3.2 Engine Rattle Under Load - 86' 911 w/ 360K Miles

[rideshotgun]

Hi all,

It's been 10+ years since I bought the 86' 911 and posted on the forums. I've driven it from New Orleans to Toronto, across the United States multiple times. I've put almost 100K miles on it since I bought it.

I've had a lot of work done over the years, including a total engine swap in 2013 (Greff Motors, for another 3.2 w/ 60K miles on it, wreck). I've had many memories with this special car, and I've meticulously cared for the car over the years, so its garage kept now, for the last 6 years. I keep it maintained by Porsche air cooled specialized mechanics wherever I go/live in the US.

I hope I don't have a serious engine problem again, so I'm posting here to see if any of you can help me and my mechanics diagnose

Last year my car was stolen out of my monitored RFID/camera security garage. During the initial inspection by Morris Brothers, some damage was found. But I'm worried not all. Over the following months a sound has emerged on the engine after the theft. I'm concerned they damaged the engine and I'd love for you to take a listen.

Listen here:
https://youtu.be/aV6XVsHW5qU

Left and right channels are different mic positions (cabin and exhaust)

- It only happens under load
- Its louder when the engine is cold
- Does not sound at all without gas/acceleration/load - for example, downhill at 5k rpm or at 900 idle, or with slight acceleration/gas
- It happens around 2-4K RPMs and quiets down/cuts out after
- From my research it could be Head Stud, Running Lean

In the very last maintenance (which my bill was upwards to 5K), Morris Brothers did this work:

- Adjusted valves/gaskets
- Replaced intake manifold gasket
- Oil change
- changed out spark plugs
- changed out distributor cap and rotor
- replaced crank position sensors

Shop said everything seems normal with oil, I'm assuming they looked at the head studs when they adjusted the valves and they were fine too. I'm waiting to hear back from the tech to call me back to confirm.

When I picked it up the owner rode with me to point it out because I think the sound has been emergent from the last year or two. I found it in a recording from a year ago before the theft. I do not hear it when I brought it on the emissions dyno in California in 2019- that was right around the time I had the ECU re-built by a specialized ECU tech out in Los Angeles (through Pasadena Air Cooled).

I'm hoping owner of the garage (Morris Brothers) and the techs didn't let me drive away after the theft in the latest maintenance visit, with a critical engine issue. But it concerns me that they did not diagnose the sound for me, but just pointed it out.


I'm going to talk to the tech/owner next week to see what we can do to diagnose.

What do you think it sounds like?

Thanks so much in advance!

Benjamin

P.S. My wife is due in October. Convinced her to do some pregnancy photos

[john walker's workshop]

They let you drive away with that noise??? Bad tensioner or a rod bearing. No more driving!!! Head stud noise is way deeper, this is high pitched and rattly. Maybe a different shop. I know Jack Morris, who split from the shop and lives in Green Acres Wa now and I'm sure he wouldn't have let that go out, except on a flatbed. And $5K for what you had done is excessive. Also, could have dropped a washer down an intake port while doing the gaskets, maybe?

[proporsche]

i`d 2nd John ..how did they let you drive away ???? and this is very strange:They said they had multiple techs listening under the stethoscope and could not figure it out".
we can hear it on video and can tell you as John said above..nut in the chambre ,collapsed chain tensioner or even bad rod bearing....
do not drive it period...!!

Ivan

[proporsche]

....

[rideshotgun]

Originally Posted by john walker's workshop

They let you drive away with that noise??? Bad tensioner or a rod bearing. No more driving!!! Head stud noise is way deeper, this is high pitched and rattly. Maybe a different shop. I know Jack Morris, who split from the shop and lives in Green Acres Wa now and I'm sure he wouldn't have let that go out, except on a flatbed. And $5K for what you had done is excessive. Also, could have dropped a washer down an intake port while doing the gaskets, maybe?

Copy that on “no more driving.” I feared I would get that on the forums. Thank you!

They let me drive/called me to say my Maintainence was “finished”. Now that I’ve had 2 weekends to drive the car, hear the sound more, and process the issue, I don’t feel good about that- at all.

Upon pickup, I specifically asked the owner and techs if they would drive it, if it were their car, and they just re-stated they didn’t know what the issue was, that it was a “unknown” sound. They only referred to a complete engine restoration that is 25k. I’m assuming that is not the only way to diagnose the issue.

I called them yesterday (Friday, 29th) mid-day to explain my position, to follow up.

I questioned why they did not diagnose the sound, especially after the theft, and told them I would post the sound on PP. What else was I to do given they are my mechanic and they gave it back to me with no recommendation other than a 25k rebuild?

I told them, given the internet’s likely responses to an engine rattling noise, it would just add to my “not feeling good” about them letting me drive away with it like that.

They said they would consult, and that tech would call me back that day, but didn’t hear from them.

I’ll be calling again Monday.


Morris Brothers has a great reputation and they have serviced my car for a few years now. I am aware the original owner left the shop to move back. I could talk the owner, and I know of course he will take it back.


Thank you for your help and reply.

[proporsche]

just for little info, for 5k i do complete-labour-engine rebuilt....minus machine shop and parts.5k for what they did is way too much...sorry for this trouble for you...

Ivan

[proporsche]

......hmm double ..screen sorry

[rideshotgun]

Originally Posted by proporsche

just for little info, for 5k i do complete-labour-engine rebuilt....minus machine shop and parts.5k for what they did is way too much...sorry for this trouble for you...

Ivan

Thank you! I wish you were in my area lol thanks for your second opinion to John’s.

I do historically trust and like my mechanic as they have a good reputation for air cooled.

However, given what happened, would you recommend I definitely bring it in for a second opinion? Or would you work it out with the original shop?

[ant7]

What happened to the engine that was rebuilt in 2013 ???

[proporsche]

However, given what happened, would you recommend I definitely bring it in for a second opinion? Or would you work it out with the original shop?[/QUOTE]
If you have nearby place you could go for the 2nd i`d would do that but you have to tow it....or at least show them the video prior towing it...what bugs me they did not hear it or they did not want to hear it?

Ivan

[john walker's workshop]

2nd opinion for sure.

[rideshotgun]

Originally Posted by proporsche

However, given what happened, would you recommend I definitely bring it in for a second opinion? Or would you work it out with the original shop?

If you have nearby place you could go for the 2nd i`d would do that but you have to tow it....or at least show them the video prior towing it...what bugs me they did not hear it or they did not want to hear it?

Ivan[/QUOTE]

Originally Posted by john walker's workshop

2nd opinion for sure.

Copy that, will be calling up 1-2 reputable options in the area tomorrow. Thank you both.

[john walker's workshop]

Any updates?

[Coastr]

Nasty noise that one. Keen to find out the result for my own understanding

[rideshotgun]

Sorry for the lack of update- I'm building a really big update with pictures/video/charts etc.

It's currently completely torn down/split/etc. Will be undergoing a full re-build over the coming weeks.

Bigger update coming ASAP.

[Mr. Merk]

We had an 87 in last week with a very similar noise, but also had a lack of acceleration. Ran smooth otherwise.

The passenger side tensioner had failed. We replaced both. FYI, it was cheaper to buy a tensioner update kit for an older 911 that includes the lines and timing covers than it was to buy two tensioners separately.

[proporsche]

so,did you ended up in a different shop where they gave you another opinion and you let them take it apart..is that correct ?
Ivan

[mikedsilva]

How did the valve springs look upon tear down?
Tops of the pistons?

I love a good mystery!

[andytat]

It sounds very much like broken head studs to me.

[jlex]

Congrats on the upcoming birth. Video looked very professionally done.