Ouch... (Jesel rocker arm failure)
Banned
Joined: Jul 2009
Posts: 72
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You state that your cam is not big but it is are fairly agressive cam with lots of overlap and lift. Was the cam degreed in and was valve to piston clearance measured before assembly? The rockers dont seem to have much meat around the pushrod end. You may have had a little valve bounce. It might be an idea to take that valve spring off and have it tested. Cheers Russ
Our set ups are similar.....I have a LME 408,trickflows,jessel ss 1.8's,...244/250 630 on the lift side...I have one of the first sets of Trickflows...Motor was built in 06'....I have 30k on the motor now and alot of 7200k clutch dumps.....
Sorry to see yours fail so early..You and I didn't have alot of options with these heads. I hope you find the reason why these took a dump....
Sorry to see yours fail so early..You and I didn't have alot of options with these heads. I hope you find the reason why these took a dump....
Jesell ss rockers should be only used as stock replacement rockers only! I had set I bought for my 408 build, and read a thread that stated he was not getting full lift out of his Jesell ss rockers. Long story short I talked with Jesel they said that the SS Rockers were for Stock Replacment only and their Web States that, Rep said needed to get the J2k rockers for anything over stock!! When I say Stock Replacement I mean Stock Lift Cam "ONLY"
Check the underside of the rockers. If I remember correctly there is a protrusion that once much above stock lift will contact the base. These rockers won't take the lift you are running. Contact "Arkay99" for the details, he ran into this on his motor and ended up with Yella Terra's instead until he figures out how he can fix the Jesel's. What he found was the rocker was being stopped by the stand prior to achieving full lift, which that being the case, you likely have an overstress issue.
Like I said earlier...I these same rockers with 30k on them 50 + 7200 clutch dumps ....This is off of Jessels web site...
http://jesel.com/index.php?categoryid=24
http://jesel.com/index.php?categoryid=24
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Depends on geometry and lift but this shouldn't have any issues. Maybe check for weird installed height on that one or a high spring but we have used those as well with no issues ever on stuff with .660 lift. One of the guys we did with them is the fastest car of his kind on here and has had them 6 years now with some pretty big spring pressure and we had to clearance them as well and still no issues. I have seen them bind at full lift if people shim them up too much.
Blaming the rocker right away without knowing the rest of the story and how they are setup is ridiculous. I've seen tons of trashed stock stuff and especially the HS modded stuff recently with welded needle bearings and grossly eroded tips and yet haven't really had any issues either with any of our own stuff using any of these Jesel or stock rockers.
Blaming the rocker right away without knowing the rest of the story and how they are setup is ridiculous. I've seen tons of trashed stock stuff and especially the HS modded stuff recently with welded needle bearings and grossly eroded tips and yet haven't really had any issues either with any of our own stuff using any of these Jesel or stock rockers.
Not blaming the rockers, but I have been thru 3 sets of these with similar problems on my 440 engine. I have sold over 500 sets and been a jesel dealer for over 12 years and never had any problem till these ? . I contacted them and the inpression I got was they never assumed these hydraulic cam profiles would ever get as aggressive as they are and now people are running more and more spring pressure on them. And the aluminum they use on these is less than impressive. They remind me of the old Crane high intensity with the flaked look to it on the bodies ? I went to yella terras and no more problems.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Yes I am just saying to make sure everything else is Kosher as it's quite strange for these to fail. We have got some of these in as well that were totally trashed but I have no idea of what went on to get them that way? The ones we have used are all still running even those from years and years ago.
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Joined: Aug 2005
Posts: 154
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From: ohio
It is odd to me that the failure occured on the #7 cylinder. I personally have talked to a number of customers who have failed Jesel's, Harlands, scorpion's, and YT's- oh and a Comp stud mount. In almost every case the failure has occured on the #7 hole but usually on the exhaust rocker and the pushrod side of the rocker always breaks off as this one did. I realize this was an intake. That is always the hole that lifts the ring lands too, could it be possible that a lean condition would create extreme cylinder pressure on that hole which would make it extra hard to initially open that valve against? Any thoughts? I do not believe the spring caused the failure. JMO
Like Erik said, check to see if there isn't anything else wrong before anyone jumps to conclusions. You could have issues like coilbind or the retainer hitting the guide, and the rocker was just the weakest link. Not to bash anyone, but installation error is more likely than a simple part failure.
OK, did a search and found Roger's thread on CF. Not saying this is the issue here, but it may help look for clues. Link
To the OP: Look closely at your rocker bottom, the photo above (the third to the last one in your first post) shows marks similar to those Roger posted in the link.
To the OP: Look closely at your rocker bottom, the photo above (the third to the last one in your first post) shows marks similar to those Roger posted in the link.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
OK, did a search and found Roger's thread on CF. Not saying this is the issue here, but it may help look for clues. Link
To the OP: Look closely at your rocker bottom, the photo above (the third to the last one in your first post) shows marks similar to those Roger posted in the link.
To the OP: Look closely at your rocker bottom, the photo above (the third to the last one in your first post) shows marks similar to those Roger posted in the link.
LS1Tech Sponsor
Joined: Feb 2006
Posts: 1,170
Likes: 1
From: Rockfield Kentucky
It is odd to me that the failure occured on the #7 cylinder. I personally have talked to a number of customers who have failed Jesel's, Harlands, scorpion's, and YT's- oh and a Comp stud mount. In almost every case the failure has occured on the #7 hole but usually on the exhaust rocker and the pushrod side of the rocker always breaks off as this one did. I realize this was an intake. That is always the hole that lifts the ring lands too, could it be possible that a lean condition would create extreme cylinder pressure on that hole which would make it extra hard to initially open that valve against? Any thoughts? I do not believe the spring caused the failure. JMO
Because the exhaust valve is still open as the intake starts to open there is never any cylinder pressure on the intake while it is opening.
As you know the exhaust does fight the cylinder pressure as it opens. This is increased wtih a nitrous application because of the increased cylinder pressure.
Most of the valvetrain failures I have seen were a result of loss of control of the valve. A weak spring or aggressive cam profile can promote the loss of control. While testing components on the Spin Tron I saw what the "hammer" effect did to components.
I would look at the RPM range verses the spring pressure. Also be sure that the pushrod is not flexing and pounding the rocker.
Oh, I have used the Jesel products for many years on several different combinations. I have never had a problem even when I was killing seats and valves from the valve float.
Good luck!
Robin
Banned
Joined: Aug 2005
Posts: 154
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From: ohio
Hey Mike,
Because the exhaust valve is still open as the intake starts to open there is never any cylinder pressure on the intake while it is opening.
As you know the exhaust does fight the cylinder pressure as it opens. This is increased wtih a nitrous application because of the increased cylinder pressure.
Most of the valvetrain failures I have seen were a result of loss of control of the valve. A weak spring or aggressive cam profile can promote the loss of control. While testing components on the Spin Tron I saw what the "hammer" effect did to components.
I would look at the RPM range verses the spring pressure. Also be sure that the pushrod is not flexing and pounding the rocker.
Oh, I have used the Jesel products for many years on several different combinations. I have never had a problem even when I was killing seats and valves from the valve float.
Good luck!
Robin
Because the exhaust valve is still open as the intake starts to open there is never any cylinder pressure on the intake while it is opening.
As you know the exhaust does fight the cylinder pressure as it opens. This is increased wtih a nitrous application because of the increased cylinder pressure.
Most of the valvetrain failures I have seen were a result of loss of control of the valve. A weak spring or aggressive cam profile can promote the loss of control. While testing components on the Spin Tron I saw what the "hammer" effect did to components.
I would look at the RPM range verses the spring pressure. Also be sure that the pushrod is not flexing and pounding the rocker.
Oh, I have used the Jesel products for many years on several different combinations. I have never had a problem even when I was killing seats and valves from the valve float.
Good luck!
Robin
thanks Robin. 
I went with T&D and got junk. Geometry was so far off the pushrods were moving towards the intake during the arc. In not so many words T&D rep said the rockers are great for anything but a race motor. Sent them back and never got a full refund(they were only used on the dyno for a fraction of time until we noticed what was happening) Went with DRE rockers are everything is beautiful to 8500 RPM.
Thread Starter
That's what she said...
iTrader: (8)
Joined: Mar 2004
Posts: 7,954
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From: Nederland Texas
Update........
So it looks like the bottom of my rockers had been in contact with the rocker stand rails. This must have happened back when I had the huge cam. I figure the rocker arms clearanced themselves and then most likely didn't hit after I put the new (smaller) cam in. You can see the marks where they were rubbing. The marks between the 5 and 7 are from the top of the bolts that sit directly below the rockers.
I drug my feet for a while then got in touch with Jesel. Rob Remesi from Jesel returned my emails and was very nice. I told them about the interference issues and the problems that others have experienced. I also expressed the fact that I understood that this failure could have very well happened due to a general installation error. He swiftly reccomended that I send the rocker arms in for inspection and he would replace the rocker bodies free of charge. I am very pleased with the service I received from Jesel and would recommend them to anyone. These showed up around 7 business days after I shipped them out.
So it looks like the bottom of my rockers had been in contact with the rocker stand rails. This must have happened back when I had the huge cam. I figure the rocker arms clearanced themselves and then most likely didn't hit after I put the new (smaller) cam in. You can see the marks where they were rubbing. The marks between the 5 and 7 are from the top of the bolts that sit directly below the rockers.
I drug my feet for a while then got in touch with Jesel. Rob Remesi from Jesel returned my emails and was very nice. I told them about the interference issues and the problems that others have experienced. I also expressed the fact that I understood that this failure could have very well happened due to a general installation error. He swiftly reccomended that I send the rocker arms in for inspection and he would replace the rocker bodies free of charge. I am very pleased with the service I received from Jesel and would recommend them to anyone. These showed up around 7 business days after I shipped them out.
Last edited by TheBlurLS1; Nov 3, 2009 at 09:48 PM.
