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Author Topic:   cracked headers
dirtbuster
Member
posted August 25, 2004 12:49 PM
Has anyone been having problems with the custom craft 747 headers cracking. WE had an older set crack and this past weekend we put on a new set and cracked the #1 pipe just outside the flange.


ssanto06
unregistered
posted August 25, 2004 01:33 PM           
Not really an answer to your question but... if you are looking to get rid of those cracked headers, I may be able to take them off your hands... I know most of us would just weld them up and race, but I've known a few who'd rather just buy new ones and junk the old... let me know.

Thanks,
Sal


dirtbuster
Member
posted August 25, 2004 01:58 PM
well i dont know what we'll do with the new set. The old ones have about a 1" hole in the #3 tube. They had been welded once after getting bent and straightened. It didnt surpise me that they cracked. Its the new ones that got me.


zeroracing
Member
posted August 25, 2004 07:37 PM
YES they are junk in my book. Between the 2 cars at our shop and some friends that run the 747 headers all of them have broke. Infact we just swapped the left side header off last night. Also these headers where jet coated and another set that wasn't.

edit: we cracked a brand new 747 the first night or two out and custom craft replaced it. Only problem was it was a coated header and they replaced it with non-coated and it too eventually cracked.

[This message has been edited by 2nd2none (edited August 25, 2004).]

JMillerJr76
Member
posted August 26, 2004 11:30 AM
We ran custom crafts on our DW, only because they showed to give more power on the dyno, ours did crack, and we sent them back. they were coated, and had the cone mufflers in them so you figure you are out 600bucks. I told the lady that and she told me to box them up and send them back. A week or so later they sent me a new set coated and everything. Put them on and the very next race we took a shot to the right side of the engine bay and crushed the right side header. so now they are in the junk pile out back of the shop


dirtbuster
Member
posted August 26, 2004 11:41 AM
Well i guess we should have sent back the newer set then. Instead we ordered another set. First ones were coated these are not but if they crack we will send them back. The first pair we ever had we ran for 3 years before they cracked, then welded them up and ran them another season, before they blew out the chunk the other night.


outlawstock17
Member
posted August 26, 2004 04:03 PM
dynatech...


JMillerJr76
Member
posted August 30, 2004 04:54 PM
Also, another guy that runs around here said that the cracking could be caused by having them coated. He told me that when they coat them, they are heated up pretty hot, and that makes the welds brittle. I dont know this for sure, but keep us informed on if the plain un-coated set cracks or not.


JMillerJr76
Member
posted August 30, 2004 05:05 PM
One of the things that people aroung here are doing, and we were going to try before we crushed our set of custom crafts, is to drill a hole in the collector, and run a bolt thru it. Take a stiff carb. return spring, secure it to the bolt in the collector. and with the other end of the spring take and hose clamp it to the frame some where above the collector. Just make sure that there is some tension on the spring. That is suppost to take the shock from the bouncing and vibrating that the headers endure. Some say it works, others say it dosent, I personally dont know for sure, but it is worth a try



dirtbuster
Member
posted August 30, 2004 07:37 PM
well tehy werent cracking at the welds they were cracking in the tubing part. The new headers are made a little better. the tube actually extends through the flange and then is ground flat and becomes the sealing surface. where as the old ones were fully welded to the flange and the flange made the sealing surface.

I have heard of the spring trick and also have heard of guys cutting the flanges out betweeen front and middle and also back and middle tubes so that if there was any tension when they were bolted down each one could flex a little.

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