Adding Bronze Bushings to Ductile Iron Rockers

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JedIEG said:
Just wondering- has anyone added bronze bushings to as set of un-bushed ductile iron W2 rockers? Mostly I'm wondering if there is enough meat in the casting to ream out for bushings or if the bushed and un-bushed castings are different.
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I would say go for it. Lots of meat on those W2 iron rockers.
 
This thread is helpful because it shows the difference between opinions based on theory and outcomes based on empirical experience.

Clearly the iron rockers can be safely bushed. Nice to know about this option.
 
Thanks for all the discussion around this. I've beed out of commission getting a tooth pulled and had not been able to check the thread. The pictures of the bushed and un bushed rockers are gold. That tells me 90% of what I needed to know. My biggest stumbling block now is cost- at $16-18 per rocker for bushings plus the set needs adjusters, I'm looking at well over $1000. At that point, I might bebetter off looking for a new set.
 
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Guess it depends on how much they are costing you. $1000 is indeed pricey.
 
JedIEG said:
Thanks for all the discussion around this. I've beed out of commission getting a tooth pulled and had not been able to check the thread. The pictures of the bushed and un bushed rockers are gold. That tells me 90% of what I needed to know. My biggest stumbling block now is cost- at $16-18 per rocker for bushings plus the set needs adjusters, I'm looking at well over $1000. At that point, I might bebetter off looking for a new set.
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Be careful making your decision on what to buy new. There will be FEW offerings as strong as the stock ductile iron rockers. The Comp rockers come to mind.....but NOBODY's aluminum rocker.
 
JedIEG said:
My biggest stumbling block now is cost- at $16-18 per rocker for bushings plus the set needs adjusters, I'm looking at well over $1000. At that point, I might bebetter off looking for a new set.
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Is that the quote they gave you?
 
I’m guessing some of you guys wouldn’t have ran these rockers unbushed running .695 mushroom lifter cams like we did 40 years ago. The rpm we turned with stock cranks and rods would have you guys searching for spare underwear.
 
I don't know what guys are making their rockers out of.

But ductile iron has yield strength around 40000 psi.
7075 aluminum is 55000 psi+
Now if it's being made from 6061, that's much weaker than iron.
 
pittsburghracer said:
I’m guessing some of you guys wouldn’t have ran these rockers unbushed running .695 mushroom lifter cams like we did 40 years ago. The rpm we turned with stock cranks and rods would have you guys searching for spare underwear.
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Yep. Properly set up engines can deal with a lot of abuse!
 
A couple more pictures of the ductile iron W2 rockers. Note thickness of these castings. Plenty of room for the thin bushing. With the bushing, any wear and you replace and hone the bushing to size. Also look at the reinforce on the nose how it extends the width into the body and the truss on the top. Stout.

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Mean416 said:
I don't know what guys are making their rockers out of.

But ductile iron has yield strength around 40000 psi.
7075 aluminum is 55000 psi+
Now if it's being made from 6061, that's much weaker than iron.
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40ksi is a min, but it can be specified as high as 90ksi. No clue what grade Chrysler used though.
 
pittsburghracer said:
I’m guessing some of you guys wouldn’t have ran these rockers unbushed running .695 mushroom lifter cams like we did 40 years ago. The rpm we turned with stock cranks and rods would have you guys searching for spare underwear.
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Yeah, but doing it 40 years ago yourself and recommending someone else do it with their own money are two different things.
 
Yeah, look at the bushed rocker in the lower pic in Post #16....& the unbushed rocker in post #35. Which one do you think will break first?
Maybe Chrys knew something because they didn't bother to bush the W2 rockers....
 
pittsburghracer said:
I’m guessing some of you guys wouldn’t have ran these rockers unbushed running .695 mushroom lifter cams like we did 40 years ago. The rpm we turned with stock cranks and rods would have you guys searching for spare underwear.
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My 340 street cast crank motor with solid cam and unbushed rockers had more R's coming out it than a pirates mouth. Ported J Heads 202-160 and Strip Dom intake and it had a small shot of NOS from a lot I got at Super Shops. I did have good pistons and the right ring gaps going for it.
 
Rocket said:
A couple more pictures of the ductile iron W2 rockers. Note thickness of these castings. Plenty of room for the thin bushing. With the bushing, any wear and you replace and hone the bushing to size. Also look at the reinforce on the nose how it extends the width into the body and the truss on the top. Stout.

View attachment 1716210587

View attachment 1716210588
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Yep that's indeed very stout. I'd run those in a heartbeat and I wouldn't think twice about offset bushing them to 1.6.
 
autoxcuda said:
And still most of the original used ductile rockers you find are scored on the bottom.
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I have only seen a few that were scored on the bottom, and I have seen a lot. Most OEM 273 unbushed rockers look almost like new unless run low on oil. I have some with 400,000 miles on them and still working fine. No spring pressures above 300 psi. The same goes for early Hemi and Max Wedge rockers. The major wear point appear to be the tips that meet the valve stem. I can also recommend RAU to bush rockers. They also hard chrome the shafts to bring them back to specs.
 
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I recently had a failure on a bronze bushed aftermarket Crane iron BB rocker on the dyno. Half of the bushing came out and tied up the rocker which in turn caused the lash cap to spit out. Luckily we caught it right away and was able to replace the rocker and finish dynoing. I have been looking for a couple replacements since with no luck as Crane is out of business. Last Saturday I stopped by a friends shop who races SuperStock and low and behold he had a set of factory stock non bushed rockers that I bought from him on the spot. My car is just a street car and will not see anything over 6500 rpms.
 
I've been running bushed ductile iron rockers for over 5 decades and have never had one fail. Some of the non bushed rockers I've picked up are galled and the simple fix was to have bushings installed.
 
What are they currently charging per rocker arm these days?
 
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