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Discussion Starter #1
Did a search and came up empty on specs. Anyone here know the specs on the rods that come with the crower stroker kit for K24? Trying to figure out what r/s you end up with using the kit and what size rod journals are used on the 102mm crank.
Are the pistons in the kit off the shelf, or pins raised?
This is probably covered in a thread here somewhere, but search function never seems to return the topics the way it should.
 

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These are good questions.

If we assume that he is using a piston with pin at the same location as OEM (compression height 1.181) then the RS would be 1.4758

Moving the pin up a little bit, could bring the RS ration to 1.52 or even more... but that is not what is really important in my opinion. To maximize the benefits of the stroker kit, you have to use a piston rod combo that has been optimized for that stroke and bore. I think the Rod width .935" for the bc cranks.. bseries

Why are you asking? Do you want to make your own stroker kit? Or thinking about buying just the crank? Wrist pin diameter, BE width, PE width, the size of bolt, the weight, the shape, the design of the piston, the skirt etc etc.. all matters and will make a difference.
 

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Discussion Starter #3
R/S isn't great to start in a k24, trying to determine how much worse it gets, if at all, with the kit.

These kits have been around a while, so someone has to know. That same person will know if the pistons are shelf or not and whether the pins are raised.

As for your points about the most important thing being that the kit is the product of r&d, I might agree if I knew what the r&d produced via some specs, which is why I'm asking what you termed "good" questions.

Crower sells the 102mm crank through its dealers, and if the pins are not raised in the kit, I'd like to raise them, get some rods made to match.

Will my stroker kit be better than Crowers? Not sure, but it's my money and I get to do what I want with it. Plus, I would share on this great forum how it turns out.
 

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Yeah, that is cool.

With the extra stroke, every piston is going to see more travel time to TDC and more travel.

My assumption is that they are not raised to keep the stroker kit cost down.

Not sure if you have seen this before, but I posted a picture of 2 99mm stroke pistons.. One is stock off the shelf wiseco 12.5.. the other is IPS spec JE...

That should give you a few ideas

 

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Discussion Starter #5
Thanks, I'm sure someone knows.

Clicking products on the IPS site shows nothing but cams.
Any specs on that IPS spec piston? Compression height? Is it even sold.

Also, you say the IPS spec is a 99mm stroke piston, was it designed for longer rods in a k24 build, or was that piston designed for a stroked k20?

Based on the diminutive skirt, doesn't look like something I'd want to get too radical with on rod angles.
 

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Discussion Starter #7
Still looking for info. Been researching the web and now I'm not even sure of the crank specs in the 2.4 stroker kit.

I see it is a 102mm stroke, but different sites have added 1.771 and 1.89 to the specs.
I know the journals take a .935 (b16 size) BE width rod, but does that mean the pin is 1.771?

Rod length in kit? Piston pin placement, compression height of kit's CP pistons?
What's custom, what's not? If I break a piston or rod is it a custom part or shelf?

Most of all, what what r/s do you end up with? If the rod is shortened, it sure doesn't sound like a motor you'd want to be running to 9,000, as the kit has been said to provide.
 

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I believe the BC stroker kits use a piston that has a shorter compression height and a stock length rod. The journal on the crank is B series LS journal so it should be a 1.771 crank journal.
The pistons are custom but I believe BC has the rods in stock.
The kit has produced pretty good power and has ran up to 9500 rpm before. A user on here Armando team1320 k26eg has this kit and had good results.
 

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Discussion Starter #9
Thanks for the info. If it has a 1.771 pin, it likely uses the crower b18 stroker rod. If that's the case, the piston likely uses a standard 1.181 comp height. Sounds like the shelf stroker rod may have driven the 102mm crank spec.

If that is the case, the kit produces a r/s of 1.52, just a bit worse than oem k24. Still, 9,500 rpm?

I'm not sure if I asked anyone here what is a safe rev limit for a built and balanced k24, they'd tell me 9,500. Hasn't 8,200-8,600 been about the ceiling in most cases?

Are we talking about that much difference between a crower balanced crank and a stock or balanced k24 crank?
 

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I believe it is a k24 rod length so the piston would be somewhere around 1.12 or so.
The ratio is more like 1.491 or close and these have seen upwards of 9400-9500 rpm.
We have taken the stock 99mm cranks to 10k before, the piston speeds are very high but the main thing is to keep the oiling up to par either with a s2000 pump or a dry sump setup.
 

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Discussion Starter #11
Gotcha. Then the rod is custom made for the kit - a .935 wide k24 rod?

Just seemed likely that the B18 stroker rod, being 3mm longer than a k24 rod, added up to the right match for a B spec crank with 3mm more stroke than a K24.

By chance do you have any tear-down data from an engine like this running those high rpms? Just curious about ovaling of cylinders, rod bearing wear...
 

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I have tear down data from other stroker stuff but with lighter components. I will tear down a BC stroker motor in the next two weeks and can let you know. Also the sleeve will have a lot to do with the ovaling of the cylinder too, we have had very good luck with Darton.
 

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Discussion Starter #14
Thanks for the feedback on this, guys and look forward to the tear down analysis.

For THAMADTECHNICIAN: Can you tell us what length rod you are running?
 

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Thanks for the feedback on this, guys and look forward to the tear down analysis.

For THAMADTECHNICIAN: Can you tell us what length rod you are running?
not at the moment i put together the block wit all the bc stroker stuff and jus wasnt happy wit the c/r so i decide to change the pistons and rods (still waitin for them to come in the mail)
all this happen like last week so all that info would be at the shop were the block is..next time i stop by the shop ill see if i can get that info for u
 
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