LSA Pistons vs LS9 Piston facts: + Pics
02-23-2010, 11:26 AM
#1
LSA Pistons vs LS9 Piston facts: + Pics There have been a few threads over the past couple of months that have wandered around the idea of using the LS9 piston in the LS3 engines. People (I guess) think this would be an easy/cheaper way to make a forged engine for boost. Well, that is not entirely true. The pistons alone are around $100 a piece. This means that LS9 pistons alone are $800 for the set. Of course they include the pin and locks. Then include the cost of the rings. GM ring set for 8 is $250. The aftermarket ones are prob in the $180-250 range as well depending on type and style. So just for 8 pistons and rings you get them all for $1050. Not such a deal. Now lets focus less on the cost and more on the math part.
The LS9 piston has a total weight of 546g. It does have a coated skirt. They also appear to have some thermal coating (or anti friction/or both) on the top ring land. The distance from the top ring land down is .217". Pretty good. The locks weigh 2g (normal) and the pin weighs 156g. That is kind of hefty for a stock pin, but it is because it is not the normal .945 pin. Nor is it a .927 pin. This one is .985 with a pin length of 2.56". So the LS9 piston will not work on any other LS rod, unless you have that rod cut out and re-bushed. Converesely, the LS9 rod will not work on any other LS piston unless you have the rod bushed smaller or have a custom piston pin fitted for it. The pin is tapered on both ends just like a normal LS pin (iirc). Compression Height on the LS9 piston is 1.443 which works very well for stability and makes a strong piston as well as making up the difference in the shorter rod length of the LS9. The piston that was shipped to me is a little roughed up, so I will have to file down the spot that is marked so that I can get a CC of the piston. This should be all the info anyone needs from this piston.
The ring set is the same as used for the LS9 and LSA. 2nd napier ring. total weight of the ring set is 30g. I have confirmed this 5 times on both the piston and the ring set, but they are measured as follows. 1.5mm top. 1.2mm Napier 2nd. 2.0mm oil with rails.
The LS9 rod is of course Titanium. It weighs in at 452g. The big end is the same as any of the other rods at a normal 2.100 pin size(2.222+/-.002 bore size). The small end pin bore (bushed and tapered) is .985+/-.002. The total rod length as measured is roughly (my calipers are not the best in the world) 5.998 +/-.005. Of course GM specifies they use a diff rod bearing just like the LS7s, but a normal aftermarket 663P or H bearing will work. The cost per rod is roughly $740 PER ROD. They use the same rod bolt as the LS7. There are only 2 aftermarket options at this time for the bolts. Katech rod bolts with the optional Dow Molykote, or the ARP LS7 rod bolt kit (234-6302) which comes with their new Ultra-Torque lubricant.
As you can see, using the LS9 piston in any other LS application would take some work. And they are not cheap in any way.
The LSA piston on the other hand IS a more viable option. I am unsure as to why everyone keeps overlooking this engine itself (14k for the LSA and 22K for the LS9) and the parts that make it easier to A) source B) retrofit and C) purchase.
So here are the stats on the LSA piston. Cost - $53 per piston. They use the same ring set as the LS9 including the 2nd Napier. They have the same skirt coating. They use the same coating on the 1st ring land (be it thermal or dry lubricant). They are also the reverse dome style. These came damaged as well so I will have to work the file a little before I can CC them. Top ring land is .219 from the top. CH is 1.351 +/-.005. Pin size is .945. Pin length is the same at 2.56. The Piston weighs 512g, the locks are 2g and the pin weighs 150g.
I will have pictures up soon. If there are any more questions, just ask. I will have a rod in here soon for the LSA so that I can report back on what it is exactly.
So, tell me what else you need. I will have the pics up soon.
The LS9 piston has a total weight of 546g. It does have a coated skirt. They also appear to have some thermal coating (or anti friction/or both) on the top ring land. The distance from the top ring land down is .217". Pretty good. The locks weigh 2g (normal) and the pin weighs 156g. That is kind of hefty for a stock pin, but it is because it is not the normal .945 pin. Nor is it a .927 pin. This one is .985 with a pin length of 2.56". So the LS9 piston will not work on any other LS rod, unless you have that rod cut out and re-bushed. Converesely, the LS9 rod will not work on any other LS piston unless you have the rod bushed smaller or have a custom piston pin fitted for it. The pin is tapered on both ends just like a normal LS pin (iirc). Compression Height on the LS9 piston is 1.443 which works very well for stability and makes a strong piston as well as making up the difference in the shorter rod length of the LS9. The piston that was shipped to me is a little roughed up, so I will have to file down the spot that is marked so that I can get a CC of the piston. This should be all the info anyone needs from this piston.
The ring set is the same as used for the LS9 and LSA. 2nd napier ring. total weight of the ring set is 30g. I have confirmed this 5 times on both the piston and the ring set, but they are measured as follows. 1.5mm top. 1.2mm Napier 2nd. 2.0mm oil with rails.
The LS9 rod is of course Titanium. It weighs in at 452g. The big end is the same as any of the other rods at a normal 2.100 pin size(2.222+/-.002 bore size). The small end pin bore (bushed and tapered) is .985+/-.002. The total rod length as measured is roughly (my calipers are not the best in the world) 5.998 +/-.005. Of course GM specifies they use a diff rod bearing just like the LS7s, but a normal aftermarket 663P or H bearing will work. The cost per rod is roughly $740 PER ROD. They use the same rod bolt as the LS7. There are only 2 aftermarket options at this time for the bolts. Katech rod bolts with the optional Dow Molykote, or the ARP LS7 rod bolt kit (234-6302) which comes with their new Ultra-Torque lubricant.
As you can see, using the LS9 piston in any other LS application would take some work. And they are not cheap in any way.
The LSA piston on the other hand IS a more viable option. I am unsure as to why everyone keeps overlooking this engine itself (14k for the LSA and 22K for the LS9) and the parts that make it easier to A) source B) retrofit and C) purchase.
So here are the stats on the LSA piston. Cost - $53 per piston. They use the same ring set as the LS9 including the 2nd Napier. They have the same skirt coating. They use the same coating on the 1st ring land (be it thermal or dry lubricant). They are also the reverse dome style. These came damaged as well so I will have to work the file a little before I can CC them. Top ring land is .219 from the top. CH is 1.351 +/-.005. Pin size is .945. Pin length is the same at 2.56. The Piston weighs 512g, the locks are 2g and the pin weighs 150g.
I will have pictures up soon. If there are any more questions, just ask. I will have a rod in here soon for the LSA so that I can report back on what it is exactly.
So, tell me what else you need. I will have the pics up soon.
Last edited by Beau@SDPC; 02-23-2010 at 01:44 PM.
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wannafbody (09-04-2019)
02-23-2010, 09:59 PM
#7
The LS9 is forged and the LSA is the Hyper E piston.
If GM deems it warrantable for them to use the Hyper E (LSA) piston in this application knowing what it will be abused, then that seems to be good enough for me really. That is what helps keep the cost down, but for the most part, this piston has all the newer features that the forged LS pistons do. I think that top land coating is one of the more impressive features. GM seems to be stepping it up really. I will hopefully cc the piston tomorrow or later in the week so that you can get accurate results from it in a calculator.
I will have the pics up prob tomorrow, as I took alot, but some did not come out like I wanted.
I have faith in the LSA piston. It may not be the easiest way to build some FI GM engine, but it works well for the price. I hope to have the LSA rod in tomorrow or later in the week so I can finish the comparo.
Any questions or special requests, I will try to get it all.
If GM deems it warrantable for them to use the Hyper E (LSA) piston in this application knowing what it will be abused, then that seems to be good enough for me really. That is what helps keep the cost down, but for the most part, this piston has all the newer features that the forged LS pistons do. I think that top land coating is one of the more impressive features. GM seems to be stepping it up really. I will hopefully cc the piston tomorrow or later in the week so that you can get accurate results from it in a calculator.
I will have the pics up prob tomorrow, as I took alot, but some did not come out like I wanted.
I have faith in the LSA piston. It may not be the easiest way to build some FI GM engine, but it works well for the price. I hope to have the LSA rod in tomorrow or later in the week so I can finish the comparo.
Any questions or special requests, I will try to get it all.
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02-24-2010, 10:53 AM
#9
They are not the same castings. Maybe after i get the piston/rod stuff all done, I can start on the heads. But that will be a different thread. This thread is all about the pistons/rods/rings though, so please keep this thread on topic.
02-25-2010, 11:16 AM
#12
LS9 Piston on the left LSA on the right. In case these photos get a little hard to figure out which is which (ill try to call them out) the LSA has the slightly goldish hue to it (making it a ringer for the Hyper E)
Side View - skirts and coating
Side view - pin holes
Bottom
Close up of bottom - LSA
Close up of bottom - LS9
Casting marks on LS9
Side View - skirts and coating
Side view - pin holes
Bottom
Close up of bottom - LSA
Close up of bottom - LS9
Casting marks on LS9
02-25-2010, 11:22 AM
#13
Ring lands on LS9 - notice the top land coating and oil holes
Side of LS9 - notice the 2nd ring land, below it is a small depression
LS9 Pin (l) LSA Pin (r)
LSA pin in LS9 Ti rod - notice how much smaller it is (gap)
Same rod with the correct LS9 pin (no gap)
Side of LS9 - notice the 2nd ring land, below it is a small depression
LS9 Pin (l) LSA Pin (r)
LSA pin in LS9 Ti rod - notice how much smaller it is (gap)
Same rod with the correct LS9 pin (no gap)
02-25-2010, 01:09 PM
#16
LSxGuy widda 9sec Mustang
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I believe that top ring groove is hard anodized to allow longer wear life. Almost all stock pistons with stainless (and even some without) top rings have that.
02-25-2010, 01:17 PM
#17
Interesting on the hard anodizing....it looks like a flakey coat actually, which made me think thermal barrier or dry lubricant.
The pistons have been tested to above the factory rated 556 (pullies and cam and tune) and held up just fine, but off the top of my head, I do not have an exact number.
The pistons have been tested to above the factory rated 556 (pullies and cam and tune) and held up just fine, but off the top of my head, I do not have an exact number.
