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Discussion Starter · #1 ·
Greetings! I'm in need of a set of ej251 connecting rods and it seems that they're rather hard to come by compared to other ej25 models. The ej251 rods are 131.6 mm and the more common versions are 130.5 mm. My question is, if I put in slightly shorter rods would it make any significant difference?
 

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greetings

why are you rebuilding a EJ251 shortblock ?

while they are just laying around all over the place waiting for you to rescue them from the crusher.

....

few = FEW. threads anywhere about ANYONE doing it on a EJ251.
(turbo engines getting their short blocks rebuilt on lots of build threads,....they get abused and rebuilt for speed, )

...but not the good old EJ251.
 

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So do you have any useful information on connecting rod lengths, or just snarky comments?




search ...you might come up with 3 -5 build threads on EJ251/ EJ252 engines on this forum.
 

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Discussion Starter · #6 ·
I've searched every forum I could find but still haven't come across a definitive answer. I'm thinking that a less than 1.5 mm shorter connecting rod shouldn't make that big of a difference. I mean, some pistons have more build-up or wear on them than that and those engines still work O.K. I realize using shorter rods may result in less compression, but they may also provide for more volume. If I do go with the shorter (and cheaper/more readily available) rods, I just want to make sure I'm not asking for trouble down the road.
 

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to look at all the photobucket pics, you will need a browser plug in to work around the photobucket mess.

and @Keyoutback has not signed into this forum for a year.
 

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You cannot use 130.5mm rods in a 131.6mm application.

The 0.9mm makes a considerable difference in compression ratio, squish, and flame propagation. You will also cause undue stress on the cylinder walls and piston due to the "relocated" combustion zone. It will run, but be down on power, higher emissions, and possibly misfire at idle.

You can run 130.5mm rods if you also change the pistons. IIRC, Manley is the only off-the-shelf mfg that offers "flat-top" (high compression) pistons for use with 130.5mm rods.
 

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Discussion Starter · #11 ·
Thanks, RoughDiamond - that's the kind of answer I was hoping for! Well, maybe not hoping for, but it does answer my question in a direct and knowledgeable way. Now I can talk smart if this topic ever comes up again!
 

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If you're looking for a good set of 131.6 rods, I do have some. Somewhat rare as usually the motors I pull apart have atleast 1 rod trashed.

OTOH, brand new rods from Subaru aren't prohibitively expensive... under $100 ea, I think...
 

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Shorter rods, besides decreasing the compression ratio if used with the original pistons as was stated, will also create more load on the cylinder walls and the piston skirts, resulting in increased wear on both. Not desirable at all.
 

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Discussion Starter · #15 ·
RoughDiamond - Could you pm with a cost for the set of rods. Since I'm a newbie here, I'm not allowed to do such things. Many thanks to you and the others for the help.
 

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RoughDiamond - Could you pm with a cost for the set of rods. Since I'm a newbie here, I'm not allowed to do such things. Many thanks to you and the others for the help.
to send a PM back you need 15 total posts....you show 5 now. (its a antispam feature, that admins won't make a easy way to circumvent).

maybe make 10 more short ones on different threads here.

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