I have a set of Dynomax block hugger headers on my 61, installed using the gaskets that came with them. After only about 350 miles they were leaking and all the bolts were loose . The supposed heat resistant coating has all burned off also. I tightened the bolts but the right one still leaks - I guess the gasket is blown.

In retrospect I should have paid the extra money for the ceramic coating.

Does anybody have any suggestions about header gaskets and how to prevent problems?

John
blu61
http://www.users.bigpond.com/blu61

 

I've had good results using Stage 8 header bolts with the locking clip over the years on several cars. Summit Racing and Jegs carries them as do most local speed shops. Keep the headers tight against the gasket and the burn through problem goes away.

 

Expensive....but you only buy them once and they last a lifetime - Mr.Gasket copper gaskets. I paid $50.00 for mine, you can find them at most local part stores or online. If you plan on keeping the car for a longtime - I highly recommend them.

The problem with keeping paint, etc...on headers is that they have a smooth surface and extremely high temps to deal with. Ceramic is probably the only thing that will stay for any length of time.

ARP makes some nice header bolts that will not back out and they have a smaller head, so that you can get a 12 point socket on them close to the pipe. I need to get a set !

 

I also use the Stage "8" Header Bolts and Locks As recomended by Rich Lagasse. My headers are made by Sanderson and have a Leak Proof Design.. They don't require any gaskets..!! Also Recomended by Rich. They are Ceramic Coated. A good Company to do Business With.

Contact http://www.sandersonheaders.com Give them a call....

 

Or you can use Permatex Silicone (Copper RTV) and coat the gasket with that. On my chevelle I used aviation bolts that would accept safety wire. I also torqed them down about 10-15 pounds more then recomended. Never had a leak or a blown gasket ever.

Mark

 

The gaskets that come with the headers aren't usually of the best quality. I've had good luck soaking them in water overnight before installing them. I also re-torque my headers after the first couple of heat and cool cycles. Felpro makes a good header gasket, and I've had good luck using the stock rebuilder type manifold gaskets. WHen you buy new gaskets, make sure you buy the shape recommended by the header manufacturer.

 

One of the biggest problems I had with headers was the stock header bolts that come with the headers.

usually 3/8"-16 reduced head bolts for a 7/16" or 3/8" wrench. And I still had trouble getting a good grip on some of the header bolts with the wrench.

My solution was buy 18-8 stainless steel allen head bolts. Note that the head diameter of these is (usually) too large to clear the header, so i turned the OD of the head down about .03" or so on the lathe and they fit fine. (Stainless amy not be the best choice, as it is weaker than steel bolts,and has a different heat expansion coefficient, but it doesn't rust, and looks good)

The allen wrench gives a much better grip than an open end wrench does. I did make up a *ball swivel*, for lack of a better term, allen socket by grinding a relief on the allen back from the heada bit to allow the allen to work at slight angles.

If you want to go pro, cross drill the allen heads for safety wire.

Also, break in the gasket. Run motor for 10 minutes, let cool, re tighten bolts, run engine for 30 minutes, let cool, re tighten bolts, repeat several times and your bolts should not loosen.

Doug

 

I used the gaskets that came with my Dynomax headers. If they have metal in them, they're fine. I also used their bolts. The only thing I did that you did not do was to use header seal. I put a good coat on both sides and retightened them after a week. They haven't leaked yet. It's been two years now.

 

A brief primer on why header bolts loosen up and stock manifold bolts don't. The stock manifold bolts are about 2-1/4" long, due to the thickness of the manifold casting, and stretch slightly when torqued in order to maintain clamping force in the joint. Header bolts, however, are much shorter (like 3/4" or so), and are too short to stretch when torqued; as a result, they don't develop or maintain the necessary clamping force in the joint, and repeated heat/cool cycles cause them to loosen up (and occasionally fall right out), which blows the header gaskets.

Trouble-free and leak-free header installations MUST use some sort of positive-lock fastener, unless you enjoy tightening all twelve bolts once a week. The easiest approach is the Stage 8 locking bolts with the clips, which are VERY effective. The other approach (which I prefer) is to use ARP NASCAR header bolts, which are pre-drilled for safety wire, and safety-wire the bolts. They come two ways - reduced-size 6-point or 12-point; I prefer the 6-point, as you can get an open-end wrench on them from the side if you have to (Snap-On makes a great little 3/8" combination open-end wrench, #VS-12A, that's angled 30* at one end and 60* on the other end, that will ALWAYS fit when clearances won't allow use of a socket or box-end wrench). The 12-point bolts only allow use of a box-end wrench, and you may not have clearance to get a box-end wrench over the bolt head. Always use anti-seize on a stainless bolt for ease of removal.

It ain't about the gaskets, it's about the BOLTS.

The pre-drilled ARP header bolt:



The Snap-On 30*/60* 3/8" wrench:

 

Thanks for all this everybody.

Looks like I need some new bolts and gaskets.

Skinned knuckle time again!

John

 

And one of these if you don't mind coupling the bolts with wire?

 

I've also had success with the Stage 8 bolts, although they can be a minor pain to install. I just put in a set of Split Lock bolts. These are hollow and split on the end. After installing the bolt, there is a smaller, allen head bolt that screws into the inside of the main bolt, spreading the split in the end. I haven't had the engine started to try them out.

 

ARP has a new header bolt that will accept a socket. At least, that is what they said on "Two Guys Garage"

You can also use Malox (stomach medicine) as anti-seize coating.

 

Has anybody used Breslin split-lock bolts?

They look like a good idea to me and I can get them here in Oz. I can't find anyone who stocks the Stage-8 bolts or the ARP bolts listed above. Having said that, I have shipped a lot of parts across the pacific in the last 6 years.

John

 

Adventureous sort that I am, I thought to myself last time I assembled my car, Why the hell won't regular exhaust mamifold gaskets work with headers? [of which I have many sets hanging around]. So on they go. 2 years now. No leaks, and my system has to be tight with an o2 sensor. I did re tighten after a few days like you should do anyway. That was even with one that backed out on a road trip that I didn't notice. Didn't blow out.

 

Exhaust manifold gaskets? You mean those silvery peforated looking ones that each piece is indivdual to the port or port pair?

What exactly was the purpose of those anyway?, as the chev engine was designed for the cast manifold to mate directly to the head sans gasket. A fix for warped or corroded manifold seating surfaces? Or a way to take pasrt of teh heat load off teh coolign system by insulating teh manifold from teh head?

Doug

 

Maybe this is a stupid question, but....

Couldn't you achieve the torque stretch effect by simply adding some 1.25" long steel sleeves on some 2.25" long bolts and then bolt the header flange down?


Doug

 

I had a set of shorties made to connect to my sidepipes and the delivery was way late. In apology for the delay, they included a set of solid soft copper gaskets, 1/16" thick. My racer buddies said they'd never seal. I put them in, torgued the bolts and they have never leaked. I checked the bolts several times and they never needed retightening. Going on 3 yrs. now. The headers do have solid 3/8" flanges and the port seal design used by Sanderson (not a flat flange, but a built up seal area around the ports.)
My latest project is using the new Earls gaskets with a SS gasket plate and carbon (replaceable) inserts around the ports. Not ready to light that fire yet, so can't advise on them.

Daffy

 

had a set on for 10+ years and no leaks...

so, now that I have replaced headers I again put on manifold gaskets... so far, no problems again and no loose bolts

Chuck