Posted by Chris Davis - UT on Friday, June 09, 2006 at 5:16PM :
Jonas has a rebuilt motor I may be buying from him after Hollister, but in the mean time, I'm trying to get the tired engine in my WC-51 to last long enough to do the 4th of July parade. I found that 20w50 oil and STP engine treatment raised the oil pressure. It idled in the driveway for almost an hour without complaint and without overheating. About the time I was ready to drive it around though, it ran out of gas. I didn't immediately realize this was the issue though, and swapped coils and checked point gap, etc before taking the fuel line off the carb and seeing nothing coming out. It sat for a day before I could get more fuel for it, and now it will start, but will not idle and runs rough, requiring almost full choke to run. There is almost a lope to it that suggests missing on a cylinder, but when I ground out the spark plugs one at a time the lope gets worse on each one, so it is hitting on all cylinders.
I suspect a jet or two are clogged on the carb and I'll be tearing it apart tonight. If anyone has other possibilities I should check I'm all ears.
But... the ground-out-the-spark-plug test reveled the source of a "knock". The knock isn't bad, almost quiet enough for me to suspect a valve being loose... more of a click, click, click. However, when I grounded out the number 6 cylinder this click/tap/knock went away. This points to a loose wrist pin/bearing or rod bearing... right? IF it is a rod bearing, in theory I could replace it just by dropping the pan and rolling in a new bearing. I'd probably just do them all, since bearings are sold in sets... you just can't by one right? I wouldn't have the crank turned or any real rebuild work done at this time, just a quick and dirty set of bearings.
I would use the same size... and here is the main question... this tag indicates 0.10 oversized rod bearings right? What about the other dimensions? Mains 0.10 oversized too, (meaning the crank was ground 0.10 undersized) but what might the 0.20 and 30 indicate.
Thanks for any advice for a guy with very little rebuild experience...
Chris Davis
Centerville, UT
'45 WC-51
Follow Ups: