'68 Sporto no turn overo

[JT912]

Quick rundown. '68 911 Sporto with original engine. Car is being restored and was running (poorly) about a year ago. I had a personal project which put getting this cars running issue resolved. Personal project completed and new Hardi fuel pump installed to resolve the low/intermiittant fuel issue. New pump clicking away happily. Went to start and it the motor won't turn over. Thought it was a low battery so added a jump charger and still nothing. Went back and I can't turn it over by hand.
Removed the plugs. Nothing. Pulled the starter (PITA) and still nothing. Loosened valves, still locked up. I am hoping to find a solution without having to pull the motor. Any other ideas? Is it possible for a garaged car to have rust in the cylinders in a year? The axle flanges on the Sporto spin free (axles not reinstalled yet).
Last time it was running I don't remember hearing any noises that would have hinted at an eminent problem.
Any and all ideas are appreciated.
Thanks.
John

[304065]

Carbon fell off the piston, sticking it in the bore. Can you borrow an LED borescope to look inside? I would think that soaking the cylinders with B12 or Seafoam might break up whatever is sticking it. The old airplane guys use ATF. Make sure you get it all out before you try to turn it over with the plugs in, hydraulic lock will bend things.

[JT912]

I've got the cylinders soaking, but I don't think there is carbon in there since the crank won't rotate in either direction. Seams like if there was debris in the cylinder preventing the piston from continuing on the compression stroke it would not effect its ability to run the other way. I am giving it over the weekend to soak and then it is yank the engine time if no other solutions pop up.

[Two Rivers]

I had a VW air cooled engine do that once. It sat in a warehouse for a year or so and the rings rusted to the cylinders. I freed it up and it ran ok for about a week then broke rings. After taking it apart where the rings got stuck there where deep grooves,Two perfect round grooves of the top and second ring. Had to replace the cylinders. I hope you have better luck. I was living in seattle at the time, My grand father blamed it on the ship ride over from germany, from the salty air. But he was always teesing me :-}It had thirty thousand miles before I stored it.

[JT912]

Hoping to not need to pull the engine, I devised a method to block off the intake and exhaust ports and fabbed up a filler tube. I filled the cylinders full of Marvel mystery oil. I let this sit for two weeks and the engine was still locked up. I did realize that the air injection lines were also full of Marvel on the couple of exhaust valves that must been open a bit.
The motor was then taken out and put on end and again soaked with MMO for a week per side. Heat was applied to the cylinders a couple of times during each of these attempts. I even tried the vibrations from an air chisel to see if that would help. Still nothing.
A local Porsche guru mentioned trying PB Blaster instead of the MMO. So again each side was soaked for about three days and.....nothing.
Today I got ahold of the magic 46mm crowsfoot wrench and P202 too. Right side come off with no problem. The left side was a bit more difficult due to the funky cam for the air pump pulley. The P202 tool won't work, but an open end wrench worked well in its place.
The cam towers and heads came off pretty smoothly. Only one nut needed some gentle caressing to get it off. With no heads on and the cylinders not locked down, I was able to get the crank to move. It did so by pushing out the cylinders (1/4"- 1/2"). I was somewhat relieved to find that the problem didn't appear to be internal. A couple of the cylinders were easy pushed back tight to the case. But...there appears to be two that are definitely one with the pistons (#5 and #6). This motor is a reasonably low mileage and all stock. The carbon build-up is very minor so I don't think this problem is a chunk of carbon. The cross-hatching is still very visible.
So I will focus these two cylinders and remain hopeful.

[JT912]

A bit of buildup on the valves.




This is a '68 911 (normal) smog-equipped Sportomatic. Interesting that the case halves are different date codes. Case halves are matching numbers.

[304065]

John, I didn't recognize you at first from the 912 BBS, WELCOME.

It is quite a surprise that the rings have rusted to the cylinders, at least you know what the problem is now. I guess the question is, how to free them without destroying the cylinders. I think you are on the right track with the heat method, that should do the job.

Thanks for the post of the case halves, it shows that they grabbed a casting for each side off the shelf and then machined them together, vs. the halves being married from the casting date. We see that later on with 4R/5R case combinations.

Good luck and let us know if you need any replacement bits for your 2,0.

[JT912]

I am first and foremost a 912'er. My first car was the '66 912 that some 22 years later still sits in my garage. This 911 was a car my brother-in-law came across thru a teachers-only classified. It has been an on-going project for the past 8 years. This was going to be the summer to get it back on the road.

[JT912]

Today's tear-down provided some interesting things.
For those who aren't familiar with the "special" '68 heads with the air injection (smog) port, here it is and the fitting that screws into it.



What I thought was a reasonably virgin engine appears to have come apart before. Each head was nicely marked with dimples to represent the cylinder number.



I think the head studs have had inserts installed.



I think mine is longer than yours. This is the end of the driver's side cam that has the smog pulley attached.

[JT912]

The Sporto oil pump which is run off the other end of the driver's side cam.





I think this next discovery is bad...Oil starvation? What causes this. 6 of the rockers have this problem.






More bad. All the lobes on both cams had very minimal wear. Except for the lobe from the above rocker. Looks like I will be doing some rocker/cam work. Anyone have a NOS USA Sporto cam?

[JT912]

The intake rockers on 4, 5, 6 have all had machine work done to them.



And it appears all the heads have had a helicoil (or similar) installed. Hmmm?



And the pistons are still holding on strong.

[304065]

John,

Great photos! I don't think anyone has ever posted good ones of the sportomatic-specific parts, at least not as long as I've been here.

It looks as though you may have a mix and match set of rockers-- the 911 rockers were originally forged with a pronounced central rib, then went through three cast styles, the first of which didn't use a bushing. The change-over point was probably sometime in 1968 calendar year. The good news is that you can have the old ones rebushed, or you can fairly inexpensively source a core set that all match. The elephant foot adjusters often have buggered slots, and the jam nuts can often be stripped, but these are not too expensive to replace.

The galling is probably normal wear for the unbushed rockers, unless the cam spraybar is clogged on that side. The flat cam lobe may be further evidence of a blocked spraybar hole that would have starved that lobe for lubricant, no other way to explain why just that one is flat. Contact John Dougherty (camgrinder here) for information.

The helicoil is a factory part for the 2,0 liter heads, the threads were integral from 1970 onward with the 2,0.

Those are also good pics of the exhaust air injection! Good luck and keep us posted!

If you search tag "901/05" you will find everything I know about rebuilding 2,0 liter engines.

[JT912]

This is definately going to be an (expensive) learning experience. I was just reading (again) Wayne's rebuild book and he mentioned a bushed rocker. I thought "maybe these were replaced". I will unwrap them and take a closer look.
I will look through the 901/05 postings to learn more new stuff.
Thanks.

[304065]

John, the good news is most of what you need is available inexpensively. A good set of rockers can be easily found here in the classifieds, or ask Tom Butler (tom1394racing), I'm sure he has a used set.

"While you are in there" I would recommend updating the cam tensioner idler arms, either with the latest Porsche part ($$$) or with the Supertec bushing kit, Henry Schmidt of Supertec re-bushes the original arms with a wider bushing that approximates what the factory did. Seizure of the idler arm on the shaft was associated with tensioner failures. I see you have the earlier 930 tensioners and safety collars, good.

If the chains aren't too worn you should be good to go, I see you have the original SWB type chain sprockets with the pointy teeth. A good check on the chain wear is how much room you have between the idler arm and the side of the chainbox-- when the chain and sprockets wear too far, the tensioner is at the end of its travel and the idler arm is bascially hitting the side of the chainbox. That is a sign that action must be taken, usually by replacement of the chain with a master link version, works just as well.

What will be hard will be resisting the temptation to bump the displacement to 2,2 "while you are in there" and to change the cam profile from the 901/06 profile to Mod-Solex. . .

Fear not, there are a couple thousand guys on here ready to help you, including some of the finest engine builders in the world. . . we SWB guys have to stick together!

[Fritter]

A lot of your parts look familiar to me, I have a 68 901/17 spare engine that I took apart. Air injection system, goofy cams, everything....let me know if you need help. I had the same galling on the rockers, that is why they started bushing them later on.

[JT912]

Mike,
Do you have the smog cam?

[Fritter]

Yes I have both smog cams.

[JT912]

I've gotten #5 freed up and slight movement on #6.

[JT912]

So this has been an interesting process. The pistons are free'd up, but not to the point I would be willing to call it fixed. So today's task was to remove them. #1 - #4 were a cinch. 5 and 6 a bit of a chore requiring some creative manipulation. Those two pistons seemed to both get wedged tight just after the wrist pin was exposed so I was able to drive those out and pull of the P&C together. I had a 2 thousanths feeler gauge that I could slide between the piston and cylinder. Both of the jambed pistons had a spot where I couldn't get the feeler gauge in. After looking at them, I could see they were slightly cocked. A gentle tappy-tap to square it back up and I was able to pop both of them out. They both have a couple spots where there is a build-up (kinda chalky) that comes right off. Very odd. I am now also coming to grips that this is a pandoras box. I am sure enough crap has fallen into the engine cavity to necessitate it coming apart.

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[JT912]

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