My 911 SC Minor Overhaul

[Mingus]

So I recently began my overhaul project. Going to be cleaning everything up, ripping out remnants of AC (hoses dryer,etc...) upgrading compression (custom 95mm 9:8.1 Carb domed JE pistons), C2 grind cams (courtesy Elgin), new steel lower head studs (one of the dilavars was cracked), new lower turbo valve covers, installing Bitz Racing EFI (clean look) with LC-1 Wideband O2, new rear half shafts and joints, rebuild the original mechanical tenisoners, 1" spacers on the 16x7 rear Fuchs, clenaing up hard lines and removing dent from PO jacking attempts, and backdating the oil lines.

What I started with was an original 1978 SC Sunroof coupe. I nixed the heater blower and A/C. I had added headers and M and K (Ben) 2 in 1 out exhaust (and modified a heater backdate using flexible exhaust tube from left block off, run along headers and into flapper box), new Clewitt wires, coil, rotor cap, plugs, cam cover and valve cover gaskets, camshaft o-rings, rebuilt alternator,... Basic stuff you can do without dropping the engine. Here she is prior to and just after the engine drop...





I have everything cleaned up and am waiting for parts at this point. Should have cams and rockers (Elgin and Ollies respectively) next week. Pistons late in March. I'll post pics of liscellaneous stuff I've been doing since then in next post.

[Mingus]

Engine bay cleaned up (used Goof Off on sound pad adhesive--spray on, wait, dab dry, then scrubbed with dry paper towel. Worked really well)



Father-in-law (Tom) did a lot of the prep work




Ripped off the CIS as one piece. Hoping I remember where all those hoses go and taking solace in the fact I have Anderson's and Dempsey's (101 and How to Rebuild) books as well as Bentley manual.




Here is child labor at it's best. He works for Mike and Ikes.




Cam towers and Heads off engine



Next up Cylinders and Pistons......

[Mingus]

Neither of these is fun, but I am satisfied with the process and result...

Here is the cracked dilavar stud. I think it cracked when spinning the head nuts off. the stud appeared bent while still in the case and on closer inspection (look to the right of the surface corrosion)



So I had to remove the lowers. I found pretreat with pene oil night b4, then a couple minutes of heat inside the spigot, and double nuts took care of the problem very efficiently. I had to use a pipe wrench on 2 of them.



Anyway, got the case pretty clean and started of the tranny next

[Mingus]

Still have to get the noons and crannies

[Mingus]

Here are the heads. No guide wear. Replacing the seals though.






Anyone looking for a decent machinist/machine shop in or near Appleton Wisconsin should call Dave at Appleton Crankshaft. Straight up guy, does nice job.

[Mingus]

Cleaned up a bit. They are round and in spec. Here is top ring land. First at .004 and then .005in. (almost go/no go)






Available over on the classifieds to anyone that wants them.

[Mingus]

Mahle

[Mingus]

Had them measured and they are

#1 95.03415/95.0342
#2 95.0342/95.0342
#3 95.0342/95.0342
#4 95.03415/95.0342
#5 95.0342/95.0342
#6 95.0342/95.0342

They are a bit overbore, even for group 3 (I think .028 was high end). The cross hatching is perfect though and rather than replate, the guys at JE (Jerry I believe) and EBS thought I should get custom pistons made. I agreed and they are getting me some 9.8:1 (compared to shelf stock 9:5.1) carb domed (switching from CIS to Bitz EFI) pistons. Can't wait.

Here is a copy of the wear tolerances for 3.0 Nikasil Cylinders and Pistons

[kiwiokie]

Should be great fun when all complete. What did you use to clean up the transmission?

[sobamaflyer]

I'd love a few details of your heat backdate using headers, kicking myself for not thinking of this several months ago to get a few puffs of warm air inside

[Mingus]

walmart citrus based engine degreaser. sprayed, scrubbed, then rinsed what i had loosened with more sprayed. every 5 minutes or so i sprayed thoroughly with water...a few people had me scared that the citrus stuff would corrode the aluminum. it didn't, but i rinsed fairly well. the caked on grease might as well be taken off with a plastic scraper first as the degreaser (any degreaser for that matter) just bounces off.

[Mingus]

from one of these air ducts sold on pelican



used proper size (dont remember) foil exhaust hose into the left side engine tray duct. out the bottom I clamped on this stuff



i used the closest diamter stuff i could find. if too small, just put a longitudinal slice in the end with a tin snips to allow it to fit over, then hose clamp it.

next i ran it (remember it's flexible stainless) sandwiched between two of the header primaries (i think 2 and 3) and clamped it to both of them. i clamped it very tight to minimize if not eliminate vibrations and vibration induced wear.

then up into the flapper box hose and clamped again.

[Mingus]

i think i have 40 bucks plus the backdate air duct into it and it keeps my windows defrosted. i have nothing on the right side but a block off plate. foot well blowers offer no heat, but i am very satisfied with the clear windshield and to be honest, the warmth. i live in northeastern wisconsin and put her away in early november (b4 snow) but the temps here in the morning at that time of the year are in the 20's-30's. i never really got cold with this set up. the foggy windshield was the main reason i did it. earlier in fall and late spring here are foggy windshield weather...really humid and cool. it takes 5-10 min to clear it (left to right) but it works well and if you hooked up both sides you'd be in the money.

i have the headers of the engine now, but the flexistainless is still attached. i'll take some pics when i get working on the car again and post them. you'll be able to figure it out in a second.

[sobamaflyer]

Thank you, that's awesome, soon as you wrote about it I could see it on my car and started kicking myself for not considering it (I even have the port already coming off my engine fan, blocked off right now). I live in S. Alabama so cold isn't something we have to worry about much but having zero heat makes those 40°-50° pre-dawn and after dark drives kinda miserable.

Interested to see the rest of your overhaul.

[snbush67]

Tom,

Great job. The tranny looks nice. Why did you decide to go with the carb domed pistons? Will you be ditching the CIS?

Shane

[Mingus]

JE suggested them because of the Bitz EFI kit I'm adding.

[Mingus]

just wanted to say i appreciate the interest in my project and the kind words. the attention and praise is motivating. this website and the community that binds it is amazing. amazing enough to make me gush like a sixteen year old girl in love for the first time... weird.

[snbush67]

Originally Posted by Mingus

JE suggested them because of the Bitz EFI kit I'm adding.

I missed that on my first read, good choice. Great thread, it looks like you have plenty of helpers.

Shane

[trond]

Nice. Your pistons look interesting. Unfortunately I already have 9.3 pistons so hard to justify tearing down the engine for such a marginal bump in compression. Or are there other benefits with carb shaped piston domes ? And looking at that almost parted cyl stud there is almost a justification in tearing it down right there. Once you are done you should start thinking about EDIS ignition. Also I recommend making a hand throttle arrangement. I used a 924 heater valve and cable. Makes tuning the EFI easier too

[snbush67]

Originally Posted by trond

Nice. Your pistons look interesting. Unfortunately I already have 9.3 pistons so hard to justify tearing down the engine for such a marginal bump in compression. Or are there other benefits with carb shaped piston domes ? And looking at that almost parted cyl stud there is almost a justification in tearing it down right there. Once you are done you should start thinking about EDIS ignition. Also I recommend making a hand throttle arrangement. I used a 924 heater valve and cable. Makes tuning the EFI easier too

The difference is the way the fuel and air is introuduced into the combustion chamber. The original CIS style pistons swirled the fuel and air mixture. Other shapes are more suited for the type of intake/ignition/cam etc.

Shane