Otto's Rebuild

[otto in norway]

Hi!
I am well undreway with my rebuild, but still a long way to go...
My car is a Euro spec 911 SC from 1979. (188Bhp, 8,5:1)

The plan is to perform a rebuild, and in the process replace the head studs for a racing-type, replace cams for "964" profiles, and get a higher compression ratio. Since I discovered that I have Alusil sylinders, I'll probably order a new P&S set... I don't have the money for this at the moment, but somehow, i'll get there. (I hope)

Guess I'll post some pictures first, with a few questions.

Engine on stand:


Rusty exchaust bolts, (no wonder many exhaust studs broke off):




Heads and sylinders off:


Alusil... -NOT what I needed, when the idea was to put in JE pistons:


JE Piston test-fit in Alusil sylinders... Looks like I'll need to sell the lot, and buy new P&S set..!


Valve carbon deposit. Notice a spray of solvant has expanded it on the right. Are they reusable? What size should I order if I need new ones? -Valves are ridicoulusly expensive over here!:



Worn CV joints:


More updates coming as I progress further...

[otto in norway]

Removing Head studs... (HARD work)

[Aurel]

Otto, I see you have bent one of your headstuds trying to remove it. They are locked with red loctite. Did you try to heat the case with a propane torch? That is the way to go...

Aurel

[otto in norway]

Yeah, I started doing that for the two latest ones I removed.

Luckily none of them were broke!

The others came off when my buddy and I worked together; One with a plumber's plyer (Is this how you spell it), and the other rotating a set of cross-tightened nuts, as shown on the picture.
As mentioned, we got out two with a propane heater so far, but tomorrow, we are starting with the remaining 5, armed with a new plyer, since the grip-teeth was quickly worn down on the previous...
Should work out well, just need to be patient while heating. (15 minutes/stud)

[Flieger]

What is the issue with JE pistons and Alusil cylinders?

[otto in norway]

Originally Posted by Flieger

What is the issue with JE pistons and Alusil cylinders?

Hi Fliger!
The deal is that Alusil is a relatively soft metal compared to Nikasil, so it has a set of different alloy pistons to go with them also...

You can look at it this way:

Nickies cylinders (Nikasil) are hard, accompanied by "softer" pistons.
Kolbenschmith cylinders (Alusil) are soft, accompanied by "harder" pistons.

JE pistons are Aluminum, and not the right stuff for Alusil, as the friction would eventually lead to seasure. On the other hand, they work great with Nikasil...


On Pelican's page for JE pistons they explain that they cannot be used with Alusil...
I chose to ignore this, thinking I had Nikasil. -But was not that lucky, as it turnes out...

[Flieger]

Thanks for the info

[sabeo.m]

you definitely need to heat up the case around each head stud. Even though it's not a good idea to heat the actual head stud, I did anyway. For me it seemed to help removing the head studs. I also used the head stud removal tool that is sold by Snap On tools. This tool is listed in Wayne's book. I carefully used a air compressor gun at 150 psi... Let me tell you these bolts are a pain in the ass to remove, if you haven't figured it out yet. I also had a head stud that was bent, it was the last one to come off the case and it took the longest time, about an hour! But, I finally got it out. Check out my thread for some possibly helpful pictures.. The best of luck!

Sabeo's 80SC Engine Rebuild

[otto in norway]

sabeo:
Thanks, I'm sure this will be of help!

Now I have another question:
I have purchased a set of JE pistons for my car. I know that they cannot be used with my Alusil cylinders. But can they be used with CIS at all?

They don't have the "swaying" top on the pistons like the original has. I understand that original pistons have this shape to help the CIS make a good flow in the combustion chamber. The JE pistons has pockets on the top to accomodate high lift cams, so I'm thinking this is primarily designed for carb setup, because that will allow for high lift cams. CIS don't allow this, wich is why I've gone for the "964" profile cams.

Hmmm... Anyone?

Pic of piston below:

[otto in norway]

Progress so far:
I'm selling my JE pistons, and if possible my old original P&S set alaong with the old cams. Then I'll buy a brand new P&S set here, (PP), together with SSI heat exchangers and a pre-muffler to replace the cat.
I've sent out the heads for refurbishment, and the oil cooler for the engine for cleaning.

Got some parts yesterday... (The list is scary, and still, ther is a lot more to come!)

[Aurel]

Otto, you can have your cams reground to 964 profile, no need to sell them, and a lot cheaper than new, or even good used cams.

Aurel

[otto in norway]

I've allready bought a set of "964" cams. So I don't need the old ones.

[911pcars]

Otto,
I suggest doing some additional background research on your options and basic assumptions. False assumptions could cost you add'l budget. Bruce Anderson and Wayne (Pelican) have gathered some very thorough information on engine rebuilding. Reference those manuals to determine what works and what doesn't.

All contemporary engine pistons are made of aluminum alloy, including the ones designed for Alusil and Nikasil cylinders. The differences include whether they're forged or cast aluminum, if piston is compatible with the cylinder surface, type of induction (CIS, MFI, carbs), mechanical compression ratio for a given engine size, etc.

Sherwood

[otto in norway]

Sherwood:
I think I allready know what I need.
It says on Pelicans info regarding JE pistons, that they cannot be used with Alusil. And I know for a fact now, that I could have used the JE pistons with Nickasil. But with the money that I got from selling some parts allow me to buy an entire set of P&C, without braking the budget too much. This means I don't have to wait 6 - 8 weeks just for a set of cylinders, made to spec. (I'd like to get on the road ASAP)
I have talked to many people about this in Norway, including the guys at the Porsche engine workshop here, and they all say this is the way to go.

[OldTee]

You might want to talk to Camgrinder or Bruce Anderson about using a 964 grind with that set up with CIS. The thought is the 964 gind creates a situation where an over rev will crash valves into pistons. Something about the down slope on the cam being pretty severe and it affects the valve springs and keepers and they fail or can't keep up. Not sure I understand all I heard, but checking may save you some trouble.

[otto in norway]

I have heard the same thing about normal SC cams.
Some say that this can occur because the chain tensioner has a slack. This is taken care of with carrera style tensioners.
Overrevving is never good for the engine, so I'll have to be careful not to do so, as always.

[otto in norway]

Progress: Opened the block today, and it looked pretty good!
I'll only need to replace the bearings for the oil pump axle. (Of course, I'll replace the chain guides and chains also)
Pic:

[304065]

Otto, you should replace the main bearings when you have the case apart, not just the intermediate shaft bearings.

[otto in norway]

That's what I thougt too..!
But my pal, who has opened a lot of engines, felt that this was a waste of time.
He said that since I have alomst no wear on these bearings, it means that the main shaft is nearly perfectly balanced and centered. So, if I keep these bearings, I will be sure this continues like that for the future. And a LONG time into the future as well! I choose to thrust his judgement; He does this for a living, and he has been spinning the spanner since he was 7 years old...

[wwhalenc]

All the 944 guys are stuck with Alusil. I've heard over there that JE has a coating availble that survives in an Alusil bore. Might be worth looking in to.