MARS928

Hello again. As some might have read my intro post, I have started working to revive my 1979 shark after a 20-year slumber. As stated, it was running without any apparent issues when parked. I did not plan on storing it for a prolonged time but as often happens, life got in the way and weeks turned into 20 years or so.
So I removed the spark plugs, poured some Mystery oil and let it set for a few days. I inspected the cylinder walls with a color camera and the walls looked good (no rust). So today I got a 27mm socket and a long handed ratchet and went to turn it, making sure it was in neutral, spark plugs removed. It started to turn with moderate effort, in a clockwise direction, then it would not turn anymore. I backed it up and again it stopped, it would not turn anymore. I marked the position of the pulley and went to turn it clockwise again and it turned about 7/8 of a turn. I tried a few more times, thinking that there might be some sort of build-up somewhere on the cylinder wall where the rings might be hitting it but it would only turn the 7/8s of a turn. I could use the starter but at this point, I would not dare. Can anyone suggest anything I can try or possible causes?
As always, you help will be greatly appreciated.

It will take a while to get my '79 in running condition, but now that I have actually started to work on it, I am anxious to be able to drive my dear shark again. With your help, it will become a reality.
Mario

Mrmerlin

is this car auto or 5 speed?

What was the reason it was parked 20 years ago?

Take the camera and put it down the cylinder that has the piston at the closest to the top of its travel turn the engine back a lil bit to lower the piston in that cylinder look for a nut or bolt in the bore. Or see if a valve might be stuck open

If no joy then determine if the driveshaft is not getting stuck somehow,
or that a valve is not stuck in the open position you might be able to use the bore scope to see this and it could lead to cam tower removal in fact it might be wise to pull the engine and swap in new head gaskets you might also need new heads depending on how the engine was stored with coolant

karl ruiter

I think everyone's gut reaction is that it has something to do with pistons or valves not doing what they are supposed to. But before you get to that, it might be worth ruling out other stuff. Other stuff could be (from rear to front):
1) It is not really going into neutral. The shift linkages have been know to fail.
2) Something in the clutch/flywheel area. For example there is a plastic cup that the release arm pivots on. That could have come apart and the bits fallen down in.
3) Water pump seizing in one position.
4) Timing belt coming apart or sticking to something.
5) Something in the timing belt path.
6) A belt driven accessory seizing.

After 20 years, it could be almost anything. Hopefully something easy. For sure you are right to go slowly and carefully.

GerritD

MARS928

Hi there fellows:

is this car auto or 5 speed?

5 speed

What was the reason it was parked 20 years ago?

A combination of factors, but essentially, had/have too many vehicles and too little spare time to drive it. It didn’t help that there are no worthy (exciting) roads to drive a car like this within 300 miles up north from where I live. Around here, pretty long stretches of endless, mostly straightaway freeways. I do miss driving it, regardless. I found this forum by accident. I came across a YouTube video and in it, the poster mentioned the Rennlist 928 forum, visited it and that rekindled my interest. I probably would not even try to revive my beautiful shark without the wonderful support given here.

As for this engine issue, I realize there are endless possibilities. I had not thought about some of them. The car is off the ground on the Porken bars. Seem to me that even if the transmission was engaged, the wheels/driveshaft would spin. Stuck open valve? Possible.

Seem unlikely that there is a bolt/nut in the cylinder as no other work was being done, only the plugs were removed but, sure, worth checking that out. Will have to get creative with the borescope to have it point up towards the valves. So far I could get it to bend near 90° within the cylinder.

As Karl suggests, I will also disconnect the fan belts and try to spin the different belt driven components to see if there is anything there. After trying all of this and before I start to tear the engine apart, I will do the diesel procedure. My gut tells me it has something to do with a sticking valve or timing belt issue, but as said, after 20 years, it could be anything.

Thank you, gentlemen, for your input

Mrmerlin

OK thanks for the info have you checked the timing belt to see if its still turning with the crank and if the cams and crank are in time?

To see if its a stuck valve all you need is a hose about 3 feet long,
turn the crank so any piston is close to the top of its travel IE you will see how close it is to the plug hole.

Put the hose into the plug hole and cover the hole then blow in it with your mouth,
any cylinder that lets air escape probably has a valve sticking open,
otherwise you wont be able to blow air into the cylinder.
.
Hardware will be easy to spot with the piston at bottom of each cylinder

MARS928

Well, good news, the engine is turning now using the ratchet/socket. The borescope had some adapters which attach to the tip and which I had not paid attention to before. One of them is a mirror placed at an angle that allowed us to view the movement of the valves, cylinder by cylinder as we turned the crank. They all moved. With that out of the way, we proceeded to mark and observe the different pulleys to see if they would make full rotations, as they are smaller than the crank pulley. We were in the process of doing that when the crank went past the point where it was stopping before. Whoa! we turned a few more times and then I felt confident that I would use the starter motor to turn it a few more times. But the starter would not do anything. I have the gas tank off the vehicle now. All wiring related to its removal is obviously disconnected. Is that related to the starter seemingly not getting power? Got a new, fully charged battery in there. Anything else to check? Again, thank you for your support.
Mario

GT6ixer

Have you checked the starter relay bridge? Make sure it's clean and pushed in all the way.

MARS928

Thanks, Nate. I will try to find it in the manual. If you all have a picture handy, please post it. I guess having the gas tank wiring disconnected is not an inherent reason then?

dr bob

The battery grounds to the rear apron. If you have an auto transmission car, the neutral safety switch on the side of the gearbox needs ground for the starter protection relay to work. On the later cars this is near the front of the spare tire well above the battery; not sure if the early cars are the same. If not automatic, there's a small copper jumper that bypasses the starter relay. Look in the CE panel for the jumper in the socket or the relay. The relay should click with auto gearbox in neutral or park position, even if the starter motor doesn't spin.

GT6ixer

Here is an excerpt from your manual.






Here is what the bridge looks like (CE panel not from a '79 but same bridge)




Here is a thread that explains what the bridge does.

https://rennlist.com/forums/928-foru...elay-does.html

Hey_Allen

Ok, I have to ask, was the change to blade fuses a year based thing, is that a community modification, or was this a picture from an entirely different model car?

I came to hate the GBC fuses when I worked with them in my first car (a 1982 Jetta), and the couple 80's MB's that I've owned.
If ATC blade fuses were an option, what year do I need to start looking for to scavenge one from?


edit: Nevermind, last night i found out through some image searching that the '86+ euro cars had the updated panel.

MARS928

Thank you dr bob and Nate, for the very useful information. I will get a chance to look into it this weekend. One of my plans is to clean every single ground point. I found the following diagrams in the New Visitor thread. It did not say what year/years they were for but it looks like a great guide. I remember seeing something similar in the manual, so I should be ok there.

[img]file:///C:\Users\User\AppData\Local\Temp\msohtmlclip1\01\clip_image001.jpg[/img]
[img]file:///C:\Users\User\AppData\Local\Temp\msohtmlclip1\01\clip_image001.jpg[/img]

(hope they show up in the post)

Mrmerlin

before you get too deep into trouble shooting you can try this little trick.
With the trans mission in neutral and the E brake pulled
connect the battery after you have cleaned every connection.
open the hood , go to the passenger side and remove the top half of the 14 pin connector,

NOTE if you dont know what this means then google Porsche 928 14 pin connector.

once this is done touch the pin thats furthest to the front of the car and closest to the fender edge # 14 to the hot post stud,
the starter should spin.
NOTE make sure the trans is in neutral before doing this.
NOTE doing this will remove the key switch and the associated wiring from the starting circuit.

NOTE to start the engine,
turn the key to run,
then touch the #14 pin to the hot post stud,
the engine will crank till it starts if its in running condition

MARS928

Thank you for the tip, Mrmerlin. I will try that after I clean all the grounds I can find. The gas tank is off the car now and off the ground on the Porken bars, so no chance of the engine starting or the car moving. All I want to accomplish right now is to turn the engine with the starter so that procedure should serve me well.

Nate, here is a picture of the CE (what does CE stand for anyway?) The bridge looks good and it is tight in place. I could not observe any type of corrosion:



Thank you,
Mario