Hi to all. This past friday I scored a recon engine from a guy not that far from me who bought it for his blazer but decided to sell the truck instead and sell the engine. It is a 4.3 bored 40 over with new cam, roller lifters,high volume pump and recon heads. He even gave me new head bolts and a complete felpro gasket set. All this for 800 bucks. Turns out the engine has a tag on the side that states it was built by proformance powertrain products. So it appears to have been built by a reputable company and not one of those do it yourself rebuilds. What do you all think? And also, I have never installed an engine with a roller cam in it so I would like to know if during initial start up do I need to break in the cam like the regular non roller type? Thanks in advance ..........Rich

 

Hi, Rich. If you manage to start the 4.3 you should always allow the engine some break in period, 500 miles is good. Remeber that these vehicles are already programmed to run according to the instructions or commands from the computer, chips, and sensors. I believe that boring the engine 40 over would call for some re-programing as apposed to a rebuilt-to-stock engine. Keep me informed

 

What kind of programing and would I need to take it to the dealer? Thanks............Rich

 

If anything, it will run SLIGHTY lean for the first couple of startups until it warms up and the PCM goes into closed loop. Once it warms up the PCM reads the O2 sensors and corrects for any rich or lean condition. By the time you hit that first oil change at around 2,000 miles it will have run in closed loop long enough that the O2 sensors will have corrected the mixture enough times that the long term injector offsets will have adjusted everything on a more permanent basis. ie No need to reprogram, just go easy on that engine don't rev the sh*t out of it for the first 20,000 miles and you should be good.

 

Rich, don't let me stop you--40 over is not much. B1 is right, "PCM reads the O2 sensors and corrects for any rich or lean condition." I didn't know that I had to run 3000 miles for PCU to recognize corrections.