Heat Exchanger Retrofit Question
 

I just read the retrofit article referencing an SC. The oil lines have to be replaced when installing early (72-73) heat exchangers.

Do the oil lines also have to be replaced on a 77 US S in order to use the early heat exchangers? Thanks!

Yes you have to backdate the lines, you can actually fit them on without backdating but the exchangers run so close to the stock oil lines you will overheat, so you must backdate to the old lines which take a cooler route.

The 77 used thermals and the early type oil line around the front of the engine by the transmission. The thermal muffler is 2 in 1 out but has back pressure so its not as efficient as the 74 muffler
Bruce

Are you saying the 77 oil line is the early type and does not need to be replaced, but the muffler warrants replacement?

The PO removed the thermals and replaced the 5-blade fan with a 12-blade, but I doubt if the muffler was replaced. How do I identify it as thermal-type or not? My car only has 42K miles on it. Thanks!

Does this help?

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_EXHprf_pg1.htm

The link says at the end:

"Oil Line Update: It is important to note that all cars with cross-over exhaust systems (all 1978-89 911SC and Carrera) require the replacement of two oil lines with two older-style ones when installing the SSI heat exchangers (or any 1974 and earlier exhaust). These lines are part numbers 911-107-729-10-M20 (cars with a front-mounted cooler) and 911-107-728-00-M20 (no front-mounted cooler) and 911-107-739-10-M20 and are available for purchase below."

I'm reading that my 77 911S does not require the oil line change??!? Right? I still have the muffler ID question too.

Also, does the shroud on the drivers side 3 into 1 pipes serve any purpose on a 77? i.e., should it be removed? See here:
http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/476193-early-mfi-heat-exchangers.html
Thanks!

Bump

Nobody knows huh?

Look under the car, if the drivers side oil line runs to the rear of the car and then turns 90 deg. to the passenger side just before the muffler you will need to backdate.

However if it runs along the front of the engine where it mates to the transmission then you are OK.

Here is a pic posted by speedracerindy, you can plainly see the hard curved oil line toward the front of the engine, no oil line running along the rear.

http://forums.pelicanparts.com/uploa...1243785407.jpg

Thanks! Mine runs in front of the engine as shown.