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Posted by: doobie123 Jun 27 2023, 10:44 AM

working on my porsche 914, 2.0, 5 spd
i'll try to keep this short and still give the details so...
i had the drive train out to do the clutch/flywheel and decided to freshen the top end. the car ran fine when i got it but, the clutch was bad so i took the plunge,(something i never did before) and went for it.
put it back together and test drove it. it ran fine for the first mile or so but on my way back to the shop, it started making a banging or, knocking noise. i decided to check the valves and use the method of pulling the plugs and turning the cage by hand. pulled the plugs, went to turn the cage and it was loose. i was able to rock it and when i turned it, the cage turned but not the three bolts holding it. upon further inspection, i was able to turn the center bolt, (crank bolt?) with my fingers.
i got a socket, (13mm) on it and can tighten it down but before it tightened, i could feel a clicking through the wrench.
so my questions are does it just tighten on the cage? should there be a key way that the cage needs to engage? will tightening it the torque specks do the trick or do i need to drop the engine again? is there a chance i've done damage by running it?
i know that there is a unknown as far as the damage but i'm just looking for some suggestions as to where i go from here.
thanks

Posted by: r_towle Jun 27 2023, 10:53 AM

There is a woodruff key on the end of the crank that holds that flange.
The flange has the three bolts for the fan (fanhub)

I would remove the three bolts, the belt, and the fan...it can come off with the engine in the car.

Take a good look at that fan hub, remove it...make sure not to drop the key...its loose.
See if the key is broken, or the crank slot is damaged.

Then decide if you need to drop the motor to deal with it.

Its hard to see, but can be done.

Mirrors and flashlights are your friend.

rich

Posted by: Olympic 914 Jun 27 2023, 10:55 AM

There is a keyway there.

Timing is set by marks on the fan, so it HAS to be in the correct spot to start with.

Otherwise you will never get the timing set right.

Posted by: r_towle Jun 27 2023, 11:04 AM

Looking at another thread..
You used the crank bolt to set the valves...so you might have loosened it while doing that.

TBH....you can turn most of these Type4 motors by hand if you remove the plugs. Pretty simple if out of the car...or use the flywheel instead of that 13 mm bolt. That bolt gets torqued...and never touched again.
It can be an expensive thing to fix if it munged the keyway in the tip of the crankshaft.



Rich

Posted by: doobie123 Jun 27 2023, 11:14 AM

QUOTE(r_towle @ Jun 27 2023, 12:04 PM)

Posted by: doobie123 Jun 27 2023, 12:17 PM

ok, so i spoke to dr. 914 and he suggested to tighten the bolt to torque spec which i found out i think, is 23ftlbs. when i did that, started it up, ran it for a couple mins and checked the bolt and it had backed out again. so what gives?
any suggestions would be great.
thanks

Posted by: r_towle Jun 27 2023, 12:43 PM

Take the fan off.
Take a closer look.

If all parts are in proper working order, the bolt should not come loose.