3.2 sounds like a diesel

[gled49]

Have u tried removing plug connectors or cap wire one at a time, the old rule was if the noise goes away it’s a rod, if the noise doubles, it’s a wrist pin, if it stays the same it’s piston slap. No hard truth to this, but something to try. Doesn’t sound terminal to me.

[Mehoff]

Originally Posted by stubble88

Yeah. Sorry.
Car was a dedicated race car
Lots of motor work done by AASE in 2018
New clutch (stock)
New lightweight flywheel
Had straight pipes now has Dansk 2/2
New oil and filter
New fuel lines
Simple race harness replaced with good used one.
DME harness not changed.
911 chips custom. (This ill seek more info on)
Headers with Dansk. No cat

2018 AASE 3.2 build in a dedicated race car was almost certainly built to run 110. Don’t think that’s your issue, but it will become one if using pump gas.

Show a pic of the car and we can tell you if it was a SP911

[stubble88]

had a lengthy conversation with Steve Wong from 911 chips. so this car has 95mm 9.5:1 Cp with pins, rings and clips. so more than likely this noise is from those cold race pistons doing some slapping before its super warm. Also tuned for 100 octane.
I'll need a new chip so I can run pump gas.

[stubble88]

SCR spec Carrera 3.2 race class

[stubble88]

Update
-Valves adjusted
-New 911 chip with pump gas tune
-Timing chain tensioners checked. Looked new in there. Chain was tight
-new plugs

At first start up I heard nothing. But then it crept on and was still there.

Stethoscope (amazing) used. Everything sounded great and even. But this knocking noise was most noticeable on the fan house. Honestly. I could not hear the knocking until I touched the fan housing. Could it be the alternator? I’m going to let it cool and take the belt off and see.

[gumby]

pop the belt off and see if the noise goes away (bad alt bearing) but dont run it to long, the motor will overheat!

[stubble88]

Not the alternator.
Seems to get louder as motor warms up. Not really there on initial cold start.
Seems to smooth out or is not present with revs

[proporsche]

i still think as i have mentioned at post 7..The wrist pin when the engine gets war-hot.Did you locate which cylinder,yet?

Ivan

[stubble88]

Originally Posted by proporsche

i still think as i have mentioned at post 7..The wrist pin when the engine gets war-hot.Did you locate which cylinder,yet?

Ivan

Ive stethoscoped a couple times. It all sounds the same on every cylinder. Fan housing amplifies this knocking sound. Bottom of engine seems quiet.

[stubble88]

Cold start. Sounds normal. But idle is a bit higher when cooler.

https://youtube.com/shorts/xoCcPnAEDok?si=KRrkkt-5kqOdrV36

Warm. Knocking sound shows up. Idle lower when warm.

https://youtube.com/shorts/m-xKjY6AADo?si=Sk4BD-UZcyNchIK2

[proporsche]

i know you cannot hear it on the 1st video but i can in the distance.On 2nd it actualy sound not as one but 2 noises ..
I do not know the history of the engine but i have heard this sounds before.
One of my friends in LA very good 911 mechanic was chasing this problem ended up taking the engine (after rebuild),apart. Heating the pistons and only after this he found the wrist pin loose in one of the pistons.Mind you the measurements cold all was perfect..So when cold no noise only after warm engine..
Ivan

maybe some other engine re-builders here will chip in another idea

[stubble88]

Pulled plug cables one by one. No change. Hardly even noticed it running worse at all.

[Dan J]

Sounds like a lazy tensioner to me
Listen with a long screwdriver to both chain cases and try to figure which side

[stubble88]

Originally Posted by Dan J

Sounds like a lazy tensioner to me
Listen with a long screwdriver to both chain cases and try to figure which side

I think your right

I did another stethoscope and this time I could definitely point to the right chain cover as the loudest and most clarity of that sound. Left side was not as loud.
I mean it does kinda sound like metal hitting plastic. There was a bit of black oil soot on the bottom when I took the chain cover off and inspected. Sounds goes away with revs maybe because chain has more tension?

[stubble88]

Originally Posted by Dan J

Sounds like a lazy tensioner to me
Listen with a long screwdriver to both chain cases and try to figure which side

I think your right

I did another stethoscope and this time I could definitely point to the right chain cover as the loudest and most clarity of that sound. Left side was not as loud.
I mean it does kinda sound like metal hitting plastic. There was a bit of black oil soot on the bottom when I took the chain cover off and inspected. Sounds goes away with revs maybe because chain has more tension?

[mysocal911]

Originally Posted by stubble88

Pulled plug cables one by one. No change. Hardly even noticed it running worse at all.

Maybe another chip with a different tune, right? Something with a little less advance*than 45 degrees.

[stubble88]

Originally Posted by mysocal911

Maybe another chip with a different tune, right?

I got a new chip tuned for pump gas yes. Made no difference. But still needed
35 degrees down to 28

[Steve W]

Chad, ignore mysocal911, he doesn't know anything about what he's babbling about - he's just a bitter old man.

Dan J, aka Dan Jacobs of Dan Jacobs Garage is one of the top tier Porsche shops on the East Coast, the nation for that matter, and a long time veteran of air cooled cars. When he gives you advice you can take it as solid gold.

[proporsche]

are you able to push down the right tensioner??
Ivan

[ant7]

As the engine speed climbs so will the oil pressure, so I guess there is a possibility that the tensioner is not holding the right oil pressure on idle, allowing the chain to rattle, but as the oil pressure rises, it takes up the slack in the chain and holds, until the revs come back down again ?

Originally Posted by stubble88

I think your right

I did another stethoscope and this time I could definitely point to the right chain cover as the loudest and most clarity of that sound. Left side was not as loud.
I mean it does kinda sound like metal hitting plastic. There was a bit of black oil soot on the bottom when I took the chain cover off and inspected. Sounds goes away with revs maybe because chain has more tension?