Are these Yella Terra rockers useable?
09-24-2012, 01:43 PM
#2
How does the push-rod look, any current issues like a sticking lifter?
I'd go a head and inspect all the rockers; if you haven't all ready.
IMO, don't run them. For one thing you've already lost some pre-load, and you might be able to have the seat replaced. You'll probably want to replace the PR too if it has any visible abnormal wear.
BTW, I just pulled a pair of my YT rockers for the same issue, except mine is worn deep enough to hold the PR up(PR cup on right in photo).
http://s523.photobucket.com/albums/w...psc9da23f0.jpg
I'd go a head and inspect all the rockers; if you haven't all ready.
IMO, don't run them. For one thing you've already lost some pre-load, and you might be able to have the seat replaced. You'll probably want to replace the PR too if it has any visible abnormal wear.
BTW, I just pulled a pair of my YT rockers for the same issue, except mine is worn deep enough to hold the PR up(PR cup on right in photo).
http://s523.photobucket.com/albums/w...psc9da23f0.jpg
Last edited by 99Bluz28; 09-24-2012 at 02:11 PM.
09-24-2012, 03:14 PM
#3
Interesting, what oil are you guys running and what valve springs? I am running Yella Terra as well and haven't inspected the rockers, what were the indications of this problem?
On your AFR's, what was your installed valve spring height?
On your AFR's, what was your installed valve spring height?
Last edited by vettenuts; 09-24-2012 at 03:24 PM.
09-24-2012, 04:07 PM
#4
TECH Apprentice
Thread Starter
There are three pairs of rockers like this and four pushrods that have similar wear on the ends. Valvetrain was making a metallic sounding noise, so tore it down and found worn cam, lifters, rockers and pushrods, and if you haven't guessed it's the famous LS7 lifters. The spring height is what AFR sets it at, I think I measured it at 1.780. Lifter preload was .055.
09-24-2012, 04:35 PM
#5
There are three pairs of rockers like this and four pushrods that have similar wear on the ends. Valvetrain was making a metallic sounding noise, so tore it down and found worn cam, lifters, rockers and pushrods, and if you haven't guessed it's the famous LS7 lifters. The spring height is what AFR sets it at, I think I measured it at 1.780. Lifter preload was .055.
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09-25-2012, 02:04 PM
#9
Ive got PAC 1521s with the recommended seat height, I think the PR might have caused my issue since I did reused the one PR that was on the YT rocker that broke last year(it seemed fine). I'm running CompCams 5/16" PRs w/.08" wall, and I just had my car retuned the first week in September, made from 400rwhp to 427rwhp and back down to 400rwhp from 5k to 6600rpm with no sigh of any valve float. That's with 66cc AFR 205s and gm stock MLS head gaskets(stock compression). I've since swapped in a spare set of the YT rockers and a new PR after checking the lifter preload to see if there was any change which was still right about .06". Also the lifter end of the PR I replaced looked perfectly fine.
I originally thought I had a sticking lifter so I went ahead and started spraying B12 Chemtool down into all the lifters and that's when I found my PR stuck in the YT pr cup an then overnight a new PR installed it and went ahead and did a oil flush and add new Castrol Synthetic 5w-30.
My gradually increase in valvetrain noise started the last week in august before my tune until I pulled my rockers and found my problem the following week after my dyno tune. My engine runs and sounds back to normal now.
I originally thought I had a sticking lifter so I went ahead and started spraying B12 Chemtool down into all the lifters and that's when I found my PR stuck in the YT pr cup an then overnight a new PR installed it and went ahead and did a oil flush and add new Castrol Synthetic 5w-30.
My gradually increase in valvetrain noise started the last week in august before my tune until I pulled my rockers and found my problem the following week after my dyno tune. My engine runs and sounds back to normal now.
Last edited by 99Bluz28; 09-25-2012 at 02:34 PM.
09-26-2012, 12:51 AM
#10
Hey Blue, how's things?
I used two of your old rockers for setup. I didn't notice any unusual pushrod cup wear. But they did set up a few thou different than the new ones I used.
So this is interesting. I'm also an AFR user, my setup has been running since July 1. Valvetrain noise is loud, but I expected that. I don't honestly know if it has changed. Something to look at in the offseason which will be about a month. BTW....the FAST 102 intake amplifies the noise like crazy.
I am also running LS7 or whatever they are called lifters and the 8019 springs on my AFR's. Set at the called for installed height. I set them up, so whatever the sheet says. My cam lift is right at .600.
FWIW, I have been drag racing the car quite a lot, so it has seen 6600 repeatedly.
Ron
I used two of your old rockers for setup. I didn't notice any unusual pushrod cup wear. But they did set up a few thou different than the new ones I used.
So this is interesting. I'm also an AFR user, my setup has been running since July 1. Valvetrain noise is loud, but I expected that. I don't honestly know if it has changed. Something to look at in the offseason which will be about a month. BTW....the FAST 102 intake amplifies the noise like crazy.
I am also running LS7 or whatever they are called lifters and the 8019 springs on my AFR's. Set at the called for installed height. I set them up, so whatever the sheet says. My cam lift is right at .600.
FWIW, I have been drag racing the car quite a lot, so it has seen 6600 repeatedly.
Ron
09-26-2012, 04:08 AM
#11
A couple of observations on my part.
I upgraded my pushrods from 5/16" to 3/8" double taper (I did write a post that detailed this swap) and picked up about 6 hp between 6,200 and 6,600 RPM. This indicates there was some pushrod flex taking place that may have resulted in issues down the road.
I have also been doing a lot of reading lately on the oils and lack of ZDDP, especially in the newer requirements. While the ZDDP is more important for a flat tappet cam, we are running pretty high valve train loads with our setups and I am thinking of going to some of the oils that are still marketed for older cars that also contain the ZDDP for the cam/lifter loads. The valve train loads in the stock setup are much lower than those we are running so the stock oil specification may no longer be suitable.
I am running the German Castrol at this time due to its higher viscosity (upper end of 30W range) at 100 degrees C where as many of the other oils out there are low in the 30W range and Mobil-1 is almost into the upper 20W range. Not sure how much oil is contributing to some of the problems but my next change will move to an oil that provides more pretection for some of these high loads.
I upgraded my pushrods from 5/16" to 3/8" double taper (I did write a post that detailed this swap) and picked up about 6 hp between 6,200 and 6,600 RPM. This indicates there was some pushrod flex taking place that may have resulted in issues down the road.
I have also been doing a lot of reading lately on the oils and lack of ZDDP, especially in the newer requirements. While the ZDDP is more important for a flat tappet cam, we are running pretty high valve train loads with our setups and I am thinking of going to some of the oils that are still marketed for older cars that also contain the ZDDP for the cam/lifter loads. The valve train loads in the stock setup are much lower than those we are running so the stock oil specification may no longer be suitable.
I am running the German Castrol at this time due to its higher viscosity (upper end of 30W range) at 100 degrees C where as many of the other oils out there are low in the 30W range and Mobil-1 is almost into the upper 20W range. Not sure how much oil is contributing to some of the problems but my next change will move to an oil that provides more pretection for some of these high loads.
09-26-2012, 02:11 PM
#12
RonSSNova, good to hear the Rockers are still going strong!
vettenuts, could you direct me to your PR post.
Thanks!
I've been using mostly using G-oil 5w-30 (full synthetic) since H/C/YT-rr install and some Quaker 5w-30 (full Synthetic). Since my very resent full engine an lifters flush I used Castrol EDGE 5W-30 Titanium Synthetic. BTW is there a ZDDP (only) additive that you can buy?
vettenuts, could you direct me to your PR post.
Thanks!
I've been using mostly using G-oil 5w-30 (full synthetic) since H/C/YT-rr install and some Quaker 5w-30 (full Synthetic). Since my very resent full engine an lifters flush I used Castrol EDGE 5W-30 Titanium Synthetic. BTW is there a ZDDP (only) additive that you can buy?
Last edited by 99Bluz28; 09-26-2012 at 02:53 PM.
09-27-2012, 04:51 AM
#13
09-27-2012, 05:25 AM
#14
Wondering the same thing about a good ZDDP additive. I went from Mobil1 to Castrol Edge over a year ago and right off the bat noticed a quieter (when stock) valvetrain, so I went to it in the LQ9 Escalade as well and noticed it being quieter as well.
Anyways, sorry to hijack. Just curious.
Anyways, sorry to hijack. Just curious.
09-27-2012, 09:35 AM
#15
RonSSNova, good to hear the Rockers are still going strong!
vettenuts, could you direct me to your PR post.
Thanks!
I've been using mostly using G-oil 5w-30 (full synthetic) since H/C/YT-rr install and some Quaker 5w-30 (full Synthetic). Since my very resent full engine an lifters flush I used Castrol EDGE 5W-30 Titanium Synthetic. BTW is there a ZDDP (only) additive that you can buy?
vettenuts, could you direct me to your PR post.
Thanks!
I've been using mostly using G-oil 5w-30 (full synthetic) since H/C/YT-rr install and some Quaker 5w-30 (full Synthetic). Since my very resent full engine an lifters flush I used Castrol EDGE 5W-30 Titanium Synthetic. BTW is there a ZDDP (only) additive that you can buy?
Interesting on the ZDDP situation. I didn't think of the need for that in the pushrod cup area. Good thinking Vettenuts. I've been running the Mobil One for older engines, I'll have to do some research. There are synthetics with higher levels available.
And no, I don't think you can buy it as an additive.
BTW, I'm having a blast with my first LS engine. Got a lot of great info here and hopefuly gave some of my learnings back as well. I was shooting for somewhere in the mid/low 11's. Didn't think I'd be knocking on the tens. I know there are a lot of good heads to choose from, but I'm happy with my 205's.
Ron
09-27-2012, 08:38 PM
#19
ModSquad
iTrader: (6)
You absolutely can get the ZDDP as an additive only. I've bought many of them from my engine builder.