Rebuilding the lump

[Lynn Kirkpatrick]

So this friend mentions that he swapped the lump in his '71 B, and the one he pulled out is just setting around. I have wondered about "power-tuning" the lump in my '68 BGT. This seemed like a cheap way to get a motor to "power-tune" with out screwing up the one that is in and running OK. So I got it.

The reason he swapped was that under acceleration, there was a "knock, not a hammer, but a knock". When winter comes and were are snow-bound I plan to open it up and fix it, in addition to adding a few enhancements.

Assuming it isn't something simple like really low octane gas, what are the causes for a knock, and how do I check for them? It is a '71 motor (18GK-WE-H).

 

[Dozuki]

Bearings are typically knocks and ticks are valves/lifters. If the engine is out of the car its a good time to check the whole lower end. If it was knocking under acceleration then you have a bad rod bearing. Good that he stoped using it before it knocked even at idle, but the crank will still need a good inspection to make sure that the bad bearing didn't mess it up. Replace the main bearings as well. A bad bearing is pretty obvious when you see one. There is a tread on here that show some pics of bad bearings I believe.

P.S. where in indiana are you?

 

[DrEntropy]

It's a great idea to have an engine "in the bank". If you're gonna do it, do it once properly: Down to component bits, and back together to spec's, from bottom end to valves. The "swap" is then a one day affair (and you have NEXT winter's project conveniently sitting there waiting!). It's REALLY nice to have a spare gearbox as well, but that's just borderline ~decadent~ /ubbthreads/images/graemlins/wink.gif

 

[Lynn Kirkpatrick]

I'm in Columbia City, approx. 1/2 hour west of Ft. Wayne.

Thanks all for the tips.
Lynn