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I'm looking at building an engine for my '67 chevelle and am debating rotating assemblies. I keep reading horror stories about the 4" and 4.1" stroked motor having excessive oil consumption, piston skirt wear, piston slap, etc due to the piston skirt extending past the sleeve and the piston rocking in the bore. I looked as this video and clearly you can see the skirt coming out of the bottom of the sleeve.
Those of you with 4" stroked LS3s what's your experience?
I also saw 1 post that said the LSA and LS9 blocks have slightly longer sleeves than an LS3. Does anyone know if that's true?
I see several professional builders pumping out 850hp to 950hp out of supercharged versions of the 416. I have a maggie tvs2300 and would like to get in that range if possible.
I would use a 3.9" stroke and let the blower do the work, 4.0" would work also but with the blower
not needed, especially a Maggie. There are other benefits to the 3.9" stroke as well besides
greater piston stability in your application.
I saw an article from JE pistons on the longevity advantage of using a 3.9 crank vs a 4.0. You wouldn't think the .05" of travel at the bottom of the bore would make that much difference but the JE article indicated it was significant. Maybe part if it is that the wrist pin doesn't get into the oil ring land.
I was looking at the GM Performance Parts catalog and would love to build a 396 to be able to say I have a "396" in it for nostalgia sake. The only problem is the only parts that seem to be available for that config are from the GM COPO program. It takes a 3.825 crank and the pistons are higher compression that I want to run. Ideally I'd like to be in the 9.5:1 to 10:1 range. I guess a 405 would be pretty good, kind of like a bored 402 (aka the later 396 used in the chevelle)
I was originally going to run an L99 with the maggie but I found a deal on an LS9 block and CNC LS9 heads so that got my "I need more HP" juices flowing. Now I'm looking at selling my L99 that has 175 miles on it (it was pulled to put an LS7 in a new Camaro) to help fund the engine project. FWIW the car is a pro touring build an not being built as a drag specific car. I'd like to drive the car a lot so longevity is a concern.
Minimal skirt taper is the key. Break point placement where it starts to taper below the oil ring groove. A well designed 4 in stroke piston will have less rock than a poorly designed 3.900 as a for instance. Most associates at most piston companies won’t ask You cylinder length when they are doing you a custom. You know you have a smart one if they ask you the question. That being said 5.500 on aluminum blocks or 5.450 is common on iron. Ls7 is much longer 5.8 if memory serves, but I’d need to be back in the office to measure lsa ls9. Every bit helps.
Minimal skirt taper is the key. Break point placement where it starts to taper below the oil ring groove. A well designed 4 in stroke piston will have less rock than a poorly designed 3.900 as a for instance.
In my experience it depends entirely on if the engine builder actually knows what they are doing when selecting pistons. The real expert LS engine builder's pick the correct piston to use for the build. As mentioned above taper and correct ring package make a world of difference.
My LS1 383 has a 4 inch stroke crank and a trick Wiseco piston set my engine builder picked to avoid piston rock and oil consumption issues. After 3 years running , 10,000 miles a lot of rpm it doesn't use any oil. I check every other gas fill.
My 416 has an LSA block and 4 inch stroke crank and a trick Wiseco piston set the engine builder picked to avoid piston rock and oil consumption issues. The engine is almost new had 3,000 miles on it and doesn't use oil. I check every gas fill.
With the right engine builder 4 inch crank isn't an issue regarding oil consumption. There can be good reasons for going with the 3.9 crank as mentioned above.
My 383 LS1's piston package is good for mild power adder use "~150 shot, maybe ~200" but not really designed for big time power adders. For big power adders the 3.9 crank would have allowed for a most robust piston choice and different ring package.
I don't have any personal experience with an engine that has a 4.125 crank.
BTW - some LS engines that guzzle oil have valve seal issues. My heads & cam 99 TA would burn a quart of oil every 500 miles at one point. Turned out the valve seals were the issue. After new valve seals it was half a quart every 2,500 miles.
Minimal skirt taper is the key. Break point placement where it starts to taper below the oil ring groove. A well designed 4 in stroke piston will have less rock than a poorly designed 3.900 as a for instance. Most associates at most piston companies won’t ask You cylinder length when they are doing you a custom. You know you have a smart one if they ask you the question. That being said 5.500 on aluminum blocks or 5.450 is common on iron. Ls7 is much longer 5.8 if memory serves, but I’d need to be back in the office to measure lsa ls9. Every bit helps.
The rotating assembly kits available seem to use a variety of piston manufacturers (i.e. Mahle, Weisco, Diamond, JE, etc). In looking at the piston manufacturers websites it looks like they offer standard pistons for this config so do you still need to go custom or is one manufacturer better than the others with having the right taper to prevent rocking/oil consumption issues?
The rotating assembly kits available seem to use a variety of piston manufacturers (i.e. Mahle, Weisco, Diamond, JE, etc). In looking at the piston manufacturers websites it looks like they offer standard pistons for this config so do you still need to go custom or is one manufacturer better than the others with having the right taper to prevent rocking/oil consumption issues?
IMO, Wiseco has one of, if not THE best skirt designs out there right now. For 4” or 4.125” stroke combos, their shelf pistons would work just fine. I have a 6.0L iron block with a 4.250” stroke crank and Wiseco built an awesome set of custom pistons for me to make it work with the short cylinder length. It has no more rock at BDC than a 4” stroke combo.
Interestingly, I was looking at a 2014 GM performance catalog and it in it states max stroke for LS1,2,3,6,L92 as 4" vs LSA/LS9 as 4.5". For the LS7 and C5R it has 4.10". For the short deck LSXs it shows 4.25" and the tall deck 4.5".
It makes me wonder if it's a typo on the LSA and LS9. Does anyone have a newer GM Performance catalog and if so what does it show for the LSA and LS9?
Interestingly, I was looking at a 2014 GM performance catalog and it in it states max stroke for LS1,2,3,6,L92 as 4" vs LSA/LS9 as 4.5". For the LS7 and C5R it has 4.10". For the short deck LSXs it shows 4.25" and the tall deck 4.5".
It makes me wonder if it's a typo on the LSA and LS9. Does anyone have a newer GM Performance catalog and if so what does it show for the LSA and LS9?
The writer for those doesn’t know about the piston skirt limitations. 4.500 has been done with a special rod design and reduced base circle in a tall deck. The standard deck 4.125 stroke Wiseco’s have a .525 break point (distance below the oil ring where taper starts to be introduced) is what makes those work. 4” stroke 1.110 Wisecos are .650.
We have hundreds of 416 motors that cruise at 3000rpm without issue. The LSA and LS9 can't be stroked and keep the piston oilier, but never looked at doing it with them deleted.
We have hundreds of 416 motors that cruise at 3000rpm without issue. The LSA and LS9 can't be stroked and keep the piston oilier, but never looked at doing it with them deleted.
When going forged pistons, plugging is s pretty good option. I did this on a sleeved Lsa block from Erl
We have hundreds of 416 motors that cruise at 3000rpm without issue. The LSA and LS9 can't be stroked and keep the piston oilier, but never looked at doing it with them deleted.
It looks like K#### offers a piston squirter for 4" stroke engines. Any experience with these?
Originally Posted by Summitracing
When going forged pistons, plugging is s pretty good option. I did this on a sleeved Lsa block from Erl
I was planning on a full forged rotating assy. Any reason not to use the piston squirters (i.e. K#####) with forged pistons? I assumed they would help keep the crown cooler to allow for higher boost without detonation on pump gas.
Different forging styles may or may not work with these. It may be possible to buy just one to test fit. The squirters can be tweaked with a section of brake line, it needs to be at least .080 away from any part of the piston. The wire vibrates enough that weve seen them snap off at anything less. Notching a piston is possible, but you don’t want to do it in a strut corner to avoid a stress crack.
I have just completed my 4” 419ci with JE pistons, it was previously a 416 with Mahle pistons, and you had to be vigilant with the oil level, at track days you would have to top up at least once. These new JE pistons I have, are fantastic being quiet and have burnt no oil whosoever, and oil still looks brand new. I ran it in using break in oil for 400 miles, and it’s now on fully synthetic and been on the Dyno for four hours and not burnt a drop.
Yeah, my post should have had stock in front of the squirter. Not familiar with the aftermarket squirters, but good to know some make them work and may have to try them one day.
We also like the JE Pistons and have no issues with them. Another option is Autotec & Racetec for custom as their price is great so you can add pin oilers and etc. Pantera EFI, Lance on here can get you good prices from them.
By the way if you are worried about 416, try building a 430ci LS3 and it will make the 416 seam like no big deal. haha
11-23-2018, 09:45 AM
LS3 415/416/418 Oil Consumption 
