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Discussion Starter · #1 ·
I'm starting a thread on roller rocker arms.

I gather that there are no off the shelf rocker arms. Looking at the posts in the forums it looks like an off the shelf rocker arm could be modified. Could someone detail what off the shelf roller rocker will work and how to modify them for the CIH engines???
 

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the man to talk to is Rally Bob, but i don't know if he's visiting this site anymore. try classicopel group on yahoo to find him. He made some in the past...i don't know if they work a spinoff of anything already out there or made from scratch. I know they were expensive though.
 

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There is really no way to modify existing roller rocker arms for Opels. That's why they have always been custom made. The recent effort to so roller cams with roller rocker arms seems to have turned sour.

I would consider producing a batch of roller rocker arms if I could get together a group buy. I am guestimating that it would take a minimum of 10 sets to get the cost down to merely unreasonable. Email me [email protected] or post here if you are interested.
 

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group buy

I would be intereted this fall if you can get the price reasonable...say under $1000 (less is always better, shoe string budget between opel parts and mac and cheese). This would be a great addition to the 2.4 I've got coming. Also, i need a little bit of reassurance that I will actually GET the part, like you mentioned the order turned 'sour'. Come on guys lets get a bunch of people in on this.
 

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I understand everyone's reservations after the previous "deal" went sour. Hopefully I can assure you that that if we go foreword with this, you will get your parts. First, I have been doing Opel stuff for many years…Opels are still my passion… so, this is not a one-time thing for me. Second, I have worked very hard to be sure that my reputation with my customers… before, during, and after the sale… stands for quality, integrity and performance. Third, I won't accept any money from anyone until I get a "firm deal".

Cost??? This is going to depend on how many we order. After I posted this I got an email from Rally Bob (good to see he's still watching us). He cautioned me on the real costs and how much can be saved with a quantity buy. For now a wild guess for a low quantity will be $800 for the complete set (roller rocker, lifters, studs, lock nuts, valve cover spacer, etc.) Based on Rally Bobs input, if we can get 40-50 sets, then the price could be half of that… but I seriously doubt that we will get that large of an order. So figure on $800 and we'll hope for less.
 

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What about a roller cam, can we get a package deal to have everything roller in our engine (yum yum)? Cams were discussed heavily in the thread that gary pointed out. If so, what profiles could we opt for. Again, my goal is to have a 'street-killer' with decent high end power. I think the best bet would be to start up a roller cam group buy thread....that would get more attention and make things a little more organized.

....as a side note, *rally-bob* or anyone else, have you gotten your roller setup working, and what do you think of it (especially in a cih engine)? I know that in a few chevy engines and some rice engines that I've put together with my firends roller setups really changed the way the power came in, but if done properly can be quite nice!
 

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The problem with a roller cam is that it drives up the cost... and the higher the cost, the fewer people who will be interested... and the higher the cost. Also, I KNOW that I can deliver on the roller rocker arms. So far, there's no reliable supplier for the roller lifters/cams. So, for now, I'm going to "tip toe" around that snake pit. If it turns out that there is sufficient interest in roller lifters/roller cam, then maybe I'll change my mind.
 

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I'm not sure on a 90 HP motor, but I think the results are even better than that. We got about 12 rear wheel HP on a 145 HP engine. Now this may be a little miss leading because the engine we tested on didn't do much below 5000 RPM and made peak HP around 6500 RPM... The roller rocker arms will have more affect as the revs go up.

Probably more important than the HP gain is the reliability gain. In the stock valve train, the stamped steel rocker arm is the weak link. In our ITB race engines (where we are required to run the stock rocker arms) we recommend that you replace the rocker arms after every 12 racing hours. These engines only rev up to stock red-line but they will break the rocker arms if they are not replaced often.

With a high lift cam, and stiffer valve springs the roller rocker arms are the only way to go. In our F-Production race engine that revs to 7750 RPM for every shift, we have never had a roller rocker arm failure... using the same set of roller rockers... over the racing life of 4 engines.
 

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FWIW, the push rod style roller rockers from Cat Cams(Crane) are supposedly available again. I don't know where to get them so you'll need to track that down yourself if you're interested.

-Travis
 

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I guess this depends on how many people want this. If I can do a large enough buy the optimum way to go is to get custom lifters... the lighter the better. But the quantity needs to be really up there to keep the cost down to mere "unreasonable".

The modified hydraulic lifters functioned OK, but they were heave... especially after they filled up with oil.

I don't like the old Crane solution with a small push rod, but lash caps over the stock lifters may be an option. I'm just concerned that at high revs a lash cap or a push rod would get "spit" out.

A last option I am working on would be similar to the stock rocker arm... with a little slider ball built into the rocker arm, That way we would use stock solid lifters.

All of this said, I am not getting the response I expected. So far only two people who are interested. I estimate that 50% will "fall out" so that's only me and one other. I'm not going to invest $20K + to stock them... I can't carve them up and eat them for dinner. So if anyone is interested this has to be a group buy.

I'm going to give this another week or 10 days. After that, I'll be buying what I need. For those who want these no mater what (like me) I am guestimating that the price will be around $1500 per set if I only order a few sets.
 

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Discussion Starter · #17 ·
I was interested in roller rockers because of there reliability. I hoped to put some parts together to for a higher performance street engine. Looks like for right now roller rockers are out of my league.

What is likely to cause cracked rockers? Over reving or valve pressures? Or ???

I’m not sure what kind of valves and springs are in there. Might be small block Chevy stuff.
I have not removed the head from the block yet...

Garry
 

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garrymc said:
What is likely to cause cracked rockers? Over reving or valve pressures?
Both over revving and high valve pressure will accelerate the life of rocker arms. My guess would be that the cracks are caused by metal fatigue. How long had the rockers been used with those springs and the current camshaft? If it's been a while, it's almost definately metal fatigue.

There is lots of great info on the 'net about metal fatique. Google is your friend:)

In short, metal fatigue starts in stress concentrations on the surface of the rocker as a small crack. These stress concentratiions are usually surface imperfections from the manufacturing process. This combined with the cycling of the part causes the crack to grow until eventually you end up with complete failure of the part. You've obviously caught it before this stage. Shot peening can go a long way to help prevent this. It essentially removes the manufacturing imperfections from the surface and their associated stress concentrations. There's lots of great info on the 'net about shot peening as well, which will explain it much better than I ever could....

-Travis
 

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This (cracks or even break) is going to happen regularly. Even our ITB engines which are required to use stock valves and valve springs will do this with about a season of racing (about 30 hours)... so we throw away a set a couple of times a season.

Another cause of what you are seeing is too much lift. The rockers will only pivot just so far until the rocker studs hit the ends of the slot in the rockers. Take a look and see if that might be the problem.

About shot peening... where rules allow we have every stressed part shot peened. A word of caution. There are very few places where you can get something shot peened properly. A guy with a sand blaster filled with "shot" is going to do more damage than good. Some machine shops also try to pass off high pressure bead blasting as shot peening... it is not... but at least it does no harm and makes things pretty. I use a place that is aerospace certified for both the government and the FAA. They are also USAC certified. So find a place that does this kind of work and you'll be OK.
 
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