226 engine knock

[Doc]

'54 Early Special. Valve job recently completed (9 springs were broken.....believed to be due to valve cover gasket folded up under, allowing moisture and thus rust over a long down time) and now the car idles very smoothly. Car has 40-50 psi oil pressure per the gauge. However under load there is a knocking sound we believe to be piston #1. Any ideas what might be the culprit? Is there any longtitudinal clearance cam adjustment on the front of the engine?

[Fabian 51K]

On the connecting rod, where the piston pin connects the piston to the rod. There is a bushing that has probably become worn with time. This usually causes the infamous piston slap! The only way to repair this is by removing the pistons and connecting rods, and pressing in new bushings. If you are going to go through this trouble you might as well replace the pistons, rings, and connecting rod bearings. Any reputable machine shop can do the work. Sense you do not have low oil pressure your main bearings should be ok. 

[Doc]

Thanks. Engine disassembly has begun and we'll try to get all new parts where needed. 

[Doc]

Engine has been rebuilt and the car driven home today some 42 miles. Runs quiet but tranny needs adjustment as one must take one's foot off the accelerator pedal before it will shift into 3rd. We tried adjusting the rod underneath the car on the driver's side and a test run it shifted a little hard, but it shifted.  After the third sequenece of shifting on the 40-mile home, it ceased to shift again withoutn pulling the fot off the gas pedal and the gas pedal seems very hard as well.

[Doc]

Short drive this morning and the car shifted normally through all gears no less than 7 or 8 times and took a hill very well, so will have to see if the Lucas treatment has now worked or it is a heat related issue.