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-   -   911 engine knocking noise (http://forums.pelicanparts.com/911-engine-rebuilding-forum/1082348-911-engine-knocking-noise.html)

speedy914 02-27-2021 05:35 PM

Quote:

Originally Posted by BURN-BROS (Post 11240332)
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.

Quote:

Originally Posted by 911pcars (Post 11240121)
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 02-28-2021 12:31 AM

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

dtxscott 02-28-2021 09:49 AM

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

speedy914 02-28-2021 12:52 PM

Quote:

Originally Posted by dtxscott (Post 11243030)
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....


http://forums.pelicanparts.com/uploa...1614549044.jpg
http://forums.pelicanparts.com/uploa...1614549076.jpg

nene 03-07-2021 08:53 AM

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

infraredcalvin 03-09-2021 08:07 PM

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

speedy914 03-10-2021 02:24 PM

Noise still there. Son of a dog.

dannobee 03-10-2021 03:23 PM

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 03-10-2021 03:32 PM

Quote:

Originally Posted by dannobee (Post 11255378)
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 04-13-2021 03:56 PM

#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 04-14-2021 04:57 AM

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

dtxscott 04-14-2021 05:20 AM

Wow, that is terrible. Sorry to hear this.

Good luck on the piston search.

gled49 04-14-2021 07:35 AM

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 04-14-2021 05:06 PM

Quote:

Originally Posted by speedy914 (Post 11296018)
#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.

Quote:

Originally Posted by mikedsilva (Post 11296466)
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.

Quote:

Originally Posted by gled49 (Post 11296659)
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 04-14-2021 10:33 PM

Quote:

Originally Posted by speedy914 (Post 11296018)
#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 04-21-2021 03:12 PM

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.http://forums.pelicanparts.com/uploa...1619046688.jpg

evan9eleven 04-26-2021 01:32 PM

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:
Quote:

Originally Posted by BURN-BROS (Post 11240076)
Porsche made a batch of 3.0 liters that had excessive crank endplay and exhibited a knock below 900 rpm


Cairo94507 04-26-2021 02:18 PM

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 11-28-2024 11:46 AM

May I ask if your pistone were 2.7 or 2.8?

Quote:

Originally Posted by speedy914 (Post 11305082)
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.http://forums.pelicanparts.com/uploa...1619046688.jpg


mikedsilva 11-28-2024 11:51 AM

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


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