LT1-LT4 Modifications 1993-97 Gen II Small Block V8

bent pushrod/broken valvespring..need help?

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Old 03-03-2007, 11:57 PM
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Default bent pushrod/broken valvespring..need help?


Well on my way to work I started getting a very loud ticking, I limped it to a gas station. about 3 blocks away.
pulled driverside valvecover. found a broken spring. pulled the rr' and found a bent pushrod. I never had a problem with the valvetrain before. had them on for about 10,000 miles. but I did put in new oem lifters about 2,000 miles ago.
I have crane gold 1.6rr's. nsa with gm guideplates. 7.2" comp hardened pushrods. k-motion k-750 or k-800 dual coil springs good to .600 lift. could the spring breaking bend my pushrod? or vice versa? and I know how to put in new pushrods, and how to adj. the lash on the rr's. but I never changed a spring, I was told to blow air into the cylinder head to hold up the valve how do I get the lock/retainer off. can anyone walk me thru the steps. I will have to wait until monday to overnight a new spring and pushrods thru jegs. do you think the valve is okay/not bent? thanks for any help...
Old 03-04-2007, 12:47 AM
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If you have a bent Pushrod, it may have possibly wedged into the Rocker. I think that even when the Spring Collapsed, the Valve should be alright. You will find out when you blow Air into it. The Valve settled down and so did the Rocker, causing the Rod to wedge under it and bend when the Cam rotated. That's my guess, cause the Piston is Reliefed to where they won't hit the Valves.
Old 03-04-2007, 10:18 AM
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This will help you with your valve spring swap:
http://shbox.com/ci/valve_spring_swap.html

Shoe Box's website is an awesome resource for LT1 owners.
Old 03-04-2007, 11:52 AM
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thanks for the help guys. glad I had the dual coil springs. the inner coil is keeping the valve up. so I know it didn't hit the piston. Im having a new spring and a new set of hardened pushrods overnighted, I hop my pushrods are the right length? it seems like the polylocks, outer nuts are rubbing the top of my rr's on each side. I can see scrapes on all of my rr's like the lockdown nuts are rubbing them, will they do that?
I was told by my head guy who built my heads, that I just needed the 7.2" pr. I think Im going to put a pushrod length checker on and make sure there right? but you would think that if there off I would of noticed before 10,000 miles...
Old 03-04-2007, 01:13 PM
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Usually good push rods only bend because they were bound up. The new lifters may have made the situation worse if the installed hieght was off. K800s can be installed at many differst hieghts. Mine are at 1.850 if I remember and I am running over .600 lift with no issues. I have been running K800s on mnany cars for 10 years or so now. There are better prings out there I am sure but we have had good luck with them. One of the reasons i stay with the dual springs is in case of a spring failure like you had

I would check for coil bind at your full lift
Old 03-04-2007, 04:36 PM
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well I just talked to the guy who did my heads, he said they are the k-750's single coil,but with a dampening inner spring? I never heard of a dampening spring, could that change my length I would need for my pushrod?
Old 03-05-2007, 09:25 AM
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Not really. Valve stem Hieght and deck surface control it the most.

Looking at that spring:

K-Motion K-750
1.265'' Dia. Single H-11 Valve Springs,
Seat Load: 130lbs @ 1.700''
Open Load: 395lbs @ 1.150''
Coil Bind: 1.050''
Max Lift: .610''
Set of 16

I would go to the K-800

1.460'' Dia. Silicon Double Valve Spring with Damper,
Seat Load: 165lbs @ 1.850''
Open Load: 495lbs @ 1.150''
Coil Bind: 1.085''
Max Lift: .700''
Set of 16


You will need new retainers but the Package is cheaper over all and much cheaper then loosing an Engine



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