China Syndrome !!!!

[61BUBBLE348]

Well I posted recently that I took the 61' on an interstate trip about 1000 miles total, and was really pleased, the car drove and handled really good with plenty of low down torque for the hills to feel nearly like flat open roads. More importantly no mechanical problems.

Last weekend the family and myself went on a Saturday night cruise, 400 plus American cars and some quite rare, like a 67' Dodge Coronet 426 Dual Quad Hemi with 727, any way I am diverging, about half way to the starting point the Bel Air starts running on 7, WTF, I have done about 2000 miles trouble free now this. I finished the cruise and put the 61' in the shed.

Due to family issues, mainly a 50th birthday party for my wife, too drunk to work on the car last weekend, I finally pulled the hood this morning. I had a gut feeling that I had bent a push rod, popped a rocker stud or broken a rocker. Well after removing the rocker cover, sure enough a broken rocker.

I had read about this on the forum, and was aware that I should purchase good quality rockers, I thought I did, Elgins from Show Cars. What a bummer, luckily I still had a set of worn originals.

I did a quick change over and now its happy again, literally took me 25 minutes start to finish.

I know this has been covered before, but is there a supplier of good quality stamped rockers ? I hope so.

cheers

 

[poison ivy]

i have found no replacement for stock stamped...orig the best..i send mine thru my tumbler...no,no failures... ..big cam elong the slot for clearance.. also tested some replacements, broke after 5 min on dyno...pi

 

[1960impala283]

Well that sucks. Crap like that turns you off the supplier as much as the brand. I wonder about the quality of the other offerings. Anyone have problem with the valves from SC?

So you are saying keep all the worn original rockers and reuse them? Wow, I have never done that before.

 

[Don Jacks]

I was talking with Ronnie Thompson,and he said he's never had a problem with the inexpensive valves on even his race motors.From what I've learned here,my little 380 will use roller rockers only,since I dont want the extra friction that comes with the stock type rockers,and the replacement ones are junk.I'm planning on a service life of at least 100,000 miles,even with boost.

 

[oil4kids]

just use the pedestal roller rockers from Lamar walden, unbreakable

 

[1960impala283]

I put screw in studs on my 333 heads, so I could use roller rockers on them, but I didn't on my 817. I understand from here that you shouldn't put roller rockers on the factory studs. I guess I am stuck with factory type on the 60 unless I pull the heads.

I've used the SC valves in both motors. The one motor will get civil driving duty, and I am hoping they should be fine. I am glad to hear that the valve are standing up to racing duty, my other motor is going to get abused.

 

[chuckl]

I put screw in studs on my 333 heads, so I could use roller rockers on them, but I didn't on my 817. I understand from here that you shouldn't put roller rockers on the factory studs. I guess I am stuck with factory type on the 60 unless I pull the heads.

I've used the SC valves in both motors. The one motor will get civil driving duty, and I am hoping they should be fine. I am glad to hear that the valve are standing up to racing duty, my other motor is going to get abused.

 

[chuckl]

Just bought a set of new Elgin rockers for my 348. Any problems with these? The motor will not be abused.

 

[chuckl]

Well I posted recently that I took the 61' on an interstate trip about 1000 miles total

Did the other rockers of the same Elgin set show any indications of possible failure?

 

[tripower]

In my case the expense to build one of these engines I think it is good insurance to spend the extra for quality rockers. I did machine my heads, 1147 castings, for 7/16" screw in studs and used the BBC 1.7 Ultra Pro Magnum Rockers. At the time I think I paid 260.00 including shipping from Race Mart. With that said my engine runs up to 6500.

 

[1958 delivery]

Seems to me that broken rockers/studs and studs pulling out has always been a problem with the W. I would think this is definitely one area that the best available is a must.

 

[Don Jacks]

I agree with Dan,and 58 Delivery here.At the cost of building ,and the decreasing availability of cores,it makes good sense to put good parts in even a stock rebuild.

 

[61BUBBLE348]

Hi Chuck, to be fair all I have done is replaced the broken rocker.

I am going on a Rod Run on the weekend, 4-500 miles round trip, If I break another I will spend a couple of hours and replace them all.

I did inspect the other 7 rockers on the side the failed one was on, all looked OK,

 

[models916]

I know in the old days we would switch the exhaust rockers to the intake side. Some old guy told me the exhaust valve would harden the rocker quicker and to get them both seasoned quickly just switch them. Not sure is that was true, but never had a problem. Was that broken rocker an intake? Maybe there is something to it?

 

[1960impala283]

Hope the rod run goes well. Hard to believe that putting a rocker or two in the tool kit is necessary. Give us an update.

 

[Phil Reed]

I will not use a new stamped stock rocker for this very reason.
I use old original GM rockers that are still good. I had a set of new rockers fail in an engine over 15 years ago.

 

[Clyde Waldo]

I will not use a new stamped stock rocker .....................

I am not a mechanical engineer but from what little that I know that failed rocker arm looks to me like a "cast" rocker arm not a "stamped" rocker arm. ??????????

 

[cac646]

Definately a brittle fracture. This defiantely happens with cast materials but can also happen with high strength steels. Should be fairly evident if you look really closely where the fracture initiated. Possibly an inclusion in the steel or a stress riser like the hole.

 

[Phil Reed]

Clyde............I apologize............they are cast rockers instead of stamped.

 

[Clyde Waldo]

No apoligy necessary Phil - I just wanted someone to verify what I suspected from the photos of the failure that those rockers are castings.