View Full Version : Engine Knock?
Slick Nick Dec 8th, 02, 08:57 AM The rebuilt 305 (original) that I recently installed on my 87 trans am knocks and vibrates. But, until recently, I assumed it was merely a symptom of a rich running problem that I've been chasing. After countless times of adjusting the Q-jet and the timing, however, the knock won't go away.
It doesn't sound like a lean running knock or like I'm using the wrong octane (93). It's very rythmic- knock knock knock?
I know that I'm using 10w-30 instead of 5w-30
and 3 months ago 2 torque c. bolts fell out,
but I replaced the bolts and they haven't gone anywhere since. Could my bearings be shot after 6000 miles? Could my crankshaft be warped.
I'm lost???
Thanks for the help!
drpm Dec 8th, 02, 05:20 PM HEY I HAVE A 85 CAMARO AND IT KNOCK TO DOSE YOUR KNOCK ENGINE WILE IDLEING, YOU SEAD YOU PUT THE ENGINE IN, HERE ARE SOME THING TO CONSIDER I'VE LEARNED THAT A CRACKED FLY WHEEL CAN MAKE A KNOCK OR THE CONVERTER COULD BE BAD (700R4) THATS WHAT MINE WAS ALSO THE CONVERTERS ON NEWER GM'S MUST BE BOLTED UP TO THE FLY WHEEL IN THE CORRECT POSION NOT JUST ANY WAY WELL GOOD LUCK HOPE I GAVE YOU SOME GOOD IDEAS
Slick Nick Dec 8th, 02, 08:45 PM Actually yea, it only knocks at idle and low RPM's and it only vibrates at about 2000.
Oh, and when I bolted the torque c. to the flywheel I honestly didn't make sure to put it back in it's original position on the flywheel, I didn't think it mattered.
I also had the idea to unbolt the torque C., run the engine and see if the knock stopped, but I didn't know if that was such a good idea?
Thanks!
novaderrik Dec 8th, 02, 08:48 PM drpm- it's nice of you to help a new member out, but i don't think you need to yell.
Slick Nick- welcome to Camaros.net- quite possibly the best group of people to help out with any problem- big or small.
the knock could be anything- it's hard to figure out what from here with only a brief description on an internet bulletin board. it could be a cracked flexplate- but, contray to what drpm said, there is no right or wrong way to bolt them up- if the holes line up, it is right. had a cracked flexplate in a 92 Caprice a couple summers ago, and was about ready to tear the motor out and go thru it. then a friend suggested to check it out, and sure enough, the flexplate cracked all the way around where it bolts to the crank- after i took it out, i hit the middle of it with a hammer a couple times, and the middle fell right out. cracked from the middle of one bolt hole to another, all the way around. still have that flexplate as a memento.
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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
Cameron Dec 8th, 02, 09:14 PM Just to repeat what was already said, check your flex plate, especially since you had some bolts back out of it. With just one bolt holding the flex plate to the torque converter, there would be some weird, uneven stress loads imposed on the flex plate and probably the converter, so check it too.
I had a friend who had this exact problem a couple of years ago. We thought that the engine in his truck (had 190,000 miles of abuse on it) had finally let go. After further inspection, we found out that the flex plate was cracked all the way around the flywheel bolts. A new one fixed the problem.
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69 Camaro
400 Small Block
Trick Flow Heads
Comp 282S solid cam
Performer RPM intake
750 CFM Holley
and a Muncie four speed
Pics of My Car (http://cards.webshots.com/cp-25368180-AyNI-album/38182394akfhbj)
drew69 Dec 9th, 02, 12:45 PM Agree with the above two posts. It's worth a shot especially if your torque converter bolts came out. The sound is more of a rattle to me than a knock on ones I've changed. But if I heard it I could tell you for sure.
You can take your starter bolts out and install the two of them in the bell housing to be used as guide bolts or get two 5"/6" long 3/8"-16 bolts. That way you don't have to pull the transmission / or engine all the way out of the car. You can slide the trans back and sneak the flywheel out in a small amount of space. Be sure to use a six point socket or wrench so you don't round the heads off of the flywheel bolts (the heads are thinner than a regular bolt).
Goodluck & Welcome
Drew
drpm Dec 10th, 02, 05:35 AM sorry about the cap lock, habit, always willing to help
drpm Dec 10th, 02, 05:42 AM oh ya about the vibration,if you changed the water pump i had a buddy that had a bent water pump shaft that caused vibration.
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