Generation IV Internal Engine - L92 Pistons?

Okay, okay...
What are the current choices for L92 pistons?
I am building two L92 engines...one N/A and another F/I.
I need two sets of pistons, 4.030", w/4.0" stroke crank, approx. 11:1 comp. ratio and 4.030, 4.0" w/8.5 or 9:1 comp. ratio. Does ANY piston manufacturer sell/stock SHELF pistons with the above size and comp. ratio mentioned above? Thanks in advance for your help.:bang:

stock L92 bore is 4.060.. well mine is anyway...? I have been searching for pistons myself, kinda hard to find ive found..

l92 pistons are 4.065 range,
4.00-4.060 are available for lq4 rebuilds, in hyperutectic material,
they come with rings package, and are in the 300$ range for set of 8.

Are you talking about the an L92 block? Or for L92 heads? I'm thinking diamond makes pistons relieved for L92 heads, but as far as in the 4.065 bore range I'm not sure... I think they sell them in a 4.070 bore, at least I think that is what was listed in their catalog the last time I checked...

We're doing a 408 for a customer right now. He is using L92 heads and wanted to spray a 300 shot so we had to order a custom set from Wiseco. I believe Diamond makes a flat top for the L92 head as well, but we're spraying a 300 shot so we opted for the Wiseco. 4.030 bore with L92 reliefs in a flat top.. had to have it made by Wiseco for our application.

We're doing a 408 for a customer right now. He is using L92 heads and wanted to spray a 300 shot so we had to order a custom set from Wiseco. I believe Diamond makes a flat top for the L92 head as well, but we're spraying a 300 shot so we opted for the Wiseco. 4.030 bore with L92 reliefs in a flat top.. had to have it made by Wiseco for our application.

Were the Wiseco pistons custom made or does Wiseco "stock a shelf piston" with a 4.030" bore, with L92 valve reliefs? What compression ratio are you running?
Thanks, guys!

Are you talking about the an L92 block? Or for L92 heads? I'm thinking diamond makes pistons relieved for L92 heads, but as far as in the 4.065 bore range I'm not sure... I think they sell them in a 4.070 bore, at least I think that is what was listed in their catalog the last time I checked...Yes I am using a 0.030 bored LS1 iron block (4.0" stock bore), with L92 heads for both engine builds. So I am asking for a set of high compression (11:1) shelf pistons and a set of turbo pistons (8.5-9.0:1 compr. ratio) that anyone sells with out waiting 6 weeks for manufacturing. I was figuring spending about $600 for each set. Am I dreaming or can this be done at all?

Your dreaming for $600 and you need to custom order them it will be 6 weeks. Diamond makes a flat top, not sure if its on the shelf or not. For my Wiseco it will be $850, -3cc piston, if you want them pm me and I'll try and get them on the same order.

Mahle has them on the shelf. I paid $540! With rings and pins and locks. They have them in a couple of different setups. Mine were 4.030" bore, 3.622 stroke ( they have them in 4" stroke), -4cc L92 valve relief flat tops, 6.125" rod, they make them in a dish for F.I. but since my heads have 75 cc chambers, I went with the flat tops with my turbo engine. Real nice pistons, fully coated with file fit rings. Diamond stocks them in the L92 bore, but they were custom for the 4.030 bore. $862!

Mahle has them on the shelf. I paid $540! With rings and pins and locks. They have them in a couple of different setups. Mine were 4.030" bore, 3.622 stroke ( they have them in 4" stroke), -4cc L92 valve relief flat tops, 6.125" rod, they make them in a dish for F.I. but since my heads have 75 cc chambers, I went with the flat tops with my turbo engine. Real nice pistons, fully coated with file fit rings. Diamond stocks them in the L92 bore, but they were custom for the 4.030 bore. $862!


Let me ask you one thing... What do you think the difference is between a $540 piston and a $850 piston? You get what you pay for in this business.
We dont use the cheapest piston we can find in our builds. We use Wiseco over Diamond as its a little better for heavy n2o and boost.

Let me ask you one thing... What do you think the difference is between a $540 piston and a $850 piston? You get what you pay for in this business.
We dont use the cheapest piston we can find in our builds. We use Wiseco over Diamond as its a little better for heavy n2o and boost.

I second that! I don't care for the Mahle's either because they don't use the 2618 material. The 2618 is not as brittle and is better suited for nitrous or FI applications. On a milder NA build the Mahle's are probably fine.
Manley also makes an L92 piston and it has the coated skirt like the Wiseco.
JE makes some L92 pistons also.
I don't know if Arias or Ross offers anything for the L92's.

Go ahead and try to justify using those wiseco pistons. I have personally seen more ruined engines running Wiseco's than I have stock pistons. You have to run a ton of skirt clearence on those things. So the OP was looking for a set of L92 shelf stock pistons for less than $600. Not $850 custom pistons!

Go ahead and try to justify using those wiseco pistons. I have personally seen more ruined engines running Wiseco's than I have stock pistons. You have to run a ton of skirt clearence on those things. So the OP was looking for a set of L92 shelf stock pistons for less than $600. Not $850 custom pistons!

Wiseco's live in 12:1 - 14:1 14k RPM Dirtbikes fine...so they have to know what they're doing!
Here's a link to the Wiseco stuff...go to page 15:
http://www.wiseco.com/Catalogs/Automotive/Chevrolet.pdf

Here's the Manley ones:
http://www.manleyperformance.com/niche/chevy_ls_pistons.shtml

Were the Wiseco pistons custom made or does Wiseco "stock a shelf piston" with a 4.030" bore, with L92 valve reliefs? What compression ratio are you running?
Thanks, guys!


No its was not a shelf piston but we are thinking about having a few sets made.

Go ahead and try to justify using those wiseco pistons. I have personally seen more ruined engines running Wiseco's than I have stock pistons. You have to run a ton of skirt clearence on those things. So the OP was looking for a set of L92 shelf stock pistons for less than $600. Not $850 custom pistons!


The OP did not state a budget, he asked for an N/A and a boost. I gave him the options I use. The piston does not ruin the engine. The inexperienced builder might or the tune being bad and running 13:1 compression and detonating might ruin. But a properly assembled engine is not ruined by a correctly selected piston. Most of my builds are nitrous or boost related but when you find a great product you tend to stick with it. We use Wiseco so that's why I recommend them. We go with quality at a price that makes sense.

If your going to be hitting this thing with n2o or boost you want a good piston with good ringlands right?

I dont sell pistons I could honestly care less where he spend his money. He posted a question so I gave him the options I would go with. I never said it was the only option out there, sorry for the confusion.

Go ahead and try to justify using those wiseco pistons. I have personally seen more ruined engines running Wiseco's than I have stock pistons. You have to run a ton of skirt clearence on those things. So the OP was looking for a set of L92 shelf stock pistons for less than $600. Not $850 custom pistons!

How much boost are you planning on running with your setup?

At 18 lbs. it made 1147 hp on the engine dyno. I feel comfortable taking them to 25 lbs.

ive never had a prob. yet with mahle's and ive used ebay set with no probs.

i have evn used hypereutectic speed pro's in n/a 475bhp 370ci 6.0 iron block with a 100 dry shot, no probs to date over 40k miles on the engine

Let me ask you one thing... What do you think the difference is between a $540 piston and a $850 piston? You get what you pay for in this business.
We dont use the cheapest piston we can find in our builds. We use Wiseco over Diamond as its a little better for heavy n2o and boost.

In all honestly, if you look at it, both sets of Wiseco and Mahle and i'm sure even the Diamond CUSTOM pistons all cost about the same. There should be a significant price difference of a "shelf" piston vs. "custom" piston. I just wanted to know my choices and options as far as shelf pistons. It seems like the difference in price between the two is about $300. I'm fine with the money part of it, but it will be better for me to purchase a piston set that is readily available. I do get your point about $540 vs. $850, but it really seems like a waste to pay for a "custom" piston when I don't have to. Maybe the manufacturers should play catch-up.
Thanks for your input...it has been very helpful!
You guys rock.

At 18 lbs. it made 1147 hp on the engine dyno. I feel comfortable taking them to 25 lbs.

I'm looking to run about 20psi with the boosted engine...Looking to make the same power as you have dyno'd....

The extra money comes down to the manufacturer having to setup the tooling and run a small, like 1 set, production run. The $540 I paid was at Jobber, retail is like $630 or so. You can't buy them direct from Mahle, but anybody that is a wholesaler for them can get them. They came drop shipped from them. I got them from Lane Automotive. I believe summit carries them. Call the Mahle tech line, they are VERY helpfull. Give them the specs of what you want, and they will give you the part number. It took 3 days to get mine. Nick @ Diamond was very helpful too, but the price and 6 week wait wasn't going to cut it, when the Mahle's were in stock ready to go. This is the second set of PowerPak Mahle's we have used with excellent results. The first set was in a 350 solid roller LT4 with a 250 shot. That one is still tearing it up, running mid 9's all day long for 3 years. So to dispel the myth that you have to have 2618 material to make big power and live, there you have it. Now if I was running 28 lbs.+ or a 300 plus shot, I would step up to the race oriented Mahle's with 2618 material etc.

We deal with people who dont always have the best tune or gas and so we play it safe.

Here is a good thread for you to read :

http://www.ls1tech.com/forums/showthread.php?t=898905

Here is a link for the Mahles http://www.lingenfelter.com/store/mahle-l92.html

bore stroke rod length compression with 68cc head
4.030 4.000 6.125 10.64 -4 piston

comp height 1.105.... vs a 1.115 this would be putting ring closer to the top right? Is that a good thing to do?

...DO you know how much you have to mill an L92 head to get it to 68cc's? 75cc chamber to begin with arent they? We went with -3cc's and will have to mill the head the normal amount for a bump in comp.
IF your running boost it doesnt matter to you but in an N/A application you want like 11.3:1 compression dont you? So you have to mill them down pretty good and I'm not sure what that does to the flow or intake floor to mate up with the intake?? Not pretending to be a head expert by any means but you at least need to look at the big picture I think?