D series rod FACTS!

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isthisnameok4u

New Member
This seems to be common knowledge now but since I have a little collection growing I thought I should share it with pictures to back it up. First off yes b18 rods will fit in the d16/d17 engines ( and the d15b) but they have to be machined because the big end that connects to the crank in .044" too wide. After it is shaved down it will bolt to a d16/d17 crank with d16/d17 rod bearings. The piston pin is larger on the b18's so a special bushing must be used. With the cost of machine work to shave down the rods to fit, we are dropping a bit of money on "stock" rods. Is there another option?........yes
 
My measurments are for comparison only( it's hard to hold a camera and measure at the same time). This will give you a rough idea to look at before you go spending needlessly. First up the d16y8 block I'm using. These are stock p2p rods and pistons
rod length=137mm
rod journal (crank)=48mm
rod journal (piston)=19mm
rod width (horizontal)=15.3mm
rod width (vertical)=11.2mm
 

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This is a set of rods and pistons (PG6) out of a '86 integra d16a1engine

rod length=137mm
rod journal (crank)=48mm
rod journal (piston)=19mm
rod width (horizontal)18.1mm
rod width (vertical) 14.3mm
 

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This is a set of rods and pistons (pr4) from a '01 integra b18b1 engine

rod length=137mm
rod journal (crank)=48mm
rod journal (piston)=21mm
rod width (horizontal)=20.2mm
rod width (vertical)=11.6mm
 

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This is a side by side comparison of all three.
 

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Ok so what? they are all still stock rods. Well in some race classes like NASA Honda Challenge all parts have to be oem. You can mix and match with any engine and any domestic market including Japan and Euro spec parts as long as Honda made it, you can use it. This makes for some interesting combos for the d series single cams. We know the LS rods are good to 300hp but look at those d16a1 rods. They might be a little skinny next to the LS ones but they are wider. Both rods shadow the puiny little d16y8 rods and those are supose to be good up to 200hp. I figure the d16a1 rods should be somewhere close to LS rods, with NO machine work! The d16a1 pistons will give me 12:1 compression with no need to swap rods and send everything in to the machine shop. I will still need to balance the crank with the different rod/piston combo but I save a whole lot of time and money. My high compression N.A. engine won't be making more than 250hp so I think this is the best bang for your buck.
 
i don't think that answers anything about rods - to me, some other questions would come to mind - the 86-87 D6A1 rods are beefier, but are they stronger? are the made from the same material as the other rods? they are also a lot heavier, and heavier is not good when talking rotating mass - did Honda go to a better and stronger material with the 88 and up rods in order to make them lighter and just as strong (or stronger) while at the same time making them smaller? going with the 86-87 D16A1 rods because the "look" stronger may turn out to be a fatal mistake - who knows?
 
That's a good point jlicrx; as the ITR rods are known to have a slightly different composition that makes them slightly lighter than GSR rods while just as strong, if not stronger. It's entirely possible that their manufacturing process changed.

Best way to find out is to analyze the grain structure and composition; or simply dig through any available Honda information regarding the "new D-series"

Good information on the physical features though.
 
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yeah, logically to me, it wouldn't make sense that the Honda engineers would just decide that the D16A1 rods were too heavy, or whatever, and then just make them smaller without thinking about the strength - i am pretty sure that they wouldn't want to use a rod that was obviously weaker by making them smaller

the information on the physical features is good to have for reference - i would point out that most all (but not totally all) of the D16 engines from 88 up use the same rod which is Honda part no. 13210-PM6-000 - true for D16A6, D16Z6, D16Y8, 88-89 D16A1, JDM SOHC and DOHC ZCs
 
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all good inputs. my goal was just to show a cheaper option to the ls rods. my build is less than $400 and all parts are oem

the ls rods are wider at the base with big shoulders above the big end(crank) where the strength is needed that's why they are lighter and stronger at the same time.

as far as composition they are all forged steel, with slight differance in alloy but not as much a differance as the type r's

d16a1 rods are just a happy medium stronger than sinlge cam engines and just a little weaker than ls for much less $
 
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Forged my friend

Good info and pictures. :thumbsup:

But they're all cast from the factory.


The facotry rod are forged. Look at the picture with the rods on thier side and you can see the raised wide die mark that runs up the side. On cast rods (cranks too) there is a sharp parting line. These bad boys are FORGED cause Honda is cool like that.
 
Um ok. You're the first person I've ever heard say that the factory rods are forged. Tell ya what- I'll go hit my contact in Honda engineering and find out for sure. :)
 
And you are absolutely RIGHT! They're forged- which doesn't necessarily mean anything for strength vs other rods, but they are forged.
 
yeah I still don't know for sure the exact limits of the d16a1 rods. The shape and design have more effect on strengh than size, but I'm willing to risk it. My build is under 250hp and low rpm (less than 8k) The d16a1 were rated at 130hp same as the ls motors so they should be good over 200hp. I just dont trust the y8 rods.

FYI
d16a1 made in Japan
d16y8 made in USA
just sayin is all......lol
 
Well, country of manufacture has little to do with it too- it's all up to the manufacturer's controls on their process and materials selection. :)

I think you'll be fine under 250hp with good tuning though!
 
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