The trend now is toward thinner rings so that they seal better by conforming to the cylinder wall and have less friction. A win/win. My usual ring package of choice is 1.0/1.5/3.0. Had the stock GM rings on my last engine and the leakdown was 4% after the rebuild and also after 80+ hours of racing.
[This message has been edited by mender (edited 03-17-2018).]
Originally posted by La fiera: The problem was that these pistons come in set of 4 and I bought 2 separately. The package of 4 were within a gram or two but the other 2 are off by a lot, 11g like you mentioned. But I'm getting there little by little. To answer your question I drill little holes at low depth under the crown. I do it a little at a time and what I do in one side I repeat at the opposite side.
I figured they were from two batches. I buy V8 sets when I can and use the best six, much less work and usually quite cheap - if you can find the right sizes.
The heavier ring requires more force to turn around. It's more likely to flutter at high RPM unless it has a LOT of tension. If it has a lot of tension, then it has a lot of drag. If it has a lot of tension, then it has a large radial dimension and will be stiffer and more senstive to imperfections in the bore roundness and hone consistency.
Even the best bores in the world aren't perfect. They aren't in a GM 60 degree V6 either.
If you're putting championship effort into the hone, then you can run a 1.0-1.2 steel top ring (gapless even better!) with lateral gas ports, 2.0 or less Napier 2nd ring and pick up power. I would say a 2.7 or less oil ring, but you like to run your bearing clearances wide, so you'll probably need a stiff oil ring to scrape all that oil off the bore walls.
Getting to 300 at the wheels takes all the tricks.
The trend now is toward thinner rings so that they seal better by conforming to the cylinder wall and have less friction. A win/win. My usual ring package of choice is 1.0/1.5/3.0. Had the stock GM rings on my last engine and the leakdown was 4% after the rebuild and also after 80+ hours of racing.
BAM!
Mender beat me to it.
[This message has been edited by Will (edited 03-17-2018).]
Well with the higher comp ratio the thicker rings can take more abuse over a longer period of time. Also they flex less under higher compression ratio.
The trend now is toward thinner rings so that they seal better by conforming to the cylinder wall and have less friction. A win/win. My usual ring package of choice is 1.0/1.5/3.0. Had the stock GM rings on my last engine and the leakdown was 4% after the rebuild and also after 80+ hours of racing.
Endurance road course. Chumpcar (now Champcar) to be precise. The double row timing chain installed during the rebuild was starting to get loose and the valve guides and seals were also worn but the ring and valve seal were where they started.
[This message has been edited by mender (edited 03-18-2018).]
Well with the higher comp ratio the thicker rings can take more abuse over a longer period of time. Also they flex less under higher compression ratio.
The piston lands support the rings so there is essentially no flexing to worry about if your pistons are accurately machined. Flexing less is a disadvantage when it comes to sealing the bore.
The rings in my 10.5:1 3500 were subjected to an air-fuel ratio of 13.8:1 and a few times the mixture went even leaner because of a bad MAF and a clogged fuel filter. No issues. I wouldn't hesitate to run 10-12 psi boost with the same rings.
Friction lost to extra drag because of the rings is like a tax you never see: it comes off the bottom line without you knowing it. When you have your short block assembled, slowly turn the engine over with a torque wrench and measure the amount or torque needed. I did a 540 that only required 24 ft.lbs to turn and it made 796 hp @ 6600 rpm.
Lower drag from the ring package is free horsepower.
[This message has been edited by mender (edited 03-18-2018).]
Well with the higher comp ratio the thicker rings can take more abuse over a longer period of time. Also they flex less under higher compression ratio.
Rings don't "flex" unless the piston flexes, but they can twist in the grooves if the side clearance is too wide. Cut side clearance down to .001 and thin rings work better than thick.
[This message has been edited by Will (edited 03-18-2018).]
Endurance road course. Chumpcar (now Champcar) to be precise. The double row timing chain installed during the rebuild was starting to get loose and the valve guides and seals were also worn but the ring and valve seal were where they started.
You mean the Cloyes Double row chan stretch in that little time?!! Wow!
Lower drag from the ring package is free horsepower.
A thin ring (especially gapless!) with lateral gas ports can seal BETTER than a thick ring under a wider variety of operating conditions. Not only is the reduction of drag a reduction of frictional parasitic loss, the better ring seal results in a higher IMEP... the engine actually *makes* more power in addition to reduced parasitic loss.
You mean the Cloyes Double row chan stretch in that little time?!! Wow!
Porsche has studied engine wear and found that 1 mile of racing use puts the same amount of wear on the engine components as 1,000 miles of street use. When you compare that to the fact that 24 hour endurance cars cover 3,000 miles in a race, you can gain an appreciation for how tough Porsche engines are.
This is the start of the race we won at Spokane. Green flag at about 14:00 and pass for the lead at 27:30. https://www.youtube.com/watch?v=pDcr5-I33WU That was my co-driver's first road course race and you can see that he backs off several times just before the main straight, making it much harder for the Fiero to out power the other car. He also overrevs the car on his downshifts; memory tach read 6600 rpm, fuel cut was 6300 rpm and shift light was 5500 rpm. After seeing the video and a short conference he worked hard on getting that under control.
And this is the middle of a run at the Ridge. That was where the MAF was causing extreme lean conditions, engine backfired hard and broke one engine mount and also the exhaust. This is after chaining the engine down and welding up the exhaust. I called it after pulling a spark plug and seeing some pepper on the insulator. https://www.youtube.com/watch?v=mXPu2cp_LPQ Same driver, still downshifts too early and drags the engine rpm up past the 5500 mark but not as bad. The worst was a rental driver that missed a downshift and spun off into the gravel at Laguna. Memory tach read 7600 rpm after that one. We had the fastest lap of the weekend but couldn't seem to stay on track for more than a couple hours at a time from self-inflicted issues.
I have more video but haven't put it up. I think there's another of my other driver but he was pretty slow.
[This message has been edited by mender (edited 03-18-2018).]
Porsche has studied engine wear and found that 1 mile of racing use puts the same amount of wear on the engine components as 1,000 miles of street use. When you compare that to the fact that 24 hour endurance cars cover 3,000 miles in a race, you can gain an appreciation for how tough Porsche engines are.
I guess we did okay then.
Average speed for those racing hours was about 70 mph so close to 6,000 racing miles on a lowly GM engine.
Originally posted by mender: The trend now is toward thinner rings so that they seal better by conforming to the cylinder wall and have less friction. A win/win.
Yep, and this is a decades-long trend. If you look at the 60-degree V6 family, you'll see the piston rings become progressively thinner as the years go by (while the compression ratios and power outputs go up). If you dig back through history, you can see the ring thickness gradually shrink from 1.5 / 2.0 / 4.75mm down to 1.2 / 1.5 / 3.0mm. (top ring / second ring / oil ring).
The GM High Feature V6 takes that trend even further, with 1.2 / 1.5 / 2.5mm rings. And just to put things in perspective, the 3.6 liter V6 in the 5th-gen Camaro was rated for over 320 HP.
Side note: I think it's great that we can talk all this "engine geek" stuff in this thread.
[This message has been edited by Blacktree (edited 03-18-2018).]
Yep, and this is a decades-long trend. If you look at the 60-degree V6 family, you'll see the piston rings become progressively thinner as the years go by (while the compression ratios and power outputs go up). If you dig back through history, you can see the ring thickness gradually shrink from 1.5 / 2.0 / 4.75mm down to 1.2 / 1.5 / 3.0mm. (top ring / second ring / oil ring).
The GM High Feature V6 takes that trend even further, with 1.2 / 1.5 / 2.5mm rings. And just to put things in perspective, the 3.6 liter V6 in the 5th-gen Camaro was rated for over 320 HP.
Side note: I think it's great that we can talk all this "engine geek" stuff in this thread.
Yup, my Fiero has the LFX 3.6 sitting in place now, just waiting for some spare time to do the final wiring. I've been impressed with GM lately, their recent production line stuff looks a lot like the race stuff I was doing only a few years back!
And yes, geeking out on engine tech is always fun. So what's the deal on tribology and rings?
Long story short, thinner rings were worth about 7 HP on an moderately tuned SBC V8. So realistically, on Rei's V6 they might be worth 3-4 HP. That definitely doesn't justify buying a whole new set of pistons and rings. But it's something to consider if you're in the planning stage of a new build.
Long story short, thinner rings were worth about 7 HP on an moderately tuned SBC V8. So realistically, on Rei's V6 they might be worth 3-4 HP. That definitely doesn't justify buying a whole new set of pistons and rings. But it's something to consider if you're in the planning stage of a new build.
I will definitely take that in consideration for my 8000RPM Supernatural!
[This message has been edited by La fiera (edited 04-09-2018).]
Are you guys familiar with a product called MotorKote? I watched a YouTube video where a guy tested it, and got some really impressive results. I'm thinking of putting that stuff in my Fiero, to keep the cam and lifters happy.
This is the start of the race we won at Spokane. Green flag at about 14:00 and pass for the lead at 27:30. https://www.youtube.com/watch?v=pDcr5-I33WU That was my co-driver's first road course race and you can see that he backs off several times just before the main straight, making it much harder for the Fiero to out power the other car. He also overrevs the car on his downshifts; memory tach read 6600 rpm, fuel cut was 6300 rpm and shift light was 5500 rpm. After seeing the video and a short conference he worked hard on getting that under control.
And this is the middle of a run at the Ridge. That was where the MAF was causing extreme lean conditions, engine backfired hard and broke one engine mount and also the exhaust. This is after chaining the engine down and welding up the exhaust. I called it after pulling a spark plug and seeing some pepper on the insulator. https://www.youtube.com/watch?v=mXPu2cp_LPQ Same driver, still downshifts too early and drags the engine rpm up past the 5500 mark but not as bad. The worst was a rental driver that missed a downshift and spun off into the gravel at Laguna. Memory tach read 7600 rpm after that one. We had the fastest lap of the weekend but couldn't seem to stay on track for more than a couple hours at a time from self-inflicted issues.
I have more video but haven't put it up. I think there's another of my other driver but he was pretty slow.
Are you guys familiar with a product called MotorKote? I watched a YouTube video where a guy tested it, and got some really impressive results. I'm thinking of putting that stuff in my Fiero, to keep the cam and lifters happy.
Only to local drivers that I know quite well. As you can expect, I have a lot of time and money tied up in the car and I have a hard time letting someone else drive it.
[This message has been edited by mender (edited 04-11-2018).]
Only to local drivers that I know quite well. As you can expect, I have a lot of time and money tied up in the car and I have a hard time letting someone else drive it.
I completely understand! There are 3 things I don't let anyone borrow and this is the order: My car, my tools and my wife!
Going back to the driving, this passed weekend I became officially a performance driving instructor. I spent the entire Saturday from 7am to 5pm from classroom to the track. It was in Summit Point, West Virginia and the track we use was the Shenandoah Circuit. I been to the Main racetrack many times but this was my first time in this one. That is an awesome and busy track, it is like a mini Nurburgring. It even has a "Carousel"! It has an uphill straight leading to it and right before the carousel there is a BIG dip! Every time I went through there with my Abarth it went airborne. It hit the rev limiter and at the same time I realized I'm off the seat and then back on it! It was awesome! It was a 10 hour drive back and forward but it was worth it! Can't wait to get the Fiero ready to take it there!
I did the Ross Bentley instructor's clinic a couple of years ago at our local track. I was paired with an established instructor who had several years of BMW schools and such. He brought his Black Series C63 and I had my son's '99 C280 Sport. We only did a few laps in my son's car then spent the rest of the day in his car.
I think he was pleased that he was my "instructor" because by the end of the day I helped him drop 5 seconds off his lap times!
I did the Ross Bentley instructor's clinic a couple of years ago at our local track. I was paired with an established instructor who had several years of BMW schools and such. He brought his Black Series C63 and I had my son's '99 C280 Sport. We only did a few laps in my son's car then spent the rest of the day in his car.
I think he was pleased that he was my "instructor" because by the end of the day I helped him drop 5 seconds off his lap times!
Thank you! Same thing here. My instructor was this old seasoned veteran guy in a 2009 Corvette, that old man can fool you! He drove like a computer, and he was fast! When it was my time to drive and him on the passenger seat, going from a Vette to a tiny Abarth was scary for him. The only thing I told him I was a Kart racer and he was like "Damn, is this how it feels like to drive a big Kart?" He didn't last 2 laps! He hated going airborne! He did tell me that I did a fantastic job on the driving but the clinic was about the student and my safety, a lot of psychology involved.
Thank you! Same thing here. My instructor was this old seasoned veteran guy in a 2009 Corvette, that old man can fool you! He drove like a computer, and he was fast! When it was my time to drive and him on the passenger seat, going from a Vette to a tiny Abarth was scary for him. The only thing I told him I was a Kart racer and he was like "Damn, is this how it feels like to drive a big Kart?" He didn't last 2 laps! He hated going airborne! He did tell me that I did a fantastic job on the driving but the clinic was about the student and my safety, a lot of psychology involved.
I taught driver training for 4 years so the in-car is easy, and I started in autocross almost 40 years ago and moved up from there. Yup, I'm one of those old guys. As to what I said to the other instructor to get him faster? "The tires are telling me things that I don't think you're hearing. Listen to them and join the conversation."
I taught driver training for 4 years so the in-car is easy, and I started in autocross almost 40 years ago and moved up from there. Yup, I'm one of those old guys. As to what I said to the other instructor to get him faster? "The tires are telling me things that I don't think you're hearing. Listen to them and join the conversation."
...I recently built a 3.4 DOHC motor, my cams spec at 286 degrees duration seat to seat (236 at .050), This is a hydraulic direct bucket cam. I don't anticipate getting much over 275 hp at the crank. The intake is a short runner, with a massive plenum, and a 3" Throttle.
Just sent you a PM regarding your custom intake. I'd love to see what you came up with, as I'm considering doing something similar myself.
As for your new project La fiera, I'm really interested to see if you hit your goal. Your 250 hp build thread was an informative read that I thoroughly enjoyed. I'm looking forward to see how this one plays out as well!
As for your new project La fiera, I'm really interested to see if you hit your goal. Your 250 hp build thread was an informative read that I thoroughly enjoyed. I'm looking forward to see how this one plays out as well!
Hello Irrarionable!!! Can't wait to meet you, you are my neighbor! I'm glad you enjoyed it , and got something out of it to move forward with your project. That is the reason I do what I do, to learn and pass on knowledge. Anything I can help you will be my pleasure! And if anybody needs some advice on anything, if I have an answer I'll pass it on, we are here to learn from each other. "There is more happiness in giving than receiving" the son of the Almighty was quoted by the apostle Paul in Acts 20:35. 3.4 DOHC have a LOT of potential, so you are on the right track!
Sorry for the lateness but you know how it is with projects! Got my rods and crank from the machine shop. Equally matched in weight! If you go back to the 1st page the stock rods are 590+- grams. The Supernatural rods are 542 grams and the crankshaft had to be lightened 1/2 pound to match the lightening of the pistons, pins and rods. These rods are Shot Peened for strength! The stock pistons are 488 grams and the Supernatural are 435 grams! The stock .906 pins are 142 grams, the Supernatural .912 are 106 grams! I already have the camshaft profile (Attitude) made for it so the short block is pretty much finished. I'll use the top end from the 250WHP project with some improvements that will boost its VE. One thing I learned with the 250WHP project is that if you put limits on yourself (Iron heads), your creativity will increase to levels you will not believe! Don't believe me?!! Look at F1!! The more restrictions they put the faster and powerful the cars get! But for the fans I can't start on this one until I get that 250WHP Dyno sheet on paper and video. Stay tuned!
[This message has been edited by La fiera (edited 06-28-2018).]
I admire your engine building skills, but pulling 250HP from a 3.1L N/A build is setting a goal of nearly two horsepower per cubic inch. That is a very aggressive goal for an engine not known for its breathing. IMO, you will probably need a turbo so prove me wrong. Interesting thread.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I admire your engine building skills, but pulling 250HP from a 3.1L N/A build is setting a goal of nearly two horsepower per cubic inch. That is a very aggressive goal for an engine not known for its breathing. IMO, you will probably need a turbo so prove me wrong. Interesting thread.
Hey Dennis! This specific project is over 3.5L with a goal of 300WHP using the same 3.4L block and iron heads. The 250WHP @ 6000rpm project is already finished and accomplished. But once I install the trans its going back to the Dyno so I can video it and have tangible proof that it can be done without a turbo or nitrous. I personally like to use the "Heart breaker" of Dynos, the Mustang Dyno; so nobody can say I'm cheating the system. Sit tight and be patient, I will not dissapoint you. Is there any way I can see The Paralyzer and The Colossus hp output? Did you make a build thread? Maybe there is something I can learn from your builds!
Look at this thread. That's what I'm using now in the 3.4 250WHP Supernatural. SBC solid lifters. The block is in machine shop getting the last bore correction to fit the pistons. The only difference between the 3.4 and 3.7 is the bore. And of course, the entire rotating assembly is lighter. But to answer your question; yes, I'm working on it. I should have the the short block ready in 2 weeks. I will not install it right away. I want to see how much more I can squeeze out of the 3.4 Supernatural and then the 3.7 will go in.
Totally agree amigo! 
