928ntslow

1985 auto...since I have had the car back together and running, there has been a ticking noise that seems to come from the bell housing area. Sounds kind of like a lifter, but I had put in Rislone from the start and the car now has 455+ miles on it since I got it running....should have gone away by now. We had it up on a lift and listened for where the tick may be coming from. It goes away when engine rpm is increased. You can hear it from the top of the engine, but it is louder from under the car right around the bell housing area as I had said. Doesn't seem to affect the performance of the engine, but at idle, it sounds like the way a diesel ticks. I haven't counted the ticks per minute, but it sounds like it would be a cam shaft, but louder at the bottom of the engine?

Anyone have a hunch on what this might be?

Just to let you know, pressure was released from the flex plate, dry rear main, all is properly torqued in the bell housing. Suggestions were maybe a lifter, chain tensioner or clogged oil drain valve. We kind of eliminated all of these because the lifter noise would have disappeared, the chain tensioner would be more than a tick and the starvation of oil would make all lifters tick. We even checked the exhaust and there are no leaks. Fly wheel teeth are not hitting the starter either. WeIRd! Maybe a bad spring or valve guide?...or would that even cause a tick?

heinrich

Pull the extra useless sensor atop the bellhousing Keith and toss it

Kevin Michael

Keith, Pull your camcovers and underlight, inspect your camshafts very carefully for cracks or breaks. I had this exact sound and one day the d-side exhaust cam let go and I limped home thankfully. Check the archives for my "ticking" threads.

Leon Speed

Here are some more possibilities..https://rennlist.com/forums/showthre...ivetrain+noise

I didn't solve mine yet, so I am watching this thread with interest.

Mrmerlin

did you look carefully at the CPS or the diagnostic CPS see if they might be rubbing on the flywheel, also check the driveshaft coupler bolts for rubbing (where the TOB guide tube bolts on)and tightness. and then check the rear bellhosing for the Loose rivets on thwe torque converter and the 6 bolts that bolt the flex plate to the torque converter

928ntslow

Thanks fellas. All good suggestions and the link almost described exactly what I hear. Mine is just audible when the engine is at idle in any gear. When I give it throttle the sounds subdues or goes away completely. This is either while standing at the front of the engine bay giving it throttle or while driving.

I had the cam cover off and didn't notice anything, but then again, I didn't look closely. Just may do that in the coming weeks. CPS seems like it would make a constant grind, not a tick, but I guess it's worth the check. I can do that when I open up the bell housing again looking for flex plate cracks or anything else that was mentioned. Lifter sounds like the obvious, but it surely should have gone away by now.

This car was riddled with issues when I got it. I have spent more time on this car than any other I have owned. I am slowly but surely eliminating all of it's little issues. I will report back at some point as to what I find over this.

928ntslow

UPDATE: I haven't had the chance to investigate this issue as of yet, but there has been a change in this noise.

Now, since I have been driving the car daily, this noise has disappeared at start up. However, after the car has warmed up a bit, the noise then reappears. Would a lifter do this?

Leon Speed

I would think a lifter would be the other way around right?

928ntslow

Yea, my thoughts too. I thought about the chain tensioners, but that would make a constant rattle. When i had the valve covers off, the chains seemed a bit loose, but I think it was because they were not pressurized with oil. Anyway, that was one guess.

I hope to get the car up in the air this afternoon to have a look in the bell housing just to ease my mind in this area.

Leon Speed

Wouldn't be piston slap either, right? I think that should disappear as the engine warms up - can somebody confirm that?

AO

Keith-

You gotta help us arm-chair quarterbacks out.

Is the sounds RPM dependent? I think the answer is yes.

Next, does the tick happen once per revolution or ever other revolution? Keep in mind that a 750RPM idle will produce a crank rotation of 12.5 revs per second, and cam rotation of ~6 per second. If you had to guess, what is the frequency of the tick you are hearing?

Have you use a stethoscope to pinpoint the location?

You say it sounds like it's coming from the bell housing area. Any chance the flex plate is loose from the flywheel? How about the flywheel itself? You should be able to take the cover off and start the engine and see if the sound is coming from there or not.

The idea of a broken cam is plausible, but I think with a stethoscope you should be able to verify/rule that out pretty quickly.

Tom. M

It's beginning to sound like an oil pressure issue. What's the pressure when hot at idle? and at what point (rpm) does it get to 5 bar (when hot). What oil are you running? and what weight of oil? Maybe try changing the oil weight..maybe a 20/50 non synthetic?...

PorKen

Too much Rislone?

Try and keep that piece together - I'm going to need a test car for my EZF superchip, once I finish hacking the code.

928ntslow

Sorry, thought I did that in the initial post.

Yes

Cam

Yes...so to speak. We had the car off the ground and listened above too with a rubber hose. we just couldn't determine where it was coming from. Sounded louder at the bottom of the motor and on the driver side.

True, but I have determined that it is not in the bell housing area....for the time being.

I would think a broken cam would have shown itself already based on the 600+ miles I have put on it and the hard acceleration I have subjected it to.

I think we might be on the same page here based on what I thought about this morning. Hot idle is 2.5 bars...full 5 at throttle. Rotella T synthetic 5W-40.

So I really listened to the process this morning....

As I had said, the tick/clack has subsided at start up. This morning, started up the car and it was smooth and quiet. A mile or so down the road after warming up a bit, the tick/clack became audible. By the time it was fully warm, the tick/clack was at it's loudest, which is how I had originally described it. It's not ridiculously loud, ...just sounds as loud as a lifter would.

I got to thinking that maybe this was either an oiling issue or a chain tension issue. However, the tick/clack disappears when I give it throttle. So it could either be starved of oil at idle or there is slack in the chain at idle.

Thoughts on this?

Thanks for the responses.


lol...yea thats all I used was 10 quarts of that...he he. I actually think the Rislone helped as the engine runs nicely now...'cept for this issue.

AO

Keith-

I tried that Rotella T and had problems. It doesn't seem to tolerate higher temps not to mention the lower ZDDP rating.

I would highly suggest going to a Mobil 1, Amsoil, or Red Line product, but depending on how pronounced the ticking is, this may not solve your problem.

Not sure if you can rent one, but one of those fiber optic scopes might prove useful down the spark-plug hole on Cyl #7 or 8. Otherwise, you might want to pull the cam cover again on that side and double check to make sure you don't have little bits flopping around. Might be useful to have someone crank the engine with the cam cover off so you can see what's going on.