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Re: #2 pushrods keep bending and breaking WHY [Re: GTSDave] #1030974 07/14/11 05:25 PM 07/14/11 05:25 PM
Joined: Apr 2005 Posts: 1,505 TN S SCATPACK 1 OP pro stock
SCATPACK 1 OP pro stock S Joined: Apr 2005 Posts: 1,505 TN	I am not enjoying senility as much as I should be. -Dave M spring pressure is 250 on the seat and 600 open. Same springs I used on the bigger cam. Here is what I found to be the problem with the pushrods getting bent on #2 cylinder. And I believe it may all be due to a lack of good oil supply to these rockers. The valve guides on just this cylinder were worn more than the other cylinders guides were. I am running big intake valves and noticed they had some scuffing around the edge on the #2 cylinder. Also noticed some scuffing on the seat face for the exhaust valve. Had to use a magnifying glass with my old eyes to even find this. I think what has happened is the low supply of oil at the #2 cylinder rockers has allowed the valve guides to wear a little bit. This wear was enough to allow the opening intake valve to push over under the closing exhaust valve. This caused the exhaust valve to be pushed open by the intake valve and allowed the push rod to drop away from the adjustor and then the cup would get caught under the adjustor when the rocker arm came back down and the valve closed. This would explain why the exhaust pushrod is getting bent, but I cna not figure out why the intake side is gettin gbent except for maybe the excess valve spring presure of opening 2 valves at the same time. I had to pull the springs off to check guide clearances anyway and I found this by accident. I really thought the valve guides were seizing up under heat or something. I am going to fix the guides and put it back together after I do some updates to make sure enough oil is getting there. I wish now I had left the stock 1.75 ex valves instead of going to 1.81. Just too close/tight with 2.25 intakes. All my fault as I moved the intakes over as much as possible when I put the samller guides in to de-shroud the big intake valves. I am going to open some oil feed holes from the heads to the rocker shaft to make sure they are not restricted and take the rockers to Hensley Racing in Knoxville so they can modify them for direct oil to the pushrod cups and valve stems. Thanks to everyone for their input. Old Geezer Racing

Re: #2 pushrods keep bending and breaking WHY [Re: SCATPACK 1] #1030975 07/14/11 06:24 PM 07/14/11 06:24 PM
Joined: Aug 2003 Posts: 43,223 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,223 Bend,OR USA	Quote: I am not enjoying senility as much as I should be. -Dave M spring pressure is 250 on the seat and 600 open. Same springs I used on the bigger cam. Here is what I found to be the problem with the pushrods getting bent on #2 cylinder. And I believe it may all be due to a lack of good oil supply to these rockers. The valve guides on just this cylinder were worn more than the other cylinders guides were. I am running big intake valves and noticed they had some scuffing around the edge on the #2 cylinder. Also noticed some scuffing on the seat face for the exhaust valve. Had to use a magnifying glass with my old eyes to even find this. I think what has happened is the low supply of oil at the #2 cylinder rockers has allowed the valve guides to wear a little bit. This wear was enough to allow the opening intake valve to push over under the closing exhaust valve. This caused the exhaust valve to be pushed open by the intake valve and allowed the push rod to drop away from the adjustor and then the cup would get caught under the adjustor when the rocker arm came back down and the valve closed. This would explain why the exhaust pushrod is getting bent, but I cna not figure out why the intake side is gettin gbent except for maybe the excess valve spring presure of opening 2 valves at the same time. I had to pull the springs off to check guide clearances anyway and I found this by accident. I really thought the valve guides were seizing up under heat or something. I am going to fix the guides and put it back together after I do some updates to make sure enough oil is getting there. I wish now I had left the stock 1.75 ex valves instead of going to 1.81. Just too close/tight with 2.25 intakes. All my fault as I moved the intakes over as much as possible when I put the samller guides in to de-shroud the big intake valves. I am going to open some oil feed holes from the heads to the rocker shaft to make sure they are not restricted and take the rockers to Hensley Racing in Knoxville so they can modify them for direct oil to the pushrod cups and valve stems. Thanks to everyone for their input. Good find, there is always a reason stuff fails Sorry for the problems How is the rocker contact to the valve stem center on those two valves I'm suprised that the valve heads stay on with them touching each other every time they opened and closed Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: #2 pushrods keep bending and breaking WHY [Re: Cab_Burge] #1030976 07/15/11 11:15 AM 07/15/11 11:15 AM
Joined: Apr 2005 Posts: 1,505 TN S SCATPACK 1 OP pro stock
SCATPACK 1 OP pro stock S Joined: Apr 2005 Posts: 1,505 TN	Good find, there is always a reason stuff fails Sorry for the problems How is the rocker contact to the valve stem center on those two valves I'm suprised that the valve heads stay on with them touching each other every time they opened and closed Cab Those 2 valves were showing some wear marks on the stem right in the middle of the contact patch. It looks like the rocker is not moving across the valve stem at all, but staying in 1 spot thru its entire cycle. Do you think this is a mis-allignment issue? too high or too low on the rocker angle? To answer the other question, I don't think the intake is catching the exhaust valve every time the intake valve opens. I only hope this is the real problem as I can not duplicate the valve action at High RPM or the Heat cycle in my testing. But when I turn the crank by hand, I can put pressure on the intake valve and move the intake valve over enough that it will catch the ex valve with just light weight valve clearance springs in place. My plan is to fix the guides and replace all of the parts that could be an issue. Picked up another set of rocker shafts yesterday to replace the ones on there now and will replace the spacers with a set that has less clearance just to be sure these are not the issue. Old Geezer Racing

Re: #2 pushrods keep bending and breaking WHY [Re: SCATPACK 1] #1030977 07/15/11 01:46 PM 07/15/11 01:46 PM
Joined: Aug 2003 Posts: 43,223 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,223 Bend,OR USA	It sounds like the rocker tip to valve contact is correct, unless the rollers are siezed Look at the rest of the valves and if they all match thier good, if #2 is the only one with that contact patch the see why BTW, Harland Sharp and T&D like .030 total side clearances I have ran more with a set of light spacer springs and had the rockers slide over off of the valve stem Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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