I got a little aggressive and tightened one of the bolts on my valve covers too tight and the cover cracked. The crack isn't just confined to the flange, it goes up the side of the cover about an inch. I'd really prefer to repair this instead of dropping $125 on a new set of covers.
Would JB Weld be OK to use on the inside of the valve cover? The manufacturer says it's good to 500 degrees. Not sure it gets that hot in there - but I'm more worried about the oil working it loose and having it end up somewhere in my engine.
These are the covers I have BTW - they're cast aluminum.
Worth a try, You have nothing to lose. Just make sure there is no oil on the crack area. You might consider making a small V in the crack on the inside and really rough up the area around the crack. Set up the valve cover so gravity does not cause the JB Weld to run. Do NOT use JB Quick Weld, It is not as heat resistant or as strong. After curing and installing, keep a watch on the valve cover for a few drives for leaks or recracking. For additional support of the crack you might place a piece of heavy sheet metal over the crack on the inside and JB Weld it in place.
Rough up the metal inside cover-like 40 grit. Get a piece of fiberglass cloth, permeate thoroughly i with JB Weld and attach. If you can see the end of crack, a small hole drilled in end and, of course filled with JB, should stop it. The hole shouldn't be noticeable with the black wrinkle. JB has been successfully used to fix engine block cracks so the heat won't bother it.
Bite the bullet and fix it the correct way, get new covers. JB Weld and fiberglass might fix it. But they might fail and then you have JB Weld and fiberglass floating around inside your engine. Is risking your engine worth $125? I cut corners on my signature car in some areas and it always came back to haunt me later.
For future reference, you don't need to tighten cast aluminum valve covers much. I use a 1/4" drive socket with a screwdriver handle attachment. It doesn't take much torque. I do a kind of crisscross tightening sequence. This way I don't over torque any of the bolts and they get tightened evenly. I also use Felpro neopreme valve cover gaskets. I've never had cast covers leak with this setup, even reusing the gaskets after valve adjustments.
1970 Fastback (to be finished outside as a Boss 302 clone)
393 Windsor AFR 205 heads with 11.5:1 compression
Tremec TKO 5 Speed
Link to my Hub Garage and blog about my car http://www.hubgarage.com/mygarage/maxum96
+1 on doing it right the first time. Why risk JB with the heat and vibration, seems like your just setting yourself up for future troubles.
Dirty Harry is a 1967 Mustang Convertible, 289 2v, automatic, soon to be 331 with Kenne Bell 2.2 Flowzilla Blowzilla, AODE. Next project is my Arizona 1966 Fastback...way down the line!
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