I'm finding that I need to continually re-tighten the L&L headers on my big-block F-250...Trying to prevent a blown gasket I've been checking the bolts every week and I always find several that are working loose.

I want to replace the black oxide hex-head bolts and internal tooth lockwashers that L&L provided and with socket-head grade 8+ (actually grade 12, the toughest bolts I can find at 65 cents each) along with hi-temp red Loctite. My understanding is that while the temperatures there will cook a lot of the strength out of Loctite, it'll still hold them in.

Looking for feedback from anyone that's actually tried this approach.
Thanks.

 

>I'm finding that I need to continually re-tighten the L&L
>headers on my big-block F-250...Trying to prevent a blown
>gasket I've been checking the bolts every week and I always
>find several that are working loose.
>
>I want to replace the black oxide hex-head bolts and
>internal tooth lockwashers that L&L provided and with
>socket-head grade 8+ (actually grade 12, the toughest bolts
>I can find at 65 cents each) along with hi-temp red Loctite.
>My understanding is that while the temperatures there will
>cook a lot of the strength out of Loctite, it'll still hold
>them in.
>
>Looking for feedback from anyone that's actually tried this
>approach.
>Thanks.


I'm not sure I'd use the high strength Loc-tite. You might need a torch to get the bolts off in the future.

There is a cool product called "Stage 8" bolts. They are a self locking system that does not allow the bolt to loosen. They were a slight pain to install, you have to grind the piece of metal that slips over the bolt so it wedges against the header, then you circlip it on. The bolts are 12 point(?) and also can be tightened with an Allen wrench.

 

Could you find a motorcycle "nut" friend that could safety wire them for you? Seems to work fine on motorcycle exhaust bolts.

 

Heat makes locktite even stronger, it's like high-temp paint, the more heat you apply, you stronger the bond it forms, that's why propane torches aid in removal.

The TorqueKing

 

I retract this comment, nevermind my counter-intuitive statement above, I wasn't thinking, it's late out here. Thanks Eric for pointing that out.

The TorqueKing

 

along the header bolt deal. i soak the header to head gasket and the collector gasket in water for a hour or so prior to using. this will extend the like of the gasket and make it extremely durable. now all the above applies to the paper/fiber type gaskets only. no loctite

 

If I remember correctly the Red loctite I think it is 271 softens up at about 400 degrees F. I like the idea of the safety wire or the bolt locking kits are a good alternative. You might want to consider getting some good quality header gaskets while you are at it. I have been using Byson gaskets and never had a leak or failure in the 6 years that I have had the headers on.

 

What are the Byson gaskets made of and where do you get them. It is a brand I don't recognize.

 

[updated:LAST EDITED ON 05-Jun-02 AT 11:17 PM (EST)]If I remember correctly they are made of a Asbestos fiber (Yeah I know that is a bad word) that is bonded within a rubber type base. You really would need to talk to Byson and here is the info to contact them.

Byson Gaskets
1845 Sampson Ave.
Corona, CA. 92879
909-734-3850
Talk to Garr or Allen

If they ask who sent you just tell them Terry from MTA.

BTW: Doug Thorley uses them with there headers.

 

 

Red Loc-tite wont work I use it all the time and can remove it with a hand held torch.Check a Loc-tite distributor for high temp applications.Any local bearing distributor should carry Loc-tite.

 

Well, FWIW it's been a month since my first post asking about the Loctite...I went ahead and replaced the original header bolts I got with the L&L headers with black oxide finish 1-1/4" long grade 8 allen head cap bolts and used no washers. I applied red hi-temp Loctite to the new bolts. I deliberately left 4 of the 16 original bolts in place as a comparison.

Where they used to loosen almost weekly, the new bolts with Loctite haven't loosened at all. I can put an allen wrench in them and they won't budge any tighter, just as I put them in. Two of the four original bolts I left in without Loctite could be turned abour 1/8 to 1/4 turn to fully tighten them again.

So far, so good. I'll post back in another month with how it goes.

Thanks for everyone's input.

-Bill in Colorado
'96 F-250 460.

 

The block that the bolts are threaded into should not get much warmer than the coolant during normal operation. Under heavy extended loading like a long pull uphill the block and bolts could get much hotter. The headers will be transferring heat directly to the bolt heads. The bolts will have to conduct that heat to the block and into the coolant. The point where the Loctite would fail is anyone's guess. If the Loctite does not fail, -good luck getting the bolts out, it will take a torch to heat each bolt.

 

Yes, you're right Eric, it's all a matter of tradeoffs.
Like I said, so far, the Loctite has done it's job.

I have to respectfully disagree with you about the temperatures involved, judging by the way paint burns off the heads, the area where the header bolts thread in around the exhaust ports has got to be much hotter than the 180 degree coolant temperature. I'm guessing at least 400 degrees. My old exhaust manifolds used to glow dull red in the dark after a long pull. Mucho heat!

I did some reading on the Loctite literature, and it doesn't seem to fail all at once, it slowly weakens as the temperature goes up. My thinking was that even if it lost 1/2 or more its strength, it would be OK. I think it's the hot-cold engine cycling that made the dry bolts work loose all the time.

Out of curiousity I'm going to try removing one of the Loctited bolts one of these days to see if getting them out might be a big problem in the future, if it doesn't want to move for now, well, that's OK, too, I can always use the acetylene torch around the exhaust ports until the stuff softens enough.

My main issue is I didn't want to hear the wife telling me, "I just pulled our trailer and now I hear this popping noise from the engine"- oops, blown header gasket because they came loose again...Two days of fun to replace...

Thanks, Eric. Best regards.

-Bill in Colorado

 

Yeah, I have seen that paint burn off also. The bolt thread temp is going to depend on the conduction path to the coolant passages. All nice and relative depending on location and engine family. I have also seen the same red color from the manifolds. Headers have a nice glow also. Some of the paint gets burned off by the radiant heat. You could also drill a small hole down the center of some bolts and put in thermocouples:-)

You are right about the hot/cold cycles.

Good luck with the Locktite experiment.