So is there an advantage to buying a “kit” as opposed to buying the parts separately with respect to balancing? Meaning are the kits custom balanced for the specific parts? Or are the parts selected for a given balance of a given crank?
Stroke with only Pistons and Crank?
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harrisonm
Well-Known Member
Let me make one suggestion. Buy the rods from whoever you buy the crank and pistons from. If there was a problem, you don't want to be in a position where the people who sold you the crank and pistons say the rod failed, and vice versa. I avoid that potential problem when I can.
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Yeah, but it took Chevy what.....20 years to finally catch on? I have a friend that has one in a snatch truck. He loves it.
CNC-Dude
Well-Known Member
The crank wont be balanced unless you buy a kit with all the pieces together. If you buy the crank separately, whoever you buy it from wont know what rods and piston and stuff you will be using to be able to balance it. And that puts all the burden on you to provide all that info to the person that will balance it. If you transpose a number or if they do you can have a big problem, and that has happened. Plus when you buy a kit you usually get a package deal as opposed to buying the parts individually.
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Sorry but i would not buy a kit with a balanced crank. Once you get the kit...look at the box of rods....bet they are all sealed up still...meaning they never weighted the rods individually....just took the numbers off the box...same thing with the pistons....just used the numbers on the box....Was using a machine shop that was doing the same thing but charging me full price for a balance job ....nope..never been back.....
I used HBR in Vegas...as you can see from the previous post everything is weighted individually ....showing calculations to get bobweight....and given a print out so that if anything is damaged it can be replaced .....plus he keeps a copy of the balance job. I asked Rick about the Kit balance job and he just laughed saying they have fixed many of them...If you are going to several thousands on a kit have it balanced correctly...
CNC-Dude
Well-Known Member
I have seen that happen as well. But my best suggestion is to take the kit to a shop and get them to check it. You really can't trust what you are buying anymore. I worked in a race shop for 15 years during the era when Scat and Eagle first came on the scene and rods still had to be reconditioned right out of the box and rods and pistons pin fit and rotating assemblies out of balance so bad that were supposed to be balanced, the engine would have jumped out of the engine compartment. Hope things have gotten better.....
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harrisonm
Well-Known Member
Do I even want to know what a snatch truck is?
Stop makin your car payments and you'll find out.
harrisonm
Well-Known Member
Oh, that kind of snatch.
Yeah. lol
mopartx
Active Member
My 340 has a 360 crank with the 340 pistons milled to clear deck. Old School Storker is what my dad/I wanted to build and he had a lot of parts lying around. I know it's not the cheapest but it does have stock rod/pistons. I apologize if I misunderstood and I am speaking way out in left field.
I wasn't aware the piston heads were that thick. That's over 1/4" (.250") difference. I bet the piston heads are pretty thin.
I wonder how far the pistons were down in the hole to start out. Would a late 340 be like a 360 .080"ish?
I believed the 72-73 340 piston is used which has a lower CH of 1.74 ish verus the 70ish 340 piston 1.84 ish CH....So about .080 plus or minus needs to b e milled from the piston if you use the 360 1.66 CH....
Easier to buy 360 pistons these days....
That makes more sense.
So would that set up make it a 360? Are the pistons set up at 0 deck?
I've built 2 strokers for my car, both used Scat I-beams, and neither needed any Mallory to balance. The first stroker I had balanced at a local shop after I purchased parts individually (Forged Eagle crank, Scat I-beams, Diamond forged pistons). That engine ran great (high to mid 10's).
The current stroker that is in the car was a Scat pre-balanced kit (Scat forged crank, Scat I-beams, forged Icon pistons). This saved me money on balancing, and to be fair, I was a little skeptical of the pre-balanced kit thing.....but after 3 race seasons of low 10 second passes, I'd say it turned out ok.
I guess do what you are comfortable with, but I personally think the Scat I-beams are the most cost effective option for quality small block Mopar rods.
The current stroker that is in the car was a Scat pre-balanced kit (Scat forged crank, Scat I-beams, forged Icon pistons). This saved me money on balancing, and to be fair, I was a little skeptical of the pre-balanced kit thing.....but after 3 race seasons of low 10 second passes, I'd say it turned out ok.
I guess do what you are comfortable with, but I personally think the Scat I-beams are the most cost effective option for quality small block Mopar rods.
aaronk785
Well-Known Member
I think a .030 over 340 with a 360 crank makes a 372. That's a Hoover design and it does use 72 73 forged 340 pistons. I just bought a stroker kit for 1600.00 balanced and ready to go. The cast steel crank has 2 plugs of mallory metal in it. Just saying buy the time you do all the machine work and buy parts the stroker kit is cheaper.
Thanks, this is really good firsthand inputs flyfish thanks for posting! Looks like this will be the best way to go.
mopartx
Active Member
I lost my sheet with all the numbers on my 340 build, it was in early 2002. It is probably pretty close, it doesn't like pump gas. When first built it didn't like pump gas much then I blew a head gasket and when I put the heads back on 2 years ago I must have put a thinner head gasket because it really doesn't like pump gas. It does just fine for putting around close to the home. Yes like AaronK says it's about 372 +/- and it would be cheaper to build it a different way. LOL
Thanks interesting build! I for sure will buy aluminum heads because of the Arizona heat and shitty fuel. I hate fighting detonation and retarding a hot motor!
aaronk785
Well-Known Member
A lot goes into fighting detonation. Cam timing, chamber design, timing curve, quench, cooling system and more. There are a lot smarter people than me on here that can help you out with the mathmatics. And figure dynamic and static compression. It's just not me.
mopartx
Active Member
The next thing I would do is buy some aluminum heads for this engine in my 66 and put the X heads on my 72 dart. I'm about to put my 72 back together and just didn't have the money to spend at this time so it will get a freshened pair of J heads. I had wanted to "stroke the hell out" of 1 to puti my 72 but I couldn't spend the money right now and I just want to drive it now.
mopartx
Active Member
When 1st built it would do ok if I mixed race fuel with super. There is a gas station close by that I get ethanol free gas from(92 octane). I'm going to try some mixture with it. It just leads to more drive time. Thanks for the input
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