What is this noise?
 

My 76 2.7 has been running and sounding great since I started her up last month after sitting for 15+ years. I just went out to take a video of the weird engine sound but decided to shut it down because it sounded so bad.

The only description I have of the noise is that it sounds like baseball cards in your bicycle spokes when we were kids. What does it sound like when the timing chain tensioner starts to go?

I know it's not much to go on but I'm terrified to start it up again to get a recording of the sound, I've never heard a noise like that coming from an engine before.

That is a common symptom of head gasket due to pulled/loose head studs.

It will happen that suddenly? one minute it sounds and runs great and the next minute it sounds like crap?

Remove valve covers and check to see if the head studs are all tight.
If good then remove chain case covers.

Thanks, will do. I had the valves adjusted about 300 miles ago, just before starting it up for the first time and all the head bolts were fine.

Read up on 2.7's and pulled head studs. Can happen whenever, wherever if time certs haven't been installed. If I remember correctly your car is a real time capsule with low mileage so it may have never failed. Seems as though they either do or they don't. The motor rebuilding forum has lots of info on how to get it fixed.
If it is the studs pulling out, it's apparently cheaper to put a good used 3.0 or larger in there. (More fun too!) As opposed to the machining needed to fix the 2.7.

if you're "lucky" it's the chain tensioners and easy to fix.

Good luck, I hope it's the latter.

Yes indeed! Several people have posted here over the years stating that they have even had studs break while the engine is on a stand!

Yes, the car has 62,000 miles and been garaged for many years. I sure hope it's the tensioners too! I can't believe it's cheaper to buy a used 3.0 than it is to replace head bolts?? How much can I expect to spend on a good used 3.0 and where the heck do you find one??

why not DIY?

I'd love to but I don't think I have what it takes to do the job without someone watching over my shoulder.

If I can, you can...
My first tear down of a motor that wasn't just for curiosity or to replace a head gasket etc. was my Porsche Motor! :eek: Runs great now.

It's not just replacing the studs on the 2.7. They actually tear out of the magnesium case. you need to have the bolt holes machined to accept a new threaded "nut" aka zert, so you can put the head bolts back in and stay.

There are a couple of 3.0's and bigger complete motors for sale right here on Pelican in the classifieds right now.

Think $5-10K for your engine if the studs are pulled, not broken.

Here's a link to my adventure so far, almost a year now and I'm ready to mod it some more....Can we say "while you're in there":D

http://forums.pelicanparts.com/porsche-911-technical-forum/621680-finally-back-game.html

I'm still keeping my fingers crossed that it might not be too bad, maybe chain tensioners and not head bolts. I only drove the car for a mile or two at about 30 mph before I heard the noise and I shut it down. How quickly will bad chain tensioners destroy an engine? I'm glad you have the confidence in me but I don't. What were your mechanical skills before you did your rebuild?

Experience...I'm a power system substation electrician Foreman so I have some skills taking apart $500,000.00 breakers and the like and then fixing them and making them work. (the first time) I have restored cars but mostly just body work, interior and suspension.
I'll give you the advice I give apprentices: Educate yourself by doing the research, take on tasks to test your knowledge, ask questions and most importantly, stop and ask when you don't know.
Wayne's engine rebuilding book and this forum were all I really needed to remove the drivetrain, tear it down, replace the studs, re-ring it and get it running again.
I wanted to do it, I bought some nice tools in the process and spent more than I should have...
If I just wanted to get on the road again as fast as possible I'd just swap out a bad engine for a good one.

buy a digital camera and post questions here -- you will have lots of people watching over your shoulder

I may try rebuilding it this winter if turns out that it needs it. I guess I can always bring it to a P shop if it turns out it's beyond my skill level.

i'd rebuild the 2.7 if needed - nothing like the sound of that 2.7

25 years ago i had a silver/black 77 911s - engine was rebuilt before i purchased it - had the devlar headstuds installed and the engine sounded so sweet. it was a great car.

I agree, I love the sound and the performance up til now!

Keep us informed when you open it up for inspection. I'm hoping it's something simple.

Exhaust manifold gasket?

one of the reasons to take the valve covers off and check the head nuts is to see if any will fall off! You are checking but also ruling out broken head studs. part of the troubleshooting process. You will ether be ok or not ok.