PLEASE HELP 99 Cobra Knocking/Ticking Sound

[svt_vnenoso]

Hi guys,

I'm new to the forum, I'm going to try and describe the problem as best as I can. I'm going to start by describing the cars mechanical history since purchase then the most recent incident followed by the first incident as it could potentially help isolate the problem.

MECHANICAL HISTORY

I purchased the 1999 Cobra Vert in May with 150,000 miles. The previous owner sold it to me for $3,000 because it had a REALLY loud knocking sound. I have someone take apart the engine and we immediately find large chunks of metal in the oil pan. The mechanic says the oil filter was not properly tightened and that he ran the car dry. After taking the engine apart he finds two damaged piston heads, one broken tie rod, a slightly bent crankshaft, and a small chip in the aluminum block. He buys new rods and piston heads (stock nothing special) and all the metals that go along with them (bearings, rings, etc.). He gets the forged crankshaft turned and fixed along with the block. He inspects everything else and tells me the other parts are in good conditions.

I take the car from LA to Vegas for my bachelor party. I don't drive it more than 70-75 mph. I make it back with no issues. I get married on 7/9 and go on my honeymoon and come back 7/20. I drive the car less than 500 miles after that because teachers don't get payed in the summer (My wife and I are both teachers). I start working again 9/8 and I change the oil for the first time since the rebuild on 9/10 (Mobil 1 5W-30 and a Mobil filter). I see shavings in the oil but nothing out of the ordinary. Then the shit hits the fan...

INCIDENT #2

https://www.youtube.com/watch?v=wckcFuxzdBY

After exiting the freeway this Tuesday morning 9/20 on my way to work, I started to hear the faint knocking/ticking when the car was idling. When the light turned green I revved up to 2000 rpm before switching into 2nd gear and the sound got louder. I hit about 5 lights before I get to work. I heard the knocking/ticking with every gear if I got up to 2000 rpm. I park the car at work and check the oil. It was slightly below max. After work I start the car again and I hear the faint knocking/ticking sound again. I revved it up again to 2000 rpms and it got louder again. Luckily my commute is only 8 miles so I take it slowly again back home.

I get home record the video. Then I ask my dad for some advice and we check the spark plugs we instaled Monday afternoon. They were clean as a whistle. Then he suggests that I buy an additive that stops valve noise and fill up on gas. I pump 91 at Chevron and I drive it 30 miles. When the car was idling it sounded much better, I don't think I could hear the faint knocking/ticking but I could hear could still hear the knocking/ticking at 65-70 mph and/or at 2000 rpm.


INCIDENT #1

Prior to incident 2, this past Sunday 9/18 I went to a car show in San Fernando Valley (Galpin Car Show). When I pulled into the lot I was assigned to, I noticed that it was idling very rough. As soon as I turn on the car to leave the lot my check engine came light on. When I hopped on the freeway I noticed a loss in power. Yay... 45 miles to San Pedro... I drive it gently (65 mph) on the way back home and eventually I make back home with no issues.

Later that Sunday afternoon, and run the scanner to check the code and it turns out I have a misfire in piston #4. I go to autozone and I buy 1 OEM Motorcraft Platinum Spark Plug. I switch them out and it starts running ok. After work on Monday 9/19, I go back to autozone to buy the remaining 7 OEM Motorcraft Platinum Spark Plugs. It runs GREAT after that. Honestly, better than when I got it back from the mechanic when the engine was rebuilt.

Any help would be greatly appreciated. If you need more info/vids/pics, I'll be more than heppy to provide them.

I'll be driving my 1999 V6 Vert to work till the Cobra gets sorted. I'm actually kind a glad I didn't get rid of it during the summer.

 

[ashleyroachclip]

I listened to your video and it surely sounds like a rod knock .
Better take it back to your engine builder .

 

[svt_vnenoso]

I listened to your video and it surely sounds like a rod knock .
Better take it back to your engine builder .

Thanks for replying. How labor intensive is the repair for a rod knock? Is it costly?

I did a little researching myself and I found that it could also be Rod bearings, Lash adjusters, Cam Followers, the Timing Chain Tensioner or maybe even bad valves. Are these potential causes as well or can I eliminate some?

I'm really hoping that it can be fixed by just removing the valve covers. Do you think the oil is too thin? Or it could be bad gas? I did pump arco 91 two weeks ago (before the oil change). It was the only gas station close by and I was running pretty low...

 

[32vApe]

That deep of a knock is definitely coming from the bottom of the engine. Sounds like a rod bearing. For that to happen that soon after a rebuild, something was not machined properly, or installed properly. With the type of damage the original engine had, the shrapnel from all the broken parts is sent through every little nook and cranny in the engine. A new oil pump and oil cooler should have been installed. All oil the gallery plugs in the block and heads need to be removed and the oil gallerys need to be scrubed out to remove all small contaminants. Any of those small pieces can block oil flow and starve bearings of oil. Modular Ford engines have very tight clearances.

 

[svt_vnenoso]

That deep of a knock is definitely coming from the bottom of the engine. Sounds like a rod bearing. For that to happen that soon after a rebuild, something was not machined properly, or installed properly. With the type of damage the original engine had, the shrapnel from all the broken parts is sent through every little nook and cranny in the engine. A new oil pump and oil cooler should have been installed. All oil the gallery plugs in the block and heads need to be removed and the oil gallerys need to be scrubed out to remove all small contaminants. Any of those small pieces can block oil flow and starve bearings of oil. Modular Ford engines have very tight clearances.

Thank you for taking the time respond 32vApe

I had two of my dad's mechanic/friends hear the engine and they confirmed your diagnostic. I'm going to make note of your details though.

I'm taking it back to the shop (on a dolly to prevent further damage) where I had the rebuild done at the end of the month. He's going to take it apart and check it out.

A few more questions:

1) Can he determine whether it was my fault or his by cracking it open? I'll own up to it if it was me but I want to make sure he's not trying to scam me either. One can never to be cautious with these things.

2) Is it possible that I waited too long to change the oil after the rebuild? Maybe the oil had too much shavings causing it block the oil flow?

 

[32vApe]

From what you wrote, looks like you changed the oil with about 1000mi on the engine rebuild? Nothing really wrong with that with stock rings. These engines also need to be warmed up fully before you go heavy throttle or high rpm. If you were winding it out on a cold engine it my be your fault, but if it started knocking just cruising around he did something wrong.

 

[svt_vnenoso]

From what you wrote, looks like you changed the oil with about 1000mi on the engine rebuild? Nothing really wrong with that with stock rings. These engines also need to be warmed up fully before you go heavy throttle or high rpm. If you were winding it out on a cold engine it my be your fault, but if it started knocking just cruising around he did something wrong.

Alright for sure good to know.

I live pretty far into my city it takes me about 10-15 to just hop on the free way. The gage normally reads right in the middle. That should be enough to warm it up no?

I'm going to taking the car to the mechanic this Saturday. He'll give me his diagnosis after opening it up.

I'll keep you posted.

Oh, I also checked the bag where I had all the old pistons and rods. I noticed that the oil pump was replaced so I can cross that out for mechanic error. I did not see the old oil cooler though.

Is this a good time to upgrade to a high performance High Volume Pan and pump? Are these good upgrades for a daily driver? Or is it only recommended for track use?


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[Zemedici]

No need for high volume pan, save your money. Let us know.

 

[omj]

IF the oil cooler wasn't cleaned out, it may have circulated old debris through the new engine.

 

[svt_vnenoso]

Well the engine was finally opened up from the bottom. It turns out that it was a rod bearing. As a result, the crankshaft has a little damage. He's trying to see if it can still be salvaged. Is worth it with 150,000 miles? Or is it better to invest in another crank with low miles on ebay?

The more worrisome part was that he also found some water in the engine. What could be the reason for this? He was going to look at the oil cooler to see if I needed to replace that as well.


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[01yellercobra]

I'd wait and see what he says regarding the crank. As long as it's not cracked turning it down a little won't hurt things.

There are a few reason there is water in there. It could be a leaking head gasket, cracked head/block, leaking oil cooler, or just from sitting outside and not being ran. If everything else checks out I wouldn't worry about it too much.

 

[svt_vnenoso]

I'd wait and see what he says regarding the crank. As long as it's not cracked turning it down a little won't hurt things.

There are a few reason there is water in there. It could be a leaking head gasket, cracked head/block, leaking oil cooler, or just from sitting outside and not being ran. If everything else checks out I wouldn't worry about it too much.

Thanks for the quick reply.

He just called my dad back. He says it going to cost $250 to get it turned. It's at 10 I believe and it would then get turned to 20. If I can get a crank from a 99 or 01 (do 03 and 04 work too?) that is either standard, 10 or 20 cut for $200-$350 with lowish miles wouldn't it be better to do that instead?

Alright then, once we get the crank situation sorted I'm sure that will be his next step


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[Zemedici]

Thanks for the quick reply.

He just called my dad back. He says it going to cost $250 to get it turned. It's at 10 I believe and it would then get turned to 20. If I can get a crank from a 99 or 01 (do 03 and 04 work too?) that is either standard, 10 or 20 cut for $200-$350 with lowish miles wouldn't it be better to do that instead?

Alright then, once we get the crank situation sorted I'm sure that will be his next step


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depends on your faith in your builder.

Could go two ways : Could turn yours and it be fine

Or you could buy a used one that you dont know the history of, and still need it to be turned, ya know? I'd just roll with what ya got vs making it more complicated.

 

[svt_vnenoso]

depends on your faith in your builder.

Could go two ways : Could turn yours and it be fine

Or you could buy a used one that you dont know the history of, and still need it to be turned, ya know? I'd just roll with what ya got vs making it more complicated.

Update on the situation.

I ended up turning my crank. It's on it's last cut at .30

Since there was a little water in the engine, the mechanic decided to open her all up again. Pistons and rods were fine but some of the piston rings were fried. Thank goodness he ended up opening her up. I'm definitely taking it easy now on the car from now on.

As far as other parts that were purchased I bought the Ford Racing Oil Pump of the AM website (quality OEM part and fast shipping).

I'll be picking up the car this weekend.