Why did my Jesel's do this?
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Why did my Jesel's do this? I have a 99 C5 stock bottom end. AFR 205's milled .030" mounted with .040" Cometics, running a 224/228 .581"/.588" 112lsa +0 cam. Kooks headers, Stingers, FAST90/NW90, and other less interesting stuff. I originally had the stock rockers and had HS rebuild them. The car ran great and had a nice lope at idle, nothing crazy, but you knew there was a cam in there. MAP was ~55kpa at 800rpm idle. I had some Jesel SS rockers and installed them. I set the preload to .050" and ground out the valve covers, etc. The car runs great with these in also. The weird thing is, it idles like stock again, the lope is gone. The valve train is quiet. I have lowered the idle to 700rpm's and it is positively stealthy. The MAP at 700rpm is 37kpa, just about what it was at stock. I'm going to the dyno asap to see if this has detuned the car, but it doesn't seem so SOTP, however, we all know how accurate the butt-o-meter is. I actually like it better the way it is, I just can't explain it to myself. Any ideas?
TECH Addict
Joined: Dec 2001
Posts: 2,907
Likes: 1
From: Bergen County, NJ
I was reading a while back - how to check if your cam is too big, you back off on the adjusters which effectively reduces duration and increases LSA. It sounds like either the rockers have changed the geometry of they're 1.5s or something instead of 1.7s?
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by DaddySS
I was reading a while back - how to check if your cam is too big, you back off on the adjusters which effectively reduces duration and increases LSA. It sounds like either the rockers have changed the geometry of they're 1.5s or something instead of 1.7s?
This same scenario happened to my friend. We put a set of heads on, and shimmed too much (it turned out). It was a 231/237 112+4 and it did NOT lope at all. Then, a month or so later, took out the shims, and it loped like it should. My guess is you aren't getting the full amount of lift.
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by Greg Fell
This same scenario happened to my friend. We put a set of heads on, and shimmed too much (it turned out). It was a 231/237 112+4 and it did NOT lope at all. Then, a month or so later, took out the shims, and it loped like it should. My guess is you aren't getting the full amount of lift.
It IS acting like the lift is getting chopped off though.
Trending Topics
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by Greg Fell
I mean to say, we shimmed the rockers, not the springs. We left the springs as they were from AFR.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by MAC4264
Your pushrods are not hitting or rubing giving you false preload measurement. I had Jesel rockers with stock 99 heads and had this problem. Just a suggestion.
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by Viper
What ever came of this?
Onto the Jesel's issue. While I was playing around trying to find the backfiring I removed my Jesel's and noticed a halfmoon shaped indentation underneath near the flucrum about the size of mt retainers and about .010" deep. I remounted the rockers with a piece of paper under them and found the retainers were hitting the rockers. I got out my dremel and relieved some of the fulcrum where the indentaion was and checked again with a piece of paper and no bind. Bolted it back up and had my lope and idle kPa back. This was enough to kill some lift because the roller wasn't on the valve tip at full close. I dodged a bullet because there is no significant guide wear and the valves aren't bent. I also ended up with the narrowest wipe pattern just a tad to the intake side with the stands shimmed .025" and using a 7.350" pushrod with ~.070" preload.
Not sure how much material you removed or how deep, but be careful of the fatigue life of the rocker arms as that location is likely in a high state of tensile stress during operation.
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by vettenuts
Not sure how much material you removed or how deep, but be careful of the fatigue life of the rocker arms as that location is likely in a high state of tensile stress during operation.
Also, I referenced this before I modded them. http://www.jeselonline.com/board/viewtopic.php?t=15
Last edited by ArKay99; Mar 6, 2006 at 02:50 PM.
Hey Roger....
"Bolt on" huh??.....LOL
Good thing I didn't get to you sooner....my advice was going to be to hit the dyno and see whats up (that could have been ugly!).
Keep us posted if you do hit the rollers...
"Bolt on" huh??.....LOL
Good thing I didn't get to you sooner....my advice was going to be to hit the dyno and see whats up (that could have been ugly!).
Keep us posted if you do hit the rollers...
Originally Posted by ArKay99
I removed my Jesel's and noticed a halfmoon shaped indentation underneath near the flucrum about the size of mt retainers and about .010" deep. I remounted the rockers with a piece of paper under them and found the retainers were hitting the rockers. I got out my dremel and relieved some of the fulcrum where the indentaion was and checked again with a piece of paper and no bind. Bolted it back up and had my lope and idle kPa back. This was enough to kill some lift because the roller wasn't on the valve tip at full close. I dodged a bullet because there is no significant guide wear and the valves aren't bent. I also ended up with the narrowest wipe pattern just a tad to the intake side with the stands shimmed .025" and using a 7.350" pushrod with ~.070" preload.
if im reading this correctly, the rocker arms hit the retainers, and bound up. where did that motion of the pushrod going up go? did it bend the pushrods or what?
Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by Tony Mamo @ AFR
Hey Roger....
"Bolt on" huh??.....LOL
Good thing I didn't get to you sooner....my advice was going to be to hit the dyno and see whats up (that could have been ugly!).
Keep us posted if you do hit the rollers...
"Bolt on" huh??.....LOL
Good thing I didn't get to you sooner....my advice was going to be to hit the dyno and see whats up (that could have been ugly!).
Keep us posted if you do hit the rollers...
That's what Steve was telling me all winter. But I just HAD to find a way to make these work. You should see the valve covers. Nothing left inside, hogging them to fit these in there. Planning on dyno'ing in a bit, as soon as the weather changes. We also put in a new operating system in the PCM's, a 2002 Z06 so we could get to the higher resolution tables and better PID selections. I'm still loving the whole package. Maybe even pick up a few ponies. Result's to follow. Thread Starter
TECH Regular
iTrader: (1)
Joined: Nov 2003
Posts: 490
Likes: 0
From: Washington Township, NJ
Originally Posted by MrDude_1
im confused a tad.
if im reading this correctly, the rocker arms hit the retainers, and bound up. where did that motion of the pushrod going up go? did it bend the pushrods or what?
Originally Posted by ArKay99
Yes, they hit the retainers, but didn't bind up. The were just tilting the retainer slightly, maybe .020", I'm not sure, I didn't measure it. I didn't run the car much at all in this condition. I'm sure the motion of the pushrod going up was absorbed by the retainer's tilt and possibly a touch of the lifter. It didn't bend the pushrods. There was plenty of motion, just that the lifter had to move maybe .020"-.030" before the roller started to push the valve down. Remember, there is a 1.7:1 ratio. So for .030" at the roller tip, the pushrod only has to go around .018". At least that is what I believe saved them. I'm sure if it was any worse it WOULD have been ugly as Tony said above.
and thanks for the heads up on something to check for before running the motor...
