Saw this video this morning. Looks like it's a lot less than we've been led to believe in a street motor.

 

It's actually more than I thought it would be.

 

I'm running 1/16" rings, so I'm kind of in the middle. For the street I wouldn't pay extra to get special pistons with the thinner metric rings. My pistons came standard with the 1/16" rings. I think more pistons are becoming available with the metric ring pack though.

I always used 1/16 rings in the nitromethane race engines because strength is a big issue.

Mike

 

In a 452 HP motor you gain 8 HP, that's 1.77%. Not much gain for the expense of a low friction ring pack and pistons.

So on a standard 350 HP build you're looking at 6.2 HP. You could get more out of a good carb tune vs a average to poor carb tune.

 

In the hot streetrod world it's pretty hard for the average joe to get the cylinder finish that OEM's can get, well impossible as far as I know, even from a good shop.

I kinda wonder at what point does ring seal start to suffer due to less than ideal cylinder roundness and prep? Not to mention longevity of the rings themselves on a less than ideal cylinder surface.

 

I've always felt that one can achieve better results than mass produced cylinder blocks receive.

You can achieve any finish you desire and I always strived for zero taper and out of round.

I always used a Sunnen hone with the industrial stones. I use a diamond flapper to finish off the cylinder. It cleans the trash out of the grooves that stones leave. The diamond stone like the factories use are available from Sunnen too.

Mike

 

The shop that did mine also used diamonds.

 

 

The more power you make the more power thinner rings will be worth.... but the less difference in ring thickness being compared the less the gain... ie, 5/64 to 1.0mm vs 1.0mm to .07mm.....

The more RPM you turn the more power the thinner rings will be worth.

The more cyl pressure you have the more power.....

Weight and friction is very detrimental for compression rings.... takes heavy thicker rings longer to seal back up after the piston changes directions at BDC and TDC compared to lighter thinner rings. This might surprise people but most of the friction in the ring pack actually comes from the oil ring assembly not the compression rings and Compression rings actually rely on compression getting behind the ring to help them seal... not tension.

Something else to consider.... even in just a low powered factory type engine, take those 5/64 rings and run it 100K miles.... then take those 1.2mm rings and do the same.... check the blocks cyl bore wear, ring lands on the pistons and leak down %.

In my experience with our limited late model dirt engines. We make a little over 600HP@7800rpm. Limited to Flat top pistons, flat tappet cam, unported cast iron heads and 362 cubic inches. Going from a 1/16-1/16-3/16 ring pack to a 1.0-1.0-3.0mm was worth 12hp peak and 8hp average. Not to mention I have run the bore the same size 2yrs before it needed to be bored again.... in a stock GM block. In the Dart blocks were are at 2yrs and so far it shows no appreciable at all. The 1.0mm ring package is actually very economical... less than $200, but its especially so once you take the wear reduction on pistons, blocks ect in to account.

A good set of 1/16 rings runs about $103-150.00. +12hp for $50? That's the cheapest 12hp I've ever seen in an engine of that class/caliber.

Will

 

This is an interesting article on cylinder prep. The shops in my area do not go anywhere close to these lengths for cylinder prep. Maybe some do in different areas. If they do I'd say it is as good as you can get. It's pretty old so maybe more shops are doing this now.

http://www.enginebuildermag.com/2000...face-finishes/

Reprinted in summary in 2004
http://www.enginebuildermag.com/2004...e-refinishing/

It seems more of the OEM engines are having oil consumption problems these days. Specifically GM that I have read about. Could this be related to using synthetic for break in or is it a ring package/cylinder prep issue? Anyone have the inside scoop on this?

 

My 2001 Avalanche 5.3 has used about a quart of oil between oil changes since new. It has not increased oil usage at 170,000 mile.

My 2011 Cadi CTS-4 3.6 Coupe uses a little oil too.

I don't think either of the engines rings are the culprit. Read about carboned up intake valves on the new engines in any brand of car with direct injection. They are sucking oil into the intake through the crankcase breather system. I took the intake off my CTS and it was wet with oil. The valves were coked up too. I cleaned the valves and put catch cans on both sides of the crankcase breathers. They have oil in them after only a 1000 miles. Not a lot, but 2 or 3 ounces in each one.

I suspect my Avalanche's 5.3 has oil going through the breathers too, but with fuel loaded with detergents flowing across the valves, it doesn't cause an issue like the DI cars.

When I get my 406 back in my 75 Vert, I'm putting catch cans on it. I don't need any oil mist in the chambers contributing to detonation at my compression ratio.

Mike

 

I think OEM problems are mostly with cyl wall prep and being able to hold the tolerances the parts need to work properly. Even the GM crate SBC and BBC engines that still use 5/64 rings are known for oil consumption problems. Most of that has been tracked to the cyls not being round/straight. I also don't think it's as widespread of a problem as it seems on the internet. You only really hear about the bad ones.... yet the OEMS build millions of these engines every year.

You got to consider the life and treatment of today's modern cars/engines as well. Turn the key and drive, lots of idle in traffic, extended maintenance schedules, and govt regulations that play hell with the ECM tunes, coolant and oil temps. I'm surprised that some of the factory LS and Ford Mod motors we build into race engines are in as good of shape as they are when we pulled them down. Alot are 200K mile engines....

My personal vehicles over the past 10yrs have been a new 2003 Avalanche Z71 with the 5.3L. Never used a drop of oil and I used a 5K maintenance schedule/OCI from day 1 till 160,000 miles when I sold it in 2014. I bought a new 2013 GMC Sierra Z71 with the aluminum LM9 5.3L. Again 5K maintenance schedule from day 1 and it just turned 50K miles... don't use a drop of oil. Wife had a 2009 Jeep GC 5.7 Hemi that used the same OCI on and never an issue from 20,000 miles till 110,000 miles when we traded for a new ecoDiesel Jeep GC last year. My folks have had a 2009 Silverado 5.3L since new and no problems either in 120,000 miles. We can't be the only people who aren't having a problem.
Will

 

That's interesting about your 2 cars. My 08 Chrysler 300 3.5L V6 with 150,000 miles on it has used about 1 quart every 5,000 miles too between oil changes since brand new and still does...no change from day 1 new. Lots of the Chrysler 300 guys run catch cans...hmmmm

 

I am surprised rod length and angles aren't being discussed!