WTB - stock dimension 312 rods made from forged 4340 alloy


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By Jerome - 18 Years Ago
Y-blockers,

I'm looking for a set of forged 4340 steel alloy rods with identical big end, little end and length dimensions as stock 312 ECZ y-block rods.

Thanks.

Jerome

By Glen Henderson - 18 Years Ago
Jerome, I don't think there is a aftermarket forged rod with the stock Y block dimensions. That is why most guys use the Eagle rods that have the 2.100 or 2.00 rod journals. Mummert has the rods and pistons or he can supply the complete stroker kit. I suppose that you could have custom rods made to stock spec's, but you are talking "big bucks".
By Jerome - 18 Years Ago
Glen

I thought I would ask on the remote chance someone made a set.

Jerome

By Ted - 18 Years Ago
Crower can build a rod to the stock Y specs but it's not very cost effective from my standpoint.  The cost of the Crower rods and using a set of commercially available pistons is still quite a bit more than using a 2.100" or 2.000" journal connecting rod and having a set of custom pistons built.  And by using the 2.100" or 2.000" journals, you can take advantage of offset grinding the rod journals for additional stroke.  The 312 crankshaft in my roadster is stretched out to 3.606" stroke by using the 2.000" journal size.
By Jerome - 18 Years Ago
Hmmm,

A 312 rod is 0.872 x 6.252 x 2.3128 x 0.9122 (W x L c-c x BE ID x LE ID) and there are an infinite choice of good 4340 alloy sbc/351W rods 0.940 x 6.250 x 2.325 x 0.927. 

Looks like I could take a set of them (say Eagle CRS6250 B3D's), rebush the LE's to 0.9122", thin the BE's to 0.872", grab a stock set of 312 rod bearings, some shim stock (target 0.006"), hook them up to my existing TRW pistons and have a pretty stout Y-block bottom end.

Seems too easy. What am I missing?

Jerome

By charliemccraney - 18 Years Ago
How will you ensure that the shim stock stays in place?  If it gets loose things will get ugly quick.
By PF Arcand - 18 Years Ago
Jerome: Are you building a racing engine? If not ECZ rods properly prepared should suffice for reasonable use. Another route would be to aquire a set of C1TE 292 truck rods which are the same dimensions as the 312 rods & supposedly somewhat heavier duty. They are the same dimensions because those engines used pistons of different pin heights. They would be found in medium duty earler trucks or Buses, up to F 600 or so. Someone else may be able to clarify what years and models.  
By Jerome - 18 Years Ago
Good points,

I don't race but want my 312 6500 rpm capable. My ECZ rods are all that's in the way. BTW, I have a set of resized C1TE's if anyone is interested. 

On the shim approach, if the bearing shell's properly compressed initially and if the rod journal's sufficiently strong - it should work. Still, I'll avoid shims if I can come up with bearing shells the right thickness. I won't know that until tear down next summer.

Jerome

By Hoosier Hurricane - 18 Years Ago
Jerome:

You can avoid the shims by using rods for large journal sbc and grinding the crank throws to 2.100.  Still have to narrow the big end, possibly narrow the sbc rod bearings, and you can avoid rebushing the small end by honing the piston pin bores to .927.

John

By PF Arcand - 18 Years Ago
Jerome; It's your call, but you have me a bit puzzled. Your engine isn't for racing but you are going to the trouble & expense for 6500 rpm capable rods. What cam & trans are you planning on using?  And I hope you haven't been taken in by all the bull spread around by the Chebie crowd, about how all their engines are good for 7000 rpm! I hung around Oval tracks for years & I can tell you that in the 60s & 70s, scrap yards had no shortages of SBCs that had been run repeatedy to those rpms. Just for info, John Mummert lists 4 performance cams for our engines & only the most radical street/strip one is good for 6500 rpm. And it requires shortened valve guides (not the best idea for street) & a piston to valve clearance check & possible reliefs in the block.. Just food for thought.. -Paul            
By Jerome - 18 Years Ago
Paul,

I sent you an email with the info you were curious about. Was wondering if you had a chance to look at it.

Jerome 

By PF Arcand - 18 Years Ago
Jerome; My comment & the question was somewhat retorical (if that's the right term). No, I did not get your e-mail, as far as I know my address isn't available. I get enought junk mail as it is. ( I'm not however suggesting that your info was junk.) However, a P.M. may be available on this site..can't remember.. I'm not a computer wizz by the longest stretch. Thanks.   
By Jerome - 17 Years Ago
Paul,

It would be under your "Messages" tab at this Forum. 

Jerome