I am getting ready to put a set of -1's on my dragster and the rockers are the 1.6 Indys. I have heard these are prone to break. The cam will be .728 lift with the 1.6's and the springs are PSI DR1224's @ 1.975 #275 on the seat and a little over #700 open. The rockers are about a year old with about 25 passes. What is the limit for these rockers?

i think you're there already. with less spring press i've had the adjuster push thru the arm. start looking for something decent now. it's only a matter of time.

Yes, I agree. My opinion, you're already there.

I had that kind of spring pressure with the
blue 1.6 Indy rockers, The ball end of the
pushrods turned blue Very bad oiling!! I had
to grind slots from the shaft oil hole to
the pushrods in the rockers. Bought a little
time. But with that much spring pressure they
are Junk. But Indy won't tell you that.
I switched to T&D and never looked back.I
love them..

Just picked up a set of -1's for my car. A good friend has several hundred passes on his Indy rockers (-1 heads) and has not had one break yet. He runs agressive roller cams and shifts in the 7k range. Never broke one yet.

My engine build is very close to his, with slightly different exhaust timing on the cam. With my luck, I didn't want to chance it. I saved up for a little while and bought Harland Sharps from Dram.

I learned my lesson back when I was running small block Fords. I destroyed 3 engines because of valve train failure.

-Dave

In my experience they're good for about 5 years of racing with those numbers, your spring pressure and lift is VERY close to mine, and i run the 1.6 indy's. I think you'll be fine for a while. I bought 1.6 indys again for ease of install when i broke one on a pass last year, but next time around i'm going to go for t&ds or harland sharps. I'm currently doing some metallography on em to see, but they all break due to fatigue (if you ask around, once one goes, they start to all break successively, and the fracture surface is a typical fatigue fracture), every one i've seen it initiates on the adjuster threads. I could be wrong, but i'm willing to bet they cut tap the threads in instead of roll them, giving a stress concentration and point of failure initiation. If i were you i'd run em for another 150 passes or so then switch to the next level up.

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What is the limit for these rockers?

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do you really want to find out? what else will happen when one fails? lose a money round, lose the engine? imho it's just not worth the agg. been there done that with b1 heads and the "as shipped" rockers. not saying that other rockers don't break or that people haven't used the "as shipped" rockers with some success but normally in the long run the vast majority end up getting a quality set of rockers such a harland sharp, t&d or jesel.

I have some 1.6 Harland Sharps for regular heads now, maybe I can just get a set of intake rockers? How much do they usually cost?

they're not cheap, looks like 67.50 direct from HS. might get them cheaper elsewhere. these for the wife's car?


http://www.harlandsharp.com/bb_mopar_ev_zi.htm

I just sold my Indy's, you can get decent money for them. Put some with it and get some Harlands or T&D's. Jack Moore has a great deal on T&D's, I believe around $1050. And Competition Wedge(I think that was his name) has a good deal on Harlands, around $930 if still available.

Do yourself a favor and buy the best rockers you can afford, Jesel, T&D or Harland's. I lost a motor with 16 passes due to a broken rocker. Block, piston, and a couple of rods all hurt. My

It is not specific to either intakes or exhaust. When you reach a load point and/or fatigue life, it doesnt matter which one it is. The spring pressures are the same, and the offset doesnt seem to really matter. I can show you a bin full of broken ones that were just over stressed. A customer of mine used to run a 451" low deck Indy Maxx with -1's in his S&W digger, and almost exact pressures as you have, just didnt last.Like any rocker, they have there place, but they also have their limits.

Yes you can get intakes only, but as mentioned they arent cheap when you buy them individually. I can certainly help either way with Harland Sharps should you decide to go that route.

Thanks for refreshing my memory. I thought you two were knocking on the 7.99 door last year. In fact, I think I was at the race she ran a 8.01 or so.

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I just sold my Indy's, you can get decent money for them.

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that's what i would do. sell them and put the cash towards a good set. if you could swing it i'd really try to put a whole new set on it. one thing i don't think people are careful enough about with rocker shafts such as the HS shafts are pulling them down evenly. they're hard and don't like to be bent. seen plenty of craks and i attribute it to being bent.