronimo]

Yea, I should know more soon, the estimate is 4500-7500 depending on the needs. 4500 isn't so bad I guess.

I have to imagine that most people running older 911 must have 50K in the bank for that just in case moment.

I love my 911, but they sure do make you appreciate what Corvettes can do in cost/performance ratio. But alas I love me some 911 so i'll soldier on... best to get very good with a wrench and enjoy the whole process.

[javadog]

What I was trying to suggest is that, if you intend to sell the gearbox in a few years to fund your 930 black hole, you might consider having a known shop rebuild it. I'd pay more money for a gearbox rebuilt by a 915 guru, than the same gearbox rebuilt by "Shop I've Never Heard Of, Inc."

Your money, your time, your choice.

[Jay Auskin]

Originally Posted by Geronimo

Yea, I should know more soon, the estimate is 4500-7500 depending on the needs. 4500 isn't so bad I guess.

I have to imagine that most people running older 911 must have 50K in the bank for that just in case moment.

I love my 911, but they sure do make you appreciate what Corvettes can do in cost/performance ratio. But alas I love me some 911 so i'll soldier on... best to get very good with a wrench and enjoy the whole process.

Wow, costs have really gone up since I owned one 6 years ago. I "rebuilt" mine, and a certain person on Rennlist got really snippy with me when I discussed it there. I also had help from a bunch of local friends I met on Pelican, and were particular about how to do things the right way. It's actually not hard to do with the right tools (like anything, right?). But, 915 part prices have gone up substantially from what I've heard.

Where in Detroit are you Geronimo? I'd love to check out your 911 someday. It's been quite a while since I've seen one up close, and as you know there aren't many around our parts.

[javadog]

Not only have costs gone up, but the availability of correct parts is less. Some of the available parts are different and not satisfactory.

Fer instance, ponder this thread:

915 1st gear pops out with new synchros

While pondering that one, you might then read this one:

915 4th gear issues

Sooner or later you might conclude there's more to the problem of rebuilding a 915 NOW, as opposed to x years ago when so-and-so rebuilt his.

It's also why I'd only use the best guy I could find, as there are some difficult choices to make.

It's also why I've essentially gotten out of the older car collector hobby and sold off all of my collection.

Have fun.

[red-beard]

The part prices have been going up for years. And some of the parts have become completely unavailable (bearings on the 901 transmissions). But there are compatible parts out there, they would just need some modification to fit.

Again, for the 914 community, the rebuilds I did were fine. Those were low torque motors with generally not much displacement and under 120 HP. I recommended a few people "upgrade" to a 915 if they were going over 200 hp. And the crazy guys with SBC conversions, the 901 is a stupid transmission.

Generally, the reason the 901/915s need rebuilding is poor maintenance. Most we found were run nearly dry. And while it would cause some "drag", I think running 140W oil is better for most street cars than the 90W oil. ANY tranny oils is better than none!

You should see my classic rants from the early days on the 914 forum. Don't even get me started on SWEPCO...

[Geronimo]

Jay, i'm in SE Michigan, Macomb Twp area.

I try to hit Woodward (pastiners old auto zone) for the Saturday car meets, lots of cool stuff shows up.

Yea, we'll see how this all goes, I really want to build the 911 that I have always wanted, but the costs might drive me out of the Porsche hobby on my first try lol.

Me and all the people running 930 transmissions in their turbo conversion will agree to disagree with you on that one.

[speeder]

How much is a good used 930 transmission these days?

[red-beard]

Originally Posted by speeder

How much is a good used 930 transmission these days?

If you are meaning the 4 speed 915, Those are rare. Or do you mean the G50?

[Jrboulder]

Originally Posted by red-beard

If you are meaning the 4 speed 915, Those are rare. Or do you mean the G50?

Maybe he means one of the following:
930/30
930/32
930/33
930/34
930/36

[red-beard]

Which are 4 speed 915s