video of motor knock

[slvr98gt]

sorry its poor quality, let me know what ya think.

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[quickstang_1994]

says no longer available

 

[slvr98gt]

its back up now

 

[Fryrice]

What mods do you have ? Mileage ? We need some background info man.

How recent were they done ,and how long have you had this knock ?

 

[slvr98gt]

it has about 130k on the clock. really no engine mods, just underdrive pullies, k&n, but the car has an h-pipe, dumped mufflers, built rear. they have been on the car for 50k miles. oil changed right around 3000 miles withe mobil 1 synthetic. knock started while driving getting on it a little(second gear, about 3500-4000rpms). tranny is leaking slightly. knock is louder on top of the motor. there was a slight knock on initial start up of the car(maybe like 4-6 knocks,very quiet compared to current knocks) for probably 2-3k miles. ran into overheating problems about 1000 miles ago. umm, thats about it. its been driven about 3 miles since the major knock started (babied it home).

 

[Fryrice]

I know they are tryin to help but I hate it when people give you 20 different opinions. So lets play the elimination game,starting with the easy fixes first.My first thought was PTV if you had aftermarket cams in there. But I doubt it now ,and that knock would be a bit more consistent.

Do the knocks get louder when you hit the gas ? Do you use a low grade fuel ? One thing it sounds like is pre-ignition . First thing I would try is a simple engine treatment formula like Seafoam. Many people have had good success with it. You can pour it straight into you gas tank.

High mileage vehicles with a lot of carbon deposits in the engine (baked to the pistons) benefit from premium or mid-grade gas, since these deposits reduce the volume of the engine's combustion chamber and make knocking more likely. The carbon deposits themselves get hot and may act to ignite the fuel if lower AKI fuel is used.

BTW - AKI stands for anti knock index.

 

[slvr98gt]

no, the knocking stays the same volume throughout. i use 89 octane fuel. i know its hard to tell from the video alone, i just put it on here for some suggestions to what it could be. oh, and i did the seafoam like 10k miles ago

 

[Fryrice]

I would try a higher octane . If the buildup is bad,your gonna need more than one application of a cleaner. 10k ago is a long time on a high mileage car.

Is the car using a lot of oil ? If your confident its not fuel related,another thought would be piston slap . That could happen straight from the factory with no intervention from you. That happens when clearance between the piston and cylinder bore is too great. Essentially, the piston moves sideways and “slaps†or “knocks†hard against the cylinder bore and causes damage to the engine pistons and cylinders, excessive smoke emissions, excessive oil consumption, carbon buildup on piston heads, decreased mileage, and a loud “slapping†or “knocking†noise,

This can happen on high mileage vehicles that are showing wear due to

1 method to check for piston slap :

"Remove three spark plugs, leaving number one in place. Crank the engine over until you feel the resistance of number one piston coming up on compression. Crank against compression until the piston is about half way up the cylinder. Now using the fan, rock the crankshaft back and forth and listen for a metallic knocking sound. If you hear a knock, you have piston slap and the only way out is to rebuild the engine."

You can Goggle "how to test for piston slap" to get a better understanding.

 

[Mr. OAM]

I can only offer a guess from the video, but I will put $5 on a collapsed hydraulic valve lash adjuster, presuming it is built as other OHC engines I have some familiarity with. Good luck.


Steve

 

[ripper]

Steve has hit it right on the head. I had a rocker come off the lash and thats exactly ( and I mean exactly) what it sounded like.

Ill bet 50 bux that brings the total to 55 dollars :hammer:

take some time and pull the drivers side valve cover off ( by the video im guessing thats were you hear it)

 

[Fryrice]

^ A strong possibility.

 

[ripper]

Yea man it happened after a pass at the track. I thought my motor was blown for sure. My motor had no tune and I was an idiot for doin it. I got real lucky. The guy that installed my motor fixed it in like 30 mins. Didn't charge me a dime. Im in no way a mechanic though but that is exactly what it sounded like. Random knock. I hope thats what it is slvr98gt. Good luck O0

 

[slvr98gt]

thanks for the thoughts guys. i pulled the valve cover and everything looked good to me, i even had my brother take a look and he thought everything looked good also. im thinking it might be a spun bearing. i found this video on youtube, http://www.youtube.com/watch?v=pMRPLN3nz_o&mode=related&search=, this is exactly what my car sounds like. its going into my buddies shop this week so ill check back in when i know whats up. either way im replacing the motor with a 02-04 PI motor with cams and longtubes. thanks again

 

[ripper]

Ahhhhh crap. Were do i send the 50 bux :rant:

 

[voidfinger]

o wow that sounded awful... I hope you get that fixed but i guess your going to like the pi motor

 

[voidfinger]

Ahhhhh crap. Were do i send the 50 bux :rant:

You can send that to my mailing address

 

[ripper]

LOL nice

 

[Mr. OAM]

I'm going to reserve sending in my $5 until the engine has been tore apart. 8)



Steve

 

[ripper]

I dont blame you that sure as hell sounds like a rocker clackin around.

 

[slvr98gt]

alright who wants to bet me $5000 i spun a bearing?? come on, ill take bets now!!!