Gen 3 Flat Top Pistons
08-09-2018, 01:45 AM
#21
Most trucks will hardly ever see above 5k realistically.
So why even look at a cam above a 112lsa really. Add in lift, and keep the duration around high 2teens low to mid 220s and youll be fine.
As far as head gaskets, you cant just throw one on without measuring the ptd clearance. If you are building it "budget" by cutting costs on lets say springs but then spending 3x the price for a thinner head gasket it doesnt make much sense. I am not saying OP is or anyone is suggesting that, but i see it said alot and its very contradictory really. Save the money, get the measurements, and do both if you want. .035 is the least amt of quench i would go for any pump gas, be it reg or corn. Base fuel quality not just octane and ethanol levels are a huge deal and so are summer blends vs winter and most dont take that into account.
So why even look at a cam above a 112lsa really. Add in lift, and keep the duration around high 2teens low to mid 220s and youll be fine.
As far as head gaskets, you cant just throw one on without measuring the ptd clearance. If you are building it "budget" by cutting costs on lets say springs but then spending 3x the price for a thinner head gasket it doesnt make much sense. I am not saying OP is or anyone is suggesting that, but i see it said alot and its very contradictory really. Save the money, get the measurements, and do both if you want. .035 is the least amt of quench i would go for any pump gas, be it reg or corn. Base fuel quality not just octane and ethanol levels are a huge deal and so are summer blends vs winter and most dont take that into account.
08-09-2018, 06:07 AM
#22
The cam LS7 colorado isn't bad but you'd need a decent size stall and more serious valve springs etc.. That cam would be a little better in a stalled car than a stock stalled 4L80 pick up. However I agree with him about boring it out to 4.065 and putting $300 LS3 pistons in it, but then you're back to the rod dilemma.
08-09-2018, 02:06 PM
#23
Most trucks will hardly ever see above 5k realistically.
So why even look at a cam above a 112lsa really. Add in lift, and keep the duration around high 2teens low to mid 220s and youll be fine.
As far as head gaskets, you cant just throw one on without measuring the ptd clearance. If you are building it "budget" by cutting costs on lets say springs but then spending 3x the price for a thinner head gasket it doesnt make much sense. I am not saying OP is or anyone is suggesting that, but i see it said alot and its very contradictory really. Save the money, get the measurements, and do both if you want. .035 is the least amt of quench i would go for any pump gas, be it reg or corn. Base fuel quality not just octane and ethanol levels are a huge deal and so are summer blends vs winter and most dont take that into account.
So why even look at a cam above a 112lsa really. Add in lift, and keep the duration around high 2teens low to mid 220s and youll be fine.
As far as head gaskets, you cant just throw one on without measuring the ptd clearance. If you are building it "budget" by cutting costs on lets say springs but then spending 3x the price for a thinner head gasket it doesnt make much sense. I am not saying OP is or anyone is suggesting that, but i see it said alot and its very contradictory really. Save the money, get the measurements, and do both if you want. .035 is the least amt of quench i would go for any pump gas, be it reg or corn. Base fuel quality not just octane and ethanol levels are a huge deal and so are summer blends vs winter and most dont take that into account.
Actually, I was assuming lol. But it seemed safe to assume based on the info in the thread. But it's also in a truck, which is another big factor.
02-17-2019, 12:09 PM
#24
Sorry for reviving an old thread, but it was better than starting a new one, I suppose. It gives the story from the beginning.
I got around to ordering the parts I need for my rebuild. I ordered my parts form the WS6Store. Got a Tooley Stage 2 truck cam. Good prices and brutally fast shipping.
I went to get my pistons pressed on and the machine shop called me to say the pistons are incorrect. Mine are press fit with a dish on top and I got flat tops with floating pins. in my kit
I gave WS6Store a call and left a message on Friday, but I didn't hear back from them (I'm sure they're busy, and this isn't exactly an emergency, so no problem).
I was waffling on going with flat tops because I'd have to change the rods, and I'm a cheapskate....but I'm taking this as a sign from God that I need 10:1 compression!
So at this point i'd like to keep the pistons and get the correct rods.
I need to be sure of exactly what I need. I believe any 5.3 or 6.0 rod made after 2004 is the correct one, right?
If so, I'm on the hunt for a used set so I can get this build going.
Thanks,
Joe
I got around to ordering the parts I need for my rebuild. I ordered my parts form the WS6Store. Got a Tooley Stage 2 truck cam. Good prices and brutally fast shipping.
I went to get my pistons pressed on and the machine shop called me to say the pistons are incorrect. Mine are press fit with a dish on top and I got flat tops with floating pins. in my kit
I gave WS6Store a call and left a message on Friday, but I didn't hear back from them (I'm sure they're busy, and this isn't exactly an emergency, so no problem).
I was waffling on going with flat tops because I'd have to change the rods, and I'm a cheapskate....but I'm taking this as a sign from God that I need 10:1 compression!
So at this point i'd like to keep the pistons and get the correct rods.
I need to be sure of exactly what I need. I believe any 5.3 or 6.0 rod made after 2004 is the correct one, right?
If so, I'm on the hunt for a used set so I can get this build going.
Thanks,
Joe
02-17-2019, 09:50 PM
#27
I don't know what you mean by this. Are you saying there will be .002" clearance using the floating pin on the pressed rod?
If not, is honing the piston pin holes all I'll need to do, or will they need more work than that?
Thanks to both of you for the help!
Joe
If not, is honing the piston pin holes all I'll need to do, or will they need more work than that?
Thanks to both of you for the help!
Joe
02-18-2019, 08:03 AM
#29
Thanks. I talked to the machine shop this morning. I'll bring my rods/pistons back to him on Friday when I get back home. He'll double check the measurements and hone them to size if necessary. I'll be happy to have the compression bump over stock.
The machine shop asked if there were locks for the piston pins in the box of pistons. I didn't notice whether there were or not, and I'm not home to check them. If they are supposed to be there, I'm sure they are.
Joe
02-18-2019, 08:07 AM
#30
You have pins that work with the press fit rods, so the million dollar question is what pins did the pistons come with? There are usually two sizes that work with OEM rods, either .945" or .943". I'm assuming that the reason your machine shop is saying there's a problem is because the pins are mismatched, but that should be a super easy fix:
If you have .943" pins in your press fit rods and the pistons came with .945" pins, then have the machine shop hone the rod pin bore a little bit so as to maintain the proper press fit and use the .945" pins.
If you have .945" pins in your press fit rods and the pistons came with .943", then you just have the machine shop hone the piston pin bore to get proper clearance and use the .945" pins.
02-18-2019, 08:28 AM
#31
I don't remember the pin measurements, but the machine shop showed me that the piston pins supplied with the new pistons would push through the small end of the rod, instead of pressing in. He stopped there and called me to ask what I wanted to do.
Joe
Joe
02-18-2019, 10:58 AM
#33
I'm no pro here but WS6store said hone the small end to have .002 clearance. If he has .943 pins with the new pistons and .945 rods then he will already have .002 clearance at the small end. Could it not just be left like that and a hole drilled in the top of the rod for oiling?
02-18-2019, 11:29 AM
#35
Joe
02-18-2019, 12:15 PM
#36
I'm no pro here but WS6store said hone the small end to have .002 clearance. If he has .943 pins with the new pistons and .945 rods then he will already have .002 clearance at the small end. Could it not just be left like that and a hole drilled in the top of the rod for oiling?
02-18-2019, 12:20 PM
#37
It’ll probably run fine, but running steel on steel like that isn’t really “the right way” to do it, which is why almost every floating pin rod has a bronze bushing or a DLC coated pin. GM uses about .0006” clearance in the LS engines and .0012” is about the most I’ve ever seen in 1500hp power adder applications, so .002” is pretty loose. If i had to guess, that much clearance is probably necessary to avoid galling. It’s usually only about $50 to have the pistons honed, and having them drill the rods is probably about the same, if not more.
Gotcha and thanks for the info
02-18-2019, 07:14 PM
#38
It’ll probably run fine, but running steel on steel like that isn’t really “the right way” to do it, which is why almost every floating pin rod has a bronze bushing or a DLC coated pin. GM uses about .0006” clearance in the LS engines and .0012” is about the most I’ve ever seen in 1500hp power adder applications, so .002” is pretty loose. If i had to guess, that much clearance is probably necessary to avoid galling. It’s usually only about $50 to have the pistons honed, and having them drill the rods is probably about the same, if not more.
Thanks to everyone for chiming in. It has been very helpful.
Joe
