Valve float, LS6 springs/1.85 RR
08-31-2011, 04:05 PM
#1
On The Tree
Thread Starter
iTrader: (2)
Join Date: Apr 2011
Location: MI
Posts: 196
Likes: 0
Received 0 Likes
on
0 Posts
Valve float, LS6 springs/1.85 RR Had a local "performance" shop install 1.85 comp pro magnum roller rockers and some low mileage ls6 springs along with DT headers. Car dynoed 274/275up from 247/262 with what looked like serious valve float long before redline. The curve up top is extremely wavy, probably +- 15 HP in spots. I'm wondering if there was problems with the installation they are trying to cover up or if they installed them wrong. The baffles had to be removed before the Roller Rockers would fit otherwise I was told everything went well.
On cold starts there is considerable more noise initially which I was told was lifter pump up, I still hear more tapping/ticking noises now than I ever have which I would imagine wouldn't just be from the baffles being removed.
Any idea what the issue is here? If the RR and springs were installed correctly why would there be valve float? Are the 1.85s allowing for too much extra lift or did I buy some bad springs???
On cold starts there is considerable more noise initially which I was told was lifter pump up, I still hear more tapping/ticking noises now than I ever have which I would imagine wouldn't just be from the baffles being removed.
Any idea what the issue is here? If the RR and springs were installed correctly why would there be valve float? Are the 1.85s allowing for too much extra lift or did I buy some bad springs???
08-31-2011, 05:18 PM
#2
were the rockers new? It is probably the ls6 springs though especially if they were used. I went with a dual spring set up to get around that problem. The problem with springs is they are all the same, the comp 918, yellow beehive, ls6 springs...they are all the same. and based on my experiences, they are all crappy. I know i will get a lot of **** for saying that but i also probably rebuilt my ls4 a lot more times then anyone else on this site.
The upgraded roller rockers will be more noisey than standard rockers. But shouldnt be really loud. I know that i bought used rockers and they were actually damaged. When installed they were loose and would clatter a lot.
What push rods are you using?
The upgraded roller rockers will be more noisey than standard rockers. But shouldnt be really loud. I know that i bought used rockers and they were actually damaged. When installed they were loose and would clatter a lot.
What push rods are you using?
08-31-2011, 07:27 PM
#3
12 Second Club
iTrader: (14)
Join Date: Jun 2007
Location: Renton, WA
Posts: 2,563
Likes: 0
Received 0 Likes
on
0 Posts
SittingMongoose is 100% correct!
Keep in mind that the LS6 cam had .550" lift with those springs and used Titanium retainers with light weight valves. You are sitting at .533 lift on the DOD lobes, and are using heavy DOD lifters, valves, and retainers. I would step up to a better spring ASAP!! .
Nice nubers BTW. You are finally making progress!
Keep in mind that the LS6 cam had .550" lift with those springs and used Titanium retainers with light weight valves. You are sitting at .533 lift on the DOD lobes, and are using heavy DOD lifters, valves, and retainers. I would step up to a better spring ASAP!! .
Nice nubers BTW. You are finally making progress!
09-01-2011, 09:51 AM
#5
On The Tree
Thread Starter
iTrader: (2)
Join Date: Apr 2011
Location: MI
Posts: 196
Likes: 0
Received 0 Likes
on
0 Posts
Thanks guys, I was really impressed to see those gains too to be honest. I guess total changes were +RR, +Headers and - CAT, not sure what gains are typical with a cat delete but I doubt more than a handful? I stopped by the shop last night to check out the curves again and grab the data, I zoomed in a bit and saw that what looked like valve float probably wasn't. It was the first of 3 pulls that had some waviness too it, but it was maybe 5hp changes. I've seen some pretty nasty dyno graphs while doing some research yesterday most have significantly bigger drops without recovery, that wasn't the case here. The 2nd and 3rd pulls were much more smooth and the area under the curve now is much better. Car pulls much harder mid-range, highway driving is a ton of fun.
I will change out the valve springs though he has some comp springs that he said he would sell me that are an upgrade from the beehive springs, maybe I'll just swap and sell the yellows.
The 1.85s that alabamaguy sold me added almost exactly 5% to the entire MAF curve. In the process of adding headers I had a bung put in, my AFR was off considerably before with his tailpipe sniffing, so some of the gains from these mods could have been had if the AFR was right months ago that may explain my relatively lower numbers compared to some stockish cars.
Haven't played with timing since install, wondering what the impact of the RR will have on knock and timing in general? Shot in the dark I'm still learning here but wouldn't it essentially change the BTDC point because it is lifting further kind of changing the timing characteristics a bit? I'm putting the wideband in Friday and gonna drive a bit to tweak out the tune now that I'm more familiar with HPtuners. Might play with timing but I've already been able to go up in timing high enough that no additional gains were seen along with no knock (25+ in WOT cells) so I don't even know if it will produce any different results, heck I may even go down a few degrees to see what happens.
Running TR60 plugs in now, considering throwing 55s in just to see what the impact is. The compression losses at altitude in my mind should offset the need for a cooler plug post tune+headers. Seems like I might get slightly better performance. I'm at max 84-86 KPa here, so it's a significant change in cyl pressure.
Man I'm all run on my bad, I'll update later with my next mod results most definitely will be LS1 or 6 intake leaning toward the 6 just to make sure I breath better if (when) I add more power later.
So where would numbers like these leave me at the track?
Edit: Yes RR were new. Pushrods are stock for about another 5 days, planning on going with comp 7162-16 3/8 inch chromemoly, unless there is a better option.
I will change out the valve springs though he has some comp springs that he said he would sell me that are an upgrade from the beehive springs, maybe I'll just swap and sell the yellows.
The 1.85s that alabamaguy sold me added almost exactly 5% to the entire MAF curve. In the process of adding headers I had a bung put in, my AFR was off considerably before with his tailpipe sniffing, so some of the gains from these mods could have been had if the AFR was right months ago that may explain my relatively lower numbers compared to some stockish cars.
Haven't played with timing since install, wondering what the impact of the RR will have on knock and timing in general? Shot in the dark I'm still learning here but wouldn't it essentially change the BTDC point because it is lifting further kind of changing the timing characteristics a bit? I'm putting the wideband in Friday and gonna drive a bit to tweak out the tune now that I'm more familiar with HPtuners. Might play with timing but I've already been able to go up in timing high enough that no additional gains were seen along with no knock (25+ in WOT cells) so I don't even know if it will produce any different results, heck I may even go down a few degrees to see what happens.
Running TR60 plugs in now, considering throwing 55s in just to see what the impact is. The compression losses at altitude in my mind should offset the need for a cooler plug post tune+headers. Seems like I might get slightly better performance. I'm at max 84-86 KPa here, so it's a significant change in cyl pressure.
Man I'm all run on my bad, I'll update later with my next mod results most definitely will be LS1 or 6 intake leaning toward the 6 just to make sure I breath better if (when) I add more power later.
So where would numbers like these leave me at the track?
Edit: Yes RR were new. Pushrods are stock for about another 5 days, planning on going with comp 7162-16 3/8 inch chromemoly, unless there is a better option.
Last edited by redlightrampage; 09-01-2011 at 04:34 PM.
