 rocker arms, need your input |
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| bernbomb914 |
 Jan 7 2005, 07:55 PM
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#1
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one of the oldest Farts on this board  Group: Benefactors Posts: 1,873 Joined: 29-December 02 From: Temecula, CA Member No.: 36   |
Has anyone used 1.5 lift rocker arms? are they any better. I have a .475 lift cam now. but was told to put in these rocker arms (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)
Bernie |
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| Jake Raby |
Jan 7 2005, 09:08 PM
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#2
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Do a search...
They are good if you like failures and incompatibilites.. I know of ONLY 4 cams that have the correct ramp rates for these rockers to function correctly... Stock 1.7 rockers with 911 adjusters is impossible to beat.... I have seen many dead engines killed ONLY because of the rockers.... They are made for race engines, and street engines really suffer from oiling issues with these rockers- especially the valve guides.. Ask Charles from LN about how expensive they can be when they cause a failure! |
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| Aaron Cox |
Jan 7 2005, 09:28 PM
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#3
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
whats so great about the 1.7 w/ swivels vs the 2.0 w/ swivels?
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| bernbomb914 |
Jan 7 2005, 10:18 PM
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#4
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one of the oldest Farts on this board Group: Benefactors Posts: 1,873 Joined: 29-December 02 From: Temecula, CA Member No.: 36 |
Thanks Jake that is what I thought. I have the 1.7s with swivel feet so I will keep them.
Bernie |
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| Jake Raby |
Jan 7 2005, 10:45 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
(1) They are forged and incredibly strong
(2) Due to this they can be drastically lightened if you want more revs and lighter valve mass (3) They are self oilers meaning that the oil that travels up the pushrod lubes the rocker shaft, adjuster and the valve guide (4) Better lube in the guides means less friction and less heat- Thus cooler heads with guides that last longer (5) For over 20 years the ratio rockers were not available. Due to this many cams were designed to use stock ratio rockers, including ALL BUT ONE of the web grinds that are catalogged! Having a camshaft with an incorrect ramp rate can acelerate valve events to the point that valves simply snap off from velocity- We see that alot with incorrectly mapped valve train arrangements. When it happens kiss the entire engine good bye. (6) Higher ratios may gain MORE valve lift with the same given amount oc lobe lift, BUT they drawback is increased tension being placed on everything downstream of the rocker shaft centerline. For instance a stock ratio rocker may put X amount of stress on a pushrod, lifter and cam lobe but when the ratio changes and the pushrod moves closer to the rocker centerline the amount of stress placed on these items is multiplied by the added ratio. This makes for pushrods that deflect, and lifters and cams that wear even more (7) NOBODY did it like VW!! we run stock rockers lightened up to 18 grams each to near 9,000 RPM and make 100HP per liter with them.... Ratio rockers are eye candy at this point. We were working on some that would actually work but it was so expensive we could never sell them... Stick with stock, its all we use as a general rule.. |
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| Dave_Darling |
Jan 7 2005, 10:47 PM
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#6
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914 Idiot Group: Members Posts: 14,981 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California 
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The 2.0 rocker arms don't fit the 911 swivel-foot adjusters. The threaded hole is too large. There may be some aftermarket ones that work, but the quality of the aftermarket swivel-foot adjusters is almost universally lousy. The 1.7 rockers with real 911 adjusters seem to be the safest way to go if you want an improvement over stock. --DD |
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| 914werke |
Jan 7 2005, 11:12 PM
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#7
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"I got blisters on me fingers" Group: Members Posts: 10,027 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest
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Jake what happend to the roller setup you were talking about ? same story (give up too expensive?)
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| Jake Raby |
Jan 7 2005, 11:42 PM
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#8
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Those were roller LIFTER, not rockers.. Totally different ... You can see those at www.aircooledtechnology.com/research.htm
They are being tested as we speak in two engines and my spintron.. |
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