Stroke with only Pistons and Crank?

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RustyRatRod said:
Never said I know it all. Simply relaying my experience. Again, read my signature, please. Tons of people have used stock rods successfully through many DECADES at over 7500 RPM a lot. They will just hold up if prepared right. Sometimes, it's just personal preference. I'm not sure I'd ever use a new connecting rod, as "for me" I can approach reconditioning stock rods more affordable, since I can do it in stages, rather than bite off the whole purchase price at once.
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I'm trying to do an entire truck one little piece at a time LOL but sometimes you got a bite off a little chunk... I have to work on a lot of Chevys and Fords to be able to afford a stroker kit... That and I sold actually a good running 360 for $650 bucks to get the ball rolling on the Stroker kit. And then I paid the machine shop just a couple hundred dollars at a time as I can get it...
I don't want to sound like pull $1500 off the tree in the backyard and call Summit...
 
j par said:
I'm trying to do an entire truck one little piece at a time LOL but sometimes you got a bite off a little chunk... I have to work on a lot of Chevys and Fords to be able to afford a stroker kit... That and I sold actually a good running 360 for $650 bucks to get the ball rolling on the Stroker kit. And then I paid the machine shop just a couple hundred dollars at a time as I can get it...
I don't want to sound like pull $1500 off the tree in the backyard and call Summit...
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Either way, you're still gettin it done. Right?
 
j par said:
Yes it's something I try to put $100 a week away and then by the end of 3 months or so I can purchase something large but it takes time and work...
Oh yeah and patience...
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I'm sure. I'm very fortunate to be able to do all that I do. I just don't have that kind of budget. I probably never will. I enjoy playing with junk. It's actually pretty rewarding.
 
Stock rods have an inherent weakness [ that's the bad news! ]. Good news is you didn't have to pay extra for it!
Any rod that uses a bolt & nut [ like the factory rod ] is weakened by the undercut reqd for the bolt head. If you see one of these rods break, that is usually where they break.
Aftermarket rods like H beams that use a bolt only, are stronger. They are usually lighter & where metal has been removed [ or added ] have been designed with modern computer assistance that was not available decades ago when the original stock rods were designed.
Not to mention the better metallurgy. Every V engine I build, I grind three reliefs in the rod cheek where it contacts the crank face. This is an escape route for the oil if one rod gets 'crowded' up against the crank face. Grinding these reliefs is MUCH harder on aftermarket rods than factory rods. The steel is simply tougher.


When you consider the cost to re-con factory rods, with equipment less accurate than the CNC equipment used to make new rods, the cost of new fasteners, the weaker rod structure that you are starting with, the answer to me is a no brainer...
 
I'll add my logic: stock rods should have new bolts put in. I think stock rods would be fine for 99% of builds, but the problem u run into is that these days it's tough to find a good/excellent machinist. If I'm getting rods redone, I have to trust the nut behind the press to not break or crack anything as he does it. If he does, will he tell me? Can I easily get a replacement rod in similar condition? How deep am I going to have to pay for the 7 good rods now, and still be short one?

With all that in mind, I treat it like a risk reduction and would hedge my bet to new rods for that reason alone. If I had a bucket of good used rods, my calculus might change. But I don't..

The added benefits of better design (bolt instead of stud/nut), more consistent weight, etc are just bonuses.

I'm also in an area where machining costs aren't yet prohibitive, but they're not like the good Ole days either. So if budget is even part of the conversation, it's worth weighing both routes.

The OP should do his homework and compare prices and values based on them. Who knows, his local shop may still be charging $25 a rod for a recondition! LOL. They're out there..
 
Phreakish said:
I'll add my logic: stock rods should have new bolts put in. I think stock rods would be fine for 99% of builds, but the problem u run into is that these days it's tough to find a good/excellent machinist. If I'm getting rods redone, I have to trust the nut behind the press to not break or crack anything as he does it. If he does, will he tell me? Can I easily get a replacement rod in similar condition? How deep am I going to have to pay for the 7 good rods now, and still be short one?

With all that in mind, I treat it like a risk reduction and would hedge my bet to new rods for that reason alone. If I had a bucket of good used rods, my calculus might change. But I don't..

The added benefits of better design (bolt instead of stud/nut), more consistent weight, etc are just bonuses.

I'm also in an area where machining costs aren't yet prohibitive, but they're not like the good Ole days either. So if budget is even part of the conversation, it's worth weighing both routes.

The OP should do his homework and compare prices and values based on them. Who knows, his local shop may still be charging $25 a rod for a recondition! LOL. They're out there..
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My question still remains in regards to balancing the entire assembly with what will likely be light weight pistons and crank with heavy factory rods... $$$???...
 
j par said:
My question still remains in regards to balancing the entire assembly with what will likely be light weight pistons and crank with heavy factory rods... $$$???...
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Maybe? With an external balance setup, the counterweights seem to be plenty big enough to allow for balancing. Mine did, and it uses OEM rods. No Mallory, and a balance is $200 in my town. Might be a different story if shooting for an internal balance.
 
Good inputs here guys. I would like to maintain the internal balance.

Question about the balancing of the rotating assembly. Is the crank the only part dynamically balanced and the rods and pistons just weighed and made all the same?
 
Buy a stroker assembly. CNC motor sports. They have several different kits from street to race and different manufactures.

Using your old rods will cost more . Once you consider reconditioning the rods and balancing the assembly for a street motor it will cost more. Even if you get a kit and your going to spin it on the high end get it balanced. My son rebalances them all and has received many that are out of balance. Just got a pro balanced kit that I believe was 26 grams out. He uses a Turner digital balancer

Best Mopar 340 Stroker Kit at CNC Motorsports
 
So here’s my .02 worth after doing this on my 340 last year.

I took apart my original 340 in my dart, hadn’t been touched since 1983. I had some wall taped so a bore job was needed. Might as well resize the rods and add new bolts. New bushings on the small end because they are 50 plus years old. Grind the crank and balance the whole thing for the new pistons.

Real life use says I don’t need forged pistons, it’s a mostly stock car. Once I priced everything out it was cheaper to go with a stroker kit from Scat. It came balanced and Ronnie at RAD machine said he likes their stuff.

It was a hundred bucks cheaper to buy all new parts and then I resold the original steel crank, 340 rods and the TRW std bore pistons that I installed in 1983 and recovered $400 towards my purchase.

The kit uses stock small block rod length 6.123” and now it’s a 372” 340 with stock manifolds and exhaust it’s a nice package in my car.

Cliff Ramsdell
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Don't mean to sidetrack (well, yes, I guess I do) but how much is Mallory these days? I have a cracked fuel crank with eight slugs of various sizes, wondering if it's worth my time to dig them out.
 
Cost is dependent on the parts you use and brands you are loyal to.

Ex. Rings range $25-$180+
Bearings $180 bucks for h series/narrow or king bearings are cheaper.
Pistons $380-$700+
Cranks $300-$1050

One could spend around 800 for a crank and pistons and cost after that for the remaining parts is the same as a rebuild roughly. You're gonna balance it anyways, bore it, the rings n bearings etc.

Kits are how much? 1600-2200?
 
33IMP said:
Don't mean to sidetrack (well, yes, I guess I do) but how much is Mallory these days? I have a cracked fuel crank with eight slugs of various sizes, wondering if it's worth my time to dig them out.
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Do it.
Ask the machinist if you were to bring them in if he could use them. I'd say they can drill to any size so yes.
 
MOPAROFFICIAL said:
Cost is dependent on the parts you use and brands you are loyal to.

Ex. Rings range $25-$180+
Bearings $180 bucks for h series/narrow or king bearings are cheaper.
Pistons $380-$700+
Cranks $300-$1050

One could spend around 800 for a crank and pistons and cost after that for the remaining parts is the same as a rebuild roughly. You're gonna balance it anyways, bore it, the rings n bearings etc.

Kits are how much? 1600-2200?
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I ordered my kit from Scat directly. Cast crank and pistons. I beam rods, rings, bearings and balanced. It was $1352.00 shipped and I think they turned it out in like 3 weeks to my door.

The cost of additional Mallory metal would have pushed up the rebuild more.

Cliff Ramsdell
 
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Oldmanmopar said:
Buy a stroker assembly. CNC motor sports. They have several different kits from street to race and different manufactures.

Using your old rods will cost more . Once you consider reconditioning the rods and balancing the assembly for a street motor it will cost more. Even if you get a kit and your going to spin it on the high end get it balanced. My son rebalances them all and has received many that are out of balance. Just got a pro balanced kit that I believe was 26 grams out. He uses a Turner digital balancer

Best Mopar 340 Stroker Kit at CNC Motorsports
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And summit is $50 less...
 
My first Scat rotating assembly I did 8 years ago and has taken serious abuse and works as if it was done yesterday. I just did my second one and bang for buck I just can't see a better way to go.
I've called the manufacturer and still Summit sells almost everything cheaper. They're able to buy in bulk and get a cheaper price to sell it but really cheaper than the manufacturer... And of course their customer service is second to none.. don't get me wrong I have called Scat and their customer service is very good as well..
Now as far as heads go I had my 592 360 heads redone with 2.02 valves springs k line valve guides the works..($900+) and a few years later discovered the straight Master aluminum heads for $700 on Black Friday sent to the door....
I've got to say I've seen budget minded people doing a lot of fiddling with a lot of motors over the years and I'm happy I just did it once or actually not twice and spent the money one time instead of several..
 
I’m not understanding the op’s question, is he using a stroker crank or not? You need to use a stroker crank to change stroke. Increased stroke piston has to have a shorter wrist pin height or a shorter rod length and to destroke the opposite. Changing pistons and rods only will not change the stroke.
 
ch1ll said:
I’m not understanding the op’s question, is he using a stroker crank or not? You need to use a stroker crank to change stroke. Increased stroke piston has to have a shorter wrist pin height or a shorter rod length and to destroke the opposite. Changing pistons and rods only will not change the stroke.
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The OP wants to stroke his engine and use the OE connecting rods. It’s cost ineffective to do that. By the time he buys a decent bolt, gets new bushings (the bushings should almost always be replaced) and rebuilds the rods he could have a set of aftermarket rods that have 7/16 cap screws rather than 3/8 bolts and nuts, plus a better grade of steel and a better design. It makes no sense to use OE rods any more.
 
Rat Bastid said:
The OP wants to stroke his engine and use the OE connecting rods. It’s cost ineffective to do that. By the time he buys a decent bolt, gets new bushings (the bushings should almost always be replaced) and rebuilds the rods he could have a set of aftermarket rods that have 7/16 cap screws rather than 3/8 bolts and nuts, plus a better grade of steel and a better design. It makes no sense to use OE rods any more.
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Cost ineffective in the short term. If you're like I am, you can do one step at a time and it be less shock on the budget.
 
RustyRatRod said:
Cost ineffective in the short term. If you're like I am, you can do one step at a time and it be less shock on the budget.
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You might be ahead to get a loan and pay the interest. Not sure about that and would need to check that out.
 
92b said:
You might be ahead to get a loan and pay the interest. Not sure about that and would need to check that out.
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No way would I take out a loan for a hobby. Thanks for the idea though.
 
I wouldnt even remotely consider using stock rods. Better off buying all new stuff in a kit. Pricewise likely little difference
Stock rods, no matter how much purists try to make them seem like Oliver Rods, are friggin 50 years old.
I would use a new Scat H beam rod WAY before stock rods, no matter how much they were upgraded with new bolts, etc, etc…. And not think twice.
Did i mention 50 years old…
 
I believe in K.i.s.s. You used to have to piece a stroker together. No reason, in my humble opinion, not to use a kit now, and as complete as possible.
I understand financial considerations, but I think I would save till I could afford the kit, rather than invest in individual pieces.
 
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