I have replaced several 2.4L Quad 4 engines in 98 to 02 Cavalier (z24) and Sunfire (GT')'s over a number of years due to spun rod bearings (usually #3 or 4) and decided to take the last few apart to try to determine a cause. Oil pressure did not appear to be an issue in either. In the 2.4L Quad 4 engines GM put double notches (for rod bearings) on the connecting rod as well as on the rod bearing cap. Normally (any other engine that I have rebuilt since about 1967) there is only one notch on each and there is no way for the rod bearing to turn in the rods. On the Quad 4 (with the dual notches the bearing will turn about 1/8 of an inch into the groove of the connecting rod cap and the ramp on the notch will put pressure onto the bearing at that spot. Also, if you look at the oil hole in the connecting rod the piston pin will not receive oil as the 1/8" turn in the bearing results in the bearing oil hole no longer aligning with the oil hole in the connecting rod. Now to my question... I am going to rebuild the engine I'm currently working on (install a rebuilt crankshaft and bearings) and was considering installing the connecting rod caps 180 degrees such that the bearing notches are on opposite sides and the bearing cannot turn in the rods. Looks like it should work - has anyone tried this?

bump, id like to know incase mine ever goes. 140k and going strong.

Not to my knowledge, no one has tried that.

BUT.... all most all of the nuked LD9 bearings are from people letting the oil get around a quart low. If you get a quart or more low you are almost guarantied to spin #3 rod bearing.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO