Custom cut aluminum pistons

Tbone3366

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So ive done a lot of thinking into making a specific piston for the 300 using a 4.01 bore and wanted to have a piston thats ideal for a daily driver, but can hold power if you use a form of external power such as boost or nitrous
 

pmuller9

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For your specified application, you can use a 4032 alloy forged piston.
They are eutectic for good thermal expansion control and are more malleable than a hypereutectic piston.
As a forging, they will offer the extra margin of strength.
Autotec/Racetec offer custom 4032 alloy forged pistons.
You can also check with Mahle, Diamond, BWE and JE.

What do you need for a piston head design?
 
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Tbone3366

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For your specified application, you can use a 4032 alloy forged piston.
They are eutectic for good thermal expansion control and are more malleable than a hypereutectic piston.
As a forging, they will offer the extra margin of strength.
Autotec/Racetec offer custom 4032 alloy forged pistons.
You can also check with Mahle, Diamond, BWE and JE.

What do you need for a piston head design?
im talking about milling out my own pistons, im wanting to work with some different piston face designs along with it being ribbed in the bottom section like an F1 piston so it can be lighter but retain the strength it should carry for a reliable maybe 200HP 300tq 300
 

Firepower354

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Billet DIY pistons? Melting soda cans ain't gonna do it... Cam-ground skirts, tapered top to bottom, precise ring grooves, pin bores, pretty tough without a half-million dollar 5-axis and a few years of experience programming it.

The benefit of ultra light pistons drops exponentially as revs decrease.
A set of Mod 5.4 rods and custom pistons to match, would be a cheap/easy way.
Or long LS tall deck rods and standard SBC solid dome slugs that you can mill the lids to match your chambers, reduce weight without having to design a piston from scratch.
 

pmuller9

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im talking about milling out my own pistons, im wanting to work with some different piston face designs along with it being ribbed in the bottom section like an F1 piston so it can be lighter but retain the strength it should carry for a reliable maybe 200HP 300tq 300
The Autotec pistons for the 300 six are ribbed similar to an F1 piston.
The stock pre 1987 pistons and pin weigh about 820 grams.
The 300 six Autotec piston and pin shown below weighs 574 grams.

300%20piston%203.JPG


As Firepower stated above, pistons at room temperature are not round and they are wider at the bottom of the skirt than at the head.
 

Tbone3366

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The Autotec pistons for the 300 six are ribbed similar to an F1 piston.
The stock pre 1987 pistons and pin weigh about 820 grams.
The 300 six Autotec piston and pin shown below weighs 574 grams.

300%20piston%203.JPG


As Firepower stated above, pistons at room temperature are not round and they are wider at the bottom of the skirt than at the head.
Im shooting to mill out billets for my engine to get a good feel for it, i plan to make my own i6 casting and head casting as a 2.0 version of the 300 like how the 350sbc evolved into the LS 5.3

Im shooting to take the shortcoming away like the poor port flow, and such but make a streetable engine with a stock powerband from idle to 4k like what the 300 was meant for, i brought up the cleveland head in the ither post to get an idea how it performs in the low end, the ports are too big so it kills low end power, stuff like that

Ive settled on a 2V ohv crossflow motor with the timing gear just take the roughness of a stock 300 polish it up, i plan to cast a cant valve head but with some cleverness involved, but back to the main subject,

I really was hoping to get some notes on how i should setup the ring lands, stuff like that for a good daily, with the intention of knowing that some people will want to make power in the top end so im pre emptively having it setup to handle the power but im really shooting for the durable low end grunt a 300 was known for just in a modern package
 

Wesman07

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I think you should work on the “big picture”. 4,000 rpm at 100% VE only needs a head to flow 180 cfm. Any ford 300/ 240 head will make that easy with some minor hand work. Why reinvent the wheel?

Edit: 4,000 rpm at 100% VE needs 160 CFM.
 
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Tbone3366

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I think you should work on the “big picture”. 4,000 rpm at 100% VE only needs a head to flow 180 cfm. Any ford 300/ 240 head will make that easy with some minor hand work. Why reinvent the wheel?
Going with a sohc design along with shooting for better fuel economy, and also beef up the block i would like to do a 4.25 bore by 3.98 stroke and run a sleeve for 4.0 bore
 

pmuller9

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I think you should work on the “big picture”. 4,000 rpm at 100% VE only needs a head to flow 180 cfm. Any ford 300/ 240 head will make that easy with some minor hand work. Why reinvent the wheel?

Edit: 4,000 rpm at 100% VE needs 160 CFM.
The peak piston velocity occurs at 74 degrees before and after TDC.
At that point the 300 six piston is traveling 4378 ft/sec. at 4000 rpm
The piston displacement at that point is 380 cfm.
 
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Wesman07

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The peak piston velocity occurs at 74 degrees before and after TDC.
At that point the 300 six piston is traveling 4378 ft/sec. at 4000 rpm
The piston displacement at that point is 380 cfm.

I won’t argue your math. I trust it. What I see is that all cylinders combined are pulling about 350cfm at 4,000.

I’m not sure what your implying. Are you suggesting that a head flowing 380cfm will make more power at 4,000rpm than a head flowing 200cfm?
 

pmuller9

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All I’m pointing out is that a single intake port services only one cylinder and the total engine displacement is not relevant.
Secondly, a 300 six has the same single cylinder displacement as a 400 V8 and peak cylinder flows can be relatively high
 

Wesman07

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With all due respect, I don’t understand why. 160 cfm per port will feed these 300’s plenty at 4,000 rpm with the appropriate valve timing.
 

pmuller9

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A 220 cfm port will increase the power at 4000 rpm with no apparent loss in lower rpm torque.
 

Tbone3366

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The goal is for about 375ish lbs of tq around 2500 rpm or so with peak hp around 3 to 4k rpm, low rpm power but reliable, no cam phasing etc... sinple SOHC design that took everything great from the 300 and improved upon it
 

Firepower354

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1.25lb/ft @2500 NA on gasoline, with 50ci cylinders? Seems pretty optimistic, even if you have obtained the abilities/facilities to carry out such lofty goals of designing, casting, machining a clean-sheet cylinder head...
 

pmuller9

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1.25lb/ft @2500 NA on gasoline, with 50ci cylinders? Seems pretty optimistic, even if you have obtained thabilities/facilities to carry out such lofty goals of designing, casting, machining a clean-sheet cylinder head...
PN managed 338 ft lbs in the video posted in the Big Six section.
375 ft lbs would not be much of a stretch with a higher velocity head.
 

Wesman07

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It is optimistic. I’m getting the impression that this is sort of fictional, and that’s fine.

Paul I think there are things that your not taking into consideration. Let’s say the head and manifold was capable of supplying the cylinders with 340 cfm, meeting the piston demands at all times. The engine would reach 100% VE at 4,000rpm and suffer from severe revision at every rpm below that.

You need a pressure differential to create air speed. That air speed will have inertia behind it to counter revision, widening the power band and making over 100% VE a possibility.
 

pmuller9

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I didn’t mean to imply that the port flow should meet peak flow due to piston movement.
I just wanted to show what the peak displacement flow was for a single cylinder and to point out that port flow considerations is based on a single cylinder rather than 1/2 engine displacement x rpm x VE.
 
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