Im at loss Rocker Snaps again(time for advanced)
Thread Starter
Staging Lane
Joined: Oct 2004
Posts: 55
Likes: 0
From: boondocks
Im at loss Rocker Snaps again(time for advanced) First heres the issue I ran into
https://ls1tech.com/forums/showthrea...575&highlight=
Well I later found out that all but 1 Intake Rockers snapped. No exhaust. Meaning obviously there is something up with the lift on the intake side. Well TSP sends me out another cam. Now Ive seen comp cams have bad cuts before and this is what I assumed, nothing against TSP because they just sell them not make them. The cam spec is 239/242 .649/.609 on a 111* Im running a 7.40 pushrod and stock lifters and PRC springs that use the stock keepers with the retainers. I stick the new cam in and the same exact thing happens. All but 2 this time in the first 2 minutes of running bust the Intake Side rockers. Is it possible that there could be a bad batch? Can I just get away with running a 7.350 Pushrod on the Intake side without any issues?
https://ls1tech.com/forums/showthrea...575&highlight=
Well I later found out that all but 1 Intake Rockers snapped. No exhaust. Meaning obviously there is something up with the lift on the intake side. Well TSP sends me out another cam. Now Ive seen comp cams have bad cuts before and this is what I assumed, nothing against TSP because they just sell them not make them. The cam spec is 239/242 .649/.609 on a 111* Im running a 7.40 pushrod and stock lifters and PRC springs that use the stock keepers with the retainers. I stick the new cam in and the same exact thing happens. All but 2 this time in the first 2 minutes of running bust the Intake Side rockers. Is it possible that there could be a bad batch? Can I just get away with running a 7.350 Pushrod on the Intake side without any issues?
definately check your rocker geometry..i would get an adjustable pushrod and check for the proper pushrod length and preload..
was everything installed correctly?rocker stands seated properly?i'm just guessing here,but that sucks man..hope you get it figured out without spending a lot of money..
was everything installed correctly?rocker stands seated properly?i'm just guessing here,but that sucks man..hope you get it figured out without spending a lot of money..
Pull off one of the springs on a cylinder that a rocker broke. I'll bet the retainer is smashing the valve guide. Also, rotate the engine through and see if the pushrod is contacting the head where it protrudes through.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
First heres the issue I ran into
https://ls1tech.com/forums/showthrea...575&highlight=
Well I later found out that all but 1 Intake Rockers snapped. No exhaust. Meaning obviously there is something up with the lift on the intake side. Well TSP sends me out another cam. Now Ive seen comp cams have bad cuts before and this is what I assumed, nothing against TSP because they just sell them not make them. The cam spec is 239/242 .649/.609 on a 111* Im running a 7.40 pushrod and stock lifters and PRC springs that use the stock keepers with the retainers. I stick the new cam in and the same exact thing happens. All but 2 this time in the first 2 minutes of running bust the Intake Side rockers. Is it possible that there could be a bad batch? Can I just get away with running a 7.350 Pushrod on the Intake side without any issues?
https://ls1tech.com/forums/showthrea...575&highlight=
Well I later found out that all but 1 Intake Rockers snapped. No exhaust. Meaning obviously there is something up with the lift on the intake side. Well TSP sends me out another cam. Now Ive seen comp cams have bad cuts before and this is what I assumed, nothing against TSP because they just sell them not make them. The cam spec is 239/242 .649/.609 on a 111* Im running a 7.40 pushrod and stock lifters and PRC springs that use the stock keepers with the retainers. I stick the new cam in and the same exact thing happens. All but 2 this time in the first 2 minutes of running bust the Intake Side rockers. Is it possible that there could be a bad batch? Can I just get away with running a 7.350 Pushrod on the Intake side without any issues?
TSP has nothing to do with it like you said and I doubt Comp does either. Also check that your ID locators are right for the springs you are using and that the inner spring isn't going into bind early or up on the spring ID locator etc. If the heads were ever repaired you may have a valve guide or two that are higher than others causing binding under the retainers.
Anotherwords could be a hundred things but should be easy to find. Check the lift at the valve on that lobe too anyway but that would be a longshot. That intake lobe is probably an LSK but that should have been accounted for when you set up the springs for that cam since it is higher lift on the intake side. The fact that it's breaking on the intakes usually means it's probably a simple bind issue
Thread Starter
Staging Lane
Joined: Oct 2004
Posts: 55
Likes: 0
From: boondocks
definately check your rocker geometry..i would get an adjustable pushrod and check for the proper pushrod length and preload..
was everything installed correctly?rocker stands seated properly?i'm just guessing here,but that sucks man..hope you get it figured out without spending a lot of money..
was everything installed correctly?rocker stands seated properly?i'm just guessing here,but that sucks man..hope you get it figured out without spending a lot of money..
You need to measure your lobe lift with a dial indicator as has been suggested. You need to turn the crank (or better have someone else do it for you while you watch what's happening at the valve). When the valve is at it's most open point, how much clearance to you have between spring coils (measure with a feeler gage)? As the rocker goes back and forth, what kind of interference do you see (use a mirror and a good light source). Can you get someone with a fair amount of troubleshooting experience to help you analyze what's happening?
Steve
Steve
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TECH Fanatic
Joined: Jun 2002
Posts: 1,979
Likes: 3
From: Upstate NY
Parts are hitting each other in your valvetrain. Until you get a real engine guy to go through your installation completely form start to finish to find the problem, you will continue to fail parts.
Whoever does the checking should not be the original installer.
If this is a hydraulic cam, checking things gets a little more complicated because the valvesprings may partially or fully collapse the lifter during your static check, but when running the lifter may stay extended and give you the parts interference you have. That is only one of many possibilities.
Please don't try to run the engine until someone finds and corrects the interference.
Jon
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Verdad Gallardo FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
You have been getting good advice from folks like Racer 7088. Repeating the same thing and expecting a different outcome doesn't work.
Parts are hitting each other in your valvetrain. Until you get a real engine guy to go through your installation completely form start to finish to find the problem, you will continue to fail parts.
Whoever does the checking should not be the original installer.
If this is a hydraulic cam, checking things gets a little more complicated because the valvesprings may partially or fully collapse the lifter during your static check, but when running the lifter may stay extended and give you the parts interference you have. That is only one of many possibilities.
Please don't try to run the engine until someone finds and corrects the interference.
Jon
Parts are hitting each other in your valvetrain. Until you get a real engine guy to go through your installation completely form start to finish to find the problem, you will continue to fail parts.
Whoever does the checking should not be the original installer.
If this is a hydraulic cam, checking things gets a little more complicated because the valvesprings may partially or fully collapse the lifter during your static check, but when running the lifter may stay extended and give you the parts interference you have. That is only one of many possibilities.
Please don't try to run the engine until someone finds and corrects the interference.
Jon
Jon and Erik are both right about the fact that the hydraulic lifters are collapsed (compared to their length when pumped-up during running) when the valve train is being assembled. Also, I question why you went with a cam with such a huge lift (.649") on the intake side. Unless you have heads with intake flows that can take advantage of this kind of lift, you're not really getting any benefit from the last portion of the valve lift and this is what is causing the grief. Very few valve springs will accomodate this kind of lift without coil bind.
Steve
Steve
Might be too elementary, but what thickness spring shims are you running? I have ALMOST installed a set of double springs with shims that were intended for anther use (out of the box). It wouldnt have mattered for a smaller cam, >.580. But on something like yours, probably would have gone to bind.