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Re: Volvo 2003 or 2002 (not 2030/2020) - anyone here ever rebuild one? Or had rebuilt
Jim - thanks for the reference to French Creek Marina. I've heard good things about them, so will give them a shout.
It appears that I've solved the torque spec conundrum for my rebuild, after weeks and weeks of poking around for info. Here's what I found out, and some background on the issue, to help folks understand a bit.
During my rebuild, we discovered two important errors in the version of the workshop manual we were using (piston ring gap and piston arrow orientation). We sorted these two things and continued with the rebuild. Later, when we went to torque the big end (connecting rod) bearing bolts, the torque wrench did not get noticeably harder to turn when it approached the torque setting we had set the wrench to (44 ft lbs). Weird, we thought, and re-consulted the manual.
Turns out, we discovered upon looking at the manual, that there were two different torque specs for the big end bearing bolts (and main bearing bolts) - the Assembly Instructions part of the manual stated 51.6 ft-lbs, while the Technical Data specs page listed 44.2 ft-lbs. Needless to say, we were totally thrown for a loop. We didn't want to use the wrong spec - either under tightening a key bolt and nd having parts work loose while running, probably ruining the engine; or over torquing a bolt, stretching and ruining it (and Volvo Penta no longer sells connecting rod bolts!).
I contacted Volvo Penta and they sent me, some months, ago a revised/updated version of the manual which they said had the correct specs: big end bearing bolts (9mm diameter) to 51.6 ft lbs, main bearing bolts (10mm diameter) to 44.2 ft lbs.
My very experienced mechanic friend helping with my rebuild took a look at the specs and said they just didn't look right to him. Why does the larger diameter bolt have the smaller torque, while the smaller bolt has a higher torque? Moreover, if you consider that the engine's cylinder head bolts (10mm) have a torque spec of 51.6 ft lbs, why would the big end bolts (smaller, at 9mm) have the same spec? FYI, there are no grade markings on the heads of the big end bolts, so there is no (easy) way to determine their grade/strength. Suffice it to say, however, that 9mm bolts apparently don't generally torque that much (51.6 ft lbs) unless they're high grade. In short, before torquing anything down and potentially ruining bolts that are no longer available, and potentially ending my rebuild (after investing plenty of time and money), I wanted to be sure of things. This was especially so after earlier finding a few critical errors in the workshop manual.
This morning I managed to locate a diesel engine shop in the UK that has rebuilt and bench tested and is selling a Volvo 2003. They told me, yeah, the specs for the various types/sizes of bolts may appear odd - "common sense" might suggest the specs are wrong - but they told me they've always used the specs from the new Volvo manual for their rebuilds, and haven't had any problems.
So, this appears to solve the issue...big end bearing bolts to 51.6 ft lbs, main bearing bolts to 44.2 ft lbs. Fingers crossed!!!