Stock pistons are hypereutectic cast pistons, they are not bad all things considered.
Alloy is neither 4032 nor 2618, its something like 390.
Alloy is neither 4032 nor 2618, its something like 390.
I am considering the AMP44 pistons. They are 4032 but have massive width of material between ringlands which is the only weak point I can think of.
I had considered the Amp44 pistons before - they don't look bad, the 4032 is what I didn't like. I did notice they appear to use a different size ring pack than the Mahles or JEs. Mahle and JE use a 1mm top ring, this has a 1.55 top ring. Mahle and JE use a 2.8mm oil ring, this lists a 2.0mm oil ring. I don't recall what the OEM ring sizes are - I'll go measure in a bit, but I would think there is a benefit to Mahle and JE being aftermarket vendors with proper R&D groups, rather than the Chinese 'copy what we can' vendor.
I didn't know they had odd ring sizes. I just noticed they had a lot of metal between the rings. I emailed them with some questions and the shipping is about $180£ or $226.00 US. That is crazy.
Ouch - thats some high shipping when you consider how much those pistons cost. You can get some 4032 forged pistons on aliexpress for like $325 shipped.
No info on the ring sizes, but likely stock sized to re-use a common size. I doubt they are low tension 1mm rings. https://www.aliexpress.us/item/3256...56A_GSsVeJhoClPsQAvD_BwE&gatewayAdapt=glo2usa
No info on the ring sizes, but likely stock sized to re-use a common size. I doubt they are low tension 1mm rings. https://www.aliexpress.us/item/3256...56A_GSsVeJhoClPsQAvD_BwE&gatewayAdapt=glo2usa
I would go forged rod and stock piston with increased ring gaps. The typical issues I've seen posted over the years are ring land failures, likely due to rings butting so I'd oped up the gaps a bit and rods starting to noodle. Since you're not chasing big power or revving higher I don't see a benefit for going forged pistons.
Yeah, I am trying to go back better/stronger than stock but my usual thought of overbuilding something is diminished by the sky high price of some of the components. I am also still considering just going with Kingtec rods and pistons. I will employ a bigger ring gap no matter what I choose. I am also going to do the epoxy closed deck. It is going to cost me $150 (plus sugar) so that is an easy choice. One of my thoughts on replacing the original pistons is the fact that I assume that after many years and many heat cycles my original ones MUST be a little more brittle than new. My main thought is I am sure that SOME (definitely NOT all) of the Chinese options are just as good as name brands but if I choose poorly, tears will happen. Kingtec was my only consideration for Chinese pistons and rods since they just make sooo many and put their name on them. Zero to 60on YouTube had a review and said they sounded pretty competent in conversations. Another choice is AMP44 pistons. They are 4032 alloy but have a massive amount of metal between the top 2 ring gaps. That is definitely to beef up the known weak ring lands. They are not 2618, but with about double the metal between the lands that would be a massive strength advantage. The price of $500lb (~$626 USD) is pretty good BUT they charge $180lb (~$225 USD) to ship via FedEx making them actually cost ~$851.00. I am a 54yr old man and have money, but I also need to keep this (16yrs old +192k miles = not worth much) "fun" car within SOME reason. I still have some time to mull this over since I am slowly taking apart 2 engines to start picking the best pieces to rebuild into my "new" motor.
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I am thinking about 600-650hp. I already have upgraded to the HP28 transmission and have an LSD block kit in my large pumpkin 2007 rear end. So the motor is now the weak link.
Then you can stay stock as long as you don´t go with stupid torque down low. Just take care of increase ringland gaps.
I’m also trying to decide if choosing JE is right for my build. My power goal is similar to JonEQuest’s, around 600–650 HP, and I’m not sure if I really need the added strength and features of JE pistons. While JE pistons are undoubtedly top-tier and come with features like a degas groove (the circumferential groove between the compression rings) and are made from 2618 alloy, they also have some downsides for a daily driver.
On the other hand, the AMP44 pistons, being made from 4032 alloy, have a lower thermal expansion rate, which means they can run tighter clearances, resulting in less noise and better suitability for a daily driver. While they might not be as robust as 2618 pistons in extreme conditions, they should still handle 600–650 HP without issues, especially if the engine is well-tuned and maintained. Plus, I haven’t found any other reputable manufacturers offering 4032 pistons for the N54, which makes AMP44 a unique option in this regard.
I’ve also reached out to AMP44 via email to get more details about the piston rings, specifically the material and manufacturer, since this information isn’t listed on their site. I’ll update here once I receive their response. If the rings are high-quality and the specs align with my build goals, I’ll likely go with these pistons. However, I’d love to hear opinions from others who have experience with either option, especially at this power level.
Edit: I’ve attached a screenshot of AMP44’s response regarding the piston rings for everyone’s reference
On the other hand, the AMP44 pistons, being made from 4032 alloy, have a lower thermal expansion rate, which means they can run tighter clearances, resulting in less noise and better suitability for a daily driver. While they might not be as robust as 2618 pistons in extreme conditions, they should still handle 600–650 HP without issues, especially if the engine is well-tuned and maintained. Plus, I haven’t found any other reputable manufacturers offering 4032 pistons for the N54, which makes AMP44 a unique option in this regard.
I’ve also reached out to AMP44 via email to get more details about the piston rings, specifically the material and manufacturer, since this information isn’t listed on their site. I’ll update here once I receive their response. If the rings are high-quality and the specs align with my build goals, I’ll likely go with these pistons. However, I’d love to hear opinions from others who have experience with either option, especially at this power level.
Edit: I’ve attached a screenshot of AMP44’s response regarding the piston rings for everyone’s reference
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Hello, this discussion is very interesting because I am in this situation, building my engine for approximately 600 HP on E85, my vehicle with automatic gearbox and driving every day. I am also wondering if I keep my OEM pistons with new rings or forged pistons (AMP44 look good) and I am in Europe so the shipping and customs costs are interesting for these pistons. After obviously other pistons like JE, MAHLE are possible but price level. As for the connecting rods, I wonder if I have much use for them in relation to my objective.
I am now planning to get the AMP44 pistons. They have a nice amount of material between the rings to make sure the ring lands are pretty much bulletproof. They offer two stock sizes: 83.98-83.99mm or 83.99-84.00mm as well as +0.25 & +0.50. I measured my bore at the top with my Fowler caliper. Then transferred that to my dial bore gauge. Odd thing is that at the top my caliper slides in tight right at 3.307" (84mm). Then I transfer that to my bore gauge to check the bore and taper at several places but I get what works out to an average of 3.305" or (83.947mm) That is SMALLER than the stock 84mm bore. It is also smaller than the two piston sizes offered. I can see wear causing my bore size to increase but NOT shrink. I even ordered some gauge blocks to check my caliper and it seems to be accurate. I am now not sure which pistons to order. I keep assuming my caliper is reading wrong. I was expecting the size to be bigger of anything, but not smaller. Anyone have a clue what I am doing wrong? I rechecked the measurements a few times. The bore gets about 0.001" to 0.002" smaller below the top ridge where there was definitely some carbon buildup. I expected that, but the size seems to measure too small. How critical is this for the pistons. I am afraid to order them until I figure this out. I also have a 2nd motor and it seems to measure the same as well.
It might help if you used a bore gauge calibrated with a micrometer for more precise measurements. Also, did you measure the clearance with the old pistons before removing them? That could provide some insight whether your measurements are accurate.
You might run into issues with the proper seating of the piston rings if you don’t hone the block beforehand. After honing, you’d need to re-measure the bore size.
I have done this once before so I did use a precision caliper to set my bore gauge. The last time I rebuilt an engine with these tools was about 5 years ago and I was going back with the same stock pistons in each bore so I was mainly just checking for bore wear and taper. So I don't remember what the size of those bores were. I boiled and cleaned the block yesterday. I plan to hone and recheck the cylinders today. I guess maybe there COULD be build up on rhe cylinder walls effecting it a few thousands.
