Alright guys, I originally planned on rebuilding my LS6 I've got with the stock rods, pistons, and crank. All I wanted to do was a big cam swap, port or mill my 243 heads, all the basic bolt-ons, and hope to hit 420-450rwhp. Should be easy with a big enough cam and ported heads. Anyways, I've been on this website waaaaaayyyyyy to much and now I am thinking about going with a forged setup. All these nitrous builds and forced induction builds have seriously peaked my interest. I come from a boosted 2011 4.6l V8Tundra (71mm Precision; and I think I was the only one in the whole world) and I am now starting to miss the feel of boost . I sold the kit so I could start my long term dream which is building a monster LS series engine. And btw, I still have a HKS blow off valve for sell and an AEM Piggyback if anyone is interested.

Anyways, I have been thinking a lot lately and I have decided to go forged. I still want to build my engine to use nitrous for a few months, maybe even a year, but eventually I would like to slap a nasty procharger on it.

My questions for you guys is; what forged pistons and rods should I use? I was really wanting to keep the stock bore of 3.898 but I haven't gotten word back from my machine shop yet to tell me if they have to bore the cylinders out. It's not a problem if they have to, I just didnt want to go through the trouble for only a little bit more of an opening. Anyways, my plan so far is Mahle 3.898 Forged Piston Kit/Set (should come with everything I need) with 6.125 Eagle H-Beams. Will I have problems going from a stock 6.098 rod length to a 6.125 rod length? Mahle has a forged 3.898 piston kit that will fit 6.125 rods; I made sure of that lol. Also the pistons they use I believe are -4cc. What would that bring my compression ratio too? Stock is 10.5:1. I plan on leaving this CR for boost in the future. Possibly even dropping it more into the 9's:1 eventually. Will those -4cc pistons give me PTVC issues with the SNS Stage 3 cam 235/243 .62x"/.62x"?

Sorry for a ton of questions guys but how will I ever learn if I don't ask.. Lol. Plus a lot of you on here have a ton of knowledge to spread around and I respect that. If any of you guys have a different setup I should run or suggest a different route then please post up your opinions/suggestions!

Like I said, for what I have planned right now; I want Mahle 3.898 forged pistons with eagle 6.125 h-beams. That along with ported 243s and a nice cam should hold a 200-250 shot eh? My goal for a completely stock engine was gonna be a 150 shot so now that I'm going forged, I should have no problems running a 200-250shot correct?

And then of course BOOST will come later on . Please post up your advice, suggestions, and opinions. This is my first build ever, literally. I could use as much help as possible.
Thanks everyone!
Nate.

 

I like Mahle products, but their pistons are a 4032 alloy. That alloy of aluminum isn't the best choice for a power adder, especially nitrous as it tends to be more brittle and less forgiving under the abuse of nitrous. Other brands like Wiseco and Diamond use a 2618 alloy. It's the more common alloy in the big power adder engines as it can take more abuse and holds up better under the big cylinder pressures.

 

Callies Compstar rods and Wiseco pistons. If you decide to stick with Mahle get into the 3.9x bore pistons. Smaller the better, but if I were replacing pistons I'd go a little larger just to give the complete bore a full cleanup. With these engines all you can do is hone. No boring required, so it should be the same price to make sure it's right. The only time to run standard bore 3.898 pistons is with a brand new unseasoned block. Good luck with your build.

On the rods, you can get the Eagles and Callies for about the same price if you check out and compare multiple sponsors from our vendor list on LS1tech. The Callies are lighter by up to 30g+ per rod and Callies uses a better rod bolt standard and their tolerances and consistencies from rod to rod is reportedly better by both users and more imporantly machinists on this board. Not saying Eagle is bad, just at the current time, Callies Compstars are better.

Don't rule out K1 Technologies rods either. They're heavier like the Eagles but their machining quality and strenght is apples-apples with Callies. They
re newer and haven't got near as much use and review as the other two rods mentioned, but their reviews have been just as good Callies and their price is on the same level as the others, usually in between Eagle/Callies. They're also connected to Wiseco I believe as a sister company so to say.

Wiseco offers a -3cc that wont hurt compression too bad. Piston to valve clearance will not an issue with aftermarket pistons unless youre shooting for combos in race gas compression areas, and most aftermarket pistons are designed around a 6.125 rod and it will be noted which rod length and crank stroke they're for when ordering.

 

Thanks you KCS and Intenseblu. Y'all's information is very helpful. Looks like ill hone the cylinders out to 3.905 so I can have more of a variety when it comes to pistons.

 

Okay guys, I'm back again for some more answers and advice. I am about to order my pistons and would like to grab the Mahle 3.905 pistons for a stock 6.098 rod length. The pistons are -4cc; what would that bring my compression ratio to with stock 243 heads? My stock CR is 10.5:1. I hope the -4cc doesn't drop compression ratio to much. If it does drop CR then does that mean I'd be able to mill my heads without worry of PTV issues or does the -4cc have nothing to do with PTV clearance?

 

The 4cc is the volume of the valve reliefs, which are there to provide more PTV clearance.

There are plenty of online calculators to check your compression ratio. Just enter the data and it will do the work for you. This site has a ton of calculators that you could find useful, including static and dynamic compression ratio.

http://www.wallaceracing.com/Calculators.htm

 

Not all of Mahle pistons are 4032. They do offer 2618 in some and you can get it in any thing they offer also. it is a bit more, but as far as great piston design, the have it down pat. I would DEF use standard tension oil rings. Depending on the boost you may need a steel top but rather than a napier second i would use either a std second or HTD. I would recommend mahle power pack piston set, which we have avail, with their standard ring set for 10lbs and under. Scat or eagle or compstar H or I beam rods will work well. Depending on the piston you can get either the 6.100 or 6.125 rod also. The smaller pin works better for a little better CH.

The mahle pistons in a 4032 wont take over 150 shot. If you are throwing the nitrous in the H beam rod would be a better buy. We can get you the whole thing.
Clevite bearings are a must.