3.0 Engine advice wanted with VIDEO CLIP

[Monkeydub]

OK i'm looking at buying a UK 1976 911 3.0 Carrera and have posted a question on the other forum....wondering if you engine types could tell me if this tapping/banging is normal.

[Monkeydub]

Oops forgot to post vid....it's in now.

[Hoffmanmotors]

Im no expert but it sounds like a cam chain tensioner failing, maybe on the right side. It has carrera pressure fed but they still fail.

-Jeff

[safe]

That doesn't sound normal, cant tell you what it is.
Is it only audible at idle?
How is the sound from under the car, thinking something simple as an exhaust leak?

[MBEngineering]

HI Monkeydub
As the 3.0Lt Carrera engine has a lot of issues from new, the noise you have is poss' valve train related, and some one has fitted the pressure feed tensioners to try to sort a larger prob'.
you need to check engine history back to day one, as the engine should have been back to the dealer under warranty for a full engine strip/rebuild with the incorrect valve spring shimming, which needed to be corrected, back in 77/78;

the job's required to be sorted; full engine strip.
head strip and new valve exhaust guides.
new bearings.
new inter-gear, chains and valve springs,
modifi the crankcases and tin work,
replace head studs.
this lot should have been corrected, and I say "should have been", I still come across Carrera engines even now that have not had the work been done, thay are now in a bad state of disrepair.
is the car in the UK or state side?? if it is UK based and any where near me I do not mind having a look for you to asses the noise.

regards mike

[Crashly]

I had almost an Identical sound on my 77, 2.7. I would guess that it is valve train related. In order to narrow it down, go and buy a stethascope from harbor freight and just start probing around the intake ports and the exhaust ports while it is running. Also dont forget to probe the injectors. On some of the other cars that I have worked on (non porsche), diesels etc the injectors can get really lound. Anyway after you pinpoint the cylinder that the noise is coming from then it is time to do some light surgery. The first step is to do a valve adjust as loose valves can also make this noise. While you are adjusting you can loosen up the elephant foot to max and slightly wiggle the valve you can also get a small peek at the springs and see if any of them are visible broken. On another posting in this forum one gentleman had a similiar sound and it turned out that his inner spring was broken on a valve. While the elephant foot is loose take a good wiggle on the rocker to check for play between the rocker and shaft. After you button it back up and if it still makes the noise then you may need to remove the rocker from the offending cylinder and pull the valve retainer and spring. Pelican Parts sells a special tool that allows this to be done while the motor is in the car. Warning, you will need to be very patient. I think it took me 20 minutes per retainer just to get them out and that was using magnets, needle nose pliers etc etc. After the valve springs are removed and with the piston at TDC then you can push the valve in until it hits the top of the piston and wiggle it side to side. On my intake valve there was no perceptable wiggle. On my exhaust there was around 1/8" of wiggle and the valve guide seal was completly destroyed, basically 100% missing except for the metal keeper that tightenes it to the valve. Hopefully it will just be a broken spring. A couple of weeks ago when I went on the hunt for my problem a couple of people here on the board said that it was more than likely a worn valve guide and they were right. Some of the other problems that I was concerned about was the possibility of a broken or pulled head stud which would allow the air pressure to escape and make a similar sound. Fortunately it wasnt. Just a worn valve guide. Now I am looking at a complete rebuild due to the weaker case on the 2.7. If I had a 3.0 I would simply do the top end if the valve guides were bad.

[Monkeydub]

Hi mike i'm in Leeds but the cars in Skipton. I'd really appreciate if you could give it a look. Are you a porsche mechanic? Just out of interest....do you do engine repairs etc and how much ££££ would i be looking at if it hadn't had the necessary work previously done?

Thanks, Rory

[MBEngineering]

HI Monkeydub
I am @1Hr away from Skipton, would you like to ring me?

www.mbporsche-engineering.co.uk

regards mike

[favrok01]

Have the owner do a valve adjustment and replace the oil
If it still makes the valve tick then offer less money.

It appears to be a very clean engine.
It has the carrera tensioners, all hoses are connected correctly and the idle was constant.
braided ignition wires

All very very good for a 76 engine it must have been well maintained