911 engine knocking noise

[speedy914]

Originally Posted by BURN-BROS

I just noticed the video, That sounds like Valve lash.

I would look at the rockers carefully and make sure the shafts are in the correct positions.

Originally Posted by 911pcars

Here's another. Rocker arm shaft only partially supported = valve noise.

removed exhaust valve cover were noise seems loudest. #6 exhaust rocker shaft is incorrect. Towards the thick side in the carrier not the thin side. Its tight. I guess I f'd up during assembly. Now to fix it and check all the others. Hard to believe all that noise just from that? A ***** to get to it. A 914-6 so suspension id pretty close to that area. Although I think I can remove the oil cooler and get it. Looks like another Sunday in the garage on my back...

[mikedsilva]

Good news thay you found it before any damage could have occurred. Good work.

[dtxscott]

So the shaft was offset more toward the thick side of the jousting than the thinner side?

[speedy914]

Originally Posted by dtxscott

So the shaft was offset more toward the thick side of the jousting than the thinner side?

Correct. Seems like a lot of noise from just that, but I had 2 other people (other then this forum) that thought rocker shaft loose or alignment was the sound. I checked them all of course, its the only one wrong (my fault of course)

Spent the entire Sunday fixing it. Easy fix once I got there. I did have to remove the oil cooler.

Now to triple check valve adjustment since all covers are off. And then a lot of re-assembly. It'll be a least another week before I start it I'm afraid. I work 50hrs/wk and have plans next weekend....

[nene]

I find that very interesting.......

[infraredcalvin]

Any updates? I’d sure love to hear that was your problem and it’s now solved...

[speedy914]

Noise still there. Son of a dog.

[dannobee]

A couple of things that might help. You could possibly narrow it down to one cylinder by grounding out the plug wires one at a time and listen for a change. If you have a stethescope or piece of heater hose, start listening around to try to narrow down the location.

[speedy914]

Originally Posted by dannobee

A couple of things that might help. You could possibly narrow it down to one cylinder by grounding out the plug wires one at a time and listen for a change. If you have a stethescope or piece of heater hose, start listening around to try to narrow down the location.

Yep. I have an engine ear (battery powered headphones with stethoscope) Can't seem to pinpoint area. I will try pulling plugs wires and see if change. Thanks.

[speedy914]

#6 piston pin retaining clip missing. Pin walked. Cylinder ok but Piston not.
Wanted 1 Mahle 90mm 2.7 10.3:1 Carb/Mechanical Piston and pin.

[mikedsilva]

gosh.. got a pic of the damage? wonder where the circlip is...

[dtxscott]

Wow, that is terrible. Sorry to hear this.

Good luck on the piston search.

[gled49]

Have you removed the vacuum line from the distributor. The vacuum cans for MFI are different to accept the pulses and a CIS can for example will clack like yours. Ask me how I know.
Never mind looks like vacuum can is disconnected.

[gsxrken]

Originally Posted by speedy914

#6 piston pin retaining clip missing. Pin walked. Cylinder ok but Piston not.
Wanted 1 Mahle 90mm 2.7 10.3:1 Carb/Mechanical Piston and pin.

Oh, that blows. That...blows.

Originally Posted by mikedsilva

gosh.. got a pic of the damage? wonder where the circlip is...

I’d worry about that clip too. Whole other deal splitting the case though.

Originally Posted by gled49

Have you removed the vacuum line from the distributor. The vacuum cans for MFI are different to accept the pulses and a CIS can for example will clack like yours. Ask me how I know.
Never mind looks like vacuum can is disconnected.

Come on, Gled. Try to keep up. LOL

[911pcars]

Originally Posted by speedy914

#6 piston pin retaining clip missing. Pin walked. Cylinder ok but Piston not.
Wanted 1 Mahle 90mm 2.7 10.3:1 Carb/Mechanical Piston and pin.

Retrieving the clip (or what's left of it) will determine the extent of the repair. If lucky, it will be in one piece on top of the screen or in the bottom of the case. It's magnetic and maybe retrievable (easier in a non-ferous case). If you can, show us your piston for further autopsy. It's curious the cylinder escaped injury.

Sherwood

[speedy914]

Tore engine completely down. Split case. Did not find clip.
Going back together with JE 10.5:1
New set of Mahle $6k just too much money.
Pistons have changed in metallurgy of the years.
So finding a single NOS or good used 10.3:1 from the 70's or 80's just not gonna happen.
Paying a professional now, cant risk anything again, plus I work 50hr/wk just don't have the time.
Sucks, but its in good hands, I trust the guy.

[evan9eleven]

Speedy, sorry about your bad luck. Hope you get it sorted asap.

I would also like to kmow more about this, I have a 3.0 that makes quite a lot of low rpm clacking and shutoff clatter:

Originally Posted by BURN-BROS

Porsche made a batch of 3.0 liters that had excessive crank endplay and exhibited a knock below 900 rpm

[Cairo94507]

Speedy914 - Wow, I am so sorry read and see this happen to your engine. But it will be back together and in the car soon.

I dreaded the start-up on my fresh engine after it sat for about 3.5 years before being fired up. We were flipping a coin to see if it would be OK once fired. Real nail biter for me.

[bertsboat]

May I ask if your pistone were 2.7 or 2.8?

Originally Posted by speedy914

Tore engine completely down. Split case. Did not find clip.
Going back together with JE 10.5:1
New set of Mahle $6k just too much money.
Pistons have changed in metallurgy of the years.
So finding a single NOS or good used 10.3:1 from the 70's or 80's just not gonna happen.
Paying a professional now, cant risk anything again, plus I work 50hr/wk just don't have the time.
Sucks, but its in good hands, I trust the guy.

[mikedsilva]

i bet the missing circlip is on your workshop floor somewhere....