apdrake – 9/5/06
My first engine rebuild is coming along nicely, I've struggled for awhile to get the pistons with new rings into the block, and finally did so last evening. The old (probably) worn 3-ring pistons would just slip right in on the test run I made, but regular pistons with regular rings (no over/under sizes) seem to be a bit stiff. I'm using plenty of graphite assembly lube, but I still get what feels to me like resistance when I try to pull the thing up and down by hand. Don't get me wrong, they'll still move, just not as easy as what I'm used to.
Is this me being paranoid and this is a symptom of new rings, or am I not doing something right? Before I actually start the motor, I plan to over lube everything with motor oil so it's not running dry.
CroleyDC – 9/5/06
Crosley19 – 9/5/06
- Just to make sure, did you check the ring gaps by putting just the rings in the cylinder and measuring? Did you rebore, or hone? New rings will feel a little tighter, and if you're using 4 ring pistons then you also have the drag of the extra ring. I'd use just oil for lubing the pistons. The thicker assembly lube could give you a false reading.
- A Crosley engine is not like a Briggs and Stratton lawnmower engine. You cannot just throw a set of rings and bearings into it and expect it to work. The Crosley engine is a very high speed engine, and must be totally within tolerances to operate correctly. You need .003 to .005 piston to cylinder wall clearance. Then you want no more than .003 cylinder taper. The piston rings should be installed into the cylinder one at a time and the end gap measured. You want .007 to .010 ring gap. If you have not miked your engine then all the work you are doing is going to be in vain.
- Coat the engine walls and piston with 30 weight oil when installing the pistons, if the engine is going to sit for more than a month after rebuilding it then use STP to coat the pistons and cylinder walls. The when you are ready to start it inject some 30 weight into the spark plug holes and crank it over till you get oil pressure up, and then put the plugs in and try to start it.
- In case a lot of you do not know this, when you hone an engine, you must wash out the cylinders with soap and water. I prefer Dawn dish washing liquid. Soap and water is the ONLY substance that will remove all the abrasives from the cylinder pores. After washing the cylinders out, spray them with WD-40 it is an excellent water disperser.