knocking in motor

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Rick - 16 May 2005 02:25 GMT

Hi gang,

Been a while since I posted anything here, but I have a problem that I cannot seem to figure out yet. I have an 84 GT and after about 15 minutes or so, I hear a knocking coming from the engine. It is not the lifters, this is a deep thud sound. If I accelerate the motor, the knocking accelerates as well. The only thing I changed were the pullies, intake and carb.. Could I have done something to throw something out of whack by changing the pullies from stock to Underdrive? Is there any test I can do that would narrow down my possibilities. I really don't want to pull the motor considering summer is almost here. (depending on the day). I can really use some expertise here. If anyone is in the Montreal/ Chateauguay (quebec area) and could maybe swing by to lend their knowledge, I would greatly appreciate it.

Hope you guys can help me solve this.

Thanks

Rick

*'84 GT - First time owner, trying his best*

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whose ya daddy 96@ yahoo.com - 16 May 2005 02:57 GMT

>Hi gang,
>
[quoted text clipped - 7 lines]
>
>*'84 GT - First time owner, trying his best*

suspect con rod brng
or collasped piston
ya foctard

BTW
FRENCHIES SUCK

hurc ast

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cprice@here.com - 16 May 2005 16:05 GMT

Sounds like maybe con rod, or a bad mains bearing. Years ago I had a
bad con rod in my 82 GT and it was most obvious at idle. That is until I
snapped the crankshaft at the #2 mains (teardown showed bad rod bearing
at #5 and it was bad enough to be relatively certain is was the
culprit). So much for shitty cheap rebuilds - an expensive, but
important lesson to learn at 18. I built/blueprinted and had balanced a
new shortblock with arp fasteners and it spun smoothly to 6200 for years.

I have also heard of weird stories where bad harmonic balancers would
hit against timing pointers and such causing knocking noises. I would
*guess* that this kind of noise would be present from engine start, not
after 15 mins.

> Hi gang,
>
[quoted text clipped - 25 lines]
>
>

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