1979 SC Chewed a Valve - Total Rebuild

[Henry Schmidt]

Originally Posted by rwest

I always wondered about the use of Loctite on engine parts as the temperatures would be likely so hot as to render the locking effect null. Am I correct?

Different LocTite products have varying operational temperature ranges.
Generally speaking, 911 engine temps will not exceed the operational range on most LocTite products.
Choosing the correct product for each application is generally made easier by the manufacturer's build criteria but with some applications, experience is key.

[OsoMoore]

Lots of scraping gently at the old sealant on the case edges today. Right arm is a bit sore!
I have a plastic "razor" blade, but there are a few tough spots left that aren't coming.

There is also what looks like old JB Weld or some such on the outside, maybe stuck there to try and cover some leaks? I'm chipping it away from an outward angle to avoid any contact with the case mating surfaces.

Supertech kit comes next week, lube and such comes Friday. Hopefully putting together the crankshaft this weekend, crank case next weekend.

[OsoMoore]

Putting the crankshaft together this morning!
I have OEM rod bolts they came assembled from the shop but of course I'm taking it apart to clean and put on the crankshaft.
So what should I lubricate these bolts with? The consensus seems to be that I shouldn't use loctite. But I got the bolts from the shop already inserted and initially torqued, so of course I had to take them off. Should I just use some engine oil? Should I use my permatex assembly lube? Should I bolt them on dry?

The lubricant they have on them now will likely be washed off by my brake cleaner and alcohol as I clean everything.

[OsoMoore]

Trying to find moly paste locally, so far nothing.

Really hoping I'm not going to have to wait for an online order.

[brighton911]

Those JB weld spots on the cases are likely the recommended repairs for known leak areas.

[OsoMoore]

Originally Posted by brighton911

Those JB weld spots on the cases are likely the recommended repairs for known leak areas.

That seems possible. I know the original rebuilder made some fixes that way.

Here's what I was able to pick up at the Honda Motorsports store.

[OsoMoore]

Shop guy messaged back, he said engine oil was fine, don't need the special moly lube.

Looking at torque spec, looks like my bolts are labeled "12.9". That means torque to 10.5 ft/lbs and then 90 degrees, twice.

I already tightened to 14.7 per Wayne's book, and then stopped before doing the 90 degrees.
Does that mean I should "back off" to 10.5 ft/lbs and then do the double-90 described in the bulletin?

[OsoMoore]

Crankshaft is back together! Still need final assessment of how to handle the torque confusion.

Old style bolts is 14 ft/lb then 90 degrees. New style bolts 10 ft/lb then 90 degrees and 90 degrees again. My bolts are new style.
Before finding the new style spec, I did a 14 ft/lb (but no 90 degree turn yet) and stopped. Should I back mine off to 10 ft/lbs and then continue?

Took some photos of it going together. Such an amazing piece of engineering!


Gathering together everything for case closing, including Supertech's kit arriving today. Do I really need the chain-holder and rod-holder to make this go smoothly? Maybe fab my own? There's a shop across town that can lend me theirs over the weekend.

[stownsen914]

I made a chain holder out of aluminum sheet. Or you could use steel strap. Wayne's book has the dimensions. To hold the rods, I actually used cardboard believe it or not. A longer piece to do I believe it was rod #6. And for the other two rods, I folded cardboard pieces and wedged them between the rod and the crank counterweight. You do want to be able to prop up the rods when you lower the top half of the crankcase, or you'll be wishing you had 5 hands. My solution is a a bit ghetto, but it worked fine. If you can borrow proper tools, I'd go for that.

[OsoMoore]

Originally Posted by stownsen914

I made a chain holder out of aluminum sheet. Or you could use steel strap. Wayne's book has the dimensions. To hold the rods, I actually used cardboard believe it or not. A longer piece to do I believe it was rod #6. And for the other two rods, I folded cardboard pieces and wedged them between the rod and the crank counterweight. You do want to be able to prop up the rods when you lower the top half of the crankcase, or you'll be wishing you had 5 hands. My solution is a a bit ghetto, but it worked fine. If you can borrow proper tools, I'd go for that.

Ok, picking up some aluminum later today to give it a try.

Any thoughts on the torquing, where I went up to 14 ft/lbs instead of 10 ft/lbs, but never did the 90 degree turn(s)?

[ahh911]

1978 SC isn't part of that technical bulletin.

I believe you have the 10mm bolt, the bulletin only applies to 9mm bolts.
The original SC rod bolts from my 81 had 12.9 as did the replacements, no difference.

I studied this at the time, I went with 55Nm with light oil on threads.

Here is my post asking the same question:

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1070840-were-1974-1983-rod-bolts-always-grade-12-9-a.html


Phil

[OsoMoore]

Originally Posted by ahh911

1978 SC isn't part of that technical bulletin.

I believe you have the 10mm bolt, the bulletin only applies to 9mm bolts.
The original SC rod bolts from my 81 had 12.9 as did the replacements, no difference.

I studied this at the time, I went with 55Nm with light oil on threads.

Here is my post asking the same question:

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1070840-were-1974-1983-rod-bolts-always-grade-12-9-a.html


Phil

My new bolts are stamped with 12.9, but I'm pretty sure my old ones were 0's. Will check later.

[OsoMoore]

This bolt torque stuff is a bit of a PITA.

I backed them off and then torqued 10ft/lb + 90 degrees, preparing for a second 90 degrees later. This was based on them being stamped 12.9.

Then I talked to my local shop and they said the spec for SC is 55 Nm (what ahh911 said above). I decided to do some measurements on just one rod. I measured it at current spec (10+90 deg), loosened and measured again, then tightened 25 Nm and then 55 Nm, and measured again at 55 Nm. This was with my dial micrometer.

2.735" at 10 ft/lb +90 deg
2.724" after loosening bolt entirely
2.736" after tightening to 55 Nm

I measured some of the other bolts on other rods (tightened 10+90 deg), and found they too were right about 2.735"
Do you think I in the clear?

[OsoMoore]

Good progress today after a non-Porsche busy Saturday.

I read and reread the crankcase assembly section in Wayne's book, and analyzed what Henry wrote in his sealant kit.
Per his kit, I installed the pulley seal dry. Does it go 100% below the lip of the number 8 bearing? Mine is just slightly peeking out.

I put the crankshaft into the first half of the crankcase, but I haven't moved to close the other half onto it yet. I'm going to lay out all my bolts and nuts and need to finish fabricating the rod and chain holders with some aluminum stuck I grabbed.

I'm not sure if I should be putting on the flywheel seal now or later. How is that usually handled? Any other tips before I take the plunge and mate the case?

[mikedsilva]

Originally Posted by OsoMoore

Good progress today after a non-Porsche busy Saturday.

I read and reread the crankcase assembly section in Wayne's book, and analyzed what Henry wrote in his sealant kit.
Per his kit, I installed the pulley seal dry. Does it go 100% below the lip of the number 8 bearing? Mine is just slightly peeking out.

I put the crankshaft into the first half of the crankcase, but I haven't moved to close the other half onto it yet. I'm going to lay out all my bolts and nuts and need to finish fabricating the rod and chain holders with some aluminum stuck I grabbed.

I'm not sure if I should be putting on the flywheel seal now or later. How is that usually handled? Any other tips before I take the plunge and mate the case?

Everyone might be different to me... but I mount the #8 crank pulley seal and knock it in as far as it will go in the bearing. I think it appears to stick out just a fraction.

I do NOT put the flywheel seal on at this point. If I did it this way, I can imagine the seal might get cocked to one side etc. For me it's easier to install after the case is together.

As for any other tips: make sure everything is so clean. It cannot be clean enough.
Use an o ring installer to get your o rings over the threaded portion of your through-bolts. Use LOTS of the Molykote 111; your o rings should not be dry.

Lay out all your washers, nuts etc before you start.
Have all your tools laid out before you start.
Make sure your #8 bearing locates on the dowel in the right side of the case.
Go through it in your head as a practice run.
Make sure you don't get interrupted once you start. (kids, pets, spouse etc)
Don't forget your o rings in the case and oil pump!

If at any point you think you are unsure, now is the time to pull it apart and re-check everything.

[OsoMoore]

Looks like my seals kit lacks nuts! And I don't think I want to reuse dozens of current nuts. For the oil pump I need 3x 13 mm. For the case... well that's a lot.
From what I read here, I can re-use everything: https://forums.pelicanparts.com/porsche-924-944-968-technical-forum/526545-crankcase-lower-section-fasteners-reusable.html

And the picture here shows the total number and count. Looks like 21 edge bolts (nylock nuts, washers, etc.) and 11 Through Bolts.

I have all my old hardware. However I think I'm going to need new nylock nuts. You aren't supposed to reuse those, right?

[OsoMoore]

The question is whether these m8 nylock nuts are 1.0 or 1.5 thread pitch

[stownsen914]

They're 8 x 1.25 mm actually

[OsoMoore]

Originally Posted by stownsen914

They're 8 x 1.25 mm actually

Aha, thanks!

I found my old nuts. Should I clean them, buy new ones from hardware store, or get special Porsche engine nuts from somewhere?
I'm reading some threads here saying nylok is a bad idea on the case. I'm a little concerned Ace Hardware drawer bolts aren't sufficient quality.

Or maybe I'm overthinking it.

[dannobee]

No nylocks inside the case. Use the friction type of lock nuts.

Something that looks like these.

https://www.mcguckin.com/2889007/product/MIDWESTFASTENER-72962

You can probably get some at your local auto parts store.

And yes, make sure the seals are in place when installing the oil pump and fitting the halves of the case together.