1.6 Roller Rocker swap
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From: Iowa
1.6 Roller Rocker swap I plan on swapping in some 1.6 RR's soon here. Looking at some Scorpions and swapping my springs for LT4 springs. Just wondering if I can use everything stock or do I have to swap shims and retainers as well? I'm trying to piece everything together and just can't seem to find any info on exactly what I require to do the swap.
LT4 springs will work perfect with stock LT1 spring retainers, locks and seats. Get self aligning rockers unless you plan to use guide plates. Change out the valve guide seals while you're there.
+1 on doing it once and doing it right, 7/16 ARP studs, guide plates, hardened pushrods, Non Self Aligning rockers (NSA). Look at ebay, Craigslist and the classifieds, I got a set of NSA 3/8 stud Crane golds for $50, NSA 7/16 comp pro mags for $75, and NSA 7/16 crowers for $90, using the pro mags sold the rest for profit.
Hope your not expecting much. Tested that on my '96 TA, the one I race now. It was all stock then. Tied it on the dyno, made three pulls. Still tied down on the dyno, swapped the rockers, (1.6 Comp Cams), warmed to the same temps as before, three more pulls. Best pull was three rwhp better. So, for about $300.00 with freight, you get about $100.00 per rwhp. More dollars per rwhp if you can't buy them right. Kinda like air boxes, etc.
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Buutttt.........I couldn't just leave those stock rockers in there after going to the trouble of changing the springs 
Leaving the shift points at 5400 back then, springs and 1.6 RR's picked the Impala up by almost 2 mph. that's a good 20 hp in a 4000 lb (at the time) car.
Edit: 2 mph back at the 90 mph trap range was more like 15 hp.
Leaving the shift points at 5400 back then, springs and 1.6 RR's picked the Impala up by almost 2 mph. that's a good 20 hp in a 4000 lb (at the time) car.
Edit: 2 mph back at the 90 mph trap range was more like 15 hp.
Last edited by bowtienut; Jan 6, 2015 at 02:15 PM.
Running it one week, then change something that small and go another weekend, you can not REALLY know what it was worth. I do all my testing of small things like that now at the track, or on an engine dyno. It cost a lot for track rental, but usually there are three or four other guys that need to test and will split it with me. Only acurate way, other than same day on the dyno is A-B-A testing. Same day, close to the same time of day. Can't believe everything you find on the dyno either, with an automatic car. Learned that the hard way. Always verify at the track. Things like valve lash changes, cam phasing, header sizes, collector styles and sizes, collector extensions, etc.
The weather stations on the dynos ain't all that great. 20 hp is a real stretch for something like that. I would have to see that one in a controled A-B-A test to believe it. Simply is not logical.
The weather stations on the dynos ain't all that great. 20 hp is a real stretch for something like that. I would have to see that one in a controled A-B-A test to believe it. Simply is not logical.
Running it one week, then change something that small and go another weekend, you can not REALLY know what it was worth. I do all my testing of small things like that now at the track, or on an engine dyno. It cost a lot for track rental, but usually there are three or four other guys that need to test and will split it with me. Only acurate way, other than same day on the dyno is A-B-A testing. Same day, close to the same time of day. Can't believe everything you find on the dyno either, with an automatic car. Learned that the hard way. Always verify at the track. Things like valve lash changes, cam phasing, header sizes, collector styles and sizes, collector extensions, etc.
The weather stations on the dynos ain't all that great. 20 hp is a real stretch for something like that. I would have to see that one in a controled A-B-A test to believe it. Simply is not logical.
The weather stations on the dynos ain't all that great. 20 hp is a real stretch for something like that. I would have to see that one in a controled A-B-A test to believe it. Simply is not logical.
I just edited my post above. You're right; 20 hp was an exaggeration.
Last edited by bowtienut; Jan 6, 2015 at 02:17 PM.
I dunno. When living in Texas and going to the Motorplex in the 90's about every Friday night they were open there were 4th gens galore there always testing out different mods. Most everything back then was bolt-on with a few on nitrous or supercharged. I remember lining up with another f-body who had the basic bolt-ons done including 1.6 rockers when I was stock and the ET's from the other car were consistently .1 to .2 better than mine (13.9 to 14.2 @ 99 to 100mph). There were enough f-bodys there to know at that point in time to gauge what the standard ET's were for whatever bolt-on mods were done, and from paying attention at the track as well as local e-mail lists and message boards (cz28.com/ls1.com had huge Texas followings) the overwhelming consensus was 1.6 rockers being good for about a 1/10th off ET's. JMO.
You can't go by that! Good grief! Stock, untouched LT1 hp numbers are all over the place! I have seen over 40 RWHP variations on my dyno. Both between F body cars, and between B bodies. Had a national Impala club meet in Tulsa, and they came for a "dyno day", some were sick after seeing their's make so much less that others. Local Camaro/Firebird club saw the same thing. That is why some stock F body cars run high 13s, others run mid 14s. Have seen a couple barely in the 14s. No way 3 to 5 RWHP is a tenth. Some in those clubs had 1.6 rockers. You could not look at their dyno sheets and tell who had them. ONLY way to know would be do what I did, back-to-back them on the dyno. Same day, without moving the car. Or at the track. Most are way too lazy to test properly. Had several guy want their car dynoed, to see what it makes. Come back two weeks later with something small like that changed, and want it dynoed again. Sometimes it would look like a loss, when I knew it wasn't trying to explain it seemed to go right over their heads.
I'm just going by what I saw at the track and the strong presence every Friday night at Ennis. You would see anywhere form 10 to 30 f-bodys out running and since the target consumers back then were IT geeks with disposable incomes and they were very open with what they did with their cars. Especially since we all belong to the same car club. It's just what I believe from what I've seen. Take it FWIW.
As far as a stock Z28 LT1 running high 13's, never saw that at Ennis. Saw a massive amount of 14.5's, but mind you, Ennis didn't open until May and it was already hot by then.
As far as a stock Z28 LT1 running high 13's, never saw that at Ennis. Saw a massive amount of 14.5's, but mind you, Ennis didn't open until May and it was already hot by then.
I agree the $/HP is not worth just doing rockers as you only mod, but like I said before, doing 7/16 ARP, good new springs and NSA 1.6 rockers are good to do as a stepping stone to future mods, as well as replacing tired old stock valvesprings that could be floating above 5500. Do it once, do it right, and you wont have to change much when you get a cam in the future.
Ed, I am curious if you had swapped to better springs if it would have made any difference. I did notice in my car when I swapped to 1.6 rockers and the Howards springs I didnt get the semi fall on the face I felt from 6000-6300 with the stock rockers and 110k mile springs, which had already seen a couple hundred 61-6300rpm passes. I shift at 6300 on the stock cam by the stock tach (which the stock tachs are a bit happy), I wonder if you had taken it to 6300 with the 1.6 rockers and better springs if there would have been more of a difference in those higher RPMs. I have done back to back to back to back runs many times trying to find the best RPM to shift my stock cam, trying 100rpm increments, and 6300 was my sweet spot for best ET and MPH. I have only gotten about 20 passes since I did my valvetrain, but I did drop 2 tenths, but that was done with the EWP and LS1 lid so no concrete data.
Ed, I am curious if you had swapped to better springs if it would have made any difference. I did notice in my car when I swapped to 1.6 rockers and the Howards springs I didnt get the semi fall on the face I felt from 6000-6300 with the stock rockers and 110k mile springs, which had already seen a couple hundred 61-6300rpm passes. I shift at 6300 on the stock cam by the stock tach (which the stock tachs are a bit happy), I wonder if you had taken it to 6300 with the 1.6 rockers and better springs if there would have been more of a difference in those higher RPMs. I have done back to back to back to back runs many times trying to find the best RPM to shift my stock cam, trying 100rpm increments, and 6300 was my sweet spot for best ET and MPH. I have only gotten about 20 passes since I did my valvetrain, but I did drop 2 tenths, but that was done with the EWP and LS1 lid so no concrete data.
I agree there's more car-to-car variation than the difference you'll see with rockers.
But, at least in my case with the B-cam which you must admit needs all the help it can get, the 1.6 RR's and springs were worth just shy of 2 mph and somewhere between .12 and .15 ET. When I upped the rev limit to take advantage of the better springs, the gains were beyond that (I know the F-cars have better springs to start with, so don't count on that part).
But, at least in my case with the B-cam which you must admit needs all the help it can get, the 1.6 RR's and springs were worth just shy of 2 mph and somewhere between .12 and .15 ET. When I upped the rev limit to take advantage of the better springs, the gains were beyond that (I know the F-cars have better springs to start with, so don't count on that part).
If your going by the factory tach, and not good tuning, 6300 is probably right. My car, just tuning, B&B cutback with an off-road pipe & Nittos went some 13.90s at Tulsa, which is over a tenth slower than Ennis for my car. Absolutely untouched with 120,000 miles on it, even the original spark plugs, it went 14.45. Not even 100 mph. 98, iirc. The factory tach is always 200 fast at idle, and gets worse as it goes up. 6000 on my Tech2 was 6500 on the dash.
