Ticking noise after rebuild 70's 911T
 

This weekend I started up my 2.2 T engine for the first time. The initial 20 min and test drives went smoothly, but after the third drive I started hearing a ticking noise. The ticks are in sync with the engine RPM and remain there on various RPM's. I can not determine a location, either left or right, top or bottom. The noise has become more loud, so I don't want to start the engine again.
What can I check without taking the engine out of the car?
Are there any usual suspects that I should check?

Check your rocker lash in the car. It possible to have rocker shaft going off location or the lash changing from running if you over look something in the build.
Chains usually go tight above 2K so it wouldnt change with RPMs
Bruce

While your checking the rockers, push down on each valve to see if there might be a broken spring.
Check to make sure the fan isn't hitting the housing anywhere, or a bad alternator bearing.
Could also be a possible exhaust leak, check around the exhaust manifold.

An update but no good news yet.

Here a link to a movie with the noise https://vimeo.com/46446866

I have checked de flywheel en pressureplate assembly and they are ok. The noise is there with the gearbox in neutral and remains if I press the clutchpedal.
I have opened all valve covers, checked clearences, all rockershaft are still in place, I cannot move the valves by hand and all head studs are still torqued to the correct value. The camshafts look like new.
I have taken off the alternator belt and the noise is still there without the alternator turning.
I have turned over the engine just with the starter motor (ignition disconnected) and the noise is still there.
I have checked the exhaust and found no leaks between the heads and the heat exchangers.

What are my next options?

Thanks for your answers!

Newly rebuilt engine - initial drives went fine. Noise now.
__________________

Something has come loose. A timing gear nut may not have been torqued properly? Timing chain may be slapping case?

Borrow a engine stethoscope and listen to each timing cover and also the distributor housing.

If you can hear it even when turning it with the starter (as mentioned), I would start by pulling the timing covers and have a look.

Tensioner may have failed?

Good luck.

Hi, you may not believe this but I'm actually going through the same thing with my motor right now. Same noise, even my car is red! Mine is a 2.8 High comp RS motor with webers, but it's freshly built and it makes the exact same noise. We've tried just about everything - including changing to fixed tensioners, swapping cam gears, re-timing it, adjusting valves, checking for broken springs and ever tearing down the entire right bank of the motor and inspecting everything.

Next we are going to try and figure out if the cam builder perhaps gave us incorrect cam timing numbers. We've checked the timing to his specs but perhaps they're off. Do you know if your cam timing is 100% correct? How about your rockers, shafts, springs - are they all new or just cleaned up and reused?

Thanks for your input!
I have counted the ticks in the movie and came to about 90 in the 21 secs of film. So that makes about 270 ticks per minute. That is about 1/3 of crank RPM. Is there any logic in this. I would have expected it be in sync with either the cams or the crank, but seems not to match with either:confused:

hello from Italy I'm also under the same conditions
my Ticking noise dark I thought it was a piston QSC
INTERMEDIATE SHAFT total changed
valve springs is ok
SPROCKET dx sx cain changed
DRIVE WHEEL ditributor changed
I'm crazy
excuse my bad English
http://forums.pelicanparts.com/uploa...1343391371.jpg
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I do not know what

Is everyone running brand new timing chains?

I'm using brand new endless chains

Me too, brand new and chains are quite tight.

More research, it's not cam timing. I also am pretty sure it's not valves after adjusting them a number of times and pouring lucas oil supplement all over them and running the car.

Is it possible that it's the oil pump? Or the new chains are too tight? Tstat? Mine sounds more like the back side of the motor, towards the right but very similar to the video you posted. Also wondering if it could be the flywheel for some reason?

the noise comes from me right to the cylinder n6
the oil pump can not 'be the noise would be more' continuous grrrrrr.....

I would cut open the oil filter and see what is in the filter element.

I had a similar noise and it turned out to be a blockage on the oil port/gallery to one of the rocker/cam interfaces causing no oil passing to lubricate....check all of your cam lobes and make sure......

Checking on this. I see where the little holes are in the oil spray bar, mine seem to be facing upwards (the photo is looking down from the carbs). Is that correct? Moreover, I've tried turning the car over 5-6 times with the valve covers removed, shouldn't some oil come out of there? Or is it just when the car is running?

https://mail-attachment.googleuserco...dGPVGUyt71xBDI

should go out a lot of oil with the engine running

Thanks. I might check them running. That being said, is that they way the 3 in the openings are supposed to face? Almost directly up, pointing towards the carbs?

What I did yesterday is to use the starter to turn the engine without the ignition on. With the top valve cover of, I quickly saw oil squirting out of the little holes. And yes they point upward, the oil ended on the bottom of the carbs.

Any luck with your car?

By using a engine stethoscope I found out that the noise is located around the nr. 4 head. I opened the covers again and found the inlet rocker moving with some resistance. Although I doubt this can cause a ticking noise I took the rocker of to have it measured.
An other possibility that crossed my mind is that the valve adjustment screw is hitting the cover, but i found no marks so it seems impossible, maybe I will check the clearance with some clay.

Sometimes you get a bearing nitched when you drive the pin through and that causes a tightness. Sometimes you just have to swap it out.
Bruce

handed over to center corrections for engine components, check all tolerances
aspect of the diagnostichttp://forums.pelicanparts.com/uploa...1343986005.jpg
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The nr. 4 inlet rocker bearing was out of spec. I bought a new bearing and it is currently being replaced. Hopefully this is the root cause of the valve clearance being of and therefore of the ticking, but I still doubt this causes such a loud tick. Only one way to know....

Today I tested the engine by cranking it with the starter. Even with the rocker removed the tick remains. So my doubt was correct. When I removed the spark-plug the tick disappeared. This supports my worst assumption that it is a drive-shaft bearing that makes a noise during the compression stroke. No spark-plug equals no compression and the tick is gone. Is there an other way how to confirm this, or should I just mentally prepare for a total tear-down?

Thanks for all your responses!

could be a piston pin?
* my experience by removing the spark plug noise diminished ..
My own thought opened the engine but the bearings are ok

Gianluca, thanks for the suggestion. It could be the pin but I installed brand new Mahle P&C's so I don't think it is likely. The chance of me not having applied the correct torque to the stretch bolts seams more likely.
But first I will travel to your beautiful country tomorrow and do some thinking floating on lake Garda;)

ok enjoy the lake excellent choice if I were going to let me know Venice
hello

Have you discovered the problem yet? At 1.3 of engine RPM it could be the distributor cap is not seated and the rotor is clipping the edge of the distributor cap. I have had this happen on an Alfa, and 6 hours later, after tearing into the cams and several other false directions, I noticed the distributor cap was not locked in correctly.

I used a stethoscope to locate the noise and it was mainly around cylinder 4, so not the distributer.
I'm preparing to take the block out of the car next week, hopefully I will find the cause then. I will keep you posted!

problem solved but not identified
only thing done reverse piston cylinders
3> 6
2> 5
1> 4
now it is ok

How on earth did you even think to try that? Glad it worked out for you...

Is there a piston pin offset in your type of engine?
If so...perhaps the piston (noisy one) was rocking in the bore slightly.
I would think that with new pistons and correctly sized cylinders...there would be very little side-to-side movement.
Bob

My engine is currently out of the car again. And I'm now tearing it down to inspect the drive shaft bearings, both big and small end. I'll keep you posted.

Finally opened up cylinder 4 to find scratch markes on top and bottom side of both pistons and cylinders. Less then 50 miles ago these were brand new. Seems that the piston tipped, but how this is possible with new stuff I don't know.
See pictures below and let me know what you think of it.

Thanks!

http://www.mijnalbum.nl/Foto-746YVZEY.jpg

http://www.mijnalbum.nl/Foto-LGKBTK7N.jpg

http://www.mijnalbum.nl/Foto-HVQSX7CD.jpg

http://www.mijnalbum.nl/Foto-WH43YNYG.jpg

Which pistons/cylinders were You using? What was the tolerance? Did You measure the piston and the cylinder at different heights before installing them?

I've been seizing a few engines in my carrier :), but in this case I'm inclined to believe that You had the wrong tolerance to start with. The wear shows a bit of a X pattern that happens normally when the piston overheats and expands due to too tight tolerance.
I'm pretty sure that if You had a lean condition the seizure would have looked different.

Something similar could happen as well if the cylinders were machined without clamping them. They would measure fine when they are not clamped, but they will have the wrong shape when clamped: narrower on the top and bottom, wider in the middle. It is common on Harley engine where the cylinders are also compressed and their walls are pretty thin. Ask me how I know....

Let's hope the experts will chime in, I'd be very interested to know what they think!!
The good news is that the cylinder doesn't look too bad, so You should be fine with a new piston, assuming that the cylinder measures fine. No doubt I'd take all cylinders off and measure them all before restarting this engine.
luca

In my rebuild I have used original Mahle forged S pistons in cast iron T cylinders. Can this combination be the source of the failure. Maybe the expansion of the S pistons (that are normally used in Nikasil S cylinders) is greater than the standard T pistons?

Does anyone have experience/knowledge on this?

Thanks!

Have You used rings for cast iron cylinders or those for nikasil cylinders? I'm pretty sure you can't use the same rings.
At which tolerance did You set the pistons?

Did they use Biral cylinders for the S originaly?

Yes they did