Volvo mechanic friend just checked out the knocking sound on my 89' 740T (133K). Said knock was way too loud to be broken spring. Because the sound increases with RPM and knocks every motor revolution, it's coming from the bottom end. My friend was able to to use a stethoscope to listen high and low on the engine. He says the sound appears to come from the #2 cylinder. His educated guess is that the rod is bent and is hitting the bottom of the cylinder bore. This was probably caused by a stuck injector (brand new, 1 week old!)filling the cylinder with fuel. Car started, and rod bent. I had been wondering if my motor had the 13mm rods. Obviously not. So my options:
1. Replace rod. (if block isn't cracked or damaged.)
2. Replace all rods with 13mm's or forged. Do 13's fit my crank if it came with the small rods?
3. Find used low mileage 90+ used shortblock. Does anyone have good sources?
And even more choices:
A. Let mechanic do all.$$$$$$
B. I pull and replace engine, letting mechanic handle the shortblock.
C. I do all. Time could a problem.
Right now I'm thinking 2 or 3, and B.
Any thoughts or advice would be greatly appreciated. Any thanks to those who've given advice so far.