Rod knock, but rods not bent?

[BiggT97Gst]

I have just taken out my 2g 7 bolt gst motor because of the knocking, but after taking of the oil pan and checking out the rods, they seem to be in perfect shape. Is it possible to knoc with a rod bent so little that i cant even see it with my eyes. Or knock without the rod being bent at all???

 

[Black 95 TSI]

the knock could even be a bad bearing , or carbon ontop of a pistion

 

[andymoraitis]

Exactly. When you spin a bearing, it'll knock, but not necessarily hurt the rod.

 

[wolf20043]

If the rod journals of your crank are out of round as the 7 bolt I have is, even with new bearings it will knock. And as stated above, it may not harm the rod as far as "bent" goes, but can damage the rod as far as where it bolts to the crank.
Mike

 

[BiggT97Gst]

well i just took a look at my bearings.... and it looks like someone had been taking a sandpaper to one of them. I think i found my problem... So, now a new question...if i replace the bearing...do you think it will stop the knocking?

 

[gr8popp]

Did you see any metal shavings in your oil pan? If you did spin a bearing you may need to see a machine shop. It has been my experience that a spun bearing means the rod needs to be ground down or replaced. Then you have to have the crank resurfaced. If the crank is resufaced then oem bearings can no longer be used and you have to have it magna fluxed for the correct bearing size. Just a heads up.

 

[BiggT97Gst]

Well thanks for the feedback guys. I was just wondering if i could easily get it running again...My first plan for this motor was to just fully rebuild it. And if the internals are wasted, then thats just what i'll do. But i guess i'll just finish my 1g swap then . Here's hoping everything goes well

 

[funkbuster]

it is probably a main bearing.

 

[95talon_in_ma]

A rod won't bend, they will keep going right through the block.....

 

[BiggT97Gst]

I dont mean to make you feel bad, but my last car bent a rod 90 degrees until it blew out a side of the block.

 

[perley03]

I dont mean to make you feel bad, but my last car bent a rod 90 degrees until it blew out a side of the block.

Now I would have to see this. I'm not calling you a liar or anything, I've just not heard or seen anything like this. I don't think you could bend a rod that far anyway without it snapping, which i've seen twice and the results not pretty either, but it was sure fun on the derby car

 

[BiggT97Gst]

Yea...bent rod on the freeway equals blown up supra

 

[95talon_in_ma]

I dont mean to make you feel bad, but my last car bent a rod 90 degrees until it blew out a side of the block.

I stand corrected....
Rods do bend....
But only on ricers...

jk.. That is unusual though. I don't think it could ever happen without noticing.

I once took apart a mustang that had a slight knock, but had lots of power. When we dropped the pan, the bearings looked OK. We proceeded to drop the crank and when we did the thing was literally in two pieces.....Snapped right in half.

 

[BiggT97Gst]

Yea, a rod knock will definitely ruin your day...but if i didnt blow that motor, i don't think i would have got my dsm...so it was for the better i guess. And i did my first motor swap on that car, which kinda got me ready for the 1g swap im doin now.