diamond or mahle pistons
I'm personally running PROBE blower pistons and to tell everyone the truth there has never been a back to back study or test regarding piston life under exteme FI conditions. Given that matter buy almost any forged piston and you can't go wrong. When was the last time anyone has ever heard of an aftermarket forged piston failure that was not caused by detonation or oil starvation???? Put that in your pipe and smoke it
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Mahle's current offering are 4032. This alloy is fine for moderate power levels Ie sub 800hp crankshaft with a very good tuneup. They have some 2618 pistons comming out. I would go with diamond if you are serious about HP.
like i said before has anyone ever seen an aftermarket forged piston fail under sheer stress and not detonation? I don't think so. So to answer the question there is no best piston for a power adder.
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even the mahle hypereutectics that are found in stock ls motors handle over 500rwhp with good tune on forced induction motors.
mahle are some very good pistons, i have no exp. with diamond, but have used je an mahle pistons for my ls and sbc motors before.
mahle are some very good pistons, i have no exp. with diamond, but have used je an mahle pistons for my ls and sbc motors before.
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TECH Enthusiast
Joined: Dec 2001
Posts: 548
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From: Dublin, CA
I would not use 4030 pistons for an FI application.
A vendor sold me on Mahle 4030 alloy pistons as 'stronger than Diamond pistons', they failed on an easy drive home from the motor install. The top ring slot is close to the top of the piston, and valve relief cut ends up very close to the ring slot with nearly 1/16" material between the surfaces. The Mahles don't have much quench area, but for a narrow flat ledge at the edge. The 4030 alloy (~14% silicon) is close to stock brittle hypertech alloy (~17% silicon).
Apparently Mahle makes a 'Turbo piston' using 2618 alloy, but those were only available for the 6.0L at the time, not the 5.7L. W2W sells 2618 alloy Mahle pistons for $920.
Mahle dished
I'm going back to Diamond forged 2618 this time for my LS3. I was concerned that the Diamonds also have a full dish with a flat edge (catalog pics showed reverse dome), but talking to Nick D'Agostino at Diamond he reassured me that the quench area is fine at .300" ledge, though they did discover detonation problems with a narrower ledge (the Mahle have a narrow ledge). The Diamonds have a nice .260" top ring down, and I went with a 3.622" stroke to keep the oil ring from overlapping the piston pin.
Diamond dished
A vendor sold me on Mahle 4030 alloy pistons as 'stronger than Diamond pistons', they failed on an easy drive home from the motor install. The top ring slot is close to the top of the piston, and valve relief cut ends up very close to the ring slot with nearly 1/16" material between the surfaces. The Mahles don't have much quench area, but for a narrow flat ledge at the edge. The 4030 alloy (~14% silicon) is close to stock brittle hypertech alloy (~17% silicon).
Apparently Mahle makes a 'Turbo piston' using 2618 alloy, but those were only available for the 6.0L at the time, not the 5.7L. W2W sells 2618 alloy Mahle pistons for $920.
Mahle dished
I'm going back to Diamond forged 2618 this time for my LS3. I was concerned that the Diamonds also have a full dish with a flat edge (catalog pics showed reverse dome), but talking to Nick D'Agostino at Diamond he reassured me that the quench area is fine at .300" ledge, though they did discover detonation problems with a narrower ledge (the Mahle have a narrow ledge). The Diamonds have a nice .260" top ring down, and I went with a 3.622" stroke to keep the oil ring from overlapping the piston pin.
Diamond dished
Last edited by blu00rdstr; Feb 10, 2008 at 02:49 AM.
A forged piston doesn't just fail on an easy drive home. If said piston had to tight of a ring gap due to a mistake of the builder, now that could cause a ringland to break.
The guy who built my motor went with Wiesco. He said wiesco has the deepest skirts which helps against any boost blow-by. I honestly don't know how true that is but it sounded good at the time. 
I know wiesco, mahle and diamond are all good piston choices though.
I know wiesco, mahle and diamond are all good piston choices though.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
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From: Savannah, GA
I think either are good. I chose Mahle for mine, but I didn't get the dished ones, I got the flat top ones with just a -4cc valve relief, which is good for 9.3~9.5 SCR with 71-72cc heads and MLS gaskets. 
I have used all of the above and they are all equivalent assumming the same alloy. It comes down to customer service and turn around time. I am having major grief with one of the above companies giving me the right rings for their pistons. They went as far as telling me to go ahead and use a set of rings that came with their pistons that had an almost 0.040" end gap! That was on a set of file fits, so there was no reason for this to happen in the first place. Second set they sent me were 0.028 and 0.035's.
Ive run Diamond in a couple motors and could of ran Mahle in the my newest moter...... but Shawn from VA Speed and Myself started talking..... we decided to go with a custom set of JE Pistons....
If ya have to choose between the Mahle and Diamonds.....
Im sure VA Speed has them cheaper then any sponsor by about $75-100.
Kyle
If ya have to choose between the Mahle and Diamonds.....
Im sure VA Speed has them cheaper then any sponsor by about $75-100.
Kyle
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
I used some Mahle's, that looked just like Blue's..
Mine worked perfectly, and I abused the life out of them I even re-fitted them for a while last year when my 382 expired. I still have them, and they are still in excellent condition....my standby pistons lol.
Mahle make some of the best pistons around, as do Wiseco etc
There are plenty of choices really.
Mine worked perfectly, and I abused the life out of them I even re-fitted them for a while last year when my 382 expired. I still have them, and they are still in excellent condition....my standby pistons lol.
Mahle make some of the best pistons around, as do Wiseco etc
There are plenty of choices really.
I'm about to find out how good the Mahles are. My enigne builder ordered custom gas ported JEs for my .030 over 402 (now 408) but after 6 weeks he gave up & ordered the Mahles & they came in a week. I had Diamonds in the 402 & they held up to 2 years of racing. Because of the long stroke they did have some skirt scoring, so if you are running a stroker I'd say get any of them coated.....
I would not use 4030 pistons for an FI application.
A vendor sold me on Mahle 4030 alloy pistons as 'stronger than Diamond pistons', they failed on an easy drive home from the motor install. The top ring slot is close to the top of the piston, and valve relief cut ends up very close to the ring slot with nearly 1/16" material between the surfaces. The Mahles don't have much quench area, but for a narrow flat ledge at the edge. The 4030 alloy (~14% silicon) is close to stock brittle hypertech alloy (~17% silicon).
Apparently Mahle makes a 'Turbo piston' using 2618 alloy, but those were only available for the 6.0L at the time, not the 5.7L. W2W sells 2618 alloy Mahle pistons for $920.
Mahle dished
I'm going back to Diamond forged 2618 this time for my LS3. I was concerned that the Diamonds also have a full dish with a flat edge (catalog pics showed reverse dome), but talking to Nick D'Agostino at Diamond he reassured me that the quench area is fine at .300" ledge, though they did discover detonation problems with a narrower ledge (the Mahle have a narrow ledge). The Diamonds have a nice .260" top ring down, and I went with a 3.622" stroke to keep the oil ring from overlapping the piston pin.
Diamond dished
A vendor sold me on Mahle 4030 alloy pistons as 'stronger than Diamond pistons', they failed on an easy drive home from the motor install. The top ring slot is close to the top of the piston, and valve relief cut ends up very close to the ring slot with nearly 1/16" material between the surfaces. The Mahles don't have much quench area, but for a narrow flat ledge at the edge. The 4030 alloy (~14% silicon) is close to stock brittle hypertech alloy (~17% silicon).
Apparently Mahle makes a 'Turbo piston' using 2618 alloy, but those were only available for the 6.0L at the time, not the 5.7L. W2W sells 2618 alloy Mahle pistons for $920.
Mahle dished
I'm going back to Diamond forged 2618 this time for my LS3. I was concerned that the Diamonds also have a full dish with a flat edge (catalog pics showed reverse dome), but talking to Nick D'Agostino at Diamond he reassured me that the quench area is fine at .300" ledge, though they did discover detonation problems with a narrower ledge (the Mahle have a narrow ledge). The Diamonds have a nice .260" top ring down, and I went with a 3.622" stroke to keep the oil ring from overlapping the piston pin.
Diamond dished