So, we got the cam broke in today. What a traumatic day.
Started off with finishing up some small details on the engine itself. Temporary fuel pump wiring and tach. Things like that.
So, we get it fired and it lights right off pretty quick. We're breaking the cam in with the old Demon carb that was removed from the crew cab. A known good carb. Using the distributor off the previous engine. At first it was a tad floody and missing a bit so it was hard to hear much of anything. Then it finally cleared out and up, up, up goes the RPM's. So we had no choice but to kill it.
Get that sorted out and fire it up again. Now, here's the first chance we really had to listen to the engine. All we can hear is Bang, bang, bang or more commonly described as knock, knock, knock. It was a different knock though. Not something we were immediately concerned about. We looked for the source and could not identify it. Stethoscope to every thing on the engine we could try. Oil pressure was a steady 60 psi at this point with the RPM's in the 1500 range for the cam brake in. We kept with it for a bit. Then Terry, the engine builder slides underneath the rig and sticks the stethoscope on the pan and yells out to kill the engine. At this point I'm starting to think my Blazer Bash efforts have been in vain.
He had found where the knock was coming from. Right on the oil pan. We were baffled. A little scared and tensions were getting thicker. We decided the best course of action was to drop the oil pan and make an inspection. Problem with that plan, the cross member is not removable. It was built way back in the day before I had the shop and was fabbing with a grinder and torch. I never made it removable from the bottom. Two choices, cut the crossmember or remove the entire drive train to in the end get the engine out. The sawzall came out and the crossmember was cut. In approx. half an hour we had the pan out and were able to look inside.
This is what we saw. Exactly what we were supposed to see. Nothing said, "Hey this is not gona work." We also inspected the oil. Nothing that caused any sort of concern what so ever. The oil was clean and new.
Then Brett looks in the pan itself and asks if this scratch was always there. Low and behold, there it is. The #3 and #4 rod were swiping the pan on every pass. Just ever so lightly. The strip appeared almost as a polished spot. We decided to go ahead and put the starter on without the pan and turn it over a few times to inspect as much as possible. Everything looked good. We decided the pan clearance on the bigger rods had to be the issue. A little ball peen action and back together everything went. Got some fresh oil in it and fired it up again. Nice and smooth no noises, good oil pressure and steady running as can be expected from this motor.
PHEW! I was exstatic. After all that, we were back together with the cam broke in and all is good. Pulled the carb and dizzy and swapped for their injection counterparts and started sorting through the wiring for the injection.
Much more excitement than what I had planned for today.