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Valve cover bolts coming loose |
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Saz2686
AMC Apprentice Joined: Jan/03/2014 Location: Lakehurst nj Status: Offline Points: 101 |
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Posted: Mar/14/2018 at 6:26am |
I have edelbrock aluminum heads, cast aluminum valve covers, cork gasket, stainless steel hex bolts.
I have about 6 - 8 heat cycles on this setup. Every time it heats up, the bolts loosen and oil leaks. I called edelbrock and guy said there is not a torque spec for the Vc bolts. When the aluminum heads heat up they expand and crush the cork. He suggested I use a rubber gasket because it has better elasticity. If that does not solve it, use studs and bolts. Seems worth a try. Previously I had stamped steel covers and a cork gasket, it acted the same way. I tried blue thread lock along with lock washers. Continued to loosen up. Am I not getting the bolts tight enough? I get them plenty snug, though I am a bit reserved as I don’t want to split the cork or strip the threads, or break the valve cover. Anyone have the solution? I want to avoid rtv, until last desperate try. |
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Scott - 73 Javelin. 401 engine. T5Z trans. 3.54 posi
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Saz2686
AMC Apprentice Joined: Jan/03/2014 Location: Lakehurst nj Status: Offline Points: 101 |
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I think a nylon locknut with a stud might do it. Blue thread lock the stud in. These are made by morose for an engine with vibration. I have a relatively rough cam, not insane but it has loosened up other bolts on the engine also.
The only thing I don’t like about studs is I am pretty sure I will have the move the power steering pump to get the valve covers over the stud. That’s fine for one time, but will Get old multiple times, if I need to remove the vc |
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Scott - 73 Javelin. 401 engine. T5Z trans. 3.54 posi
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Saz2686
AMC Apprentice Joined: Jan/03/2014 Location: Lakehurst nj Status: Offline Points: 101 |
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So far the problem has been resolved. I have three rides on this setup with no sign of oil leakage.
I used Edlebrock 7532 valve cover gasket. It did need to be trimmed on the corners for a decent fit to the valve covers. The bolt holes did not line up great either, had to hone out a few. I used 3m spray adhesive to get proper alignment to the valve covers and let it setup with clothes line hangers to hold form. Used jegs brand studs and nylon lock nuts. Part number 555-50148. I just used antisieze on the studs for the head side, nothing on the nylock side. The studs and/or nuts have not come loose |
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Scott - 73 Javelin. 401 engine. T5Z trans. 3.54 posi
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White70JavelinSST
Supporter of TheAMCForum Joined: Aug/08/2012 Location: Minnesota Status: Offline Points: 4867 |
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Nice, easy solution, well done !
I'll have to remember this ! |
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70 Javelin SST, second owner, purchased 1972
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Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4210 |
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Use a mild Locktight like blue and the rubber gaskets.
Over torqueing will ruin the covers. |
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Gremlin Dreams
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Saz2686
AMC Apprentice Joined: Jan/03/2014 Location: Lakehurst nj Status: Offline Points: 101 |
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Borris, I would have used blue thread lock except I installed the previous bolts with antisieze and I didn't want to clean all the head threads. So I just used antisieze again.
Rubber gasket is next if it leaks again. Glad it's good for now. Will advise if it leaks again |
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Scott - 73 Javelin. 401 engine. T5Z trans. 3.54 posi
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Saz2686
AMC Apprentice Joined: Jan/03/2014 Location: Lakehurst nj Status: Offline Points: 101 |
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Here is a picture
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Scott - 73 Javelin. 401 engine. T5Z trans. 3.54 posi
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6768rogues
AMC Addicted Joined: Jul/03/2007 Location: United States Status: Offline Points: 6241 |
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I would use Locktite or it would look good with drilled bolt heads and safety wire.
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Located usually near Rochester, NY and sometimes central FL. |
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Red20
AMC Addicted Joined: Jan/29/2013 Location: Oceanside CA Status: Offline Points: 1556 |
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I don’t know why I never thought of the nyloc nut idea... I thought you just snug them back up every 100 miles as a rule!
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1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018
1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER |
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Lyle
AMC Addicted Joined: Jul/17/2014 Location: None Status: Offline Points: 772 |
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I believe the problem with leaks is you have three different metals and a gasket with different heat expansion coefficients.
The nylocks may or may not help. They have another heat expansion coefficient. AMC used cast iron heads, steel covers and steel fasteners all working closely together with a gasket. In the end if you do not "seal" the rocker covers with Form a Gasket, Hylomar or some other adhesive sealer in this assembly. Three or more different heat expansion materials used in a seal face will likely fail. Later AMC engines with polymer rocker covers did not use gaskets for this very reason. |
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