On center vs Off center rods

[Eticket]

I've never seen Off center rods advertised used.. What do most guys do? buy custom mades?

What modifications need to be made with on center rods to work with off center motor? Custom piston only? Rod and piston changes?

Thanks

 

[qwknuf6]

Off center rods are for off center eng's.stock eng's are off center. earlie stage 2 eng were off center , but most of the stage 2's out there are on center , On center blocks were shifted just for the purpose of centering the rod to the rod journal .Off center rods are hard to find but they are out there , carrillo will make you some for 1200.00 and take about 4 to 6 months

 

[TurboTR]

Last I checked Cariilo had a few sets of off centers on the shelf I believe.

TurboTR

 

[EightSecV6]

I can convert on center rods to fit off center engines at rate of $25 per rod.
Thanks,
Bill Anderson

 

[KendallF]

Originally posted by EightSecV6
I can convert on center rods to fit off center engines at rate of $25 per rod.
Thanks,
Bill Anderson

Bill,

Do you narrow the pin end to achieve the offset, or how is this done? How do they hold up? I'm just curious...

Thanks,

 

[LikeMy6]

To my knowledge one side of the rod is milled about .100 to achieve clearance that would include both the small&Big end,a good example is the pictures on gnttype.org you can clearly see one side of the stock rod is machined more into the beam than the other. so my guess is a set of steel on center rods machined the same way would fit just fine. but Bill is the expert maybe he will be willing to explain.

 

[norbs]

This is what an on-center rod looks in an offcenter motor

 

[Ron Tarabori]

Rods

OK Bill whats your secret. Yes milling one side of the rod to center it up sounds just fine except now instead of having .005 side clearance you have a about .105. Back in my budget days I ran an offset motor and needed one more offset rod so I threw in and on center rod and just ground some extra clearance on the piston boss. Not what I would recomend but it stayed together.

 

[EightSecV6]

Side clearance is not determined by the small end of the rod, you cannot take any material off the big end as the bearings will not fit. Careful machining is required and reliability is not sacrificed.

 

[Ron Tarabori]

Rods

OK I see now. I was talking big end and you just modify the small end so the rod is still actually off you just modify the small end for clearance on the piston boss. Right!

 

[EightSecV6]

That is correct Ron

 

[9SECVSIX]

Bill, What's your opinion on using the Ruggles style bushing between the small end of the rod and the piston boss?
Am trying to get a Stg11 short block togeather for a friend, it's a off center block and we have a set of on center rods, should be try to swap them for off centers or just modify the small end of the on center rod to clear the piston boss, in this application would the on center rod put anymore of a side load on the piston?

Thanks

 

[EightSecV6]

I am not familiar with a Ruggles bushing, obviously the best way to handle this is to get an off center rod, but they are all but gone.I wouldnt cut any off the piston boss, the small end of the rod will suffice, you may need to mill some under the dish where it is blended into the pin boss area. The rod will be side loaded somewhat in the pin area and you will have less surface area because the rod has been milled on one side, but remember on an off center rod the bearing is side loaded and when you really lean on an off center rod, the side loading of the bearing is obvious upon teardown. I have not seen this when using an on center rod in an off center block, therefore I believe reliability is not compromised.
Bill

 

[Louie L.]

Bringing this topic back up!

Bill,
In tearing down off center motor with on center rods, Have you seen any signs of pistons side loading in the bore? Any abnormal bore, piston skirt wear? Is any strenght or durabilty compromised above that of a dedicated off center rod?

With knowledge of how hard off center rods are to find, im looking into building an off center early block. Just trying to gather ideas if this is the way to go.
Thanks
Louie

 

[EightSecV6]

No evidence of abnormal wear, the only strength that would be comprimised is the pin area on the rod because it is now a thinner width. I have not seen this as a problem.
Bill