Contour Enthusiasts Group Archives Forums Modifications Forced Induction Rod tolerance

Does anyone know the thresh hold of pain that a 2.5 rod can take before it goes? Has anyone ever had one go? Thanks.

I'm VERY curious as to the response on this. I heard 300 crank HP was the limit. However the cougar eliminator ws 290 crank hp and it used STOCK rods, just low CR pistons, that seems dangerously close for something built by SVT/Roush.

Terry any words of wisdom? And since you were involved with the design of the streetflight TC kit and the kit was designed to work on stock engines, can you assure buyers that upgraded rods won't be needed? Thanks!

Ever S/C contour is running over 300 crank power so I'm sure it's higher than that. I also would think that the upgraded DMD would help keep everything in line.

Yeah I'm starting to wonder how tough they are. Here are some specs I found on them:

CONNECTING ROD
Piston Pin Bore Diameter=21.017-21.032mm (0.827-0.828in)
Crankshaft Bearing Bore Diameter=53.015-53.035mm (2.0872-2.0879in)
Length (Center to Center)=138.06-138.4mm (5.435-5.448in)
Twist = 0.050mm per 25 (0.0019 per 0.984in)
Band = 0.038mm per 25 (0.0014 per 0.984in)
Standard = 0.100-0.30mm (0.0039-0.0118in)
Service Limit = 0.35mm Max (0.0137in)

They probably don't mean much for strength but might be good knowledge for some people. Also we should see if buckshot77 can comment on the differnces between his forged Cunningham rods vs stockers.

According to Mr. Haines (forgive me Terry if my memory butchers this) under some testing they had con rods begin failing around 280 crank hp.

Originally posted by kinger:

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Also we should see if buckshot77 can comment on the differnces between his forged Cunningham rods vs stockers.

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Different material processing for one. The stock rods are sinter forged, which is an easy metal to break once you go above it's rated stress point vs. "normal" forging methods. Sinter forgings can not be shot peened either or the "skin" of the metal will be compromised, leeding to unit failure. The Cunningham rods that Buckshot has are a bit beefier around the piston pin location as well as through the middle.

Damn i wish I could afford $1000 for new rods

Any chance in h-e-double hockey sticks we could get a mass GB for set down to like $500 for a set?

OR Terry is there anything in the UK that is a Ford part that we could use that is beefier, ie from mondeo, cosworth, etc?

Originally posted by kinger:

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OR Terry is there anything in the UK that is a Ford part that we could use that is beefier, ie from mondeo, cosworth, etc?

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Just a thought..the 3L taurus I think uses same rods as 2.5L but how about the 3L 240 HP JagV6? How about rods from 3.4L SHO V8..same bore & stroke as 2.5L. anyone?

Now were cookn' anybody have access to the specs on these that can share? Thanks!

I'll be buying some rods from Cunningham for my 3.0 LS in the next couple weeks. I'm just waiting for Terry to checkout the specs on the LS rods to make sure they are the same as buckshot's. I'd be in for any kind of group buy.

Josh