Piston discussion

[CammedS197]

Hey guys,

First I'm curious if we have Hypereutetic pistons in the 4.6 3 valve or cast. I believe it's hyper.

Now just wanting to discuss the limits of "cast", "hypereutetic", And the different forged pistons along with the many different types of forged pistons.

Also has anyone done like a serious budget build on their 3valve and kept the stock pistons and just swap out rods and went boost or bottle fed?

The main difference is what silicon and the strength of the metal made from and the density.

I am making a build list of parts for a refresh on my motor for 450-500HP and will maybe hit the track 3 times to see what it can do and then that's probably it. Other than that it will be a daily driver and not completely beat on but will have fun with it.

So I will definitely be using my stock crank and mostly likely boss rods. Now I also have my eyes on molnars but those are crazy overkill for me. The pistons I have had my eyes on are Manley or Weisco due to the skirt coatings off the shelf. Rings no idea yet and bearings no idea yet. But I was curious what if I kept my stock pistons or got a new set of Hypereutetic pistons? My goals arent too crazy and I will be doing 500rwhp maybe. It will have a vortech v3 intercooled.

SO has anyone kept and used their stock pistons or used any aftermarket hyper pistons for a build? Also I don't want piston noise and a tighter piston to wall clearance which is why I just now thought of the hyper piston. I know they can blow apart when over their limit where forged won't.

Are there other types of forged out there besides 4032-alloy and 2618-alloy. If I recall the 4032 has like 11% silicon and the 2618 has like 2% so it expands much more than the 4032 and the 4032 can have a tighter piston to wall clearance.

Hypereutetic is around 16% silicon and cast is around 12% and I believe it's said Hyper is a little stronger than cast.

So lets talk types and why along with limits you'd go with them.

Also if we could put bearing types and why and comparing others and why. What you would use in a daily vs a race motor or something you just want reliable OEM like but you're boosting it.

Then the different types of piston rings, what they mean by material made from and best application for each.

My goal: 450-550rwhp daily not really raced but some spirited driving with a v3 blower. Looking at it can take that power and can be reliable OEM like with reliable good bearings, rings, and just anything else. I'm planning on full valvetrain overhaul. Inspect heads and valves. New seals, springs, roller followers and lifters all OEM spec with better springs but OEM ratings in pressures.

 

[JeremyH]

You did enough research to answer all your own questions really, and no I don't think you will find anyone that built their motor and put hyper pistons back in for boost. A quick google search of "hyper pistons and boost" will give you a lot of info. Also take a look around at what pistons oem's put in factory boosted vehicles.

A typical budget build for the 3v is forged rods and pistons new bearings and stock hardware. Some would include billet oil pump gears in that list. The ones that didn't often later wish they did.

4032 sounds like a perfect fit for what you want. For your power goal and mentioning of noise and reliability moly rings would be a good fit.

 

[CammedS197]

You did enough research to answer all your own questions really, and no I don't think you will find anyone that built their motor and put hyper pistons back in for boost. A quick google search of "hyper pistons and boost" will give you a lot of info. Also take a look around at what pistons oem's put in factory boosted vehicles.

A typical budget build for the 3v is forged rods and pistons new bearings and stock hardware. Some would include billet oil pump gears in that list. The ones that didn't often later wish they did.

4032 sounds like a perfect fit for what you want. For your power goal and mentioning of noise and reliability moly rings would be a good fit.

Awesome, thanks a ton Jeremy. Yes I have heard lots of people tell me to do oil pump gears. I have seen Apocalypse performance has a really nice one with boundary gears and upgraded backplate.

 

[CammedS197]

Jeremy,

Should I look at file fit or not file fit? is there a large difference between them? I plan on doing myself.

Also what are all good options for a 4032 forged piston? Others out there that have off the shelf coated skirts?

 

[tjm73]

Current production 5.0 rods, forged stock spec pistons, TSS oil pump gears in a GT500 oil pump. Bolt it all back together with stock stuff. Good for a long time at that level in my untested opinion.

Depending on your mileage, you may want to opt for new timing chains/tensioners.

Since you will be running a centri type supercharger, have you heard of wastegating them like the turbo guys do? In theory you can pulley for more boost to hit your boost target sooner and then dump the extra boost you don't need allowing you to have say about 8psi for a much longer time. This should be able to be done with an electronic boost controller wastegate.

Say you want 8psi at 2000 and your max RPM is 6000. If you pulley for 24 psi at 6000 you will get 8 psi around 2000 rpm. Then you dump the extra and maintain 8 across the board. At least that is the idea.

 

[01yellerCobra]

If you can find Bruce's build thread he should have some good info there. I'm pretty sure he went with Weiscos in a 4032 alloy. And I don't think he had the machine shop use a torque plate. I don't think the machine shop used a torque plate on my engine either. But it was an iron block.

I prefer file fit myself. I gap each set to the cylinder it's going into. At least for engines like this. The 3.8L I rebuilt we went with pre-gapped rings, but we still checked the gap in each cylinder. But it wasn't a performance build. It was a "get it running" build.

 

[46addict]

I think @eighty6gt did what you're trying to accomplish.

 

[CammedS197]

Current production 5.0 rods, forged stock spec pistons, TSS oil pump gears in a GT500 oil pump. Bolt it all back together with stock stuff. Good for a long time at that level in my untested opinion.

Depending on your mileage, you may want to opt for new timing chains/tensioners.

Since you will be running a centri type supercharger, have you heard of wastegating them like the turbo guys do? In theory you can pulley for more boost to hit your boost target sooner and then dump the extra boost you don't need allowing you to have say about 8psi for a much longer time. This should be able to be done with an electronic boost controller wastegate.

Say you want 8psi at 2000 and your max RPM is 6000. If you pulley for 24 psi at 6000 you will get 8 psi around 2000 rpm. Then you dump the extra and maintain 8 across the board. At least that is the idea.

Yeah I know exactly what you are talking about with the torque boosting on the centri. I'm having a rough time finding 4032 forged pistons. Almost all seem to be the 2816 I find. I also want stock compression to most of 10.2:1. Stock is what -6cc? If I get -6cc I plan on milling the head and deck the minimum just to clean the surface and have a very fresh and square mating surface and stock or one step thinner gasket. Should keep me in my compression range.

If you can find Bruce's build thread he should have some good info there. I'm pretty sure he went with Weiscos in a 4032 alloy. And I don't think he had the machine shop use a torque plate. I don't think the machine shop used a torque plate on my engine either. But it was an iron block.

I prefer file fit myself. I gap each set to the cylinder it's going into. At least for engines like this. The 3.8L I rebuilt we went with pre-gapped rings, but we still checked the gap in each cylinder. But it wasn't a performance build. It was a "get it running" build.

I will definitely try to find Bruces build. Also not sure what you mean using a torque plate and also what is the main difference between the file fit and pre gapped? Performance reliability/longevity or whatever else it could be lol? Not going for an all out race motor lol.

Also did more research, seems that Mahel, Weisco, and Manley are the only coated off the shelf I believe. I'd love an off the shelf piston that's -6cc and comes with rings and coated skirt.

How important or how big of a difference does the coated vs non coated affect performance, noise, reliability/longevity?

 

[46addict]

I thought stock pistons are -9cc to achieve 9.8 compression. DSS pistons come standard as 4032 and 2618 forging is extra. Torque plates refer to a tool used during the cylinder honing process. It's supposed to help keep cylinders round so they all come out to the same measurement. Most people will recommend using torque plates for max effort builds but Bruce was an exception to the rule. He did also use the iron 5.3L big bore block if that matters.

 

[CammedS197]

I thought stock pistons are -9cc to achieve 9.8 compression. DSS pistons come standard as 4032 and 2618 forging is extra. Torque plates refer to a tool used during the cylinder honing process. It's supposed to help keep cylinders round so they all come out to the same measurement. Most people will recommend using torque plates for max effort builds but Bruce was an exception to the rule. He did also use the iron 5.3L big bore block if that matters.

Okay, thats what I thought it meant. I plan on going .020 to .030 over to clean it up.

Well then I hope someone chimes in that know's the factory dish lol.

Will any 4032 forged piston suit my needs or is the coating much worth it? I think if I go forged pistons I may as well go with the molnars too. But also I wanted the boss rods for lighter weight. Want to keep near factory weight. But if I can get a killer ass deal on molnars Id get some.

 

[Badd GT]

i have a set (4032 Mahle pistons,pins,and rings.020 overbore0 that i bought from BruceH a few years ago, that i never built the motor t,hat i would part with. PM me if interested

 

[01yellerCobra]

I will definitely try to find Bruces build. Also not sure what you mean using a torque plate and also what is the main difference between the file fit and pre gapped? Performance reliability/longevity or whatever else it could be lol? Not going for an all out race motor lol.

How important or how big of a difference does the coated vs non coated affect performance, noise, reliability/longevity?

I don't think there's a real difference as far as longevity and reliability between file fit and pre-gapped rings. I think it's more about that detail working better with your engine. The pre-gapped do tend to be on the wide side in order to accomadate different tolerances. File fit are just for your engine. Just make sure not to go with gapless rings and I wouldn't bother with stainless for your set up.

My understanding about the coatings is they're to help with the first start up. Since there isn't much oil on the cylinder at that point. Once the engine is run they don't matter much. My pistons were coated and when I pulled them around 20k miles the coating was pretty much gone.

 

[eighty6gt]

Stock pistons, boss rods, mahle non file fit rings went in my engine. It's taking me forever to finish the car. Shooting for 550+ rw.

When I do it again I'm going with cheap 2618's (actually I just looked and the dss pistons look good and are priced right.). Ebay h beams. The boss rods were a pain to balance, and the tty bolts make clearance checking more difficult. For the mains I reused my old ones for one cycle.

I wish there were someone making cheap good 4.6 cranks. I've done a lot of looking around right down to some bending simulations in my fea and I'd feel better with a forged crank.

 

[msvela448]

Gibtec Pistons in Denver, CO will make you a set of 100% custom billet pistons, in any size, any ring package / sizes, and any compression ratio for about $1100. That also includes tool steel wrist pins and Total Seal rings. You can also add skirt coating and anodizing if you want. I know that's not exactly "budget" but it's really not bad for what you are getting. They will also do wrist pin offset, gas ports, anti flutter grooves etc... Like I said 100% custom to your specs, down to the thousandth of an inch... So you don't have to bore your block to .20 or .30 over if it doesn't need it. If some random amount like .086 will clean it up then Gibtec can make you a piston for that bore size.

I prefer file fit rings so I know they're dead on for each bore. Especially if you use custom pistons in a custom sized bore.

Mate those pistons to a decent set if H-beam rods and you should be good for at least 750hp, but I'd worry about the stock crank as you approach 550 or more.

I went with King Bearings on my last build after years of using Clevite bearings. So far the King Bearings seem to be working great.

I'd definitely do the TSS billet oil pump gears while you are in there, and perhaps consider getting the Cobra Engineering dowel pins for the timing chain guides.

Assemble and enjoy.



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[RocketcarX]

Gibtec Pistons in Denver, CO will make you a set of 100% custom billet pistons, in any size, any ring package / sizes, and any compression ratio for about $1100. That also includes tool steel wrist pins and Total Seal rings. You can also add skirt coating and anodizing if you want. I know that's not exactly "budget" but it's really not bad for what you are getting. They will also do wrist pin offset, gas ports, anti flutter grooves etc... Like I said 100% custom to your specs, down to the thousandth of an inch... So you don't have to bore your block to .20 or .30 over if it doesn't need it. If some random amount like .086 will clean it up then Gibtec can make you a piston for that bore size.

I prefer file fit rings so I know they're dead on for each bore. Especially if you use custom pistons in a custom sized bore.

Mate those pistons to a decent set if H-beam rods and you should be good for at least 750hp, but I'd worry about the stock crank as you approach 550 or more.

I went with King Bearings on my last build after years of using Clevite bearings. So far the King Bearings seem to be working great.

I'd definitely do the TSS billet oil pump gears while you are in there, and perhaps consider getting the Cobra Engineering dowel pins for the timing chain guides.

Assemble and enjoy.



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Any piston manufacturer will build you a set of custom pistons for that price point.
Deviating from standard bore dimensions is just asking for problems.
Why run a custom piston in a weird size when a shelf piston will do with readily available off the shelf parts?
The stock crank is good for much more than 550HP
Why switch bearing brands if Clevite did the job flawlessly.
Advice like this is what ruins builds for novice builders with novice goals.
K.I.S.S.

 

[CammedS197]

i have a set (4032 Mahle pistons,pins,and rings.020 overbore0 that i bought from BruceH a few years ago, that i never built the motor t,hat i would part with. PM me if interested

If you still have these when I'm able to purchase a set (currently building a house and baby#2 is almost here) I will gladly take them. What cc are they btw? I want -6cc to flat top.

I don't think there's a real difference as far as longevity and reliability between file fit and pre-gapped rings. I think it's more about that detail working better with your engine. The pre-gapped do tend to be on the wide side in order to accomadate different tolerances. File fit are just for your engine. Just make sure not to go with gapless rings and I wouldn't bother with stainless for your set up.

My understanding about the coatings is they're to help with the first start up. Since there isn't much oil on the cylinder at that point. Once the engine is run they don't matter much. My pistons were coated and when I pulled them around 20k miles the coating was pretty much gone.

Okay thanks for that. It's not a huge deal for me to have them 100% filed to my motor so Pregapped will be perfect for me.

So as of now this will be my choices for the build whenever it happens.
-Stock crank (will have it gone through by a shop)
-Molnar rods or boss/current 5.0 rods (depends on funds at the time)
-Whatever the best deal is that I can get on a set of 4032 forged pistons (coated or noncoated)
-Clevite OEM style bearings (Main and rod)
-All balanced by speed shop
-Moly pregapped rings
-Oil pump with steel backing plate and billet gears from Apocalypse performance
-All new timing chain, phasers, guides and other components OEM
-Comp beehive valve springs OEM specs
-FRPP roller follower and lash adjuster kit
-Valve stem seals (whats recommded?)
-New valve guides
-Valve job (clean and work valves)(Keeping stock valves)
-Any other recommended head maintainence
-Best gasket kit/most reliable.
-Stock intake with CMDP's
-Full exhaust with longtubes
-New water pump
-Detroit rocker cams (already running these)
-CX racing intercooler kit with tread-stone intercooler or the vortech air to water set up
-Fed with a Novi1200 or vortech v3 all wrapped up by Lito.

Did I miss anything. Will get all FRPP hardware for heads and other stuff. ARP if funds allow when this time comes.

Complete overhaul if this is the plan.

 

[tjm73]

I plan on going .020 to .030 over to clean it up.

Overbore only if needed and the minimum needed to clean it up.

What kind of mileage does the engine have? I have read that lots of engines with 100K or more often don't need any kind of bore work other than a hone. Modern engines just don't seem to wear like the old ones did.

 

[CammedS197]

Overbore only if needed and the minimum needed to clean it up.

What kind of mileage does the engine have? I have read that lots of engines with 100K or more often don't need any kind of bore work other than a hone. Modern engines just don't seem to wear like the old ones did.

I'm currently at 125k miles.

I'll talk to the machine shop and see what he recommends at that time. But it will be probably 150k-160k when rebuilt.

 

[eighty6gt]

Machine shops do not know what they are doing.

 

[RocketcarX]

Overbore only if needed and the minimum needed to clean it up.

What kind of mileage does the engine have? I have read that lots of engines with 100K or more often don't need any kind of bore work other than a hone. Modern engines just don't seem to wear like the old ones did.

YOu can thank fuel injection and nearly zero fuel wash for that one, I was going to say the same thing.