Need advice with piston selection
09-18-2018, 09:34 PM
#1
Launching!
Thread Starter
Need advice with piston selection Ok so I. Got a gen 4 lq4 block for nothing and I知 going to be doing a 4.030 bore with a 4.000 stroke. I値l doing an ls3 top end with this build as well. Not really looking for criticism or anything just looking for some help with piston selection. Wanting to have the C.R. around 11.5:1 when all said and done. Car is a full weight trans am with a 6 speed, 4.30 gear, looking for a nice street/strip setup with the ls3 top end. I致e always ran the cathedral port heads and wanted to try something different for this car. Anybody got any input? Thanks in advance.
09-18-2018, 10:01 PM
#2
What do you mean input they have pistons on the shelf for the given combination... . .They list the given compression with the heads depending on how many CC's. 408 is as basic as it gets Lil buddy ...
09-18-2018, 10:12 PM
#3
Launching!
Thread Starter
Guess I should致e been a little more specific lol. Mainly looking for a reputable brand like diamond, je, Mahle, etc. I know all are good brands, just don稚 know if either was preferred over the other.
09-19-2018, 07:46 AM
#7
Don’t listen to Patron, he doesn’t really know what he’s talking about. There are a lot of differences between brands when it comes to shelf pistons.
Wiseco/JE, Diamond, CP all generally use a 2618 alloy of piston while Mahle generally uses 4032. Mahle has the thinnest rings available for a shelf LS piston at 1.0/1.0/2.0mm while Wiseco is usually 1.2/1.5/3.0, and the others I think are all still 1.5/1.5/3.0mm. JE has an asymetrical skirt that you can use which supposedly also reduces friction.
Personally, I like the Wiseco pistons. I’ve used them in many builds and have always had good luck with them.
Wiseco/JE, Diamond, CP all generally use a 2618 alloy of piston while Mahle generally uses 4032. Mahle has the thinnest rings available for a shelf LS piston at 1.0/1.0/2.0mm while Wiseco is usually 1.2/1.5/3.0, and the others I think are all still 1.5/1.5/3.0mm. JE has an asymetrical skirt that you can use which supposedly also reduces friction.
Personally, I like the Wiseco pistons. I’ve used them in many builds and have always had good luck with them.
Last edited by KCS; 09-19-2018 at 11:59 AM.
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09-19-2018, 11:53 AM
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09-19-2018, 03:55 PM
#11
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Milling the heads to 66 is the common way to get a flat top two valve relief piston to net you that compression. The Wiseco K464X3 with the heads whacked about .025 would put you very close to 11.5:1 and they accommodate either Cathedral or Rectangle ports. They have a good 1.2 Nitride 1.2 Napier 3.0 GFX ring pack and some other nice features like skirt coatings, offset pin, 2618 alloy, strong ring lands, etc. All forged pistons for strokers aren't nearly the same and you'll want to make sure the skirt profile is correct to prevent piston rock at bdc. The Wiseco's are designed for up to a 4.125 stroke with an iron block cylinder length..
09-20-2018, 08:53 AM
#12
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I had Diamond in my first 383, and they burnt oil like mad, pistons were too short i reckon. Then I had Mahle in my 416, these were fine, I've just completed a 419 build replacing the Mahle with JE as they had a 4.085 solution. The JE were significantly lighter so I had to spec a heavy wrist pin. The JE can be bored with closer tolerances due to a coating if Im not mistaken, engine sounds very quiet even when cold, very pleased so far. But its still being run in Im at around 11:8 with these, being dyno'd next month.
09-20-2018, 09:15 AM
#13
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I had Diamond in my first 383, and they burnt oil like mad, pistons were too short i reckon. Then I had Mahle in my 416, these were fine, I've just completed a 419 build replacing the Mahle with JE as they had a 4.085 solution. The JE were significantly lighter so I had to spec a heavy wrist pin. The JE can be bored with closer tolerances due to a coating if Im not mistaken, engine sounds very quiet even when cold, very pleased so far. But its still being run in Im at around 11:8 with these, being dyno'd next month.
09-20-2018, 01:16 PM
#14
I put these in my daily driver 4.070" bore LS3 and the valve reliefs ended up having enough clearance for the LS7 heads as well.
I wanted a 4032 material piston for the tighter clearances and hopefully longer life. I still have the stock 3.622" stroke though, so wear and piston rock at the bottom shouldn't be an issue.
https://www.summitracing.com/parts/srp-298616-8
I wanted a 4032 material piston for the tighter clearances and hopefully longer life. I still have the stock 3.622" stroke though, so wear and piston rock at the bottom shouldn't be an issue.
https://www.summitracing.com/parts/srp-298616-8
09-20-2018, 09:33 PM
#15
Launching!
Thread Starter
Thanks everyone for the help! I知 looking at both the JE and Wiseco set for the build. I like the fact that you can run a little tighter tolerance with the JE but in the other hand I致e never heard heard anything bad about Wiseco.
03-01-2019, 07:56 AM
#17
Launching!
Thread Starter
Completely forgot about this thread but figured I’d check back and let everyone know what I went with. I ended up offing the lq4 and picking up an ls3 block and went with the Mahle part #197714870. Decided on a dome to make it a little easier to reach 12.5-13:1 compression. I figured it would do well with Mast 255’s, Holley hi-Ram, and the LLSR I was spec’d from Cam Motion. It was between these and the asymmetrical JE’s but the Mahle were able to get here in 3 days rather than 3 weeks. Thanks again for everyone’s input!