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To those of you considering aftermarket forged pistons...


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True but I have seen factory cast pistons crack the ringlands with very little detonation where forged pistons can take smaller dets without any failure.

 

How do you know they had seen very little detonation?

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You better pull those pistons and check them. Were you burning any oil?

 

Pulling the pistons to check would be smart. I tend to not be smart however. :spin:

 

I only had the car for 4k miles, right where I usually change my oil (I use royal purple, wix filters, and commute ~55 miles one way to work). I was at least a 1/2 quart low...when putting the oil in I was half way up the dip stick, at disassembly I wasn't on the stick at all, but there was a "decent" amount of oil in it. I never noticed any smoke at all ever out the tail pipe. The intake tract on the other hand was coated, there seemed to be puddles of oil everywhere inside there. I'll be installing two catch cans (one in crankcase PCV line, one in valvecover vent line) when it goes back in.

 

I see there's clever ports for removing the wrist pins. How do you make sure the small end of the connecting rod aligns with the wrist pin hole in the piston when you reassemble?

 

Oh, when it's out I'll also reinforce the oil pump pick up, I hear these crack.

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The author repeatedly refers to "silicone" in the pistons. That instantly makes me doubt his credibility. (silicon is the proper term)

 

Note he only refers to "all motor" in recomending cast pistons. 4032 is much stronger than cast, period. Detonation will kill any piston regardless of it's composition. I still feel the 4032 is a great choice for a DD. You can run OE clearance and get the long service life without beating the crap out of the cylinder walls.

 

Just because Stephen Hawking can barely function doesn't make him any less of a genius. This guy made a 1-letter typo, and anyone reading the article knew what he meant. This is an article explaining the differences between a typical forged piston and cast, and makes people aware of the differences. I feel it is beneficial to note that 4032 pistons are more prone to causing ring lands, but 2618 pistons have sloppier tolerances and will wear down the block faster due to piston slap. I just wanted to point out the pros and cons of each. But keep in mind, this article was written for naturally-aspirated Honda all-motor builds, not turbo applications. It was a good resource to point out the facts.

Edited by Boostin
On the search for a new DD...
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How do you know they had seen very little detonation?

 

The cast pistons were smooth on top and looked fine until you got to the ringland area. The forged pistons had what looked like marks that I assumed was caused by detonation. The ringlands on those were still intact and in perfect condition other than the marks on top.

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True but I have seen factory cast pistons crack the ringlands with very little detonation where forged pistons can take smaller dets without any failure.

 

 

No doubt......BUT, You can even break a 2618 piston if there is enough detonation.

 

What about the Swain heat coatings, has anyone here tried that service?

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I see there's clever ports for removing the wrist pins. How do you make sure the small end of the connecting rod aligns with the wrist pin hole in the piston when you reassemble?

 

Remove the oil pan, pick-up tube and baffle plate and hold it up thru the crankcase.

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There are two places you apply coatings on pistons: skirts and crown. Stock pistons have skirt coatings, and you want that on your forged pistons as well. Swain tech skirt coating is rumored to be very good and robust, better than "stock" coatings e.g. by CP.

 

Crown coating should be used only in race applications. It keeps piston cooler, maybe "too cool" under regular low load driving. Even if it's not detrimental, it's really not needed.

 

 

Thanks for clearing that up. I would never use a piston in a DD without the skirt coating, it works wonders. My 83,000 mile pistons hane no wear on the skirts at all. I was just wondering about that heat coat for the top, I agree it is probably overkill for a 300whp DD.

 

What I did notice was the underside of my pistons have a brown "burn" spot right in the center, like oil was cooked a bit slinging off the small end of the rod. Thats why I was considering the top coating.

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No doubt......BUT, You can even break a 2618 piston if there is enough detonation.

 

What about the Swain heat coatings, has anyone here tried that service?

 

I completely agree. My point was that the forged pistons can take more abuse than the stock cast pistons.

 

I accidentally knocked off one of my EWG lines once and hit 30psi of boost. Got a cel with 3 cylinders with knock detected. Did a compression test and everything was fine. If that was the stock pistons, they would have been toast.

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  • 4 weeks later...

I had a list of Mods installed onto my 05 LGT. I was a victim of the original VF39 going bad (bearing). So i decided to do upgrades on my car while it was down. I got a list of things added and done, than off to the dyno it went.

A shop in my area while it was on the dyno made it through 3 pulls close to 300whp. However after the third they noticed a bad rattle in the engine and they went to expect it and now can no longer turn the engine over. They thought that it might be pistons, but its purely speculation. (lets get past the shop issue and the tune and focus on the pistons)

Basically, is this the type of situation where I go back to OEM pistons and risk this same incident or Forged? It will be a daily driver, either way I want reliability.

 

Just curious on opinion.

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Basically, is this the type of situation where I go back to OEM pistons and risk this same incident or Forged?

 

I really doubt that the pistons have anything to do with your current problem, other than perhaps being collateral damage. Based on your wording ("go back to OEM pistons") I'm guessing that the motor was taken apart and reassembled. Since it only lasted for a few dyno pulls, I'm guessing that one or both of the following is true:

 

a) A serious mistake was made when assembling the motor

b) A serious mistake was made when tuning the motor

 

Hopefully a teardown will indicate which. Regardless of the answer, I don't think I would make any component changes at this point, other than simply replacing the busted parts with new versions of the same parts.

 

If you're lucky, the builder or tuner will accept responsibility. If you're not lucky, they'll point fingers at each other. In that case I'd take the motor to a shop like Maxwell (in Arlington) that can do the building and the tuning, so there will be no finger pointing if this happens again.

 

Good luck...

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  • 2 weeks later...
Guest LGT-NY

Great info in here. My '07 LGT with 50K miles just pushed a rod through the side of my block while I was leisurely cruising on the highway at 75MPH. I heard a pop, white smoke started pouring out and that was all she worte.

 

I am debating on getting a stock EJ255 block or going with a EJ257 block with CP Forged Pistons, Forged Crankshaft and Forged Rods. Raw1Performance offers some reasobaly priced "street blocks", see bleow:

 

http://www.raw1performance.com/index_files/Page523.html

 

My current mod list is:

 

  • Perrin TMIC
  • AEM CAI
  • Maddad UEL Header/UP combo
  • Invidia Catless DP
  • Perrin CBE
  • Cobb AP v2 Pro-tune
  • 298whp-325ft/lbs

I was running moderate boost ~ 18.6psi on my summer map and ~15psi on my winter map. My winter map was loaded at the time my engine blew.

 

Do you guys think it would be worth it for me to go with a "Stage 1" block with forged internals at my power levels as an "insurance policy"?

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Clark on NASIOC had a good post, can't find it right now, on the stock pistons.

 

But basically our pistons are bigger then most, and that inherently leads to certain problems.

 

FWIW engine builders have learned a thing or two in the past few years building suby motors. I believe the Cosworth pistons are becoming the piston of choice ($1000 or so) as they are forged have a very good rep, and have no audible piston slap at temps around -15F. A local had a SB with their pistons in it, and after me bugging him he did some cold starts in the winter w/o plugging it in.

 

I agree that the tune is responsible for the vast majority of failures, but at some power level if one blows an engine, these might be the best option, and they seem to work just as well as OEM for a DD that puts many miles on.

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Great info in here. My '07 LGT with 50K miles just pushed a rod through the side of my block while I was leisurely cruising on the highway at 75MPH. I heard a pop, white smoke started pouring out and that was all she worte.

 

I am debating on getting a stock EJ255 block or going with a EJ257 block with CP Forged Pistons, Forged Crankshaft and Forged Rods. Raw1Performance offers some reasobaly priced "street blocks", see bleow:

 

http://www.raw1performance.com/index_files/Page523.html

 

My current mod list is:

 

  • Perrin TMIC
  • AEM CAI
  • Maddad UEL Header/UP combo
  • Invidia Catless DP
  • Perrin CBE
  • Cobb AP v2 Pro-tune
  • 298whp-325ft/lbs

I was running moderate boost ~ 18.6psi on my summer map and ~15psi on my winter map. My winter map was loaded at the time my engine blew.

 

Do you guys think it would be worth it for me to go with a "Stage 1" block with forged internals at my power levels as an "insurance policy"?

 

Any time you are doing a motor build (any motor build really) you have to ask yourself a lot of questions first.

 

1. Will you be depending on this car--as in, when it runs will you need to keep it running?

 

2. Are you be making payments on this car? How much of a concern is depreciation and ease of resale?

 

3. How often do you think you will drive it? I think people have a lot of trouble estimating this. People who do hardcore builds end up wanting to drive the car more than they expected, and grow tired of certain parts they chose for the car. Other people think they'll love the thing and drive it all the time, but it just sits there because it's impractical or because they got bored with it for whatever reason.

 

4. How much power do you want to make? Now take the number you just came up with and add 10-25% to that value. That's how much power you will really want to make after the car has been running for a while. Trust me on this one.

On the search for a new DD...
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Guest LGT-NY
Nothing - forged pistons are better than stock POS pistons!

 

That's what I've read ;)

Goddamn you with your sarcasm!!! :lol: I never know when you're being serious. :mad::lol:

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I had the same trouble when I lost my cyl#4 ringland... very tough to separate the sarcasm (or humor, depending on how you are looking at it) from the good info. :)

 

Your goals are not that far off from mine, power-wise. My engine rebuild thread may be relevant for you, since I hashed out the whole aftermarket/OEM piston thing too.

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