Rocker / Pushrod issue! please help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

NewRevNorton · 05-07-2012, 08:37 PM

I rebuilt my 283 roughly two weeks ago and added a Howards cam to it during the build. I will have to find the exact part number but I believe the lift was 449 and the duration was 290. I looked it up at the speed shop and was told it would be fine with the stock valve setup on my double hump heads. Shortly after the rebuild I found a broken pushrod. I replaced it and did not notice any issues. I had an exhaust leak so ticking was expected. I had another weekend off so I set out to fix the exhaust leak. Fixed that and found the ticking noise to be a rocker arm that was sideways off of the valve seat and the pushrod bent again. So I replaced the pushrod again. The truck ran nice and quiet for about 15 seconds at idle and the began ticking again. SAME ISSUE! SAME VALVE! So I checked the rocker arm and it was pretty worn where it contacts the valve. So this time I replaced the rocker arm, nut, pivot ball, and pushrod. Put it all back together, got it running for a short idle, and yet again... Rocker arm sitting off to the side of the valve and pushrod bent. I pulled the heads and noticed a nice gash in the rocker stud cutting over half way through it. I have the heads at the machine shop now getting a new rocker stud and valve to be safe. Any ideas or experience with this guys? It is always on the same valve, the pushrod guide has no visible wear or damage, and the valve seat seems nice and flat. I hate to waste my time getting a new stud if the issue will continue.
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jj1965 · 05-07-2012, 09:03 PM

I was thinking valve train geometry might be off but it is on the same valve. Lifter could be collapsed if you are running hydraulic lifters. I would watch your rocker arm to valve when you turn the engine over and verify it is riding in the center of your valve and not binding the spring. I also had a similar issue with aftermarket valve covers rubbing on the rocker arm causing a ticking sound and some binding, Summit Racing brand. Longer pushrods can help to correct spring binding if you have an issue with it.

NewRevNorton · 05-07-2012, 10:09 PM

I thought about a bad hydraulic lifter so after pulling the intake I switched the lifter from the problematic valve on cylinder 7 with a lifter from cylinder 1. I am hoping this switch will allow me to see if the problem remains on the valve on cylinder 7, moves with the lifter to the valve on cylinder 1, or maybe the issue will be fixed with the new rocker stud and new valve on cylinder 7. I guess I will see when the heads come back and I get it running again.
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crazy longhorn · 05-07-2012, 10:52 PM

Quote:

Originally Posted by NewRevNorton

I thought about a bad hydraulic lifter so after pulling the intake I switched the lifter from the problematic valve on cylinder 7 with a lifter from cylinder 1. I am hoping this switch will allow me to see if the problem remains on the valve on cylinder 7, moves with the lifter to the valve on cylinder 1, or maybe the issue will be fixed with the new rocker stud and new valve on cylinder 7. I guess I will see when the heads come back and I get it running again.
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You should not swap lifters from hole to hole, on a set run in. If it were mine, I would put the lifters back in order(replace the suspected bad 1 with a new lifter)....use some good old moly paste, & figure that you are seating that new lifter to the lobe. Before you start, you might check the lobe for wear on your #7 problem.

Other than that, it sounds like it could a coil bind problem. Best of fun,crazyL

dwcsr · 05-07-2012, 11:04 PM

That was a problem on the 283 and 327 with hi lift cams. I think if you look you'll find that the slots in the rockers are hitting the rocker studs. If your using stock rockers you need to get a set of long slot rockers so the can move the full distance and not clip the stud. Get a set of Comp cams roller tips There cheap and have a long slot.

crazy longhorn · 05-07-2012, 11:20 PM

Quote:

Originally Posted by dwcsr

That was a problem on the 283 and 327 with hi lift cams. I think if you look you'll find that the slots in the rockers are hitting the rocker studs. If your using stock rockers you need to get a set of long slot rockers so the can move the full distance and not clip the stud. Get a set of Comp cams roller tips There cheap and have a long slot.

2nd that one....I have been running aftermarket rockers for long enough to forget! Glad you brought it up

crazyL

dwcsr · 05-07-2012, 11:41 PM

Quote:

Originally Posted by crazy longhorn

2nd that one....I have been running aftermarket rockers for long enough to forget! Glad you brought it up

crazyL

And the studs need to be pinned if they are not already. That old school stuff was a lot of work to keep running back then.

NewRevNorton · 05-07-2012, 11:47 PM

Would you guys happen to have a link the these rockers? Still not understanding the "long slot" style.
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NewRevNorton · 05-07-2012, 11:56 PM

I found this set of self aligning rockets. Would these be a compatible set?

http://m.summitracing.com/parts/cca-1417-16

Or this set...
http://m.summitracing.com/parts/SUM-141707

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**Captainfab** · 05-08-2012, 12:06 AM

A set of long slot rockers wouldn't hurt, but at the lift you posted, I'm not convinced that is your problem. Were all the rocker arms new when the engine was rebuilt? I assume the heads were rebuilt, to the tips of the valve stems should be flat and true. So theoretically with flat valve stem tips, new rocker arms and straight pushrods, the rockers should stay centered on the valve stem. Many years ago, I had a similar issue with a basically stock 300hp 327. I ended up just having the heads rebuilt and had them machine for screw in studs and guideplates while they were at it. The guideplates may have been overkill for what the engine was, but I didn't want to have to deal with bent/broken pushrods again.

Edit: The self aligning rockers would certainly solve the problem of the rockers slipping off to the side. I would stay with the 1.5/1.52 ratio rockers though. Since you have the heads off nayway, I would also have the valve stem tips checked for flatness.

NewRevNorton · 05-08-2012, 12:24 AM

Thank you captain. That is actually what they are doing at the machine shop. Replacing the stud due to the gash and valve do to uneven wear on the valve tip. I could get a set of factory vortec rocker arms that are self aligning for a very low price from work. You think that would be a wise investment over spending twice the cost on aftermarket roller tip rockers? I still haven't even gotten to the brakes yet so the bracket I bought from you is still new in the package just looking pretty on the seat in truck. Found a spun bearing before I could get to the brakes. Hence the REBUILT 283... And as you see the surprises continue...
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NewRevNorton · 05-08-2012, 01:11 PM

Bump for an opinion on the factory vortec self aligning rocker arms...
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Marv D · 05-08-2012, 09:52 PM

I suspect CrazyL means to use the self aligning IF you machine the heads for them. I'd NOT use the self aligning rockers on any early style head. The early heads use a pushrod pinch to aligns the pushrod, you attempt to use TWO methods and you asking for trouble IMO. If the heads have been machined for guide plates (the pinch is drilled) and your not using guide plates,, well If that were the case you'd have screw in studs... so that's a moot point.

You have some other issue going on to keep bending breaking pushrods. You see no evidence of the valve contacting the piston?? The heads you have,, what are they. Hopefully not 2.02 itakes and even some of the 1.94" intake valves will contact the edge of the small 3.875" bore with lifts aproaching around .48 - .50. Just depends on which head and the chamber configuration. Look at the edge of the valve to be sure.

Lastly, with no evidence of a cracked valve guide, bent valve etc... I'd look for a broken valve spring. A broken spring will let the pushrod to jump out of the cup and jam cockeyed into the rocker.

RanchFlyer · 05-08-2012, 10:43 PM

To me 2 things break or bend valve train. Flex at crazy stress, and collision. In the break-in stage, where you are collision is the only one in play. Inspect every thing very closely. As others have said check the valve for hitting the bore. You may put some solid lifters in there for checking while reassembling. Role it over by hand with the solids watching closely for impact. Gently, you can bend a valve by hand.

dwcsr · 05-08-2012, 11:15 PM

Quote:

Originally Posted by NewRevNorton

I found this set of self aligning rockets. Would these be a compatible set?

http://m.summitracing.com/parts/cca-1417-16

Or this set...
http://m.summitracing.com/parts/SUM-141707

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Make sure you have a 3/8 stud. http://m.summitracing.com/parts/lun-85025

NewRevNorton · 05-09-2012, 11:10 PM

Well guys I got the heads back today and the valve spring retainer had excessive play and scored the valve stem quite a bit. So hopefully this created a bind and replacing the valve, retainer, rocker arm, rocker stud, and pushrod will fix the issue. I'll keep you all posted once it is running again. I looked at the cam lobe through the lifter bore while I was switching the lifters back to their original homes and it looked nice and smooth. Thanks for all of the help.
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05-07-2012, 08:37 PM	#1
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Rocker / Pushrod issue! please help! I rebuilt my 283 roughly two weeks ago and added a Howards cam to it during the build. I will have to find the exact part number but I believe the lift was 449 and the duration was 290. I looked it up at the speed shop and was told it would be fine with the stock valve setup on my double hump heads. Shortly after the rebuild I found a broken pushrod. I replaced it and did not notice any issues. I had an exhaust leak so ticking was expected. I had another weekend off so I set out to fix the exhaust leak. Fixed that and found the ticking noise to be a rocker arm that was sideways off of the valve seat and the pushrod bent again. So I replaced the pushrod again. The truck ran nice and quiet for about 15 seconds at idle and the began ticking again. SAME ISSUE! SAME VALVE! So I checked the rocker arm and it was pretty worn where it contacts the valve. So this time I replaced the rocker arm, nut, pivot ball, and pushrod. Put it all back together, got it running for a short idle, and yet again... Rocker arm sitting off to the side of the valve and pushrod bent. I pulled the heads and noticed a nice gash in the rocker stud cutting over half way through it. I have the heads at the machine shop now getting a new rocker stud and valve to be safe. Any ideas or experience with this guys? It is always on the same valve, the pushrod guide has no visible wear or damage, and the valve seat seems nice and flat. I hate to waste my time getting a new stud if the issue will continue. Posted via Mobile Device Last edited by NewRevNorton; 05-07-2012 at 08:48 PM.

05-07-2012, 09:03 PM	#2
jj1965 Registered User Join Date: Feb 2011 Location: Stillwater Oklahoma Posts: 56	Re: Rocker / Pushrod issue! please help! I was thinking valve train geometry might be off but it is on the same valve. Lifter could be collapsed if you are running hydraulic lifters. I would watch your rocker arm to valve when you turn the engine over and verify it is riding in the center of your valve and not binding the spring. I also had a similar issue with aftermarket valve covers rubbing on the rocker arm causing a ticking sound and some binding, Summit Racing brand. Longer pushrods can help to correct spring binding if you have an issue with it.

05-07-2012, 10:09 PM	#3
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! I thought about a bad hydraulic lifter so after pulling the intake I switched the lifter from the problematic valve on cylinder 7 with a lifter from cylinder 1. I am hoping this switch will allow me to see if the problem remains on the valve on cylinder 7, moves with the lifter to the valve on cylinder 1, or maybe the issue will be fixed with the new rocker stud and new valve on cylinder 7. I guess I will see when the heads come back and I get it running again. Posted via Mobile Device

05-07-2012, 11:04 PM	#5
dwcsr Hollister Road Co. Join Date: Apr 2005 Location: Houston Posts: 6,131	Re: Rocker / Pushrod issue! please help! That was a problem on the 283 and 327 with hi lift cams. I think if you look you'll find that the slots in the rockers are hitting the rocker studs. If your using stock rockers you need to get a set of long slot rockers so the can move the full distance and not clip the stud. Get a set of Comp cams roller tips There cheap and have a long slot.

05-07-2012, 11:47 PM	#8
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! Would you guys happen to have a link the these rockers? Still not understanding the "long slot" style. Posted via Mobile Device

05-07-2012, 11:56 PM	#9
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! I found this set of self aligning rockets. Would these be a compatible set? http://m.summitracing.com/parts/cca-1417-16 Or this set... http://m.summitracing.com/parts/SUM-141707 Posted via Mobile Device

05-08-2012, 12:06 AM	#10
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Rocker / Pushrod issue! please help! A set of long slot rockers wouldn't hurt, but at the lift you posted, I'm not convinced that is your problem. Were all the rocker arms new when the engine was rebuilt? I assume the heads were rebuilt, to the tips of the valve stems should be flat and true. So theoretically with flat valve stem tips, new rocker arms and straight pushrods, the rockers should stay centered on the valve stem. Many years ago, I had a similar issue with a basically stock 300hp 327. I ended up just having the heads rebuilt and had them machine for screw in studs and guideplates while they were at it. The guideplates may have been overkill for what the engine was, but I didn't want to have to deal with bent/broken pushrods again. Edit: The self aligning rockers would certainly solve the problem of the rockers slipping off to the side. I would stay with the 1.5/1.52 ratio rockers though. Since you have the heads off nayway, I would also have the valve stem tips checked for flatness. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

05-08-2012, 12:24 AM	#11
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! Thank you captain. That is actually what they are doing at the machine shop. Replacing the stud due to the gash and valve do to uneven wear on the valve tip. I could get a set of factory vortec rocker arms that are self aligning for a very low price from work. You think that would be a wise investment over spending twice the cost on aftermarket roller tip rockers? I still haven't even gotten to the brakes yet so the bracket I bought from you is still new in the package just looking pretty on the seat in truck. Found a spun bearing before I could get to the brakes. Hence the REBUILT 283... And as you see the surprises continue... Posted via Mobile Device Last edited by NewRevNorton; 05-08-2012 at 12:33 AM.

05-08-2012, 01:11 PM	#12
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! Bump for an opinion on the factory vortec self aligning rocker arms... Posted via Mobile Device

05-08-2012, 09:52 PM	#13
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: Rocker / Pushrod issue! please help! I suspect CrazyL means to use the self aligning IF you machine the heads for them. I'd NOT use the self aligning rockers on any early style head. The early heads use a pushrod pinch to aligns the pushrod, you attempt to use TWO methods and you asking for trouble IMO. If the heads have been machined for guide plates (the pinch is drilled) and your not using guide plates,, well If that were the case you'd have screw in studs... so that's a moot point. You have some other issue going on to keep bending breaking pushrods. You see no evidence of the valve contacting the piston?? The heads you have,, what are they. Hopefully not 2.02 itakes and even some of the 1.94" intake valves will contact the edge of the small 3.875" bore with lifts aproaching around .48 - .50. Just depends on which head and the chamber configuration. Look at the edge of the valve to be sure. Lastly, with no evidence of a cracked valve guide, bent valve etc... I'd look for a broken valve spring. A broken spring will let the pushrod to jump out of the cup and jam cockeyed into the rocker. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

05-08-2012, 10:43 PM	#14
RanchFlyer Registered User Join Date: Jan 2010 Location: Flint, TX Posts: 147	Re: Rocker / Pushrod issue! please help! To me 2 things break or bend valve train. Flex at crazy stress, and collision. In the break-in stage, where you are collision is the only one in play. Inspect every thing very closely. As others have said check the valve for hitting the bore. You may put some solid lifters in there for checking while reassembling. Role it over by hand with the solids watching closely for impact. Gently, you can bend a valve by hand.

05-09-2012, 11:10 PM	#16
NewRevNorton Registered User Join Date: Mar 2012 Location: Falkville AL Posts: 17	Re: Rocker / Pushrod issue! please help! Well guys I got the heads back today and the valve spring retainer had excessive play and scored the valve stem quite a bit. So hopefully this created a bind and replacing the valve, retainer, rocker arm, rocker stud, and pushrod will fix the issue. I'll keep you all posted once it is running again. I looked at the cam lobe through the lifter bore while I was switching the lifters back to their original homes and it looked nice and smooth. Thanks for all of the help. Posted via Mobile Device



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