Cliff's Quadrajet Parts and Rebuild Kits
General Category => Quadrajet Carb Talk and Tips => Topic started by: qjetsrule on August 12, 2019, 12:39:00 AM
-
Is it possible to dress out nicks/gouges in the top of the threaded seat receptacle where the gasket sits? Or is it a waste of time?
-
Difficult to say the least.
If the sealing surface is damaged, pitted out, etc, it's difficult to repair without coming in and machining a new surface. Very light damage or imperfections can sometimes be effectively repaired by putting grease on a seat and "working" it some by tightening and loosening it.
Sometime very light bead blasting with ultra fine glass beads will clean them up as well......Cliff
-
I have turned the threads off an old steel seat on a lathe, with the threads gone it will go into the hole is the main body like a pilot. put some valve lapping compound on it, and turn it with a screwdriver to form a new seat. If that doesn't work, Cliff recommends putting Marine Tex on the threads to form a seal. it works. Just make sure you install the steel gasket under it to maintain the float geometry.
-
There is nothing wrong with backing up the threads with Marine Tex. I've repaired quite a few with that method and never had one returned because the epoxy failed. Sometimes, to save an old or valuable main casting you do what you need to.
I've seen (and even paid for) machine shops bore out the entire deal and press in a new threaded seat. 9 out of 10 times that ruined the castings as a pressure test showed tiny streams of bubbles around the pressed in area.
A heli-coil is not a good repair in that area as it removes most of or all of the sealing surface you you'll end up gluing it in anyhow, or trying to find and use a wider and thicker gasket under the seat. That throws off the float geometry and not really a good repair....IMHO.
I've done the hand-lapping deal using a seat with no threads, hit and miss depending on how deep the pitting or damage is. A good tool to turn the seat is a long tapered punch that fits it pretty tight, then you can two-hand it like a lapping tool and cut it much faster than turning it with a screwdriver...........Cliff
-
excellent advise, thanks