Porous Heads repairs

[LGAFF]

Porting heads can be a sticky situation.....repairs often do not seal...check this out...I brought this up before, using vacuum to pull a sealant into the weld..apparently loctite has a product and process for this.

http://www.henkel-loctite-kid.de/en/...S_brochure.pdf

[Paul Workman]

Yep!

I had some pinhole leaks following a repair on one of my heads. The leak was opposite the valve spring seat where the runner gets very thin. I couldn't pull up the pdf file (long story) so I'm not sure which LockTite was being used to make the repair. However, I used some LockTite that Marc recommended, applied vacuum to the runner to draw the goop in until I could see little beads of the stuff coming through the pinholes. I let it cure 24 hours and re-applied the vacuum and tested for leaks with soapy water. NO leaks.

That was a couple seasons ago, and upon inspection last fall, still no leaks.

Bob G tried to use the same stuff, but for some reason couldn't get it to set set up. (Bad batch or something???) It never would harden - just remained liquid even over night . So, he ended up using some type of aviation-grade aluminum-impregnated epoxy and massaged it into the pores and then sanded the runner smooth. Seems to have done the job!

P.

[LGAFF]

Also reading an article on welding....guy flooded the coolant area and runners with Argon to get good results

[Paul Workman]

Originally Posted by LGAFF

Also reading an article on welding....guy flooded the coolant area and runners with Argon to get good results

Yes. This allow the gas shoud on the tig welder probe to be removed. That makes it a lot easier to get int tight spots and do a good job, i'm told.

I understand too that the rod material selection is critically important. (I can tell ya that Marc's guy 's welds were glass-smooth and form fitting to the runner shape. This made for very easy touchup)

P.

[rhipsher]

Even good sand castings have porosity in them. Investment castings are better but more expensive.