Stock Header removal

[earlbrown]

I cringe everytime I see ''use a belt sander to make it flat''


A belt sander will flat out, 100% NOT make anything flat.    It would make a bunch of parrallel lines of uniform finish that are pleasing to the eye.  But that part WILL NOT be flat.


  As someone that that's machined my share of heads and manifolds, I can tell right off the bad when that part has been ''flattend'' on a belt sander.   The leading edge will be low as hell on every single relief area and ten taper upwards as the debris turns into small roller bearings.
   ....then I have to make extra passes to get the damn thing to a machined surface (noticed I didn't say 'flat') and get rid of all the channels that could let pressure, fuel, or exhaust where it shouldn't go.

On that sanded exhaust flange, put some layout die on that surface and get a small cocaine mirror (flat enough to this) and rub it on there.   It'll highlight all the low spots for you.    Honestly, if that flange is actually warped from using a gasket in the past, and can't be machined correctly, the better plan of action would have been to peen the ears down with a hammer and leave the ID alone.

[gnonyx]

Well I never made it to starting the engine since my previous threads stating that I had to repair the driver side header which had a crack.After installing the turbo flange gasket and wrestling with all the P.I.A. parts, I already had the DS header welded, drilled pilot hole at each ends of the crack to prevent from cracking, and added a piece of metal across the base of both exhaust ports for strength.Once the DS header was welded, I took a straight edge ruler and found the header to be warped.From the pictures I think the center exhaust port may shows a high spot, maybe others can chime of opinions.Monda y I will call a Machine shop to see if milling the head is possibleClick on photo to see full pictures

[gnonyx]

Replaced the ds header after being resurface from machine shop, ran engine but still had some blm issue.
Keep in mind prior to the ds header leak I place a shop vac in the exhaust tail pipe and block off the other end, and used a soapy water solution and spray all engine exhaust area. The only area that was leaking was the turbo flange up pipe and also the ds header.
I repaired the turbo flange area and used the Remflex gasket and installed the ds header, ran the engine again, but still having high blm reading.
I again place the shop vac into the tailpipe, and block off the other end, to recheck engine exhaust system.
Now the pass. header is leaking as before it wasn't leaking, I glad I found the leak, but not happy since now I have to deal with the down pipe, and stubborn bolts that haven't been remove for about 20 years ago when I replaced the both header gaskets.

[Steve Wood]

Personally, I prefer to use the old dribble some engine top cleaner into the throttle body while it is running at about 1500 rpm...penny between the throttle stop and the arm to speed it up....and watch for smoke to come boiling out of any leaks.  Transmission fluid smokes good as well, I think

[gnonyx]

Took the pass header, without removing the turbo and without removing the downpipe, yes it took some maneuvering around, but I did remove the header from the top of the engine and not through the bottom end.
After cleaning the header, I put a straight edge and of course, this pass header is also warped.
So this coming Monday I will send it to the machine shop to be resurface, but in the meantime I will check for any cracks before Monday comes just to sure everything is ok to be resurface.
Will post again once everything is all put together.