Broken Valve Spring and More
05-29-2003, 07:41 AM
#1
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Broken Valve Spring and More
I'm a bit behind schedule this year. The winter cover is still on and I just started going over the motor. It's a 421" SBC, Dart block and heads. It had a valve tap at the end of last season so I pulled the valve covers and found a broken inner valve spring on #8 exhaust and about 3/16" valve lash on #6 intake. How do I determine the type, size, rating, etc. of the broken spring so I can replace it with the same thing? I'm thinking that the #6 intake problem could be a bent push rod or maybe just that the lifter collapsed over the winter. The lock nut on the rocker arm is still tight so I don't think the adjustment opened up. Please give me your opinions and suggestions on how to correct my problems.
05-29-2003, 07:57 AM
#2
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Sounds like it is time to change out the rockers, springs, and lifters and the push rods, cam and valves should be checked. The above I mentioned is for sure if the motor is equiped with a solid roller cam and I would do the above regardless what type of cam is in there. Have a competent shop help you select the proper components since they have the necessary measuring tools to check what you have now. Only my opinion. Good luck.
05-29-2003, 08:38 AM
#3
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Thanks for the reply. I'm sure you're correct. It would be the best thing to go through the whole valve train but I am trying to get by doing something that's a bit quicker and cheaper. The motor only has about 40 hours on it. Forgot to mention its a flat tappet hydraulic cam.
05-29-2003, 07:46 PM
#4
I hate the winter!!
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What I would be worried about is-- How the spring broke with only 40 hours on it. You have a flat tappet hydraulic cam so the lobe profile can't be too big or radical. My guess would be that the heads were not set up correctly when they were done last. Possibly you are getting coil bind, or maybe #8 exhaust valve is sticking in the guide. Do you have bronze guides? Do you have screw in studs or press in? If they are press in, it is possible that the #6 intake stud is pulling out. Check to see that all the studs are the same height. I would also check the lift on the #6 intake lobe with a dial indicator. You may have lost the lobe or lifter.
