!HELP PLZ! Knocking from rebuilt engine? - Hot Rod Forum : Hotrodders Bulletin Board
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Old 11-22-2003, 08:48 AM
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Red face Tapping from engine? Possible rocker problem?

Hello,

I am new to this forum and I'd like to start off by saying "Hello" to everyone

Now on with the knocking!

I have a 1986 Chevy S-10 2wd 2.8 v6 Blazer, the engine was rebuilt about 3 years ago, the oil has been changed and new sparkplugs installed about a month ago.

My problem is a knocking sound coming from the engine. It happens wether in drive or park. I've done some extensive research on this problem and since the engine has been recently rebuilt I thought I'd rule out a rod. But I've had a few random people tell me it is my rockers? I am not very vehicle literate as of yet but I am trying my best to solve this problem and as a last resort I joined this forum

The knocking sound is at quite an annoying sound level and is consistant. It showed up a few days after the oil and sparkplugs were changed but I don't know if that has any connection. The sound is coming from the center of the engine possibly the top of the engine. I've done my best to locate the sound.

The only odd thing thats happend recently is I hit a curb doing about 30 and it jerked the car. This happend befor the knocking, a few days after this it started having start up problems. It will turn over the first tryafter letting it set (some times second try) then after that "Nothing" The alternator being unplugged could be the couplrate to this problem but not to the annoying knocking sound?

Once again form what I have gather'd and sustained I believe its a loose rocker or possibly a rod? Mabey someone can help shine some light on this? Thank you!

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Last edited by 86_Chevy_Smokey; 11-22-2003 at 09:54 AM.
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Old 11-22-2003, 08:58 AM
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Have to ask but is there oil in the engine? You said you hit a curb... Did you knock the drain plug out and lose all of the oil? Go check if you haven't lately...
It sounds like a rod bearing has bit the dust... A rocker would be more of a clicking or tapping sound rather then a knock...
And why is the alternator unplugged?
Mark
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Old 11-22-2003, 09:07 AM
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The oil level is fine its been checked since the incident. I had a friend who threw a rod and they said the sound was not the same sound as a rod.. but mabey a valve or a rocker?

As for the alternator.. the vehicle's previous owner's have been moronic in trying to hardwire "things" directally into the wiring system and left it all in a mess so why it is unplugged is a enigma.

It sounds as if something metal in the engine is barly "tapping" up aginst another piece of metal. Almost as if somthing might be loose. I could be wrong but thats just to clear up the "Knocking" comment. Sorry
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Old 11-22-2003, 09:14 AM
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Okay... The best thing to do is pull a rocker cover and check all of the rockers. You may have a broken stud or a collapsed lifter. if everything looks okay with the rockers there may be a wrist pin going bad.
There is only so much speculating we can do here so you will need to get greasy to figure this out...
Mark
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Old 11-22-2003, 09:21 AM
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I'm not trying to sound stupid or helpless here but

I'm not fully understanding what a rocker cover is?

I use to build computers then after I got my first car i switched from comps to cars and this just recently happend.

I've never dicected an engine.

The only maintinance I've done on a vehicle is add oil, gas and fixxed a broken electric window. I recon a rocker cover is a cover for the rockers but I'm still unsure where the rockers are located.
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Old 11-22-2003, 10:23 AM
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Since you say that at this time your knowledge is very limited concerning engines; I would suggest that you get a shop manual for your vehicle and read it from cover to cover. They are available at most auto parts stores. You will find a wealth of info in them. If after reading the book you are still unsure as to what to do with your engine; it would be best for you to take it to a shop.
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Old 11-22-2003, 08:25 PM
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You might try getting a piece of rubber hose roughly 24" long. Use that to track down the area where the knock is coming from. Simply put one end to you ear and while you have the engine running try touching the engine in different places,front to back and top to bottom. That should give you some idea as to where the sound is coming from.
Also you might want to look for damage around the rear section of the engine under the truck. Possibly you have damaged something in the area of the starter or flywheel. If that fails offer to do a trade for some computer tech work for someones mechanical skills.
Lastly try taking it to the local high school or college with a mechanics course and ask the instructor to see if he can detect the knock. Good luck.
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