Loose valve cover bolts on 350 sbc

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GreenSwamperin
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Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Sat Jan 24, 2015 2:02 pm

Well, my time to work on the boat and install my anti dieseling switch was ruined by the rain this morning. I did have a chance to take a quick look at it in between showers though and noticed my valve cover bolts are coming loose again.
I just replaced the gaskets and bolts last week. I drove it around the pasture for 5 minutes and the bolts are already loose enough that oil was seeping out of several of them.

Is there any fix for this?

The previous owner just kept cranking them down until the bolt heads were almost stripped and the gasket was mushed flat as a pancake. I had to scrape the old gasket pieces out when I changed it. The factory bolt torque specs are only like 4lbs or something. I'm past that I know. Lock Tite sounds like a bad idea for several reasons.
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kwanjangnihm
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Re: Loose valve cover bolts on 350 sbc

Post by kwanjangnihm » Sat Jan 24, 2015 5:22 pm

back in the day I've seen guys use RTV, Locktite and even a lock & flat washer combo! :rebel:
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Junker
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Re: Loose valve cover bolts on 350 sbc

Post by Junker » Sat Jan 24, 2015 5:57 pm

1/4 in - 20 thread studs and nylon insert lock nuts.........
14 x 8 Hamant
383 - 2.38 Stinger
80" 3 Blade
Stainless rigged

GreenSwamperin
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Re: Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Sat Jan 24, 2015 6:51 pm

I guess it would've been pertinent to mention that the motor has Vortec heads with the 4 bolts that go through the center of the valve cover. Sorry about that. I don't think there is any way to use a lock nut of any kind.
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Re: Loose valve cover bolts on 350 sbc

Post by wildcard » Sat Jan 24, 2015 6:51 pm

don't use junk cork gaskets

GreenSwamperin
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Re: Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Sat Jan 24, 2015 7:10 pm

I used a Felpro cork gasket which I was told are some of the best. What is wrong with them?
What is better for this application?
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Re: Loose valve cover bolts on 350 sbc

Post by highlife57 » Sat Jan 24, 2015 7:36 pm

I think they make rubber valve cover gaskets.

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Re: Loose valve cover bolts on 350 sbc

Post by OLD MAN JONES » Sun Jan 25, 2015 12:56 am

ULTRA-BLACK
ULTRA- GREY
PERMATEX, you will find this stuff to be very useful in many applications for airboats, keep a tube on the boat at all times.

Also:
RIGHT STUFF 1 Minute gasket is a life saver in a pinch :thumbleft:
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Re: Loose valve cover bolts on 350 sbc

Post by AirHog » Sun Jan 25, 2015 9:40 am

Is it possible to use any longer bolts ? If not a mechanical lock like the lock washers mentioned is another possibility.

I can tell you if a bolt comes out and goes through your prop, you will not like the result!

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Re: Loose valve cover bolts on 350 sbc

Post by ddriver » Sun Jan 25, 2015 9:46 am

spend the money to buy good rubber gaskets for vortec motor and be done with it.

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Re: Loose valve cover bolts on 350 sbc

Post by terrible ted » Sun Jan 25, 2015 10:00 am

kwanjangnihm wrote:back in the day I've seen guys use RTV, Locktite and even a lock & flat washer combo! :rebel:

I used this method high temp silicone on header bolts valve covers= locktite makes all grade just make sure it removable yes they make none removable locktite.


http://www.mcmaster.com/#standard-cap-screws/=vmcix4
Last edited by terrible ted on Sun Jan 25, 2015 10:13 am, edited 1 time in total.

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Re: Loose valve cover bolts on 350 sbc

Post by terrible ted » Sun Jan 25, 2015 10:09 am

GreenSwamperin wrote:I guess it would've been pertinent to mention that the motor has Vortec heads with the 4 bolts that go through the center of the valve cover. Sorry about that. I don't think there is any way to use a lock nut of any kind.

If you need to be 100 percent safe at mind. Take the bolt out to the vise drill a small hole side ways thru the head and use aircraft wire thru each. I never had that problem on my vortec 350 dd or geared boat. yea it was cork gaskets.

Olf Art
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Re: Loose valve cover bolts on 350 sbc

Post by Olf Art » Sun Jan 25, 2015 10:22 am

I guess I'm more concerned about why they're loosening. Do you feel a lot of vibration when it's running hard?
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Re: Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Sun Jan 25, 2015 10:50 am

Thanks for the replies and recommendations everyone. What makes this particularly difficult is that the bolt heads are tapered and not flat. The threads are only at the very bottom where they go into the heads. I've searched high and low without finding any type of locking nut/bolt solution for the tapered style bolts.

Old Man Jones: Does the Permatex go on the gasket?
I think the only thing that could help gasket wise is to have something that's providing more push back against the valve covers and thus providing more resistance on the bolt threads.

I'm still a little unclear as to how rubber gaskets will help this issue. Can someone explain?

Old art: The engine was moving all over before I had Chris @ Dakota Airboats build me a new stand. It's rock solid now with very little vibration and appears to still be having the problem.
One of the old bolts did come out and go through the prop. That was how I originally discovered the problem. Thankfully there was little to no damage and nobody got hurt.

I'm kind of leaning towards red Lock Tight right now.
Clark Modica
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Aquatic Management & Consulting
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Environmental Permitting, Planning, and Design

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Re: Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Sun Jan 25, 2015 10:54 am

The threads are not bottomed out by the way. I can tighten them up further, but was hesitant to crank them down given how light the factory torque specs are.
Clark Modica
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Re: Loose valve cover bolts on 350 sbc

Post by terrible ted » Sun Jan 25, 2015 11:00 am

When I used the silicone -RTV to stop a bolt from backing out there's some on the treads and some under the head. I wonder if the silicone under the head is just acting like an ant vibration agent or a binder or both.

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Re: Loose valve cover bolts on 350 sbc

Post by zrackers » Mon Jan 26, 2015 10:16 am

I have a 4.3l vortec with the same style bolts and used lock tite on mine. I've had them back off since no problem. Just clean with wire brush and put new lock tite on each time.

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Re: Loose valve cover bolts on 350 sbc

Post by GreenSwamperin » Mon Jan 26, 2015 12:54 pm

Are you using blue or red zrackers? If you're using red, how do you heat them up for removal?
I have a heat gun, just not sure what it'd do to the powder coating on my valve covers.
Clark Modica
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Re: Loose valve cover bolts on 350 sbc

Post by terrible ted » Mon Jan 26, 2015 12:58 pm

red lock tight is listed usually as permanent torch it red hot to remove.

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Re: Loose valve cover bolts on 350 sbc

Post by zrackers » Mon Jan 26, 2015 10:27 pm

I use the blue. I can easily break mine loose with a ratchet and then clean and reinstall.

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Re: Loose valve cover bolts on 350 sbc

Post by Longdraw » Tue Jan 27, 2015 9:26 am

The factory style valve cover has a tube for bolt,so you can't over tighten. Wrap some teflon tape on threads and tighten down should have no problems

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