i have a 2.8 liter 173ci. and it started to nock one night. i have the engine apart right now and i see no sign of wear except the 30 thoushand lip in two of the cylinder 2 and 3. does anyone have any reasons for the knocking. thanks jason

 

what are the specs on the rod and main bearings? did the knock seem to be coming from the top end or lower end? how do the cam and bearings look? crank look? any other signs of top end wear?

 

i didn't mesure the rod. but the all the bearing looked good except there was a wear mark in the front crank bearing. other then that they are good.

 

was the mark a good size mark? could you catch your fingernail in it? check out the crank on that bearing for any marks? on any of the bearings, do you see any brass color?

 

it was a grove all the way around the bearing. but there wasn't any thin on the crank that i could see.

 

you need to get measurements on the rod/bearings and crank/bearings. you can get, i forget the name of it (someone help here) but its this little thin stick with measurements on the package. you put a piece on the bearing and torque the cap on the crank/rod and then take it off. measure how thick it is to see what the clearance is, if its below specs, you need to look into new bearings, or the crank being ground.

the biggest thing id say is where did this noise seem to be coming from? top or bottom end?

 

the knock was coming from the top end of the motor. also the oil light was coming on when i was stoped at a light and idling.

 

then it was probably a lifter noise. was there a lot of build up inside the engine from the oil? youd probably be wise just to get a 3.4, itll cost less probably than rebuilding (THE RIGHT WAY) what you have plus youll end up with more power. that 2.8 may have been neglected at some point in its life as far as maintenance or just may be tired. your best cost/benefit would be a 3.4.

if you wanna go the cheap route, get a cam and set of lifters for it, maybe rings and bearings too. but you still could find a good 3.4 for about the same cost once you get into bottom end stuff.

 

82-84 2.8's had smaller main Journals than the 85 and up. They changed to a larger size mains in 85 for added durability.

When I bought my 83 it had a loud rod knock and the oil light would come on as well.

If you are going to rebuild the original motor, have the block align bored to accept the later model crank. Or move up to a 3.4. You will either have to get the crate 3.4 or use an electric fuel pump as all 85 and later blocks (except 85 s-10's) have no provision for the fuel pump

 

I agree. The 3.4 is the way to go! mine was used form a junkyard...50,000 miles $600.00. Sold what I did not need. Ended up with $400 or so in the block! You really only need the long block. All the 2.8 top end will bolt up. We reused my 2.8s heads and cam (as they were modified from stock). 3.4 accepted them just fine!