Another 911SC Engine Rebuild

[porschedude996]

Cleaning up and about to join the cases.

[porschedude996]

I got the case together today. No hitches. The Con-Rod and Chain holders I made worked well. Many years ago, 1986, I recall fishing everything through as I joined the case. Extra hands would have been nice, but none around at the time.

[LukasM]

Very nice and clean work, fingers crossed that it stays dry, you certainly gave it the best chance! ����

[porschedude996]

Originally Posted by LukasM

Very nice and clean work, fingers crossed that it stays dry, you certainly gave it the best chance! ����

Thanks, I have a strong feeling from the Sealant Gods “Loctite”.

[porschedude996]

I was looking at my photos and I didn’t take one of the sealant on the drivers side. I guess I started the sealant time clock in my head and subconsciously avoided the camera.

[porschedude996]

ARP Head Studs in. Cylinders to be installed tomorrow with the pre-appoved kitchen pass. I’ve earned hours of shop build time. I finished installing a new master bath granite vanity…

[proffighter]

Nice built so far

As you are torquing heads soon: What torque you choose and why? According to ARP or lower as discussed here:

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/1155672-arp-head-stud-torque-value.html

Br
Roland

[porschedude996]

Now you got me thinking. I had planned to go with what is shown in the bulletin from Parts Klassic. He has some good youtube videos and present well. Lots of experience, not unlike Henry and others. They all bring great things to the table. Problem with the layman, it’s more like a restaurant with a huge menu.

I didn’t find that whole piece of paper in my box from ARP. I saw a tech bulletin from Porsche thru PartsKlassic.com.

https://www.klassikats.com/technical-service-bulletin-cylinder-head-torque/

I think i’ll test the 11lb and 90 degree and check the final torque value on one head without the head gasket. In my profession, now retired, we tightened some fasteners on spacecraft in this angular fashion.

I’m going to check with all the sources I can find and confuse myself further. Back to the restaurant, ask the waiter what’s good. ???

[porschedude996]

Henry, what are your thoughts and recommendations on head torque procedures?

[porschedude996]

I just tried the torque methods spelled out in Wayne’s book, the Bentley Manual 91SC, Technical Service Bulletin (86-13) from PartsKlasick, and the Porsche Technical Specifications book.

Wayne’s Book:
Step One: 10Nm (7.4 lb ft)
Step Two: 32NM (23.5 lb ft)

Bentley:
Step One: 15Nm (11 lb ft)
Step Two: +90 degrees

Porsche Technical Specifications book:
Step One: 10Nm (74 lb ft)
Step Two: 32NM (23.5 lb ft)

PartsKlassic.com
TSB 86-13 For Production Date June 30, 1986
https://www.klassikats.com/technical-service-bulletin-cylinder-head-torque/
Step One: 15Nm (11 lb ft)
Step Two: +90 degrees
I’m not sure of his numbering scheme, all the other Porsche Tech Bulletins are differently numbered.

All the above come out the same, identical as I see it (on my not lately Snap-On calibrated torque wrenches).

ARP:
Step One: 19 lb ft
Step Two: 38 lb ft

The not so much shocker is the ARP. A bit of difference. It’s only 1.6 of the others ways above. But for the sake of conversation, ARP knows there stud reactions to pressure, tension, coefficient of material heat expansion. Maybe this the ultimate cure in my YM?

Knowing your materials, their reaction to tension/pressure and heat is done better these days. Metallurgical studies today I believe to be far superior to old Porsche material science. At least more clearly. Not to bad mouth, but Porsche screwed the pooch with head studs on 2,7L year models. It has been ghosted for years.

[porschedude996]

Work continues with the build.

[porschedude996]

These went together swiftly. I used RSR Seals on the rocker shafts.

[porschedude996]

Started installing the very first piston and cylinder and piston and broke a ring. Ahhhhhh!!!

I have a new Hazet Ring Compressor that I was using it upside down. The band that goes around the piston/rings is higher on one side. My cylinder was hitting a part of the handle and skewed cylinder and I broke the ring. About a 1/2” was broken off and I couldn’t find it. I bore-scoped it for an hour the first day. I had magnets on a stick down and around. I moved tote boxes and looked under, on, and around them. I looked at the expansion joint cuts in the concrete floor. I slithered on the floor for an hour. l wrestled with the thought that it’s not in the engine all night long. I had a hard time sleeping. I was sure it wasn’t in there but I was not moving forward without finding the 1/2” piece. I had my hawk-eyed wife out to help me. We both looked and finally I took a air hose and blew out the case from every angle. I was still using the air when my wife picked up the piece off the floor just below the engine. We did it, I really didn’t want to split the case.

I ordered a single cylinder set of rings from pelican and should be here tomorrow.

The other five went together with no problems.

[porschedude996]

I got my replacement ring and installed the jug. My glossy powder coated baffles went on. Heads went on without any problems. ARP’s to 38ft lbs

[porschedude996]

Cam Chain Cases are on. Using the Threebond 1184.

I was looking at the Stomski tool to tension the chain during timing, but thought of making my own adjustment tensioner out of my original spring loaded tensioners.

[porschedude996]

I got the engine all timed and sealed up. I borrowed a digital timing device and worked great. I think the numbers are good. I got both sides within (0.8 degrees). I tried either side of the pin hole that gave me .8 degrees and it was somewhere in the 3 degrees.





I was looking for a chunk of steel to set my magnetic holder for my dial indicator on to check TDC and found this lathe/mill fixture that i’ve had for decades and take a look at the hole spacing.

[PeteKz]

Lucky you!

[porschedude996]

I finished the Tin install with my freshly powder coated gloss black tins. I went without the gloss so it’s easy to clean.

[Dpmulvan]

Brilliant idea with the 123 blocks, tell us about the digital timing rig. Nice job

[porschedude996]

Thanks, I was trying to hold a different straight edge and a vernier caliper at the same time and knew that wasn’t working when I kept coming up with different measurements.

The digital cam timing device was borrowed from a new friend on the forum. He generously offered and I took him up on it.

If you’re interested I can ask if he wants his name in my post or would like to give people his handle.

So the digital resolver fastens to crankshaft, and sends a signal via an either net cable (RJ45) to the display/controller. First you determine TDC using a dial indicator or a mechanical device that screws into the aft cylinder spark-plug hole. Cylinders 1 and 4. I used a dial indicator which I found easier. Then you zero the display. A dial indicator is moved to the intake valve of the bank you’re timing. Also very important to have the valve clearance as best you can. I also use the dial indicator for the valve adjustments of all the valves. Once you zero the dial indicator on the valve adjustment nut, you would rotate the crankshaft in the normal direction of travel until you teach your cam spec. My target number was .050” or 1.26mm lift. Once you get there, read the display on the device and you are looking for zero on the display, when your lift spec values are met. I was able to achieve .8 degrees. I tried using the cam timing hole on either side and came up with a higher value. I think it was in the 3 degree range. in my case the best I could achieve was .8 degrees because that is as fine an increment possible between the holes. You need to perform this on both sides. Two cams to time…

Originally Posted by Dpmulvan

Brilliant idea with the 123 blocks, telus about the digital timing rig. Nice job