[Cool53]

Yikes, moose. Good subject, but really complicated. I went to a class held by the School of Automotive Machining while I was at PRI a few years ago and I was really blown away. It kind of boils down to the new high strength blocks and older blocks, like you are asking about. Most of the class revolved around new engines like Gm's LS series,mFird's mod motors and Chrysler's Heminline. They all have one thing in common. The cylinder material is so hard that the bore sizing has to perfect because nothing breaks in. The rings have to be round, as do the bores, most have a service limit of .0002" cylinder taper and out of round, and the finish has to be done with very expensive diamond hones. Older blocks are still going to use (typically) moly filled and cast rings for top and second. There are options, such as gapless, but rings are going to break in with the cylinders, just as always. Because of all of the manufacturers you should do a bunch of research before just buying a ring set, but the important thing is to make sure that whatever you decide to use the machine shop you pick has the right honing stones to get the rings to work. If you are having the engine dyno'd the dyno shop should have a blow by meter to guarantee the rings are working. If the shop doesn't have a blow by meter I would be concerned. The blow by meter is absolute proof that the engine shop is doing things correctly.
A lot depends on what piston material you are using, also. If you think you are going to run a power adder such as nitrous, turbo or supercgarger(s) then you want to stay away from Hypereutechtic pistons and stay with 2618 forged pistons, and file fig ring end gaps accordingly. Engines with power adder engine rings need a little more ring end gap to keep the ends from touching due to expansion under additional heat, which can break rings or remove the tops of pistons in some cases.

[themoose]

Jef

Thanks  for the info. It looks like for the everyday cruise around engine that a guy might be rebuilding himself and just running the old style hand held hone down the bores just to break the glaze it's best to stick with the standard style rings. You know I have to ask what your going to be using in you new engine.

One other question...A friend of mine is going to attempt to install a set of Time-Serts in an old Northstar and is thinking of replacing the rings and bearings while he has it out and apart. All of the Northstar engines that I have seen apart still show the cross hatch in the cylinder walls. Can you just put as set of rings in without having it honed and would you go with OEM or something on the aftermarket ?

Moose

[Cool53]

Hey Moose,
Chances are his rings are fine. If they are stuck with years of baked oil then the finish is too rough (that's why so many LS series engines burn oil) and because the bore material is so hard and tolerances are so tight the only way to fix it is to go the boring route. If the rings are fairly free and the bores aren't scored I would ball hone it, wash the bores thoroughly with a good fish washing detergent, replace the rings and away you go. All of the tech info on the ball hones is at brush research.com. Have your friend contact them about the best material and grit to use. The site gives drill motor speeds and all that.
Just a little trivia, the Cadillac engineers claim the Northstar engine, with stock hydraulic lifters, is capable of 11,000 rpm. I started building a twin turbo Oldsmobile version for my truck but what I wanted to do was going to be too expensive.
My new engine is a late model GM 4 bolt main, roller lifter, one piece rear main seal block. Because I run nitrous on occasions I will run 2618 alloy forged pistons, 6" H beam rods, at about 11.3 to one compression. I plan on running Total Seal Rings with a crankcase pressure control system that will keep up with the engine.
I run all coated bearings. If I can't get them off the shelf I go to Calico Coatings. The most important are cam bearings. With the engine sitting for a long time the cam is virtually trying to push it's way through the bearings because of valve spring load, so start up is very important for cam bearings.