I am rebuilding my 305 on my 1990 RS . I have de-glazed the cylinders and put a new piston ring in each to measure the gap. I consistently have a .016 end gap. I still have a bit of a ridge on the tops of the cylinders. Based on the gaps I've measured could I hone the cylinders more to try to get rid of the ridge?

 

You can't get rid of the thrurst ridge by honing.

Also, if you're setting up rings on a used (and as such tapered) bore set them up pushed almost completely down the bore, using an upside down flat top to push it down straight. the lower part of the bore is least worn. If you set it up on the worn top, it'll be too tight on the bottom and lock up.

 

Either have a machine shop cut the ridge and hone the cylinders and have
them press in a new set of cam bearings while your at it. !

A lot of miles on that engine ????????

OR buy or rent a ridge cutter tool.............

 

Yeah, I think you need a tool called a ridge reamer, my understanding of it is, that in applications where the cylinders don't come quite all the way to true TDC, they wear down only some of the bore, but leave a little bit at the top that doesn't get worn, and thus the ridge forms.

 

ridge reamer, the best way to F up an otherwise good usable core.

 

Thanks for the replies , I checked the end gap at the bottom of the cylinders and I'v got .015 to .016, so I'm good to go. We'll see what happens when I put it together.

 

Personally, unless I broke a piston prematurely, or swapped them on a low mileage engine, I wouldn't drop new pistons or rings in without reboring, no point going to all that trouble to only do half the job, my Also, I believe a ridge reamer should be used before honing, but I don't know for sure, I don't know anything about them really, just know of them.