Author Topic: 1.6 roller rockers  (Read 4294 times)

Offline SUX2BU99

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1.6 roller rockers
« on: March 19, 2008, 12:37:27 PM »
So I was planning on getting some nice aluminum 1.6 roller rockers for when I do the cam and head swap on my 350. Are there any downsides to using 1.6 vs. 1.5? I was thinking it would be a good way to give a litte 15-20 HP boost with the larger lift. My truck has stamped roller-tip rockers right now of unknown ratio. I've seen on Ebay sets of 1.6 alum. rollers for about $100. Chinese-made I'm sure and about 40-50% cheaper than the name brands. Wondering if they are crap or not. Typically I do not trust anything Chinese-made as the quality is almost never there, but that's my experience on non-automotive products.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline VileZambonie

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Re: 1.6 roller rockers
« Reply #1 on: March 19, 2008, 01:55:27 PM »
Try to build the lift u want into the cam as you can and don't make the reciprocating valve train have anymore stress than necessary. Most of your valve train stuff you buy will recommend a 1.5:1 ratio for SB Chevy. Once I used a set of those proform roller rockers and there was some wear and clearancing but once I had them set up just right they worked well. I always recommend screw in studs and guide plates with roller rockers.
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Offline SUX2BU99

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Re: 1.6 roller rockers
« Reply #2 on: March 19, 2008, 02:47:22 PM »
I suppose with the larger ratio, it will move across the end of the valve more but the roller should take care of wear on the end right? But would it also induce some more wear on the valve guide, perhaps pushing and pulling on the valve more than the 1.5 would? The .525 springs in my new heads will handle the addtional lift. I think the .480 lift on the exhause lobe of my cam with a 1.6 ratio = .512 lift. I always figured going with a larger ratio rocker was kind of a free lunch (besides the cost).
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline VileZambonie

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Re: 1.6 roller rockers
« Reply #3 on: March 19, 2008, 04:02:17 PM »
If you are changing the cam, and aren't going ginormous with the valve lift, let the cam do the lifting it's designed to do. If you are going well over .500" lift then you might benefit from a higher ratio. If you aren't changing the cam and are looking for a cheap way to get more lift and slight increase in duration then that works too.
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Offline SUX2BU99

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Re: 1.6 roller rockers
« Reply #4 on: March 19, 2008, 04:07:44 PM »
I get ya. I think I fall right in between that, so maybe best to keep it at 1.5
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline VileZambonie

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Re: 1.6 roller rockers
« Reply #5 on: March 19, 2008, 05:32:03 PM »
what camshaft are you using?
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Offline VileZambonie

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Re: 1.6 roller rockers
« Reply #6 on: March 19, 2008, 05:42:41 PM »
Here's an interesting article where they dyno'd 1.5 vs 1.6 using the same cam

http://www.vetteweb.com/tech/0204vet_small_block_rocker_arms_ratio/index.html
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Offline SUX2BU99

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Re: 1.6 roller rockers
« Reply #7 on: March 24, 2008, 12:34:05 PM »
This cam here:
http://store.summitracing.com/partdetail.asp?part=CCA%2DCL12%2D242%2D2&autoview=sku

Comp Cam Xtreme Energy 268. PN  CL12-242-2   

Duration at 050 inch Lift: 224 int./230 exh.
Advertised Duration: 268 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.477 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Valve Lift with Factory Rocker Arm Ratio: 0.477 int./0.480 exh. lift
Lobe Separation (degrees): 110
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 1.6 roller rockers
« Reply #8 on: March 24, 2008, 12:45:52 PM »
That's a very interesting article. Was I missing the dyno results though? All I saw was the 40 HP drop, but 30 FT-LB increase from the binding pushrods with the 1.6 rockers. I didn't see what increase they got with the stamped roller-tip 1.52 over the non-roller stamped rockers, nor with the fancy stainless rollers. And was the binding they got from the typical rubbing of the pushrod on the head that can happen with 1.6 rockers? I didn't quite follow that part.

Maybe it's best to stick with the roller-tips I have now.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.