I need to buy a new or used engine

I guess the language has changed in Pa. What is the top and down gaskets, and how did you change the cylinders without changing the block. Just trying to understand your post.

Hello mide… There are several reasons of sound origination from an engine that you can read briefly at http://auto.howstuffworks.com/engine-knock.htm. If you decided to replace it eventually, then I have some suggestion hopefully useful to you!!! Well new engine of 2008 Acura MDX is costlier at every place. If you can afford then definitely should go for new one otherwise there are numerous reliable used engine dealers like http://buyusedengine.com or others to whom you can consult to get a good condition exotic piece at reasonable price.