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Old 01-17-2017, 08:11 PM
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Join Date: Feb 2012
Location: Keller, TX
Cobra Make, Engine: Lonestar Classics LS427. Self-built 408W, AFR 195 heads, Performer RPM Intake, Quick Fuel 750, 407rwhp, 479rwtq
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OK, installing the studs (with thread sealant), guides, and rockers. Well, the guide plates keep breaking where the stud bolt goes thru the small ring. I give up! I'm torquing to the required 55 ft-lbs. Why is this hardened steel breaking? First, multiple spring failure - machinist says if they weren't heat treated, they would just get weak and sag. If they were over-heat treated, they would fracture/break. Then the valve guide wear. Still no idea why. I've been paying close attention as I've been putting it back together to make sure the geometry was correct.

Now the steel guide plates are breaking. Makes me wonder if I am not getting enough oil into the heads and everything is overheating, the metal becoming brittle, then breaking. Are these guide plates just a one-use item and need to be replaced once heat cycled?

How does a hydraulic lifter function in respect to oiling? I ran the oil pump with the drill. I see oil coming out of some of the lifters. Pushrods are not installed yet. I didn't run the engine over with a wrench or the starter, just driving the oil pump. Oil didn't come out of all the lifters. If I grab one lifter set (Howard brand link bar), oil come gushing out of the lifter hole. Will a lifter only pass oil if it is in the right place up/down in the bore? Will it only allow oil if a pushrod is installed and "pumping" the lifter as it lifts against the spring?

I'm about to invest in some dynamite for these heads...
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