Nocking at high RPMs

[James]

While the crank is out you should check the connecting rod for out of round. While it was knocking it might have cause the rod to go egg shape. To check for it place the rod cap back on the rod and torque the nuts then mic the rod end, it should be round. If not corrected it can cause your rod to knock again and you will be back to square one again. If you're not able to check this the machine shop can do it for you. If it is out of round they can resize it.

[bigblockv6]

I would never re-use a connecting rod that had spun bearings unless it's been resized

[HOTRODJOHN]

Big Block V6 is right, I would cut the mains and rods to whatever size to make it right. Also, I would have the assembly balanced. In the long run you will end out on top and not doing the job twice and possibly ruining the rest of the motor. Most of the time a short cut leads to more expenses than what's it's worth. A good machine shop will tell you exactly what is needed and then you can hunt down the parts if he cannot.

[surfamtn]

Ok, got the crank out today. The #4 journal is darn rough. The others seem ok to my finger nail test but I'll be dropping it off at the machine shop next week.

Called Egge machine today and they have bearings in stock, sizes up to 30 thousandths. Forgot to ask about mains tho.

Thanks everyone for the input. I marked all the caps and such, pretty simple if you know to look, the caps are all stamped with a number that goes on the rod of the same stamp.

So my next source of anxiety: I tried to keep the timing chain sprockets in the same place but I ad to move the cam sprocket to get the chain off...
How the heck do I make sure I get the cam and the crank lined up again???

[TJ's GMC]

There are timing marks on both gears. They will be Dots. When you go to install, line them up so both marks are lined together at the closest spot.

So basically...if the motor is on the stand....TDC would be Dot on Top for the Crank and Dot on the Bottom for the cam. Lined up and closest together. Maybe someone has a picture.

[surfamtn]

TJ--- so the dots point toward each other? (I'm trying to imagine this while it's in the stand upside down when im working on the crank lol)


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[surfamtn]

Ok... since I have hijacked my own thread and it's now "help the new guy rebuild a 305"...

Rings??? I'm staring at the pistons and scratching my head if I should pull them out and re-ring them? The top of the cylinders have a slight ridge that I can feel with a fingernail. (Was not planning on having the block machined due to cost)
When running the motor used a little and leaked a little oil, only smoked for a second on start up. Had good power. The heads are already removed (cuz I'm an idiot) so I missed the opportunity for compression testing.

I kinda want to leave the rings alone.

What say the forum???


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[Funky61]

Check out this link on Rufton;

http://67-72chevytrucks.com/vboard/s...d.php?t=575596

[TJ's GMC]

Yep, they don't actually Point to each other, but if you rotate the assembly you'll see they where they line up Closest together...Upside Down would be the dot on the Crank would be on the Bottom and the dot on the cam gear would be on Top.

[turbobill]

Originally Posted by surfamtn

Ok... since I have hijacked my own thread and it's now "help the new guy rebuild a 305"...

Rings??? I'm staring at the pistons and scratching my head if I should pull them out and re-ring them? The top of the cylinders have a slight ridge that I can feel with a fingernail. (Was not planning on having the block machined due to cost)
When running the motor used a little and leaked a little oil, only smoked for a second on start up. Had good power. The heads are already removed (cuz I'm an idiot) so I missed the opportunity for compression testing.

I kinda want to leave the rings alone.

What say the forum???


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That engine should be pulled completely down and cleaned at least. There is probably metal from the bearing failure that got pulled back into the oil pump and some usually finds it's way into the oil galleys.

Oil smoke on startup is usually valve guide seals.