Header bolts backing out

[mowog1]

I've been experiencing header bolts backing out of my Buick 300 heads, especially on #3 cylinder.

Wonder if any of you have tried these bolts and what your opinion is?

http://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=PRO-66753

[DC Townsend]

Can't speak to the one's in your link but I use Stage 8 (last 3 projects) and they work as advertised.

[rficalora]

How many many miles do you have on the car Rick?  And how many times have you retorqued them?  I was having the same problem & got some locking bolts.  But i got advice not to install the locks till I'd gone through several heat cycles & retorqed them a few times.  Did that & now they don't back out -- never even installed the locks.

[britcars]

Rick, I did the same as Rob.  Have over 6500 miles on the car and re-torqued the header bolts four times over about a two week period, getting a small amount of movement the first three times and none the fourth.  I had drilled the stainless bolts for safety wire before installation but haven't put the wire on yet.  May get to it over the winter.
Phil

[74ls1tr6]

Same as others...tighened 5 times...now they stay tight.

[ex-tyke]

I'll echo Rob and Phil's post. Takes 3 or 4 attempts at retorquing before the gasket settles in and the fasteners hold torque....but those fancy lock bolts will work too!

[classic conversions]

I don't think is the gasket settling, I think it is heat, moisture, rust thus keeping the bolt in place. But it does work after a few cycles of re-torquing the bolts.

One drop (small drop) of blue Loctite the first time install will keep them in place.

[rubbinisracin]

Some of mine backed out and fell out within the first few miles, I had to keep re-torquing.  I eventually got bolts with drilled heads and I safety wire all of them.  I think the problem I am having though is my header rubs the frame a little and therefore they they get worked a little under acceleration.  You might check to be sure you don't have a clearance issue on the headers or the rest of the system for that matter.

[Moderator]

Okay... This thread has convinced me I was right to save my money and simply use regular grade 8 bolts, and with anti-seize at that!

[britcars]

I did use anti-seize but just grade 5 stainless bolts.  Not a lot of torque involved but antiseize is always a good ideal, especially going into aluminum.  Remember that torque requirements are usaully smaller when bolts are lubed with anti-seize or some other lubricant.

[pspeaks]

Thanks for the tip Phil.  I don't have aluminum heads yet put was thinking of going that route this winter  At $35 for a set of 12 (I couldn't find a price on the set of 16) I might save my money for something else and go with grade 8 too.  Still, they do look pretty cool.


Paul

[BlownMGB-V8]

This is a big issue with the I-H crowd and we did some serious evaluation of it over the years. Two big issues became apparent, well three if you count rust separately. Gasket compression was a big factor, even with steel shim gaskets (stock) as they would flatten out completely. Gasket blow-out was a factor if the bolts were not tightened regularly until all compression was eliminated, and even then the seal was never completely reliable. Use of the later Rover multi-layer stainless steel shim gaskets eliminates this problem for many of us and I cannot recommend those enough. Truly a breakthrough solution, these do not take a set and are reusable, meaning it is a permanent remedy. Rover is to be commended for this in spite of the cost which is quite high, but it should be remembered that this is a one time purchase and eliminates a lot of woes and labor. The metallurgical issues in header  bolts are another big deal. It was found that grade 8 did not fare as well long term as grade 5 primarily because they were more prone to corrosion and would stick and then break off. Stainless, although corrosion resistant, was prone to galling. There was never found any single ideal solution, most favoring grade 5, some favoring stainless, but in every case liberally coated with a high grade anti-seize coating. I personally like the stainless because it eliminates the rust problem and the strength is similar to the grade 5.

Thermal expansion was found to be an issue and we were dealing with iron head engines and usually iron manifolds. The Grade 8 had a lower coefficient of expansion and would tend to loosen when cold where the grade 5 and stainless was less likely to, and this could and did result in tensile failures where expansion of the manifold literally pulled the head off the bolt. With an aluminum head it would more likely result in pulled threads. We also resorted to such remedies as long bolts using high temperature die springs and stacks of alternating flat and lock washers to form a heat shield for the spring, to place a constant load on the gasket but still allow some movement. These type of remedies did work, but in much the same way as the stainless shim gaskets mentioned above.

Jim

[mgb260]

I had a few old Y block Fords years ago that used studs on the exhaust with conical washers and what looked like brass but was probably Marine bronze nuts. Never loosened and when time to rebuild removed easily. The conical washer create tension like a spring and the bronze nuts didn't gall. These were cast iron manifolds but, I always thought they would work just as well for headers.

[mowog1]

Found the lost header bolt...it was lying in the frame rail channel next to the firewall. It probably backed out during the trek to and from Michigan....amazing that it found a cozy spot in the car rather than commit suicide by falling on the road!

I needed the hands of a six-year-old to get the bolt back into its spot on the header....but managed with out drawing any blood.

Everything now torqued up...we'll see what happens.

BTW...these are aluminum Buick 300 heads with stainless steel RV8 headers.