Hole in my head

[bobphd]

I’m doing a set of heads for a friend and came across something I’ve never seen before. The rear intake lower spring cover was loose and upon removing it and cleaning the gasket area there is a hole that goes through to the intake port. The casting is extremely thin in this area and I’m not sure if the lower spring cover being loose caused this or how it happened. I have had success using a palco cast iron rod for other head repairs but am concerned about trying to weld in this thin area or causing hairline cracks in the intake port. I have given some thought to making a larger gasket between the lower cover and the head and some type of sealer. Any thoughts or ideas would be appreciated.
Bob E19ACE9C-F701-4A52-BD94-170EC2CB6690.jpeg526A0BAD-29E8-4130-A05D-7DD09F8E1612.jpeg

[larry]

Everdur bronze wire could be used as a filler. There are other low temperature options.

[T. Cotten]

I would first consider, Bob,..

"Sealmaster" stitching pins (used with "Fluid Weld" for a "zinc/bond process").

But that's only because I am experienced with them.

If that failed, I would choose a silver-solder, if only to avoid 'chilling' the iron with bronze.

....Cotten

[Jerry Wieland]

I had a head like this 30 years ago or so and just brazed it up. Jerry

[bobphd]

Thanks Larry and Cotten. I did experiment with a junk front head that I have by making a similar hole in the same location and welded it with the palco cast iron rod. It did not cause hair line cracking but also does not seal completely and when pressure testing with 10 psi I get some bubbling at the weld, I had a similar result with an exhaust port weld several years ago and used seal-lock fluid weld to seal the small pinholes in the weld. I did use some fluidweld on the test repair but have not pressure tested yet. I too think it would be best not to weld this hole and am familiar with the stitching pins but have never used them. I have always used the seal-lock when installing new valve seats and never had a problem yet . I will check into the stitching pins and some type of low heat silver solder . I have not told my friend yet that he has a hole in his head but will do that tomorrow and see what he thinks is best.
Bob D998F36D-E8DC-4137-9158-8E51E36B16D1.jpeg

[T. Cotten]

I've got an unopened bag o' pins left over from the Ninety's, Bob!

I think it has the tap with it.

(Never got around to fixing Panheads with them,)

....Cotten

[bobphd]

05ED1518-C330-47E6-8164-0A7E22905193.jpegD69B91A1-CE25-46C8-9572-4F74464A3E37.jpeg Thanks Cotten I may be interested in buying them from you if you want but I am concerned about how thin the casting is in this area where the hole is. It is paper thin and for whatever reason it is considerably thinner than on the other couple of bare heads that I have left. Thanks for the brazing tip Jerry but I have never brazed cast iron and am not very good at brazing steel either. I repaired a set of pan head tanks several months ago that I am using on my last bike. Last because I am pretty much out of parts and money and it will take the rest of my life to keep the junk I have running. Pan head tanks because a friend gave them to me and I cannot afford the stupid prices for knucklehead tanks and the repops are junk and unusable. These tanks had several brazing repairs that were leaking. A couple I was successful at heating and rebrazing but 2 I could not get and struggled with. I ended up cutting out the brazed areas so that I could weld patches in. I am leaning towards some type of lower temperature silver solder and a slightly larger od valve guide / spring cover to head gasket. As it can’t be built up on the top side of the head maybe I could silver solder it from the inside through the valve seat hole. The bike picture is the one with the pan head tanks.

[larry]

There are soft silver solders that melt at 450+. Silver brazing alloys melt at much higher temperatures.