swapping header gaskets, any tips

legalize420

Active Member
May 21, 2005
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South Florida
i did a search and was reading some of the old threads and i came to the conclusion that i am going swap out the copper gaskets that came with the mac headers and going with the felpro. i have that ticking noise and im hoping this will solve it. i wanted to ask if anyone knows any good tips to make this go smooth as possible. also, what tools or wrenches does everyone find to work the best. my bolts backed out a little while back and one even fell out. i originally had some buddies of mine do the exhaust and i guess i never made sure to check them after a few heat cycles. i know that when i replaced the one that fell out and when i tighted the loose ones it was a huge PITA with a 7/16 ( i think thats what it was) wrench. any suggestions, thanks.
 
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loosen the bolts at the collector, remove all header bolts. should be enough room to move it over so you can slip the old gasket out, and a new gasket inplace.

start the first and the last bolt to get the gasket in place first. thats how ive always done it.

ratcheting wrench and 3/8" header bolts> allen head bolts in my experience
 
Get the stage 8 locking bolts. They are worth every penny. I had this problem with my BBK's and I'm pretty sure you've got the same deal. Once the bolts back out, the gasket burns up and falls out, and you get that ticking exhaust leak sound. I never had this problem with my first set of Mac's, I was assuming because of the seperate header flanges for each pipe let the bolt stay tight. Which was exactly the same reason I didn't want the Mac's the second time around. By the time you ding them to fit around the steering shaft those damn pipes were sprung out all over the map, making it nearly impossible to bolt them on. Anyway, on the BBK's I used the Stage 8's and they can't back out. They are the be all, end all.
 
mackey said:
Get the header bolts which have hex heads that can also be tightened by allen wrenches. If you don't want to pay the money for the stage 8 locking bolts throw some lockwashers under them.

do most of the hex head ones have the allen key heads or is there a certain one i need.
 
I just got them as loose grade 8 allen head bolts of the same size and length as regular header bolts. Any well-equipped hardware store should be able to come up with them. I also used locktite red on them. Also, I got a ball-end allen wrench, which really helped, because you can get the wrench in at off-angles.

There's another issue here however. My Mac shorties had individual flanges at each port, and when I pulled them at engine swap time, they would not line back up -- the cycling heat caused the tubes to bend, and unbolting them set them free. I ultimately got them back on by standing on the collector and using a barbell pipe in each flange/tube to bend them back into approximate shape, using my stock shorties as a guide.

The point is that you will probably face this tweaked tube syndrome as well, and I am wondering if it would not be possible to get the old gaskets out without fully removing all the bolts. Does anybody know? Could the bolts be backed out a bit, the old gasket cut out and the new one installed by keyholing each bolt hole in the new gasket, for a drop-in install? Not fully removing those bolts would probably save a big pain in the a$$ if it could be done. Anybody ever try this?
 
SamSnyder said:
I just got them as loose grade 8 allen head bolts of the same size and length as regular header bolts. Any well-equipped hardware store should be able to come up with them. I also used locktite red on them. Also, I got a ball-end allen wrench, which really helped, because you can get the wrench in at off-angles.

There's another issue here however. My Mac shorties had individual flanges at each port, and when I pulled them at engine swap time, they would not line back up -- the cycling heat caused the tubes to bend, and unbolting them set them free. I ultimately got them back on by standing on the collector and using a barbell pipe in each flange/tube to bend them back into approximate shape, using my stock shorties as a guide.

The point is that you will probably face this tweaked tube syndrome as well, and I am wondering if it would not be possible to get the old gaskets out without fully removing all the bolts. Does anybody know? Could the bolts be backed out a bit, the old gasket cut out and the new one installed by keyholing each bolt hole in the new gasket, for a drop-in install? Not fully removing those bolts would probably save a big pain in the a$$ if it could be done. Anybody ever try this?


i hope that is not the case. i guess i will need to find out if the gaskets can slide out just to be safe and get some that will drop in. does anyone know if the felpro 1415 drops in?
 
An allen head bolt (aka socket head) is usually round, so you can't uses a regular wrench on it. Instead, it has a socket that will accept an allen wrench, also known as a hex key. A regular bolt has a hex-shaped head on it and works with a regular wrench. And yes, I am afraid that the curse of the tweaked individually flanged Mac header tubes awaits.
 
You should be able to get them at any well-equipped hardware store. Grade 8 allen head bolts. I'm not sure about the size -- was it 1/2 x 1.5" or 7/16 x 1.5"? Something like that.
 
SamSnyder said:
You should be able to get them at any well-equipped hardware store. Grade 8 allen head bolts. I'm not sure about the size -- was it 1/2 x 1.5" or 7/16 x 1.5"? Something like that.

is that the size for the lock washers. i was actually asking about the bolts. the header bolts are 3/8 16 right. but which length with the washers,3/4 or 1 inch. i will check into finding a good hardware stoe around here
 
First step in this is probally ordering a set of BBK shorties with the one piece flange, toss the gaskets and 3/4" bolts. Buy a set of 3/8-16 x 1" header bolts and some permatex ultra rtv. Put a 1/8" bead areound each port and lock it down. The gasket swelling causes the bolts to loosen so no gasket no loosening of the bolts. The BBk 3/8" flange needs a longer bolt to get plenty of threads holding it together.

This is what I do on customers cars and I will never ever install another set ot MAC headers. You can eBay them for around $60-80 and be better off in the long run.

Jamie
 
SamSnyder said:
I just got them as loose grade 8 allen head bolts of the same size and length as regular header bolts. Any well-equipped hardware store should be able to come up with them. I also used locktite red on them. Also, I got a ball-end allen wrench, which really helped, because you can get the wrench in at off-angles.

There's another issue here however. My Mac shorties had individual flanges at each port, and when I pulled them at engine swap time, they would not line back up -- the cycling heat caused the tubes to bend, and unbolting them set them free. I ultimately got them back on by standing on the collector and using a barbell pipe in each flange/tube to bend them back into approximate shape, using my stock shorties as a guide.

The point is that you will probably face this tweaked tube syndrome as well, and I am wondering if it would not be possible to get the old gaskets out without fully removing all the bolts. Does anybody know? Could the bolts be backed out a bit, the old gasket cut out and the new one installed by keyholing each bolt hole in the new gasket, for a drop-in install? Not fully removing those bolts would probably save a big pain in the a$$ if it could be done. Anybody ever try this?

looks like i can take the gaskets out without taking them completly off. do you think i will still have a posible problem with the flanges regardless?

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