911 engine wont turn.

[Lyndon302]

My new purchase. Engine will turn at a guess 45 degrees each way very smooth. A metalic noise can be heard. Not a low knock but a quite metalic can be heard if I'm quick the spanner. Oil drained. Filter cut. Screen removed. All clean as. Plugs removed All good except number 5 is oily. . Its a 68 and purchased as a non runner.any thoughts. I'm going to pull the engine of course but I'm about 9 months away from that because time constraints. Is it with pulling the top rocker covers and timing chain covers. I would like to know what the issue is.
Lyndon

[da Vinci Dan]

My guess given this info is a piston, head or bearing issue on #5. Sounds like you know what to do. Pull the heads and go from there. Hopefully just a top end but sounds like maybe bottom too. Much experience with Porsche flat 6’s?

[cmcfaul]

Tried starting it?

Gets gas and spark?

Chris

[Jack Stands]

You could take a look down the spark plug hole with a borescope (they’re now so cheap and Bluetooth equipped) to see if there’s anything obviously, but I also think you’ll need to at least do a top end teardown to be sure.

[964TargaC2]

i thought turning it the wrong way was verboten

[proporsche]

Hi Lyndon...as you know there is something kaput inside the engine.So you will be taking it apart anyway.
Maybe the chain tensioner collapsed and the cam jumped.Do not try to start it at all.
As the boys above said take the heads of,but before check the camshafts for alignment and timing with a tool...once the heads are off you will know more....
Consider your self happy to get such a nice and classic 911;-0
Ivan

[Trackrash]

I agree, probably valve hitting the piston.

I would pull the chain covers, valve covers and plugs and see what is going on. I think at least a top end rebuild is in your future, but at least you will know what to expect.

BTW what motor is this, the '68 is the motor or the car?

[T77911S]

pull valve covers and check for a very lose rocker.

sorry, I think the chain cover is a waste of time at this point. If it did jump time, which I would be curious how often this actually happens, you cant tell unless you actually check timing with the dial gauge and you cant rotate the crank enough to really do anything.

you might try putting something down #5 and turn the crank to see if the piston is still connected to the rod.

45 degrees? thats not very far. one valve would have to be pretty far down in there for only 45 degrees or you have multiple valves bent

my bet is an over rev.

[proporsche]

yes what was i thinking no worries to check the timing if you cannot turn it..my bad..just take it apart and enjoy the work...
Ivan

[Trakrat]

well it's anyone ones guess.... could be bad piston rings, a bearing that's come loose, a bent rod, a broken valve that's hitting something (could be sitting on top of the piston even)

[Lyndon302]

I bought it as a none runner. E.g. it had been sitting for 18 plus years. I was told it was running when parked. Keep in mind the seller was just a middle man. It was just what he was told. The seller was spot on about the rest of the car. In fact he told me it turns over by hand but that is far as he got.
When it arrived I fogged the carbys and I'm sure I turned it over quite a few times. I held the belt and turned the alternator. I'm not an amateur and if the crank wasn't turning it would have clicked. Then after a few days of preping it for a engine run I went to turn it over again it won't go. I have a feeling its a valve as its not a solid stop. What I can feel when it stops is the chain tension. E.g. if it was connected to the crank it would be a dead stop. Maybe a collapse in a tensioner and jumped a tooth. Is it that easy to do on one of these. If so can it I repair in car to get it running if that is the problem.
Lyndon

[Lyndon302]

Its not a bearing or engine failure at revs. The filter . strainer and oil are fine. I cut all my filters and there is no debris or white metal any where. I will have a look at the engine number and check what motor is in it.
Lyndon

[proporsche]

Lyndon ..in any case i would not turn it by starter at all..set it up to your TDC and open the chain housing....easy job..muffler ,sheet metal and the covers on chain housings then you will see what is up..
Ivan

[Lyndon302]

Will do. I won't use the starter. I have a busy few days but I will have very soon. Be nice to know the problem.
Lyndon

[Trackrash]

I wouldn't be surprised if one of the chain tensioners has failed since it has been sitting so long. Hope you didn't bend a valve.

[Lyndon302]

If that's the case. There won't be any bent valves. It was never cranked and I didn't force it.
Fingers crossed that's all
Lyndon

[911pcars]

Don't be tempted to force it with the starter motor or piece of fence post.

Could be as simple as a pressure plate bolt intruding too far and hanging up on the crankcase or a TDC pin doing the same. Begin inspecting or disconnecting any and all external rotating items that could impede rotation, then gradually work inward until you find the culprit. It could be cheaper in the long run and less work. Pull the valve and chain box covers and take a look. You don't want to disassemble the engine unless it's the only recourse. In the end, it is what it is.

Sherwood

[Lyndon302]

I'm going to bore scope it first. Then chain covers and the rockers. If I can't see anything it will wait till the end of the year and engine out.
Lyndon

[Lyndon302]

Do I really have drain all the oil to check the cam chains. Its new and hasn't even been started 😦
Lyndon

[proporsche]

If you want to check the chain housing area drain the oil in the engine only.Then again if you drain it all .Put it in a clean bucket and then back in the car.So easy really;-)

Ivan