blown header gaskets

[dirtslinger71]

My 604 has blown the header gaskets 3 weeks in a row. I have shoenfeld headers and use ARP bolts drilled for safety wire. I have blown the shoenfeld gaskets and felpro's. This is my third year running crate and just started having this problem. Any opinions?

[hanginitout]

I dont even use a gasket per say, I only use the high temp silicone, apply let it set up a little then install.

[Matt49]

I would leave the safety wire out at first. With a new gasket, tighten the bolts up. Run the motor in the shop up to temp, let it cool, and tighten the bolts again. After the first time on the track (first session, not first night), get a wrench on them again. If you don't do this, the gasket is hardening up and will tend to blow out and you will also end up losing some header bolts if you don't do this. Let me guess, gaskets blowing out between 3 and 5 and 4 and 6?

[Kwoods25]

Ultra Grey Rtv. I used to run gaskets and blew them out every week with my beyeas. Tried 2 gaskets. All types and brands. Diff. Style bolts. Nothing helped. People say the high temp, but talked to some older guys and they say the Ultra Grey and it works. I got the new Dynatechs now they are supposed to have a better flange to fix this problem

[powerslide]

Yes keep checking them every time the motor heats up. As Matt stated they are drawing up little by little. After a couple weeks they will stay tight.

Before you put new gaskets on take a straight edge and lay across the header make sure its pretty flat. If they have been cracked and welded up they aren't flat anymore and need to find someone with a big belt sander to flatten them back out.

[dirtslinger71]

Yep blowing at 4-6 and 3-5. I always run motor in shop and retighten and safety wire after cool down. Never had a problem in the past till this year. And all I did was change fuel... Maybe I will rtv the gaskets and retorque several times... Thanks guys.

[Matt49]

Yep blowing at 4-6 and 3-5. I always run motor in shop and retighten and safety wire after cool down. Never had a problem in the past till this year. And all I did was change fuel... Maybe I will rtv the gaskets and retorque several times... Thanks guys.

I'm not an engine guy but my guess would be that your new fuel has changed your EGT which is causing some different behavior.

[brad hibbard]

I agree with Matt's earlier post about tightening the bolts everytime on the race track for a few races and until they stop feeling loose

i am not a big fan of silicone on headers----it does work and many use it BUT it can signifcantly cut power when used carelessly ------"silicone sealers" used today are so good that in many cases they will not burn away in the exhaust port------so that big bead of silicone that squeezed into the port and sealed the header also restricted exhaust flow

back to tightening the bolts---------
many guys are using header bolts with a 5/16 head for clearance and then they try to tighten it with a cheap 12 point wrench or even worse an open end wrench
use a quality 6 point wrench from Snap-on or Mac etc.

as ever
Brad

[twisterf5]

do you have the headers bolted out at the end. if not the flex in the headers will loosen the bolts when using gaskets. we never run gaskets just rtv.

[dirtslinger71]

I have 3/8 6 point bolts that I tighten with a long quality 12 point wrench that works increadably good. And I do have hangers on the headers. I will be very conservative with my rtv to avoid oozing... I have to try it because buying $37 gaskets every week is getting old. Lol

[rakracing]

ive found that if the header flanges are machined flat orange rtv works great but if the headers have bead around the ports the gaskets worked better.

[brad hibbard]

something else>>>>>>>
many header flanges are not straight

lay a straight edge across the flange and see if it has a gap in the center

some gap is normal and aceptable but if its like .060" or more you can bend the header back by placing some washers between the outside bolts and the head and then tightening the center bolts

NOT recommended to do on your race head find an old head (cast iron preferably)

you will have to shim at least twice as far as the warp -----
if its warped .060----shim it .120 to bend it back

over bending (straightening) (within reason) is not a big deal as the end cylinders have 2 bolts and a much better seal surface

Brad

[restad4r]

I had the same exact problem on my crate, blew 3 gaskets in 3 weeks. I tried different gaskets and even tried just silicone as well. Finally I tried a new hanger on it and made so it was pulling up slightly on the header. Problem solved haven't blown one since. hope this helps

Ant

[racin6mod]

I went to cooper header gaskets because I was having the same issue on a non crate motor. never blew out and have reused them on another motor.