Chain sound?

[4sd911]

From this video does it sound like my chain are to loud?
YouTube - SDV_0149.MP4

[cgarr]

Sounds like bad alt only because I don't know what bad chains sound like. Its is pretty loud!

[JFairman]

I've never heard an alternator sound like that.

some thoughts...
Are the cam sprockets and chain rails installed and aligned properly with the intermediate shaft spockets?
Passenger side cam sprocket on the correct way - faced the opposite way as the driver side?
Worn sprockets and new chains?
Have you looked at the oil and drain plug magnets for metal dust or particals?

You might even feel a vibration that matches that sound on the chain cases and holding a long screwdriver or wooden dowel rod against the chain case and against your ear will help locate the noise.

If it sounds like this under the motor I think it's your cam chains and sprockets complaining. something is not right.

[4sd911]

I just ran the engine with the belt off, no change in the sound.

I did use new chains with new intermediate sprockets but I did use the old sprockets at the cam and idler arms, they look good and only have 40,000 miles on them.

I believe the sprockets and guide are installed correct. The alignment should be good as this was checked many times although quite tough getting repeated measurements trying to hold the straight edge with one hand and measuring with other.

Oil was drained once after about 4 start ups and 8 miles on road with only minute fuzz on magnet in tank, no magnet on sump plate.

I did open the right chain box to have a look when changing the oil did not see any problems. Checked the alignment, this time it was 0.010" shorter put still in spec, but I could not push the sprocket back because the rocker are installed.

The new chains roller are split, the old ones were solid. Would this make noise?

[cgarr]

Are the cam sprockets installed both the same or is one flipped?

[JFairman]

Everytime I've put new cam chains and sprockets in BMW and Porsche engines the the cam chain whir was a little louder for the first 3000-6000 miles and then it would quiet down a little. It was never near as loud as your video though.

I don't have any pictures of the new chains and sprockets I put in my porsche motor and I don't remember if the rollers were split like yours. They were IWIS or something like that, and I put a master link in them since I didn't split the case.

If you're using mechanical chain tensioners maybe they are too tight? thats just a wild guess...
The only other possiblitiues I can think of are the ones I wrote before.

good luck with it.

[4sd911]

cgarr, Yes the cam sprockets are different, one faces out one faces in.

I don't have a picture of this but the Carrera tensioners are installed on this engine, the piston rod in the tensioner doesn't extend up much. Is it possible that the pressure feed tensioners are to tight? Or does it matter how much the rod in the tensioner extends?

Chains are iwis made in Germany.

[4sd911]

OK, I guess I'll remove the chain box covers and get a look at them. I'll buy the Stomski sprocket alignment tool to get a better measurement of the sprockets.

How should I push the cams back (toward the flywheel) with the rockers installed, any problem of damaging the cam or rockers doing this?

[4sd911]

OK, I bought the Stromski tool to check the sprocket alignment. Checking the right side first as that side seems to be the side the sound is coming from.

Checked the IMS sprocket, and it measured the same as past, 2.039". Then installed the tool and measured the right sprocket, 2.025", so I removed one shim had 3 shims now 2. Now measured 2.045".

The not so straight edge?
The Stromski tool & supplied straight edge isn't measuring the same at all 4 corners. If I check the sprocket using each end and flipping it using each end, on one side it measures the same on both ends, on the other side one end is 0.005" longer, and the other end is 0.010" longer than the other side. The side that measures the same at both ends is what I used above to adjust the sprocket and it is close to what I measured at first oil change without the stromski tool it measured 2.029". So at the best the sprocket is 0.006" longer that IMS at worst 0.016" longer.

I'll check the left side in a few days and report back. Below is a picture of the right side before adjusting.

[4sd911]

Left side checks fine, even with the warp in the straight edge the measurement will either be long 0.005" or short 0.005".

Now I'm questioning if I should of removed the one shim from the right side. Unfortunately I didn't discover the warp until after the shim was removed. If I assume that I can split the difference in the warp I'm off the IMS buy 0.011". So adding or removing the shim wouldn't make a difference. Monday I'll call stromski about the straight edge.

[JFairman]

This may sound like a dumb question but did you install the idler sprocket shafts so the oil collection cup is facing upwards? I can't tell for sure from that picture.

The shaft can install either way so each side faces up and I think most people install them correctly but thought I'd ask anyway.

[4sd911]

Yes, shaft opening is up.

[Flat6pac]

In the picture the rail pins look recessed and they are suposed to have the nipple sticking through on each of them.
Im probably wrong because there is an indent for the rail to snap into.
Just a thought
Bruce

[JFairman]

Good eye Bruce, you may be right.
You have to push the chain rails on with your thumbs pretty good until they snap into the right position on the pins.

Here's a pic of my origonal passenger side chains before I removed everything and it looks like the chain rails may be around 1/8" farther on the pins than his are.
The plastic chain rails have raised grooves on them that line up in between the links on the chain and if it isn't on all the way than they will be out of alignment with the chain and maybe thats making the noise... hard to say from the pics.


And the driver side chain case with new parts on both sides: 964 cams from webcam, rocker arms, rocker shafts, chains, chain rails, cam sprockets, idler sprockets, and idler sprocket shafts.. while I was timing the cams.

You can see how much less extended the chain tensioner is with the new chain in the driver side pic.
The intermediate shaft sprockets looked good from what I could see in there with a flashlight.

I have no where to do it so I did it in my driveway with the motor in the car lowered around 6" in back onto a jackstand.

[4sd911]

Since I'm here I took the right cover off again for one more inspection. Everything looks good, ramps are in place. I removed the cam sprocket for a picture of the back side as there is some minor scuffing on the edge of a few teeth, these marks can barely be felt with a finger nail. I think I'm going to put it back together and run it.

[4sd911]

Update:
I've removed the pressure feed tensioners and installed turbo style tensioners, the chain sound is much lower at the engine compartment, there is a huge difference in the engine sound siting in the drivers seat driving down the road. Here is a video of the sound now, there is a little back ground sound at the beginning, I think it's a small plane flying over head. I have about 600 miles on engine at the time of changing the tensioners. The sound was driving me up the wall it may only be noise but it bugged the hell out of me.
YouTube - Porsche 74 911

[Daviboy]

I had a similar sound when I was running my engine in although only under load. I suspected my chain tensioners as well. However I left it alone and now after 500 miles the sound is gone completely. I attributed it to new chains on old sprockets and intermediated gear. She is running like a champ now.

[adam.shelton]

Originally Posted by Daviboy

I had a similar sound when I was running my engine in although only under load. I suspected my chain tensioners as well. However I left it alone and now after 500 miles the sound is gone completely. I attributed it to new chains on old sprockets and intermediated gear. She is running like a champ now.

I’ve had a similar experience. Once they smoothen up, the sound goes away gradually.

[cmcfaul]

This may sound stupid, but it is possible to install the chain tensioner line into the wrong hole. The left side chain tensioner is just beneath and slightly hidden by another hole (don't know what it's for) but the banjo bolt screws right into it.

If I were a betting man I would say that you could have done that. Took me a while to discover my mistake a while back.

[johnman001]

I had a chain noise on a freshly done motor I rebuilt. It was using pressure fed tensioners and I thought that a tensioner was going bad. I took the NEW line off to find that nothing could pass through the small line. I couldn't get ANYTHING to pass through the line. I swapped that out with a used line and the noise went away.

Examine all your new parts well!

I should have sent that line back to our host.......