One of the best things this forum offers...is the ability to speak out ideas and plans...the process of typing it out...aligns our thoughts in a more clear and concise than they were in our heads.

Always appreciate the Kaama posts.

I re-read the Smokey section on his Power Secrets book. I remember reading it as a young lad...thinking about internal combustion engine designs. To support the long rod ratio...of up to 3.0 (rod length/stroke). Essentially a horizontally opposed engine with offset bores to the crank. The higher rod ratio would reduce the thrust side loading of the piston on the upswing, but it would provide massive mechanical advantage for the compression stroke, as the majority of pressure energy transfered to the crank is within 10° ATDC.

There are offset piston wrist pins...that do much the same.
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The higher rod ratio creates more dwell time of the piston at TDC, as it rocks over. But of course...it has less piston side thrust as well.

I'm not sure I'm going to stroke the 454s or not. I have 25hr factory GM forged 1pc gen V cranks from 1992. Having a hard time finding 4.25" stroke forged for reasonable prices that are US made.

Your engines found a sweet spot. 300-400hrs...tear down and inspect...quick hone to create the break in surface for new rings. Inspect bearings and heads. Good to go for another 300.

Oil sampling is also a benefit if used correctly at exact intervals. Now that synthetic is so costly....but it also gives us data on engine health.

You are going to get various opinions on "ring wear" as to how long they will last on a given engine combination. So you can make up your own mind and trust your own instincts from this read

I stopped by Performance Engineering yesterday and asked them about ring wear on a NA 9,80" deck BBC marine engine with a 4.250" stroke like mine and they told me about 250-300 hours, but I think they're also talking about including replacing valve springs, roller lifters, and a valve job

Then, I stopped in Dave Wesseldyk's shop iust down the street yesterday also and Dave (who completely rebuilt my NA 565cid engines after the North Carolina disaster) told me my engines would most likely last for 500-600 hours---but he said that's with a change-out of new valve springs, lifters and a valve job after about 250 hours or so. He also mentioned how important oil change intervals are---he said, "If you keep that oil clean it helps everything when it comes to wear and the engine will last longer".

And I spoke with yet another friend of mine this morning known as "Crazyhorse" here on OSO from many years back who is very intelligent and has experience working at an engine machine shop for a number of years when he was younger and building a few BBC's there. Anyway, he assembled a pair of NA 454cid engines (bored to 461"), stock GM rods with upgraded ARP rod bolts with a flat tappet hydraulic cam that made 505hp on the dyno (this was about 18-20 years ago) he told me those engines are still running very strong @5600rpm since the day they ran on the dyno and now with 400+ hours in a 28' Challenger and still not burning any oil. He believes they will last for 800 hours if they are properly maintained, etc. Of course now we are talking about a BBC engine with only a 4.00" stroke and not as much side loading, etc.

My NA 565" 9,80" deck 4.25" stroked engines I usually changed the oil every 15-20 hours----and my Bravo XR drives too. I am sure that's why my pistons looked so good and barely looked used after 220 hours---and that goes for all my rod and main bearings too,----but my valve springs (Isky Tool Room) were becoming very weak as we tested them on the Spring pressure testing equipment and losing their strength.

I love this thread and want to talk more in it but its a pain on my phone

Some random thoughts.....

1. All respect to the great Smokey Yunick....he was a national treasure and I have his picture hanging in my shop for more than just looking up to him. A lot has happened since he was inside an engine. You can have too long of a rod in an engine.
2. There is so much technology in piston design now, and a lot of it is still trial and error to see what you are putting an engine through and then seeing what you can get away with. You can run a big stroke in a short deck block and get reasonable wear if the piston is designed for it, and a 1.5 R/S ratio is no issue at all for a LONG life engine. That isn't a blanket statement...depends a lot on the stroke and other factors. There is a lot in ring technology that the average engine shop will never even see.....there are some rings that are $400 per hole. I'm not big on coatings at all...but there are a couple that have really made an impact for me. 1. DLC....when used in the right places its the ticket. 2. I have a piston in a terrible engine application 4" stroke and 12,000 rpm...it's hard to make a piston and cylinder hold up. We have a hard anodizing and teflon mix that makes both the piston and bore look MINT during service intervals where the same exact piston uncoated will be in poor shape. I'm going to use it in my boat when the times comes.
3.. There was some talk about bore size with regards to block wall thickness, and reference to the new Rottler and Sunnen hones dealing with this no problem. I can tell you with first-hand experience with both machines that they have some work to do and my experience is the opposite. When they released those things all I could think about was an employee not having to sit there and babysit the thing while it goes cylinder to cylinder and automates a lot of the process...improving some production capability. It's perfectly fine on iron blocks with a thick wall, it's perfectly fine on an aluminum block with a small bore and thick sleeve, and it's better on a billet block with a small bore and thick sleeve. However...you push the limits on bore size and get that sleeve thin, they aren't worth a damn. You'll fight out of round bores until you are exhausted. Right now, if I build one of our race engines that pushes the limits of bore and sleeve thickness....its 100% going on the 30 year old manual hone in the corner with an old salt working his magic to make that bore perfect. We are getting better on the new machine, but it is not there yet.

DRAG,

Awesome post. Smokey contributed a lot to the performance engine community. I have no doubt a lot of his SOPs were to solve symptoms for issues that would get solved with tech as time progressed. Rod ratio, for sure there is a limit to effective, and the LS engines being designed with longer rods is a testament to the benefit of a reasonable ratio.

Anodizing pistons is an interesting direction. There was a test of piston crown coatings, where they used an acetylene torch on the piston top to see how long it would take to melt. I'll have to dig it up.

Boring blocks. I appreciate costs etc, but I would expect my performance block to at least be monitored while being bored/honed. Local machine shop for me is an old school guy with old school equipment. Good for certain procedures...but a lot of tech now available. Blueprint engines has an amazing machine shop setup, now that they're casting their own blocks.

What is the consensus for thinner rings on marine engines?

I think I have heard that Mahle makes a very thin, badass piston ring

Great thread, great reading!

I love the guys willing to test the theories!

Thanks guys!

I really like the Mahle SBC package for a 400 or 383. They let you use the 6" rod, with 3.75" stroke, and keep the wrist pin out of the oil rings. Pretty spectacular achievement.
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Ellwein Engines has a great build on a 406 with dyno sheets using the Mahle. Build #104.

I'll have to check out their BBC offerings a little deeper. I think the dome size options for my 088 heads (119cc) were in between CCs to give me a good 8.5:1 CR

i think the whole game has changed in the last 5 years we now have watercooled billet blocks and heads that allow wild combinations 4000-5000hp yet drive it 200 miles overnight ck out some of steve morris videos or tom bailey and the sick week series the game has drastically changed

Yes, the engine technology has greatly kicked in over these past few years. When I originally built my 565" engines 20 or so years ago Cometic/MLS gaskets had not been invented yet and I needed a .051" gasket for my piston/block deck situation with my pistons peeking over the decks of my blocks by .003" ...thankfully Felpro had a gasket for my situation...and I cannot remember exactly, but hydraulic roller lifters were NOT yet able to RPM safely much beyond 5700rpm or so back during the time I had my engines built.

I think they were able to extend the RPM range on the hydraulic roller lifter by being able to redesign the internals of the lifter shortly thereafter my engines were built (I cannot remember the exact timing) but it heavily influenced me enough to "err" on the smaller side of a cam profile at that time.

Anyway, all kind of parts improvements have come a long way since that time----with all kinds of options and combinations to make BIG power. It's very interesting to watch it all happen in the hi-perf/racing industry.