915 trans into a SWB - step by step conversion
 

I'm converting my '66 to a 915 and 3.0L. after much searching I couldn't find much on the conversion. so I figured I would document my experience thru the process.
the trans is a '72 915. this thread shows the start -

http://forums.pelicanparts.com/porsche-911-technical-forum/446271-help-please-putting-915-into-swb-axle-set-up.html

http://forums.pelicanparts.com/uploa...1229587253.jpg



so now I have a 915 with 901 flanges from a 914 trans. using the 915 front support bar because of the replaceable mounts. tonight I trial fitted the engine/trans combo in the car. as expected there was a slight clearance issue at the upper left side of the front of the trans. dropped it down and spent 2 minutes with a deadblow hammer. jacked it back in and no clearance issues.
before:

http://forums.pelicanparts.com/uploa...1229587154.jpg

after:


http://forums.pelicanparts.com/uploa...1229587213.jpg


now for the axles. I installed one of the original lobros, no problems, bolted right up to the 914 flange.

http://forums.pelicanparts.com/uploa...1229587478.jpg


jacked up the suspension until the car was off the jackstand. can't get full suspension compression until the complete engine is in but it's close. I sat on the back and didn't drop much further. the axle still has about 5/8 inch axial ( ? ) ( back and forth ) play.

http://forums.pelicanparts.com/uploa...1229587687.jpg

also checked the angle of the axle related to the trans centerline. would be 90 degrees ideally. I come up with 4-5 degrees off of that, so not too bad.

http://forums.pelicanparts.com/uploa...1229591100.jpg

that's it for now. will update as things progress. Don.

Don, Looks like it's all coming together fine. If you have 5/8 inch axial play with the axles at 90 degree, that's sounds ok, but you must check to see at full angle that there is still some axial play and no CV joint binding. Keep us posted.

Mark, by full angle, do you mean with the car supported and the suspension at full droop?

Yes Don, This is how I did it. I wanted to see the full movement of the rear SWB arm. I removed the torsion bar on one side and installed a torsion bar (used old one) that I modified one end by grinding down the splines and then buffing it smooth. I installed the modified bar, smooth end first, reinstalled the spring plate, shock, etc. Then I installed the axle I was going to use with the CV's, "cleaned and no CV grease" and without the CV boots.
By hand pushed the SWB arm to full compression, check the axle and CV joints, then pulled the arm fully extended, and again checked the axle and CV. This told me if there was any problems with the CV's binding and if the axle was the proper length.
Hope this helps.

" install 915 shift tower "

installed the 915 tower tonight, not quite a bolt-in.
first had to get rid of the heater control that was mounted to the front of the 901 shifter housing. since I'm running headers, cut the wires and pulled them out the back, also removed flapper boxes. I do have a 915 tower that was notched at the front, I assume to allow for the heater control.

the mounting bolt holes didn't quite line up, so I drilled all three mount holes on the tower out to 3/8 inches to give me some wiggle room. used metric internal hex machine screws to mount, no issues. connected coupling at the rear.

wasn't finding all the gears and was starting to fret a little. then thought it thru and went back to basics. a quick linkage adjustment as outlined here:

http://www.pelicanparts.com/techarticles/911_shifting_improvements/911_shifting_improvements.htm

and now I've got all my gears. that's it for now. I've ordered a new ( '72-'73 ) clutch cable because the 901 cable is too short to reach the hole in the transmission casing. also changed the accelerator thingy from the 901 onto the 915.

so far so good.

http://forums.pelicanparts.com/uploa...1229938117.jpg

note: will buy some nicer fasteners, but these were 'in-stock'
http://forums.pelicanparts.com/uploa...1229938170.jpg

it progresses. apparently in the trial fit up I squished the steel fuel line. no biggy, I cut it off shorter and will run a new rubber line over the torsion tube.

http://forums.pelicanparts.com/uploa...1234948876.jpg

I've replaced the output seals on the trans and am about ready to install. re-packed the old CV's, will get new halfshafts from PP once I know everything will work as hoped/planned. put in the new clutch cable ( LWB version ), no issues.

trans installed. fuel line re-routed, didn't see how it got pinched in the first place, not in the way of anything. extended back-up switch wiring to reach switch location on the 915. axles bolted up. seems to be lining up right, the shift rod is centered on the tunnel hole. put new bushings in the shift coupler, a 10 minute job, tops. picked up some ABS plumbing caps to cap off the heat ducts to the cabin. put new seals on the inner wheel bearing. now just waiting to finish off the 3.0.

http://forums.pelicanparts.com/uploa...1235177221.jpg


http://forums.pelicanparts.com/uploa...1235177245.jpg

Wow Don, looks like everything is coming together nicely.
How's the new motor coming along?

Cheers
Duane

hey Duane. motor stalled a bit, put a heater backdate in the SC and wanted the trans into the '66. now I need to get Kevins911 to come over and help me time the cams. then it's just bolt on the goodies and throw it in.
it's nothing exotic. a 3.0 with webers, headers, bursch, dougherty cams, 9.5:1 JE's, euro dizzy with MSD. hoping for 200 hp at the wheels.

( gratuititous pics )



http://forums.pelicanparts.com/uploa...1235198464.jpg


http://forums.pelicanparts.com/uploa...1235198485.jpg

Nice project. Subscribed.

update and gratuitous engine pic. shroud is painted to match the car. hope to have the engine in next week.

http://forums.pelicanparts.com/uploa...1238957446.jpg

finally moving ahead. Kevins911 came over tonight to help install the engine. no real issues. hoping to fire it up by the weekend, then we'll see if it all works.

http://forums.pelicanparts.com/uploa...1240807928.jpg


http://forums.pelicanparts.com/uploa...1240807949.jpg


http://forums.pelicanparts.com/uploa...1240807967.jpg

ran into a small issue. the shift rod at the front of the trans was a little low in the hole to the tunnel. after monkeying around with the mounts a bit I came up with a simpler solution. I used four 1/4" thick nylon spacers between the bottom of the trans and the trans support. shift rod is now nicely centered in the tunnel hole. put in new engine/trans mounts front and rear.

NOTE: the stock bolts that bolt the trans support to the body are too short. you need bolts that are 75mm long ( about 3" ), shank length.

dropped the car down to check the axle angle and play. they're sitting pretty much dead level, should help CV life a little, not having to compensate for two different angles. still have about 1/2" axial play so axle crunch shouldn't be an issue.

next is hook up fuel/oil/ignition and fire the sucker!

the fun never ends.
when adjusting the shift linkage I couldn't get enough forward throw at the shifter. the shift rod length was too long. so I cut about 1/4 inch off the shift rod in the tunnel and the same off the splined shaft of the shift coupler because it was bottoming in the tunnel rod. maybe a little more than I needed but I didn't want to do it twice, cutting the rod in the tunnel isn't much fun.
adjusts fine now.
fuel connected, sorting electrics.

http://forums.pelicanparts.com/uploa...1241041389.jpg

time to finish this off. car is on the road and doing fine. a few engine issues to sort out but nothing terrible. as far as the 915 conversion.....no problems whatsoever! now I can go back and forth between the SC and the '66 withour having those DUH..... moments between gears. with CV's warmed up I checked the axial play, at least 1/2 to 5/8 inches, good enough considering the axles are near level and the clearance will never be any tighter.

for any considering this I highly recommend it. a fairly easy switch. bigger (stronger ) CV's might be an idea. I'll think about doing that next winter. the 15X7 tt's even fit inside the wheel lips. I think I'll put in nylon spring plate bushings to minimize movement there. the wheels fit, but just barely.

note: a warmed 3.0 in a SWB is a ridiculous amount of fun. there oughta be a law. makes the car feel very light and throttle responsive. a LSD wouldn't be a terrible idea. first time I've ever felt a need for one.

note: if anyone doing this runs into problems, drop me a PM. I'll do what I can. I tried to cover everything but I may have missed something.

http://forums.pelicanparts.com/uploa...1242540258.jpg


http://forums.pelicanparts.com/uploa...1242539945.jpg

Where does the muffler go?
 

Hi

Great post by the way!
I'm runnig a 3.2 in my longnose however the muffler won't fit... Any ideas?


http://forums.pelicanparts.com/uploa...1267659356.jpg


http://forums.pelicanparts.com/uploa...1267659392.jpg

sorry, I don't think I can help you too much. my set-up was 'two out' into a bursch extractor, and briefly, a stock banana muffler. your problem must be in the space at the rear of the body. the longnoses don't have much room as the license plate panel is tight to the back of the car. the impact bumper cars have a little more room. I see some fabrication in your future. ;)

Suggest you will have fewer issues by using SSI heat exchangers made for 3.0/3.2 engines. Maybe a little more power too. If you keep the 3.2 exhaust, you will probably require a custom muffler/tailpipe solution.

Sherwood

something I missed mentioning along the way. a pelican doing this conversion asked me a question and I realized I didn't mention the clutch cable.

I used a new 915 cable ( '72 - '73 ) . it fit from the firewall to the pedal fine, but as you can see from bow in the cable in the first pic it has a little extra length between the firewall and the trans ( due to the shorter wheel base I assume ) and as you can see the adjustment is pretty much used up.

that said it works perfectly as-is. if I need to adjust the cable down the road I'll figure out a spacer or something.

http://forums.pelicanparts.com/uploa...1271916217.jpg


http://forums.pelicanparts.com/uploa...1271916237.jpg

Confirm the clutch cable routes above or below the bellcrank on the gearbox. I think it's above, but I could be mistaken.

Sherwood