"Clacking" noise in the motor....

[kwkshift]

\"Clacking\" noise in the motor....

Here is a video that I shot trying to figure out what that horrible noise is:

http://members.cox.net/kwkshift/CIMG1588.AVI

I had noticed that occasionally, after I drove the car say, to dinner and I came back out to start it up to go home, I would hear some ticking for a second or so. It sounded like a lifter tick because it would only make the sound for a second or so and then go away. Now, it makes that horrible sound.

What do you guys think?

Thanks!!

 

[Saint_Spinner]

Re: \"Clacking\" noise in the motor....

I was posting a similar question here: http://www4.forum.viperclub.org/showflat.php?Cat=&Board=UBB14&Number=682443&page=0&view=collapsed&sb=5&o=&fpart=1

But mine was no where nearly as bad as yours...does it sound the same with the cover on?

 

[kwkshift]

Re:

Yes, it's the same sound with the valve cover on, just more moffled. Mine is only one cylinder, though. And it just started out of no where.

I hope my problem is just a lifter or something, rather than in the bottom end.

 

[hemibeep]

Re:

hhhhmmmm,

have you taken off both valve covers?

When I had a dropped lifter, you could see the one that wasn't working.

A few things to try:

1. carefully place a wood rod(hammer handle) on each rocker to see if you can take the slack out while it is running.
2. stethascope on each rocker while running.
3. check the flywheel and clutch bolts for tightness.
4. stethascope the injectors whie running.

Really spend time with the stethascope probing while motor is running.

Don't panic.

I was under the impression that a double knock was a bearing(rod or main). try to steth that area also.
5 sizes of bearings and they are color coded, so if you dissassemble, tell dealer color and they can match.

My car had a knock, but it was a cracked piston. (sounded different than yours)

 

[Jack B]

Re:

It sure sounds like a very bad lifter. How about another list of to do's:

1. Check each push rod for clearance by rotating the motor with a remote starter switch. Bring each valve up to zero lift to verify the setting and the lifter status.

2. Check the plugs for a sign of a non-firing cylinder.

3. Has the oil pressure been consistent.

By the way - good luck.

 

[Warfang]

Re:

Stethascope to diagnos a Viper engine... now i've hear it all! Shoulda listened to my momma and taken a mechanics class.

 

[hemibeep]

Re:

Warfang,
The steth is pretty cool....actually a craftsman part that looks normal on top, but has threaded alum rods to lengthen the probe....B.T.W. the injectors were the loudest part on my motor...

 

[kwkshift]

Re:

I pulled the head, oil pan and windage tray yesterday.

There was no debris in the oil or in the pan. The lifters looked ok on the outside, but that doesn't really mean anything. I know that there's a lot of parts inside of those things. I also looked at the cylinder liners for any evidence of scoring from a wristpin or metal flying around in there and there wasn't any.

I didn't turn the engine over because I was afraid that the liners may move. But, everything in the bottom end looks good.

Should I just get some new gaskets, lifters, headbolts, etc and reassemble everything?

What do you guys think?

 

[hemibeep]

Re:

The liners are pressed on GEN II. My cracked pistons were visible from the bottom. The cracks were in the skirt. I would bump over the motor and check each piston from the bottom. plenty of light and mirror to get a really good look.

Also, my cylinder walls did not show the problem as much as the piston itself.

 

[Jack B]

Re:

Oops - The liners can still move, if they do, the engine has to come out. Order the dog bones from DC to hold them down. The gasket kit is about $350 from Tatar. You don't need to change the head bolts. At this point you will have to change the lifters at a minimum.

You still haven't found the problem, it would be a shame to put it back together and still have the noise. You still haven'tchecked the pistons and bearings.

Did you use the stethescope to try and isolate a bad lifter or at least check each one at TDC, that should have been done before tearing it apart.

 

[kwkshift]

Re:

I found the source of the noise. #7 piston just started to come in contact with the counter weight on the crankshaft. Luckily I cought it when I did and I didn't drive the car! The car only idled for a few seconds each time I started it when I was trying to track down the noise. There was no metal in the pan or anything on the drain plug. Basically, it looks like they just started to rub together, rather than a straight impact.

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The shiny spot on the crank is so minute that I can't even feel it with my fingers. It's amazing how close the pistons come to the counter weights in these motors. I don't think I've ever seen a production motor come so close!

Hopefully, this will be an "easy" fix by replacing the rod bearing, polishing the journal, bolts, gaskets, etc. I want to drive my car!

 

[kcobean]

Re:

I found the source of the noise. #7 piston just started to come in contact with the counter weight on the crankshaft. Luckily I cought it when I did and I didn't drive the car!

What changed to allow that to happen?

 

[kwkshift]

Re:

I have no idea. Like I said earlier in this thread, when the engine was warm, I would start it up I could hear some ticking for a second or so and then it would go away. Maybe the problem progressed into what it is now.

 

[viper spray]

Re:

I would pull them all and check for damage , does it run lean with the spray?

 

[big-n-italian]

Re:

how / why, would the rods shrink or the counterweights grow in size?

 

[hemibeep]

Re:

thinking crushed bearing in rod allowing rod to seem shorter and/or longer...

These are pressed wrist pins. I wonder if wrist pin is also an issue?

 

[kwkshift]

Re:

I would pull them all and check for damage , does it run lean with the spray?

Actually, it's quite the opposite. The car was lean on motor only and pig-rich on the spray. I don't have that sorted out yet.

 

[kwkshift]

Re:

I found the problem. I bent the rod and there is a hairline crack in the piston skirt. It must have happened when I was swapping injectors. I think I hydraulic'd that cylinder. There must have been just enough residual fuel that got in there to cause the problem.

Damn it.

 

[hemibeep]

Re:

I feel your pain....I had two cracked pistons and 1 cracked sleeve.

I changed to the ross pistons as they were cheaper for the set than D.C. factory parts.

 

[big-n-italian]

Re:

<< ...must have happened when I was swapping injectors. I think I hydraulic'd that cylinder. >>

can someone explain what this means? i dont know exactly, and maybe a few others dont either. thank you.

 

[kwkshift]

Re:

Well, I was having a lean condition in cylinder #1. So, I decided to swap #1 injector with #7 injector to see if I had a weak or dirty injector. I figured that I'd drive around for a few days to see if the problem followed the suspect injector. Basically, I'd check on the plug in #7 to see if it would look like the #1 plug.

The car sat for over 24 hrs, plus I opened the fuel line to my nitrous solenoid that comes off the fuel rail to relieve any excess fuel before I pulled the injectors.

Either some of the residual fuel that was in the rail and/ or fuel got past the o-ring on the injector when I pressurized the system got into the combustion chamber. When I cranked over the motor to start it, that may very well have been the cylinder hydraulic'd.

 

[GR8_ASP]

Re:

Hydraulic lock is when enough fluid enters the combustion chamber so that when the piston returns to TDC it cannot compress it (the fluid which is essentially incompressible) and the piston is prevented from getting to its full height. That may result in bent rods (most common), damaged piston, damaged bearing, etc. The

 

[big-n-italian]

Re:

so - this may explain the bent rod and the bearing crush mentioned before. GOT IT!

 

[kcobean]

Re:

This is often referred to as "Hydro-lock" by many people. We see this sometimes in cars with Cold-air intakes that sit low to the ground (this from the 350Z community) and injest water from driving through puddles. I've seen some severely bent rods from this, but never heard of it happening from too much fuel in the cylinder. That's unfortunate. Any guesstimate on the repair cost of something like this? Does the engine have to come out to replace pistons and rods?

Sorry this happened.