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kevin
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MAR 22, 04:27 PM
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Fellas,
I was wondering how much extra horsepower I can expect to gain by installing roller rockers? Or maybe combining then with 1.6 rocker arms? Has anybody completed this upgrade to a 2.8?
Thanks,
Kevin
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Patrick
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MAR 22, 04:44 PM
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Lots of threads about 1:6 roller rockers here.
I installed them in my Formula. Not really worth the effort/expense performance-wise... unless combined with other mods.
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pmbrunelle
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MAR 22, 05:20 PM
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I'd avoid the Comp Cams Magnum roller-tipped rockers.
Honest Don had problems:
https://www.realfierotech.c...opic.php?f=3&t=21767
So did I, and if you continue reading my thread, it leads to the investigation and the design flaw of the Magnum rockers:
http://www.fiero.nl/forum/F...L/142133-5.html#p165
Before the pivot balls got shredded, I think I had about 4% more air in the 5500-6000 RPM range. That's with a turbo; hard to say if the different would be the same for a naturally aspirated engine.
But a car that runs reliably is more fun, so I installed stock-style stamped steel rockers.
If you want fancy rockers, I suggest going to full-roller rockers. These ones may require the valve covers to be made taller.
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Patrick
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MAR 22, 07:09 PM
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Damn, it's kind of a shock to see that this...
...once looked like that. 
That's a lot of metal to be worn away! I certainly hope that my balls are in better condition. 
| quote | Originally posted by kevin:
I was wondering how much extra horsepower I can expect to gain by installing roller rockers?
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If after all this, you're still considering to be going this route... you'll find some figures in this old thread of mine.
Is there an "ideal" pushrod length for use with 1:6 rockers in a 2.8 engine?
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pmbrunelle
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MAR 22, 08:29 PM
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| quote | Originally posted by Patrick:
That's a lot of metal to be worn away! I certainly hope that my balls are in better condition.
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I find that wearing surfaces kind of follow the life cycle of humans.
Death is likely at birth and in childhood (well, before industrialized country health care), but if the person makes it to late adolescence, he is likely to make it to middle age and beyond.
Towards the end of life, health problems begin to appear, and death occurs rapidly when all the problems feed into each other.
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The hardest part in the life of wearing surfaces is in the initial wear-in. In this initial high-friction phase, it's easy for the friction to cause heat and burn everything up.
However, if during the wear-in the high spots are knocked off without carnage, then the parts will be able to easily rub against each other with little friction. The parts should last a while.
Towards the end of a lifetime of wear, the damage will accumulate until it creates more heat, more damage, and it goes into runaway. Broken!
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Conclusion
If your rockers have made it beyond the first few hours of life, they've likely made it past the the critical wear-in phase and should be fine. So if it ain't broke, don't fix it.
...but not exactly. I found that my rockers were OK for perhaps tens of hours (over a period of maybe two months) of city driving. But the first time I took the Fiero on a 2-hour trip (almost all highway), the continuous high RPM (about 3000) was too much and the rocker balls died.
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Patrick
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MAR 22, 08:48 PM
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| quote | Originally posted by pmbrunelle:
If your rockers have made it beyond the first few hours of life, they've likely made it past the the critical wear-in phase and should be fine.
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I actually bought a used set of CompCam 1:6 roller tipped rollers from a member of this forum. I honestly don't recall whether the balls had grooves or not  , but there was absolutely no indication that the rockers had ever gotten excessively hot. Anyway, they've been in my engine for six years now. The valve train is just as quiet all these years later as it was back then, so I believe the installation to be a success. 
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pmbrunelle
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MAR 22, 09:24 PM
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| quote | Originally posted by Patrick:
I actually bought a used set of CompCam 1:6 roller tipped rollers from a member of this forum.
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Maybe good used Magnum rockers should be worth more than brand-new ones, given that they've proven themselves in service.
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Patrick
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MAR 22, 10:46 PM
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| quote | Originally posted by pmbrunelle:
Maybe good used Magnum rockers should be worth more than brand-new ones, given that they've proven themselves in service.
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My biggest concern when I bought the used roller-tip rockers was whether or not the rocker balls were partnered with their original rocker. I didn't want the rocker/rocker ball pairings to be mixed up after they had already established unique wear patterns with each other.
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PatrickTRoof
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MAR 23, 02:46 PM
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I installed Comp Cams 1.6 roller rockers last summer. Having seen this thread, I'm a little concerned now.
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kevin
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MAR 27, 02:51 PM
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Patrick,
I have read your response (and the other PFF members conditional thoughts) and one particular thought of mine is: SMOG! I live in the heartbeat of where ‘all smog-nazis’ live. By upgrading to 1.6 roller tip valve rocket arms, would the SMOG referees know that my engine was upgraded? If any changer was made to an engine in California, the BAR would not allow your car to be licensed. Thoughts?
kevin
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