Engine knock

If you have run it at a high RPM before the oil pressure came up, ,it is possible you have spun a rod bearing. I have gotten away with changing lower end bearings and changing the crank in the pat with engines with much less mileage, BUT in my opinion, with 130K a lower end rebuilt would not be money well spent. I would look into a compression check. The bad rod would have lower compression than the rest. If that is the case, you have a few options.

I have done some research on doing the conversion (I own a 1996 GMC Sierra with a V-6) It will cost me $1500-$2000 depending if I buy a used low mileage 350 or a stock crate motor. I have been told that the ECM is the same, but have to change the chip. The harness will have to be changed to match the motor. I was also told, but have not verified for sure that all of the accessories (alt, A/C, P/S) bolt up to the V-8 brackets.

So you can figure out for sure what is wrong...knocking is bad no matter what the reason. Get it repaired before the motor grenades and you won't be able to use your motor.

Well that is my opinion...I'm sure there are more to follow.

Eightupman

Just a thought. If that engine has an oil pressure cutoff switch then maybe your oil pump or drive went out. Therefore, the early noise and subsequent no start.

"MaxAluminum" wrote

As far as I know, GM's in general, and this particular vehicle for sure....do not use the oil pressure switch as a "cutoff".....it is used as an alternative path for the fuel pump in case of fuel pump relay failure.

Ian

. . . . Take a look at the valve covers.....see if there might be a nice shiney object the size of a pencil sticking through one of them..... if not....then see if one of the valve covers has a bump the size of a marble on the top of it....

Both will indicate a push rod that's gone fubar on you.

If there's no indication of a push rod failure....

check the damper on the crank pulley to see if it's coming apart on you....wobbling around a bit, generally loose and sloppy, sorta falling off in the extreme.

If there's no indication of a damper failure....

buy a motor.....it's the cheapest way out with that blown engine you have.

hopefully helpfull,

marsh monster ~:~ =3D=3D=3D=3D=3D =3D=3D=3D=3D=3D Engine knock Group: alt.trucks.chevy Date: Sun, Nov 2, 2003, 10:31pm From: snipped-for-privacy@crosstel.net (Jerry=A0Stockton) I have a '94 Cheyenne with a 4.3 liter V-6 with 130,000 miles. Day before yesterday it wouldn't start the first time, as it usually does, I had to crank on it several times then it started. Yesterday it did the same thing and when it did start I raced the engine a couple of times and it started knocking pretty loud and wouldn't stop. I shut the engine off and restarted it again and it still makes the loud noise. Today it won't even start at all. Have I damaged a lifter, or push rod, or worse yet...a connecting rod! The noise is much louder than a sticking lifter, but while the engine was running it ran smooth. Any suggestions would be greatly appreciated. Jerry