Porous Heads repairs - ZR-1 Net Registry Forums

LGAFF · 02-26-2012

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 · 02-26-2012

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 · 02-26-2012

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

Paul Workman · 02-26-2012

Quote:

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 · 02-27-2012

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

02-26-2012	#1
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Porous Heads repairs 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 __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

02-26-2012	#2
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: Porous Heads repairs 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. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry Last edited by Paul Workman; 02-26-2012 at 08:00 AM.

02-26-2012	#3
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Porous Heads repairs Also reading an article on welding....guy flooded the coolant area and runners with Argon to get good results __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

02-27-2012	#5
rhipsher Join Date: Aug 2008 Location: Houston 90 Red ZR-1 Posts: 2,320	Re: Porous Heads repairs Even good sand castings have porosity in them. Investment castings are better but more expensive.