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Discussion Starter #1
Stumbled across these rods the other day. Wondered if anybody has any experience with them. They are for a c24ne.


I am building a 2.2 and having custom pistons made. So the fact the pin is different doesn't matter. And they are 134mm. But once again, shouldn't matter due to custom pistons.

By the time my forged 1.9 rods are magnafluxed, resized and balanced I'm halfway to the cost of these rods. Not to mention new rods bolts. And no ARP's available.

So basically a stroker, better rod ratio and more horsepower.

Any down sides? So far all I can come up with is maybe a slight loss of vacuum and possibly low rpm throttle response.

Thanks all!
 

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The 134mm rod length should be just fine, based on that Opel itself used them in the six cylinder 24V C30SE and C26NE CIH engines with the same 69,8mm stroke as in the four cylinder ones. And the 88,8mm bore C26NE had a high toque rating for its size with a wide powerband.
 

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Don't worry over the low RPM response. Keep your static and dynamic CR's up and you won't have a worry. I'd use these without a concern if they fit the need.

The longer length will push the pin up but I suspect it will be fine for the rings. What is your planned stroke?
 

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PJ, you didn't happen to take note of the wall thickness of the bushing in the amall ends of those rods, and the overall thickness of the side of the small ends? I'd be curious to know that.
 

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Sorry, never took that measurement. By the way, they come without squirt hole. I believe K1 Technolgies also come without it. Here is a picture from other angle.
425960
 

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These appear to be nothing more than "rebranded" eBay rods that have been available for years. It seems that any outfit with a laser engraver can now be in the racing business. That being said, the technical aspects of using these do represent some gains, regardless of the CR of the piston you choose. Without changing the stroke, the longer rod length will significantly reduce sidewall pressure in the cylinder bore and piston skirt oiling issues. It also smooths out the erratic transition to the roundy-round motion at the rod journal which makes more torque and reduces strain on the rod bolts. This allows lower gearing and ability to turn higher R's. (AKA "turning up the wick"). There are basically two trains of thought for race motors... With proper oiling, you can spin up a small block, or you can stroke the crank and build a bigger engine. Doing both will reduce reliability, especially for a circle track motor that gets hammered twice a lap. If you are worried about low RPM response, you should lighten, knife-edge and rebalance the crankshaft with an aluminum flywheel. Mate it to an S-10 light truck clutch and it should get all that extra HP a little closer to the ground. Be careful what you build, or you will be like me, and have to upgrade the remainder of the running gear as well. Also, big brakes never hurt, but they just slow you down. Have fun.
 

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Sorry, never took that measurement. By the way, they come without squirt hole. I believe K1 Technolgies also come without it. Here is a picture from other angle.
Squirt hole is not critical for an inline four cyl unless you lay it on its side or have a crank scraper with a dry sump system. That is a V-8 thing.
 

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Discussion Starter #9
Not sure about stroke, M.R. I have been reading up on all this. It is all gonna depend on C.R., right? I'd like to get as much displacement as I can.

My block and head are in great shape. I plan to have them surfaced only. And shooting for 10.25:1.
 

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Not sure about stroke, M.R. I have been reading up on all this. It is all gonna depend on C.R., right? I'd like to get as much displacement as I can.
You must have an idea of what size of engine your building right?

Knowing your bore & stroke would seem important before looking at what parts you mite need....
 

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Discussion Starter #11
Haha Absolutely!

97mm bore. Wasn't sure about stroke. A stock 2.2 has a 77.5mm stroke, but I wasn't sure what it would change to going from 128 to 134mm rods.
 

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Stroke doesn't change unless you replace the crank or weld it up to move the rod journals. Extra rod length only changes the compression height of the piston required. You need the deck height of a 2.2 in order to calculate. Centerline of crank to top of bore. Half of stroke plus rod length plus compression height is the formula you need to work with.
 

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So you have a 22E crank ? In that case you will get 2,3 liters with a 97mm bore.
I would have loved to get my hands on a 2.2 crank and build a 97mm bored engine.

As my much as I love my strong reving and sporty 2L, they just don't make strong torque t I'll 3000+ rpms.
 
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As good as forged Opel rods are, the ratio is low. Thats why most Opels cant get out of their own way. No torque. I wish I would have ponied up for a Euro OHC crossflow motor.
 

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Discussion Starter #19
Thanks, y'all. That's why I was confusing myself. I thought the stroke would change with the longer rods.

Now if I could just find a cam that is a happy medium between an OR-77 and OR-99.
 

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As always... Take a look at RB's cam specs discussions. He posted a recipe for a split duration, custom grind that should help you out for a street application. There is power to be made there. I'll see if I can find it and repost a link to it.
 
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