Author Topic: Stock Header removal  (Read 695 times)

0 Members and 3 Guests are viewing this topic.

Offline earlbrown

  • Turbo Street Eliminator
  • ******
  • Posts: 1515
  • PSI: 6
    • View Profile
Re: Stock Header removal
« Reply #45 on: March 21 2020, 12:24:11 AM »
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.
'87 GN - 4.2L SFI Turbocharged innercooled V6 - Chrome valve covers - supra pump - 14" K&N - 52mm throttlebody - rocker shaft supports -  1/2 intake spacer - TB coolant bypass - 3" ATR exhaust tip - Alum intake pipe - NOS timing cover - chip - relocated charcoal canister - CR42's - stock