Tick/Tap/Knock - Long Post - Video Inside

[SVT Sam]

Hey guys,

Looking for a bit ofinformation here and some opinions. Sorry in advance for the long post, I justwant to give all details up front.

Last Wednesday, Iwas driving back home. Previously car had been running great, no issues. Ipulled out into traffic and gave her some juice, nothing crazy, probably ran1st up to 5800 rpms or so, then a nice smooth shift to second, then to 3rd justto get up to speed.

After reaching asteady cruising speed, I could faintly hear a tapping/flapping (maybe buffernoise from the window being down) sound a bit. Anyway, I got her home and sureenough I had a nice tapping noise going on.

I checked the oiland she was low. I never realized how much oil these things drink between oilchanges. With the oil being low (1-1/2 qts) I immediately figured it could be aspun bearing. I didn't drive the car except another 15 miles to work and over tothe garage. Saturday, I changed and strained the oil looking for metalshavings. To my surprise, there were none in the oil. Drained the filter andnothing as well. Oil was dirty, but not to awful bad.

So I figured a lashadjuster may have gotten some trash in it, especially since the oil had been abit low. I added a small bottle of Marvel to see if it would clean it out overa couple of days. Well, as of yesterday, it was still ticking. No loss of powerat all, no loss of oil pressure, just a nice tick.

Saturday when I waspoking around with the stethoscope, I couldn't get a definitive spot where thesound really increased. However, without the stethoscope, I could here adifference right behind the CAI on cylinder 3 and 4. I got thinking and thoughtabout how these things like to blow out plugs sometimes. So, I pulled coils on3 and 4. The spark plug well on cyl 3 was nice and clean. The spark plug wellon cylinder 4 was pretty nasty. Almost like exhaust had been blowing up throughit. Anyway, the plug was tight on 4, but I changed it anyway. Still no dice. Tick/Tap continues.

So here I am. I'vehad several guys listen to it familiar with the 4V. Some say its valve train,others say its too deep to valve train, not as low as a rod should be, but theyare thinking bottom end.

No metal in the oilor filter when it was changed
No drops or spikesof oil pressure
No change in toneover the past week
No loss of power atall
No CEL codes

Uploaded a video ofthe tick to photo bucket here: Engine was still warming up a bit, so there a few creaks here and there unrelated.

 

[George Wax]

Towards the end of the video it sounded like "rod knock".

 

[SVT Sam]

Maybe. BUT, I would be amazed if it was. It doesn't sound deep enough to me to be a rod knock.

I would also assume, it would have gotten a lot louder over the past two weeks of driving it.

I could have swore the sound was coming from either cylinder 3 or 4. So, yesterday, I pulled the valve cover and started poking around. I pulled the lash adjusters for both cylinders. I measured them as well. One of the intake lash adjusters on cylinder 3 was about 11 thousandths shorter than the rest. I went ahead and swapped the lash adjusters for #3 and #4. Put her back together and fired it up. Cold idle all sounded well. Once the temp gauge started to move up a bit, same tap started to come back.

 

[RX1Cobra]

Disconnect the coils, one at a time, and see if it stops.

 

[SVT Sam]

I will do that when I have a bit more time. Getting ready to go out of town for a bit.

However, I did find a good handful of other with the exact same sound. It seems to be a rod bearing issue, but not a spun bearing. In most cases, the bearing was de-laminating and coming part. In most cases if its not driven, you can pull the oil pan, do a hand polish on the crank and make sure its not damaged, then replace the bearings.

I think I am going to order a K -member kit to have on hand. Once I get the pan off, if the crank is OK, I'm going to replace the bearings then add the K and possibly some long tubes if budget allows. Car is currently not being driven.

 

[CFulton89]

sounds almost like timing chain guides, it doesn't sound deep

 

[cobraetti]

im saying lash adjusters had mine changed a few years ago

 

[SVT Sam]

UPDATE: Car is Fixed!!!

Hey guys,

Just wanted to follow up with an update here. I was so infuriated with what happened, I let the car sit for about two months before messing with.

Around the second week of September, I was still undecided on what the issue was. I had a strange suspicion that it was rod bearing failure based on what I found online and SVTP. I then stumbled across this thread....

http://www.svtperformance.com/forum...What-Does-a-Cobra-Do-When-The-PCV-Valve-Fails

These symptoms matched my problem exactly. Also, DC97Cobra had commented on a few other posts with sound clips and said it was rod bearing failure (Specifically delaminating) Well, I found my old oil filter I took off right when I stopped driving it. I cut it open and WOW....what a nice sparkly surprise!

At that point, I wasn't sure what to do. Pull the pan like DC97Cobra and give it go, pull the engine and rebuild, sell it as is. Well finally after another month and a half, I got my shit together and decided I was going to give it a shot just by pulling the pan and taking a look. It was going to be a lot of work, but it was the cheapest option at this point. I almost feel that, although this was a pain in the ass, it was meant to happen so I would get it together and get alllll of my other parts put on as well. Brakes and rotors, ball joints, bushings, motor mounts, h-pipe, etc. etc. etc.

Well, after several hours of work, the oil pan was off, all rods were disconnected from the crank. I found that rod #5 had bearing delamination failure. How funny! Upon inspection of the crank, just a thin piece of bearing material had transferred to the crank. I was able to pick it off with my fingernail. I then took a leather welding apron and cut a long strip like a belt, then added a bit of valve grinding compound and began to polish ever so lightly. It only took about 20 to 30 minutes and the journal looked spectacular.

I plastigauged the new bearings and everything was within spec. Added some assembly lube to the crank journals, threw in the new bearings, and torque down the new rod bolts. Zipped the k- member back in a fired her up. No noises! Changed the oil after about 15-20 minutes of idling and have driven about 500 miles since with no issues.

I just wanted to give a HUGE THANKS to DC97Cobra and SVTP.

Dan, you are the man!

If any one is experiencing the same issues, please, feel free to PM with questions. This is a lot cheaper than doing a rebuild if you are not a a point where you are able to pull and rebuild, assuming you have the same issue that is. (Mine is my DD right now, so it needed to be on the road as quick as possible)

Thanks guys!
Sam

 

[murse]

That's GREAT news!!!! and svtp is a wealth of knowledge.. It's also a nice feeling too, when you fix it yourself and..... it runs!! nice job.

 

[DC97Cobra]

SVT SAM... I know that this is an old post but I have been away from the site and didn't see it till now. Hope you car is still running great a couple years later! Glad to hear that it did the trick and saved you from rebuilding the motor!