Forged pistons or cast?

[Intercooler]

Originally posted by 86brick
For a couple of extra hundred bucks it's really foolish to use hypers cause I think most people like not having to worry about what will happen if they race and drive there car like they did when the motor wasn't touched. If it only took him one time being slightly out of tune and leaning out too melt those hypers and I can asure you it did cause he only had about 3k miles on the rebuild and the car was street driven and not raced all that much. I know it will take a LOT more than being out of tune for such a short period of time to melt a forged piston and that's why the hypers are crap IMO. I like being able to race my car and having the peace of mind it won't need a rebuild if I'm a bit out of tune and lean out. I wonder why all the big time gurus like Red Armstrong and Jack Merkel only recommend forged pistons on rebuilds??? Maybe, it's because they know the difference between what works and what doesn't! The next post about n.a. cranks I'm gonna tell people they should use them cause Intercooler likes hypers and if you're never out of tune and don't lean out you should be okay

Like showing up at a gunfight with a knife here trying to make a point I keep seeing you make reference to others. Do some on your own. Obviously what I said earlier fell on deaf ears because forged will melt just as quick. Don't tell anyone on my behalf anything, I do just fine in that department and have "actual" experience with things I say. I have also used a NA crank and .040" block but wouldn't suggest one in most cases but for a low power build (400-450 HP) it has worked ok. If you don't like the hypers without "actually" ever using them in an engine that is great. For me I have had J&E's and hypers and prefer the hypers to bottom 11's. I could have gotten forged for the new motor I will be putting together in a week or so but chose hypers instead. I plan on bottom 11's with them and don't feel scared with tuning issues. I like both and they both have +/-'s to them. Do what you wish and like but to say hypers are junk without any first hand knowledge throws up the B.S. flag IMO.

 

[Steve Wood]

Talk about the bs flag!

 

[TurboMike]

ah, the great hyper piston debate. Some guys like 'em, alot of guys hate 'em. For myself, I would NEVER put a set of hypers in anything blown or N20'd.

Stockers- Don't discount them, many, many cars in the 10's.

TRW forged- Ok if you don't have alot of $$. Make sure you have the pins "fit"

JE- My pick if you have $500.00

check out these links of this topic:

http://www.turbobuick.com/forums/sh...&threadid=27151

http://www.turbobuick.com/forums/sh...?threadid=27469

 

[Steve Wood]

Mike, do the later sets of TRWs still have that problem or was it corrected? I thought they had increased the pin bore size. Of course, such thing should always be double checked but I don't think I have heard a report of any being too small in a long time....maybe we just all check them.

 

[Intercooler]

Mike,

Both do not work Unless you can get stockers in an oversize your choices are hypers and forged. I like the J&E's better and have used them in two of my motors. The J&E's can be gotten in any size. Can you even get TRW/Federal Mogul forged anymore to fit a 3.8? I tried to have them looked up and nothing showed up and from what was relayed they don't plan on making any more. Even when you could get them you were limited to std., .030" and maybe .060" if I remember correct. The hypers have more size offerings and I picked up .020" for my std. bore block. If you mainly have a high boost car with more track than street driving go forged all the way. Now for a sane boost level car going mid 11's or a little less with mainly street driving it warrants taking a look at the hypers.

 

[REDS HOT AIR]

im a hypo fan...

only sterling brand which are federal mogul,speedpro's whatever you want to call them..

to use an example

my last sb chevy motor i was running hypo's in i was running a 300 shot of n20 in and leaned it out going in high gear one night and heard it detinate which we all know its usually too late on that kind of shot.
well my motor was fine and i continued beating it like that a complete summer racing on the street pretty much every week and 3-5 times on some weekends and never did the hypo's fail ..

well after removing the motor we installed the n2o system on my buddy's car which was built pretty close to my combo except he had more money in his trw forged pretty rockers ...you know all the stuff that i short cutted on to save money ....well needless to say the first weekend out not even thru a full bottle yet which on 300 shot isnt but a couple passes he had one of his trw's blown apart and the wristpin hung into the water jacket..

and his car did not lean out it just plain blew it apart.

so basically you wont tell me one is better than the other just some people have better luck than others..

btw: both motors were the same compression and had the same cams

 

[GNVAIR]

I agree with Red. I used to be biased towards forged. But after seeing a few of the Mustang guys around running high 9's-low 10's on their factory hypers, I changed my tune.
From what I remember from previous debates, Jack Cotton was a hyper piston user when he was still running his stock block motor. Many of his customer used them as well. Maybe he could chime in?
I have stock pistons in my dad's car and in my original engine. My new engine will have J&E's because I plan on pushing it really hard. My back up engine will have hypers just because I want to try them out. I dont think there will be any problems as Jesse, Red and a few others said.

 

[Steve Wood]

Strange that Speed Pro does not recommend them for our use but suggests forged.

On the other hand, KB claims his are stronger than other hypers and appears to suggest they will work.

 

[SideSlip]

I didn't realize the only cast pistons available were hypers, otherwise I never would have started this thread.

I have been a Mustang guy for over a decade, and had direct experience with hypercrap pistons. I know of more cases than I can count where ring lands have cracked on 2000 and 2001(especially) Stangs with 8-10 psi superchargers and a supposed "good" tune. We tune our Stangs on wideband O2 sensor equiped dynos, between 10:1 and 11.5:1 air fuel ratio..........relatively safe ............NOT..........only last week my buddy punched a hole in one of his hypercraps....his was tuned to 10.5:1, and was constantly too rich.....we thought. One cylinder (#5) was "slightly" lean and let go. We are convinced that with forged, this would NOT have occured. Mabey the piston design differs between Buicks and Mustangs(weaker ring lands???) I don't know, but my confidence has been shattered. Thank God he and I keep a spare shortblock in my garage.

Those guys running 10's and 9's on hypers have tuning experience and equipment that 95% of us do not have access to........they tune for zero detonation, very slowly from a safe base tune.........plus the boost they run is relatively constant, whereas our Turbo Buicks can vary considerably by just throwing in some race gas, a chip and cranking the boost. We pull back when we sense knock.......they start from scratch.

There may be some guys out in Stangs that have had success with their stock hypercraps....I personally know a few, but they're running on borrowed time. Just float a thread on Stangnet.com or The Corral and ask. JMHO Cheers.

 

[Intercooler]

Originally posted by SideSlip
I didn't realize the only cast pistons available were hypers, otherwise I never would have started this thread.

I have been a Mustang guy for over a decade, and had direct experience with hypercrap pistons. I know of more cases than I can count where ring lands have cracked on 2000 and 2001(especially) Stangs with 8-10 psi superchargers and a supposed "good" tune. We tune our Stangs on wideband O2 sensor equiped dynos, between 10:1 and 11.5:1 air fuel ratio..........relatively safe ............NOT..........only last week my buddy punched a hole in one of his hypercraps....his was tuned to 10.5:1, and was constantly too rich.....we thought. One cylinder (#5) was "slightly" lean and let go. We are convinced that with forged, this would NOT have occured. Mabey the piston design differs between Buicks and Mustangs(weaker ring lands???) I don't know, but my confidence has been shattered. Thank God he and I keep a spare shortblock in my garage.

Those guys running 10's and 9's on hypers have tuning experience and equipment that 95% of us do not have access to........they tune for zero detonation, very slowly from a safe base tune.........plus the boost they run is relatively constant, whereas our Turbo Buicks can vary considerably by just throwing in some race gas, a chip and cranking the boost. We pull back when we sense knock.......they start from sctratch.

There may be some guys out in Stangs that have had success with their stock hypercraps....I personally know a few, but they're running on borrowed time. Just float a thread on Stangnet.com or The Corral and ask. JMHO Cheers.

Tore out ring glands. Well I did help my machine shop guy document a ZZ4 350 Chevy engine that tore a gland out of #7 piston. He placed the rings in the bores and I recorded the readings that were to be sent to GM. What we found was all rings had a minimum of .010" end gap or more except #7 which had .007". Guess why the ring tore the gland out? This guy was going ok until he started to make the combo more radical then the rings butted in #7 tearing the gland out. If it was a factory set ring gaps like this I can see why. If you run hypers in the high horsepower ranges the gap needs to be opened up on the rings. Factory cast pistons have been seen with cracks in the ring glands but not all the way tore out in Buick V6 motors. The ring gland is one area I give the nod to on a forged piston hands down. If the hyper is set up with the correct ring gap butting should not occur and tearing out a ring gland also. In this case running rich had nothing to do with it but merely closing the gap being run down too far with heat and not enough gap. Was any of this measured on the failed motor to get the cause? Things do not just happen except once in a freak while.

 

[Steve Wood]

nope, but they do happen when using a piston in a manner for which it was not intended.

You can always blame the user but using the pistons intended for our particular use will provide the level of comfort that us mere mortals may require once in awhile.

Reading the Speed Pro pages will not give too many of us positive feelings bout using hypereutectic pistons in our cars.

 

[Intercooler]

Originally posted by Steve Wood
nope, but they do happen when using a piston in a manner for which it was not intended.

You can always blame the user but using the pistons intended for our particular use will provide the level of comfort that us mere mortals may require once in awhile.

Reading the Speed Pro pages will not give too many of us positive feelings bout using hypereutectic pistons in our cars.

But indeed the 7.9:1 compression hypers are listed in the Federal Mogul catalog as replacement pistons for the turbocharged Vin 7 motor. So our motors come with forged eeh? Don't think so! Proper setup for intended use outweighs band-aids IMO

 

[n20junkie]

personally, from my n20 experiance and turbo experiance, hypers are great for the street, seems to be less wall scuffing and you can run a tighter piston to wall clearance, and they always hold up to the nitrous, but i am carful and have NEVER leaned out or detonated, just a precautious tune. Fordged are great for all out max effort racers, they like to scuff on the cylinder walls, the fordege are noiser thing is BS, if you set the engine up properly then at temp the wall clearance wil be the same, but hte fordges will expand more, so the initial cold setup is looser, but if you are running around when your engine is cold, and you can hear the pistion slap, your a dumbie, i think the no boost while cold rule has gone to the wayside latley, but both piston shave there place in life, but proper tun is the key, a poor tune will melt or shatter anything
Grant J Farmer

 

[Steve Wood]

c'mon, Jesse...stop playing the circle games.

You know as well as I do that our engines came with a cast piston with a steel insert that are very similar to a diesel piston. In fact, GM described them as being similar. There are those that believe that this is a superior design, heavy as it may be, as it dampens detonation pulses rather than developing cracks and may actually out last forged units in its intended design usage. Unfortunately they are no longer available and many of us exceed the original design intent.

I am sure that you also know that Federal Mogul, Speed Pro, Sealed Power, TRW are all the same company.

I am also sure that you can go to the site and read the suggested applications for the varying types of pistons and see for yourself that the hypers are not suggested for serious forced induction engines.

Now, whatever ground you wish to break, n.a. cranks, .040 over engines, hypers, etc. That is fine. It is your money. Just don't try to sell other people on the story that they will be fine without warning them that they may be exceeding the manufacturer's own suggestions and caveat emptor.

 

[Steve Wood]

Grant, it really depends upon the alloy. The alloy used by TRW/Speed Pro expands less than that used by the higher dollar, lighter weight units by JE, etc. Clearances are still greater than cast tho, and your points are correct.

I did find it interesting to see that Keith Black suggests similar clearances to TRW on his hypers when used for forced induction.

 

[GNVAIR]

Again, I wish Jack Cotton would jump in on this. I am curious what he has to say on this as well.

 

[Intercooler]

Steve,

I do my own work on everything but the transmission so if I break something I fix it myself. I have never seen a forged piston melt in all the motors I have tore down. I did see a stocker in Steve Blake's motor melted down because of leaning it out and also one Federal Mogul hyper in Eric's motor melted again because of leaning it out. Both cases were rear cylinders. I have also seen more cylinder scuffing in the cylinders with forged pistons like mentioned above. I do think for all-out the forged are better since intended use is to beat the hell out of it. Now for the guy making 5-10 track visits a year, running no more than 24 PSI, making 400-450 HP, going 11.3 and above, tuned properly and set up correctly I like hypers. Mile-Hi 11's, Lee Thompson 11's, JBanning 11's and will have more soon all use them and have had zero problems. My old 12 second motor is now Banning's 11+ motor and it has .040" hypers. If he reads this I am sure he can tell you if he has been in tune without detonation the whole time. I am sure he hasn't! Still going strong and will be at the Nat's again this year. I think I outlined pretty well the way hypers will fail so everyone has been warned.

 

[Steve Wood]

We agree on just about everything other than the use of hypers.

I am interested in the Keith Black units because they claim to be 30% stronger than conventional hypers and they do show clearances for nitrous/force inductions...but those clearances if I recall correctly, start at .0025 and go up. I sent them a note asking if they had experience with high boost cars such as ours and did they recommend them? I will post their answer.

I have seen a number of the others broken in the last 15 years and don't trust them. I think it is more a question of being brittle than melting.

I still recall what either Robert Caruth said (worked in the Buick engine group) or perhaps, Steve Y, about stock pistons..that they outlasted TRW forged units by a factor of ten in detonation testing.

Again, I suspect it is because they absorbed the shock wave better. It may have been the steel insert around the pin tho.

I wish they were still around in various oversizes. I have seen some cracked when they came out but seldom destroyed.

 

[n20junkie]

note: the hypers i have used are the KB units, which are a very high quality piston, for the price they are second to none in my opinion, I wonder why companys making hyer pistons do not have a series with a steel insert, i know that alot of us and other engine builders from other camps would eat them up, it must be an engineering problem or the might just be lazy, but in the end its the car owners choice on pistons, and the engine builders job to suggest.
Grant J Farmer

 

[Steve Wood]

Probably low volume and high cost is the reason.

Most want lighter weight for higher rpm, including a bunch of us, but, it has been demonstrated that one can go into the tens with very little more rpm than the stock engine pulls and they live forever. well.....maybe not forever, but a bunch of miles.