5.7L pistons

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2734bbl

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Ive got an 07 5.7L Hemi core I'm going to build for My Dart.It will be a budget bearing/ring build and 6.1L cam.

It appears that .550 lift cams is about the max you can run with stock pistons.

My question is can you fly cut stock 5.7L pistons safely and if so how much?
 
OK I did alot of searching and found 2 different threads that both said that the stock pistons are a No-Go for fly cutting.
 
2734bbl said:
OK I did alot of searching and found 2 different threads that both said that the stock pistons are a No-Go for fly cutting.
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I'ts not the .550 lift that will hurt you, it's the LSA and the duration. I think the max LSA and duration for a stock pistoned engine is 112 deg LSA and 225 deg at .050 with around a half inch of lift. Which in most cases is fine. Most of the issue is all in the valve timing. You could run 1 inch of lift if you could get the parts in there to make it live, and as long as the valve action was fast enough to close the valve in time so that it would clear the piston. I don't think a .030 eyebrow would hurt but one of the Inertia motorsports guys should be able to answer this question with more accuracy. I have aftermarket pistons and a big cam in mine so I havn't tried to do what you would like to accomplish.:thumrigh:
 
I agree I just needed to alter my post.I may postpone my build long enough to get a set of pistons.

It seems that some real duration with the airflow these things have will really wake one up. Needless to say even with a narrow cam Gen III motors run really good.

I was just tryng to cheat a little.:banghead:
 
2734bbl said:
I agree I just needed to alter my post.I may postpone my build long enough to get a set of pistons.

It seems that some real duration with the airflow these things have will really wake one up. Needless to say even with a narrow cam Gen III motors run really good.

I was just tryng to cheat a little.:banghead:
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Cast piston, no oil squirters and .12" above ring land. Kinda shakey. Probe, CP. and others probably have good pistons in stock now, at good prices. Perhaps Flatlander Racing. Good Luck, ateam.:eek:fftheai:
 
Probe Ross mahle cp bullet series, I'm probably missing some but the stock pistons are to much of a risk unless it's bone stock, your best way to stay in budget would be a 6.1 crank because there forged and not cast like the 5.7 and same specks get a set of shelf pistons that are .020" over from weisco and k1's stock length forged rods. You will have a forged engine that is way stronger and not break the bank. Then you can upgrade your heads and so on when budget permitting.
 
I'm still in the parts gathering stage right now. I have managed to score a set of 6.1L heads but for what I'm doin I'm not sure I need them to reach my HP goal.
 
I've got a complete 07 and now an 05 motor. I'm only looking to get my Dart in the 11.50 range so I think the 6.1L maybe better left on the shelf for now.
 
I would highly recommend swapping out the pistons the stickers fail in a stock application. And for piece of mind should be replaced. A stock rod and crank with an aftermarket piston (bump up the compression a little about 10.5 or so) a nice cam and a set of free flowing heads should make a little over 500 at the crank. I know in my ram I ran all the supporting bolt on's and a set of pitted heads and a cam. And giving it a 150 shot it put out over 515 to the wheels. And launched my 5000 pound 4 door brick to the tune of 12.7@105 and was cutting a 1.65 60ft. A similar set up less 2000 pounds and nitrous should get you really close to your goal.
 
That is borderline cadistrofic for the stock rods and crank! If your gonna get a forged piston your better off to spend the 7-800 more to get a 6.1 crank and stock length forged rods, with the new pistons its going to NEED to be ballanced anyway. If your gonna use nitrous then head studs should be used instead of bolts.
 
Man I'm not disagreeing with you. And nitrous was not part of the OP it was something I tossed in there. But I did not have an issue with this motor. The weakest link is the piston ring lands. And for what he is after replacing them would be a good idea. The crank and rods will hold up to what heis lookingto do. (and I proved that with my motor) but on that note if your replacing pistons, upgrading the rods and crank to, is not a bad idea. I know I would.but for his application not nessacary.

Now abut my motor my head bolts did just fine. My motor survived for over 150 passes on nitrous and as a daily driver. The motor was pulled from my ram and now sits idle in my duster, ita getting ready to be twin turboed now. And it will see about 8psi of boost. And once the new motor is built I'll be hitting it with 20psi or so. (but it will be forged and studded all the way around)
 
I'm not trying to say anyone is write or wrong, my only point is that with a forged piston or anything new in the rotating assembly will need to beballanced. If your going to buy a better forged piston the cylinder needs to be measured and torque plate honed. So if your already going through that process then a 6.1 crank and stock length k1 6.243" rods would be ideal.
 
Actually in my other thread "In the real world" I did mention spray but it was mostly a fleeting thought.

I'm basically just looking to go as quick as I can on stock reciprocating assy and heads but Ive seen a few threads around about the pistons breaking so it appears as though a set of pistons(and rebalance) will have to be budgeted in but I could sure use the $450 in other places on the car right now.

My car needs attention in other areas before I start goin faster than 11.50. If Ramit can get a 5000lb truck to my present speed(I'm impressed with that 60ft for a truck BTW) with a 150 shot I should be able to get my goal at 3350lbs(actually less as a Gen III motor is 180lbs less and the 904 trans is lighter than a B/RB 727) with a similar set up and probably even without the spray.

Just to be clear....this first motor will be my stepping stone to get the car up and running and sorted out. The next bullet will be a stroker with heads and whatnot.
 
I ran a 12.7 in that truck on 11's just to be clear, but that's still quick for a vigil truck. I raced a 1st gem lightning that ran low 10's and was within .05 in the 60 ft of his truck so I was reLly happy. If you need money elsewhere don't bother and run the motor as is and upgrade all at once later.

2734bbl said:
Actually in my other thread "In the real world" I did mention spray but it was mostly a fleeting thought.

I'm basically just looking to go as quick as I can on stock reciprocating assy and heads but Ive seen a few threads around about the pistons breaking so it appears as though a set of pistons(and rebalance) will have to be budgeted in but I could sure use the $450 in other places on the car right now.

My car needs attention in other areas before I start goin faster than 11.50. If Ramit can get a 5000lb truck to my present speed(I'm impressed with that 60ft for a truck BTW) with a 150 shot I should be able to get my goal at 3350lbs(actually less as a Gen III motor is 180lbs less and the 904 trans is lighter than a B/RB 727) with a similar set up and probably even without the spray.

Just to be clear....this first motor will be my stepping stone to get the car up and running and sorted out. The next bullet will be a stroker with heads and whatnot.
Click to expand...
 
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