Metal in Heads..Where Could It Be From?
#16
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Thanks to all for taking the time to share your thoughts. I found the culprit. I knew that the PAC beehive valve springs rotate above a certain rpm. The spring rotation speed increases as rpm increases. In past inspections I noticed a light polish where the spring contacts the retainer. This time I found scoring on most of the retainers from that spring contact/rotation. That is where the metal came from. I will be talking to PAC about this.
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To reduce dynamic valve train weight so as to increase rpm threshold for valve toss. Smaller valve spring retainer and spring coils at valve tip end versus straight coils and multiple coils.
I ordered tool steel retainers to replace the chrome moly retainers that were producing the metal.
I ordered tool steel retainers to replace the chrome moly retainers that were producing the metal.
Last edited by Rage; 10-22-2018 at 05:15 PM.
#19
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I had the same issue. Turned out, the shop that put the heads together, didnt use the correct hardware, for the springs. The locator shoulder measured like .680, and the inner springs ID measured like .740 if I recall. The retainer fit also wasnt the best. The springs were rotating, and digging into the locators, leaving tiny metal specks in the heads where the oil pools. Also, the inner spring was rubbing on the stem seal, likely from the pizz poor setup. Springs had good pressures, around 180/470 when tested, but were the wrong springs. They were a mile away from coil bind. Probably surging, wobbling, and dancing all over the place. Lesson learned with that shop.
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Thanks for sharing that. Identical condition to my retainers. PAC recommendation for 0.080" coil bind clearance was followed. The beehive allegedly has some inherent surge damping because of its range of spring coil diameter and spacing. Did you see any evidence on valve stem tips or rocker arm rollers that indicated valve train instability?