sportomatic trans for 74-77 911

johng964 · 02-25-2010, 06:44 AM

hi guys

just wondering what a complete sporto trans costs. how about in great shape or needing rebuild? thinking of buying a 2.7 911 and converting to sportomatic.

thanks
john

Grady Clay · 02-25-2010, 07:20 AM

John,

It is probably easier to find a Sportomatic 911 from those years than to convert one.

That said, you can find owners who have removed the Sportomatic 925 and installed a 5-speed 915. A few have carefully removed every little piece to make their 911 where it would be difficult to tell it had been equipped with a Sportomatic. Finding that collection of parts is the only (economical) method of converting.

Even then there are features of the 911 that are unique to the Sportomatic. For example, the mounting for the vacuum reserve tank is welded to the rear shock cross members.

Too often not everything is changed. For example, the oil tank for a Sportomatic has two additional fittings for the oil circulation to/from the torque converter. Often, these ports are simply blocked off and there is not a Sportomatic oil tank left over from the conversion.

I hope this helps.

Best,
Grady

RS#007 · 02-25-2010, 07:58 AM

I have had two of these transmissions, they each sold for $500.00, But like Grady said there are many additional parts for oil lines and vacuum boosters on both the car and motor. Best to sell your 911 and wait for a sportomatic version to come up for sale. Both easier and might not cost you anything.

johng964 · 02-25-2010, 08:27 AM

thanks for the responses. the 5sp car in question is a project car. i don' t own it yet. considering the other work that needs doing, it may not be too expensive to make the conversion.

Matt Monson · 02-25-2010, 08:45 AM

I would expect the conversion to cost you somewhere between $2500-5000. It would very likely not be a cost effective endeavor. Some of the little bits and pieces for that conversion have gotten really rare and expensive. The gearbox will be the cheap part.

johng964 · 02-26-2010, 06:16 AM

Quote:

Originally Posted by Matt Monson

I would expect the conversion to cost you somewhere between $2500-5000. It would very likely not be a cost effective endeavor. Some of the little bits and pieces for that conversion have gotten really rare and expensive. The gearbox will be the cheap part.

yes, it's the little things that kill.

Grady Clay · 02-26-2010, 06:50 AM

John,

You might try finding someone with a Sportomatic who wants a 5-speed. Do the conversion to both cats simultaneously, side-by-side. Convert your 911 to Sportomatic and the other 911 to a 5-speed.

Both should research all the parts that may (or should) need to be new or up-dated. Seals, clutches, syncros, hoses, CV hardware, etc. come to mind.

I recommend you find and keep a set of pieces that will allow you to convert back to a 5-speed whenever you want.

Keep in mind that the 925 Sportomatic came as both a 4-speed and 3-speed. I suspect you will only consider the 4-speed.

Best,
Grady

stownsen914 · 02-26-2010, 10:00 AM

Since we have a Sporto discussion going here, I have a relevant question. When did Porsche start building 915-based Sportomatics? From looking at parts manuals, I've been led to believe that for at least the first couple years of 915 trans production, Porsche still used the 901-based Sportomatic.

Also, how long did they make the 915-based Sporto? Was it an option on 911SC's?

Scott

Grady Clay · 02-26-2010, 10:45 AM

Quote:

Originally Posted by stownsen914

Since we have a Sporto discussion going here, I have a relevant question. When did Porsche start building 915-based Sportomatics? From looking at parts manuals, I've been led to believe that for at least the first couple years of 915 trans production, Porsche still used the 901-based Sportomatic.

Also, how long did they make the 915-based Sporto? Was it an option on 911SC's?
Scott

The 915 based Sportomatics (Type 925) start with the 1972 model year. The ’72 and ‘73 911TV (Zenith carbureted RoW 2.4T) used the 901 based (Type 905) Sportomatic.

I think the 1980 911SC 3-speed 925/16 was the last official one.

Best,
Grady

rsnodgrass · rsnodgrass's Garage

What is the difference between the 925/02 and 925/04 Sportomatic transmissions? I believe the 925/04 was briefly used in 1975 and was still a four-speed. Was the 925/02 ever used in 1975?

pkenney · 03-11-2011, 01:12 PM

I know this is an old thread, but I have a 1976 911s Sportomatic that I'm pondering converting to a manual. I pulled the motor last night to replace the oil seals on the back of the motor along with the rear seal. I'm awfully tempted to convert now since i have the engine out. Tranny has 83K on it and works perfectly.

Just in case you're interested.

If anyone has a 915 tranny they'd like to part with for a reasonable price...I'm in the market.

Thanks.