Sportomatic Conversion

[pennwood]

Hi, I have a '77 911s targa sporto which recently became stuck in 1st gear after being downshifted too abruptly as I observed it from the passanger seat. Now that I'm faced with putting more money into this already rebuilt transmission I'm considering converting to a standard transmission. The car came from CA 3 years ago and the previous owner had the drivetrain rebuilt along with new paint and interior. The car is in great shape with only 117,000mls except for an oil leak and now being stuck in first gear. Our local vintage porsche mechanic and PCA member Ken Daugherty suggested not converting from the sporto but I would really like to know of any members experience in doing so. What is the cost? How complicated is it? What parts do I need? Any special tools required? What should I be careful of? I would greatly appreciate your help. Thank you.

[the]

Like most people, I've never been a fan of the Sporto, but believe it or not, there seems to be an increasing interest in them. Particularly for SCs, which are very rare (although your 77 Sporto is very rare, too).

If it doesn't cost too much to get your shifting again, you may want to consider doing that, selling the car, and buying a different one with a 5 speed. If you find the right buyer for your car, you may be able to get a good premium for it.

[Zeke]

There is plenty of info here in the archives. Basically, you need a pedal cluster (with board), a trans, pressure plate (disc, too), and the cable. The shift rod may not tbe the right length, I can't say. The Sporto shares oil with the engine, so you need some fittings as you go. There's also a lot of stuff to remove.

Can you speculate as to why it's stuck in 1st? Seems to me that's been covered here, too. How are the vacuum lines?

BTW, welcome. You bring a good question.

[pennwood]

I'm new to the forum and will review the archives. I apologize if I'm covering old news. 20 years ago I owned several old VW's and thought I would pick up the hobby again with a 911. I bought a mechanically sound car but within one month I'm back into the old VW mode of working on a car instead of driving it but I'm having a good time.

Getting a sporto wasn't my preference but I couldn't pass up the car for the price. I'm happy with the performance of the car and feel some obligation to maintain the integrity of the car by keeping the sporto but also like the thought of a 5 speed.

I can engage and disengage the clutch by pushing on the shifter but it just won't come out of gear. I disconnected the linkage and the shifter freely moves the full range. I will check the vacuum lines but if I understand this correctly the clutch wouldn't operate if there was a problem there.

The car was downshifted rather abruptly without the normal half second pause for the syncros to line up and accept the gear change. So my speculation is that this caused the problem but I don't know.

If the problem can be fixed without cracking the case I will keep it a sporto and will be able to keep money in my pocket to show for it and be happy. Otherwise I will compare the cost of conversion.

[1982911SCTarga]

Having never owned, let alone driven, a 911 equipped with a Sportomatic, price my view at the appropriate 2 cents.

I think your car is fairly unusual. I just can't imagine that there were that many '77 Targa Sportos made. If your car is mostly original, I would try to keep the Sportomatic.

Someday, I'd like to get a ride in a 911 Sporto just to observe how it's driven. It was a neat concept from Porsche.

Brian

[scarceller]

Originally posted by pennwood
I'm new to the forum and will review the archives. I apologize if I'm covering old news. 20 years ago I owned several old VW's and thought I would pick up the hobby again with a 911. I bought a mechanically sound car but within one month I'm back into the old VW mode of working on a car instead of driving it but I'm having a good time.

Getting a sporto wasn't my preference but I couldn't pass up the car for the price. I'm happy with the performance of the car and feel some obligation to maintain the integrity of the car by keeping the sporto but also like the thought of a 5 speed.

I can engage and disengage the clutch by pushing on the shifter but it just won't come out of gear. I disconnected the linkage and the shifter freely moves the full range. I will check the vacuum lines but if I understand this correctly the clutch wouldn't operate if there was a problem there.

The car was downshifted rather abruptly without the normal half second pause for the syncros to line up and accept the gear change. So my speculation is that this caused the problem but I don't know.

If the problem can be fixed without cracking the case I will keep it a sporto and will be able to keep money in my pocket to show for it and be happy. Otherwise I will compare the cost of conversion.

In the past I owned a 75 Sporto for 15yrs and even rebuilt the tran myself. With the car not running you can't get it out of first gear? is this correct? If the car is not running you should be able to move through the gears regardless of the clutch. So, are you saying this tranny is stuck in first even as it sits not running? If this is so I suspect a shift fork problem within the trans. You can remove a cover plate on the bottom of the tran that has 2 screws, this cover is part of the shift fork mechanics and you may see some damage through this plate. It's been 10+ years since I worked on a sporto but try looking in this access plate before you pull the tran.

A good person to get advice from on this is Gary Fairbanks
in Norwalk, CT his number is (203) 866-2466, he rebuilds 911 trans all the time, he's one of the best and has helped me with several trans.

If I owned you car I would not convert it (If it's a street car) I found my sporto very nice once it was working properly. Most of these older sporto trans ussually do not have the sporto vacuum valve adjusted properly, but if all is correct they shift very smooth and fast.

Good luck.

[pennwood]

Even with the engine not running it is still stuck in first gear. First gear runs out fine though because we had to drive a few miles to get back home. I will remove the access panel and check out the shifter fork and if I do detect a problem will I still have to drop the trans to make the repair? It's been a long time since my VW days when I last pulled an engine. My chilton book actually covers the sportomatic. I'll review it thourghly when I get home.

Attached are some photos from just before it was converted back to EFI.

[MBEngineering]

HI if you are intent on changing to manual ,I have a list hear on the desk I could fax to you with all the parts you require, it is from when i use to do the conversion back in the 1980's.
Nice motor shame to change it?


regards mike

[scarceller]

Originally posted by pennwood
Even with the engine not running it is still stuck in first gear. First gear runs out fine though because we had to drive a few miles to get back home. I will remove the access panel and check out the shifter fork and if I do detect a problem will I still have to drop the trans to make the repair? It's been a long time since my VW days when I last pulled an engine. My chilton book actually covers the sportomatic. I'll review it thourghly when I get home.

Attached are some photos from just before it was converted back to EFI.

Hate to give you the bad news, but if this is a shift fork problem you will have to remove the tran. It will be the only way to be 100% sure what the damage has been.

As I mentioned above give Gary Fairbanks a call to get his oppinion.

Good Luck

[Grady Clay]

pennwood,

Welcome to the Forum.
You will find a lot of help here.


Congratulations on your 911.
“20 years ago I owned several old VW's and thought I would pick up the hobby again with a 911. I bought a mechanically sound car but within one month I'm back into the old VW mode of working on a car instead of driving it but I'm having a good time.”
That is part of the fun and makes the driving more memorable.

To keep the Sportomatic or convert to a 5-speed is a matter of your personal choice. I enjoy either and being a tinkerer would make slight mods either way.

The best advice above is to fix the immediate problem with the shifting. That is most likely a separate issue from the Sportomatic/5-speed question. Sorry that this is your first project.

First let’s diagnose the problem.

First, does the clutch work? Can you activate (disengage) the clutch and start the 911? If the linkage is in gear, you may have to use a remote starter switch to defeat the electrical lockout for the starter.

In spite of being able to drive home, does the engine run properly? No noises? Runs on all six cylinders? Idles OK? You might consider a cylinder leak check and cranking compression check to confirm everything is proper. (Any time a 911 is put in a wrong lower gear there is the possibility of an over-rev.)

With the engine running and the rear wheels off the ground does it act like it is in first gear with the torque converter working? The wheels should turn as you rev the engine and at idle you should be able to stop the wheels turning with the brake without stalling the engine.

Are there any unusual noises from the torque converter, clutch or transmission?

Drain the transmission and remove the shift pivot plate (four nuts and you will need a new paper gasket available from our host). Are there any errant pieces in the transmission? Use a magnet to fish about.

With lights and mirror inspect the 1st gear syncro (if still stuck in first, the sliding sleeve will be over the syncro). You are looking for the possibility the circlip that retains the syncro parts is partially off (very difficult to see).

If still stuck in 1st, inspect that the 3-4 shift rail is in neutral and the reverse rail is in neutral. If so, try and move the 1-2 shift rail out of 1st and into neutral. Is there any sign the 1-2 fork has moved on the rail?

This might be a good place to stop and report back.


You have a Type 925/17 3-speed Sportomatic. If you have to do some internal repair, you might consider converting it to a 4-speed. With a donor transmission it is easy to do. Actually you use both transmissions and assemble a 4-speed with all the best parts and new pieces where necessary.

Converting to a 5-speed 915 is relatively easy with some cautionary notes. Finding a good 5-speed will be the challenge. Most will probably need a maintenance rebuild at least. You will want a ’77 or later transmission with the over-center clutch spring arrangement. Aside from the transmission you will need:
Shift assembly.
Pedal assembly.
Floor board.
Floor carpet at pedals.
Clutch cable and hardware.
Complete clutch assembly (flywheel, pilot bearing, disc, pressure plate, release bearing and hardware).

There is a LOT of stuff to remove. You should remove everything peculiar to Sportomatic and save all of it. There are fittings on the oil tank and on the engine for Sportomatic connections. All of that should be properly plugged, etc.

Don’t be afraid of dropping the engine and transmission. It is as easy as a 40 hp VW, just more things to detach. The transmission is actually easier than a VW. The best part is everything is much higher quality.

The good news is your 911 should have been delivered with a front oil cooler (standard with Sportomatic).

As mentioned above, another possibility is to trade cars. A 5-speed 911SC or Carrera might be a consideration.

At this point, don’t dismiss anything.

Best,
Grady

PS: The name Ken Daugherty rings a bell. Ask if he knows me.

[cnavarro]

Did you just get that car on ebay? I had bid on that car a little over a month ago. Were you the lucky winner? I'd say fix it or trade it, don't butcher it please! :-)

[rcooled]

I did a fairly similar conversion some years back on a Karmann Ghia equipped with a Sportomatic. The system is virtually identical to the Porsche setup with the major difference obviously being the transmission itself. As mentioned before, you'll need all the missing bits that are required for the manual shift transmission....pedal cluster, gearshift lever, shift rod, flywheel, clutch parts, etc. I bought everything except the clutch disc, pressure plate & t.o. bearing from a VW salvage yard for a very good price. The biggest hurdle to overcome will be if you have to weld a clutch cable guide tube into the tunnel. On VW's, some of the Sporto cars had the tube in place....on others it was missing. I had to install my own and used a piece of 1/2" dia st. steel tubing for which I made up the necessary support bracket and had welded in place. Of course, I had to cut two holes in the tunnel to weld the tube in place, which I then had welded shut afterward. If you already have the guide tube in your chassis (look under the car....you should see about 1" of it sticking out of the rear bulkhead, just to the left of the hole that allows the shift rod of the trans to pass thru) it's just a matter of removing the parts that are no longer needed and adding the ones that are. Everything just bolts into place and I don't recall any special tools being required. Even if you need to weld in the guide tube, it's not that big a deal.

Good luck....

[pennwood]

Thank you everyone for all the help. You guys are great.
I really appreciate it.

MBEngineering,

I would love to receive your conversion parts list. A comprehensive list will help me to determine the approx cost of conversion compared to the estimated $1500 - $2000 to have a pro to pull the trans and fix the problem.

My fax # is 812-248-4705.

scarceller,

I will give Gary Fairbanks a call and see if he can help me out.
Regardless whether I convert or not this trans will need to be
fixed.

Grady Clay,

With the car having aftermarket headers and no heat I won't be doing much driving this winter which time-wise actually works out OK for me to work on this problem now that it is just sitting in the garage with the cover on.

The clutch works fine engaging and disengaging as I push on the shifter and the car will start even though it is in gear. The electrical lockout is either not working or disconnected. Good thing I had the emergency brake on after starting it in the garage.

During thie first gear only trip home the engine ran strong with it's
usual power and no funny noises from the engine or trans. The car was not over-reved it was just shifted too abruptly just before becoming stuck as I saw it. But that may be totally unrelated to the problem. The car also won't come out of gear even when not running.

Switching to a 4 speed sporto has not entered my mind but that is a thought. With the three speed not exceeding 6000rpm 1st runs up to about 35-40mph, 2nd to about 55-60mph and 3rd to faster than I'm willing to drive in a 30yr old car although reaching 120mph was easy and the car felt very confident and ready for more. You can tell these cars are built for speed. I imagine a 4 speed sporto would be even better.

I'll be talking to Ken next week and will mention your name. He is
a big 356 guy from what I understand but his son specializes in 911's.

cnavarro,

This was an ebay purchase from about a month ago. Someone bought it but the seller felt uncomfortable about an international transaction and he still had my number from a previous discussion we had about the car. I do feel some obligation to maintain the integrity of the car by keeping the sporto but wanted to consider all options. Ultimately I would probably sleep better at night knowing that I kept it original if that turns out to be my best option.

rcooled,

20 years ago a friend of mine had a ghia sporto and I really liked it. This memory is what made me feel OK about the purchase.

I'll get a new set of ramps this week-end and get a closer look at
the problem and try to come up with a plan.

Thanks again to everyone.

[Porsche]

I had a 77 targa sporto and it was great. Late model sportos are not common and some people love them. May be best to sell it on to such people.

[MBEngineering]

HI It's a pity you are not round the corner as £1061 =$2000 to look at the trani' is a little steep?? the fax has gone through .

regards mike

[Grady Clay]

Mike,

Could you email me the list ... please. gradyclayathotmaildotcom.

Best,
Grady

[MBEngineering]

HI Grady I have no scanner on this old bit of junk, so if you have a fax No' I can send it to you, if not maybe pennwood has a scanner and could forward it on to you, as I have sent it to him today by fax.

regards mike

[scarceller]

BTW - my 75 sporto was a 3 speed but I swapped it for an older 4 speed sporto (73 I believe) I loved the 4 speed sporto it was a great improvment over the 3 speed. Had a much shorter powerfull first gear. This is one change I would make if I had a 3 speed sporto. I even think the gears can be added right into that 3 speed you currently have. Talk to your re-build person if you decide to re-build your current 3 speed.

[jkarolyi]

Nice car...I see it has the comfort package that came with the Sportos and had 14" Fuchs from the factory. This is the last year you could get 14" Fuchs. Unique car you have. I see you have a red fan...was you engine or trans rebuilt by Motor Meister? This could be the cause of some of your difficulties.

Why did Porsche reduce the Sporto down to three speeds? Seems like a step backward.

[1982911SCTarga]

Why did Porsche reduce the Sporto down to three speeds? Seems like a step backward.

Maybe for easier around town, stop-and-go driving (less shifting)?

Anybody ever seen a Sporto autocrossed?

Does a Sporto transmission use the same/similar slider/dogs/synchro ring arrangements as, say, a 915?

Brian