Alright guys, had another thread started that got off on this topic but was getting long. I have a 97 4.2 that i recently discovered has a 3.8 (2002 model) balancer on it. The truck has a hard vibration and is doggy. The engine runs good other than that with no codes. I have a brand new Dorman balancer for the engine but CAN NOT find a crank pulley to save my life. Could the reluctor ring be causing the loss of power since it is designed for a Mustang? Had a brain fart on that one today and made me think that maybe the spark could be retarded/advanced from this or the injectors out of time. If this sensor is not timed right it seems like it could throw everything off. The numbers on the block came back for a 99 but after looking at the balancer for a 99 4.2 there is no way it would work unless changing all the engine accesories make it possible and the same guy that looked the numbers up tried to sell me another 3.8 balancer...So, this is turning into a headache!

 

I would stop at a junk yard ask some questions and take some pictures. Obviously u perfer not swapping out motor. They know whats up, can offer u answers. U have been fighting this 4 three months now. Post some pictures so we can see what it happening with UR project.

 

I will try to take some pics when it goes back in the shop. I have been dealing with a salvage yard that has a hell of a parts locator. Found an under drive pulley and that seems like the only resort at this point.

 

I saw a picture of a 2001 F150 4.2 and that pulley looks to be 8" in outer diameter.

 

I see there are a lot of new harmonic balancers for a 2001 4.2L. on Ebay. They are an assembly with timing tooth ring and belt pulley attached.

 

I guess for superseded the original balancer that the pulley bolted to with the press on style and the 4.2 and 3.8 will interchange. I tried a new balancer and it didn't help so on to check the balance shaft and if that isn't the problem then a new short block will be in the future! Someone has been in the engine before and by the looks of the silicone they used on the oil pan they were idiots.

 

I'm going to guess yes to balance shaft timing over out of balance rods n pistons but game is on.

 

Usually a bent rod will cause a knock or piston will actually contact crank.

 

It has been a wild goose chase so far. LOL But it has been a good experience also. It's hard to find time to work on your own rigs most of the time.

 

The digference in ur 2 engine aplications are at the center of it all. Possibly wrong parts all along.

http://www.enginebuildermag.com/Cont...0000003366.gif

 

Here is some great info on it.

http://www.enginebuildermag.com/Item...8l_engine.aspx

 

Did you ever figure out the problem with your truck?