Advice on rockers

[Belair348]

Hello,

I've got about 100 miles on my 348 rebuild and this morning I broke two rocker arms. I broke one about 70 miles in, and thought that I'd gotten a bad casting. So that's three in 100 miles, must be something else.
I spoke to the shop that set up the heads and they believe that it's because the rockers I'm using aren't set up (too short a slot) for the amount of lift I have in the cam. I'm only running a 512 lift cam and I'm running stock rockers (show cars).
So three questions, A. does that sound right? B. If A. is correct, does anyone have a supplier for a long slot rocker with 3/8" studs? C. If A is incorrect, any other ideas?
Thanks.

 

[62impala409]

You are going to get a lot of feedback on these crappy aftermarket rockers. They have a high failure rate. Find a set of used stock rockers with balls and everything will be fine again. Leo

 

[tripower]

If you do a search I think you will find that those rocker arms have been an issue. Several members here have had the same issue with breaking the rocker arms. I think the main issue is the ball does not mate up to the rocker properly. Made in China ring a bell. If you can find a good set of used originals you would be better off. I have several sets if your interested.

On a side note in your avatar it looks like you are running a 3X2 set up with the small single air filters. If that is indeed your set up you may want to do some research on those air filters as well. They seem to rob hp and efficacy. Just something to think about.

 

[Last 60]

I believe Show Cars received a bad batch of rockers. A few of us have had that problem. The engine in my '60 was put together I think in '08 or'09 but had very little run time on it till I bought the car in 2010. Within 500 miles I broke three. If you can find a used original set you will be better off. No knock on Show Cars, they were just sent a bad batch of offshore rockers I believe.

Lonnie

 

[tripower]

I believe Show Cars received a bad batch of rockers. A few of us have had that problem. The engine in my '60 was put together I think in '08 or'09 but had very little run time on it till I bought the car in 2010. Within 500 miles I broke three. If you can find a used original set you will be better off. No knock on Show Cars, they were just sent a bad batch of offshore rockers I believe.

Lonnie

Don't quote me on this but I think Show Cars has discontinued those rockers. Here it is post 43.
http://www.348-409.com/forum/index....ts-by-bruce-showcars.19587/page-3#post-167154

 

[Belair348]

Thanks for the info.

OK, I just went out and found the originals. They look OK, some wear, but at over 50 years old, who doesn't have some wear?

What's your thoughts on not having the same ball and rocker combo? 10 of the originals still had the same ball and nut together, the other 5 had fallen out in the bin. Is this a deal breaker?

 

[Belair348]

Dan,

Thanks for the heads up. I'll check into it.

 

[Belair348]

I believe Show Cars received a bad batch of rockers. A few of us have had that problem. The engine in my '60 was put together I think in '08 or'09 but had very little run time on it till I bought the car in 2010. Within 500 miles I broke three. If you can find a used original set you will be better off. No knock on Show Cars, they were just sent a bad batch of offshore rockers I believe.

Lonnie

Lonnie,

That sounds like exactly the time I bought those rockers. This has been a long drawn out process, now made longer..........

Thanks.

 

[jim_ss409]

Thanks for the info.

OK, I just went out and found the originals. They look OK, some wear, but at over 50 years old, who doesn't have some wear?

What's your thoughts on not having the same ball and rocker combo? 10 of the originals still had the same ball and nut together, the other 5 had fallen out in the bin. Is this a deal breaker?

I don't think it'll matter that the rocker parts got mixed up, assuming that they're all the original factory parts.

 

[Last 60]

I agree with Jim, I believe you will be ok with those rockers. Only thing is, you found ten together, and five scrambled. You still need one more or else you will have one unhappy cylinder!!

Lonnie

 

[chuckl]

I believe Show Cars received a bad batch of rockers. A few of us have had that problem. The engine in my '60 was put together I think in '08 or'09 but had very little run time on it till I bought the car in 2010. Within 500 miles I broke three. If you can find a used original set you will be better off. No knock on Show Cars, they were just sent a bad batch of offshore rockers I believe.

Lonnie

I bought a set of Show Cars rockers a several months back for my 61 348 but haven't installed them. In one of the past posts, there was a reference to a number "43" on the bottoms of the bad rockers. Mine have no identification on them. They have a high pitched ring when suspended and tapped with a piece of metal. They ring like stamped steel. Is there any foolproof way of determining if they are a bad set? Can one test the rocker/ball mating surface with dye to check for a mismatch or lap them in with compound. I have the original set as a back up. Thanks, Chuck

 

[oldskydog]

http://www.ebay.com/itm/330746979002?ssPageName=STRK:MEWAX:IT

 

[Belair348]

I agree with Jim, I believe you will be ok with those rockers. Only thing is, you found ten together, and five scrambled. You still need one more or else you will have one unhappy cylinder!!

Lonnie

Lonnie, I had already used one when the first rocker broke.

 

[Last 60]

Then you are good to go!!!!!!!!!!!!!!!!!!!!!!!

Lonnie

 

[johnnyrod]

I broke 2 on my 348. I have a set of old ones thank christ. Very low mileage at that.

 

[61BUBBLE348]

Belair348,

If you look close at where the ball meets the rocker it will probably look fairly ordinary, compare that to your original set, matched or not and the wear pattern will be very even, I believe that the main problems with the inferior aftermarket rockers is the forces put on the mating surfaces of the ball and rocker causing them to fail. best of luck getting it all back together.
cheers

 

[entourageguy]

Well I've broken a few of old ones on my 348. Twice on the same cylinder. Last time I took my dremel tool and worked on the top and bottom of the slot and no trouble since.

 

[62impala409]

Well I've broken a few of old ones on my 348. Twice on the same cylinder. Last time I took my dremel tool and worked on the top and bottom of the slot and no trouble since.

Is this the same cylinder that just wiped a cam lobe?

 

[entourageguy]

Cam lobe was #1 intake . Rockers were #6 exhaust.

 

[johnnyrod]

Thats exactly how mine looked when they broke. I dont remember off hand but I think #6 exhaust was one. I had 2 brake.