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Rusty headers
Here's one that might jog a few memories.
I have the cylinder head off and on the bench. The exhaust headers are rusted into the ports, big time. Penetrating oil has been applied over several days. I've been attacking them with a cold chisel, but they won't budge. Anyone had this problem and got round it? I'm reluctant to use heat because of the aluminium head. Or is that OK? |
Alloy will expand quicker than steel - and the head does get a bit HOT when running !!!!
Heat head & when nice & hot, whack some ice inside the header & then ATTACK it. |
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removing headers
Hi Black dog,
Just to let you know, Aluminum melts at 650 C. You should only need about 300 C. There is no colour change when you heat aluminum. If its too hot to touch with a quick tap with the finger, it should be right.:thumbup1: Best of luck. Cheers from Oz. |
Thanks for that.
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Sorted
But not by me :(
I must have put in hours with the head on the bench, using hammer and cold chisel, angle grinder, and lots of heat (I even caused a small fire in some nearby steel wool). Eventually, I was getting nowhere and afraid that I would damage the head, so I took it to a local bike shop. It took one of their guys two hours, welding a nut onto the stubs, using a slide hammer, and finally virtually burning them out with oxy. He said he almost couldn't do it, which made me feel a bit better. But now the stubs are out, the new headers test-fitted, and it's all ready to go back together. If I were fitting standard headers back on, I would be planning to remove them for a clean-up once a year, so that this kind of thing doesn't happen again. The new ones are stainless, so I should be fairly safe. |
you should have used the needle type bearing removal trick when the outer case seizes you grind it away from the inside so its waffer thin then it should release any friction presure, in the case of the header stubs grind it thin in two places so you can pry/chisel a section free then roll the material inwards like those food cans/tins with a key :thumbup1:
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I understand the principle, but I don't have a tool that could grind inside the header stubs like that. The nearest I have got is an angle grinder - far too big. The Dremel lookalike I have would have taken weeks :)
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Differential corrosion
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I've had real problems of this sort on winter commuter Guzzis with stainless guards/studs and alloy spacers/fork sliders. BTW are they the Motad headers? Is the fit/finish good? |
Just use some coppergrease on the top of the headers that goes into the cylinder. Same wiht all bolts and nuts on the exhaust system.
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I intend to do just that, Jens - thanks.
Bob - thanks for that. I intend to loosen them off once a year, clean the joints out and recoat with Copaslip. I never want to have a job like this one ever again. I think it is over 30 years since I had to take something to a mechanic because I just couldn't do it myself. My pride doesn't like it. Talking of Guzzis reminds me of one of the bikes I 'loved' most, my old 1979 V50II. It's the one I most regret selling. Fantastic bike. In fact, I like all the old Guzzis, and I plan to get a T3 or T5 to go touring with one day. Not so keen on the newer ones, though. |
Coppergrease verses Nickle based anti seize
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If you use a Nickle based anti seize, you will not get the reaction between Aluminium - Stainless & copper. Check engineering supplies for Nickle based product specially made for Stainless steel. Cheers from Oz. |
never seez by bostic from cromwell tools is a good one i got mine years ago it lasts for ages :thumbup1:
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Is it up to handling exhaust temperatures?
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where the headers sit in the ports is actually cooler than the down pipes and you will probably be ok with the copper based but if you can afford it get the nickle one :thumbup1:. |
Guzzi lovers
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I'd never come across nickel-based grease - will get some. Hope it's not as expensive as some anti-electrolytic grease I bought a few years back - about 8 quid for a small toothpaste sized tube as I recall. |
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but i did spot some 1000 MOLYKOTE ANTI-SEIZE thread paste for £5 a tube and that stuffs rated to 650°C :thumbup1: |
Never seize
Hi black dog,
never seize, and all these type of products will easily take the Temps generated by exhaust. I've used them on steam, and high temp hot oil rigs for years with no problems.:thumbup1: Cheers from Oz |
Thanks Chucky!
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