Chalkboss

JB weld? Are you guys kidding? Why not do it right?

Ad0911

To be perfectly honoust. I had both heads reconditioned (valve stems, seats cut at all angles, surfaced) but when I got them back there was some pitting left. Located outside the contact areas where the head meets the cylinders and where the head meets the block, so right where the head is not covered by metal on the other side of the gasket. I was told it would not be a problem. But after reading this thread, all kinds of horror thoughts cross my mind. I was thinking about monitoring the pH value of the cooling liquid and changing it every year or when the pH drops below a certain value.

James Bailey

Because it sounds like it would cheaper and easier to do it wrong !! But that of course is nearly always the issue with any Porsche ....

BC

Everyone was kidding about JB weld, right?

Ad0911

I was already at the point of believing that this could stop any further eating away of aluminium. It probably wss too good to be true!

Ad0911

Checking the pH value of the cooling liquid seems like a good habit, according to Cummins. The pH value shouldn't drop below 7.0. When new, it is about 8.5.

https://www.cumminsfiltration.com/pd...LT33020-GB.pdf

mark kibort

I dont know why it wouldnt work and work well. this is a guess on my side.. but that stuff seems to be pretty bullet proof

not I... but you knew that.. But remember, my surface of 50 on my heads didnt live up to your visual standards (even though it was well below the spec for surface condition)..... the car stilll runs like a raped ape at 85 race days!

sometimes doing it "wrong" is right, when the "right " way can induce more or some risk.
my only thoughts was that to weld, the temp goes up in the surrounding metal and might warp something... but i guess this could be machined flat no problem afterwards. but what about that heat.. could it weaken the areas around the pitting to cause more damage than good?.. just ask'in

thats what i was thinking... again, my experience with JB weld is fixing holes in the front of a radiator and numerous topical applications again, just tossing it out there .

Cosmo Kramer

Google "repairing pits in aluminum heads". Machine shops use JB weld or equivalent products regularly for pits outside the gasket sealing area on aluminum heads. There is a risk to welding like MK says, and if the pitting isn't under the gasket I don't think the risk is worth it. The big thing going forward is using quality coolant and keeping an eye on the Ph level.

Imo000

The other problem with welding a head is the heat and if to warps, even a little, the head gasket area can be machined flat BUT what about the camshaft side? That side will be stay warped and considering the length of a camshaft, this would be a problem. Inline 6 BMWs have to deal with this all the time. Yes, our heads are much shorter but still.....

James Bailey

Since this pitting IS UNDER the gasket and very close to the flame ring.....welding is clearly the correct option but truly must be done by an experienced TIG welder using correct technique which includes preheating the head and carefully controlling the temperature including the cool down time.... the corroded oxide needs like 1,700 degrees to melt vs 600 or so for the aluminum so it MUST be removed to allow the aluminum to easily pool.
And I am not naïve enough to argue right or wrong with Kibort even on a topic he admits he knows NOTHING about.

Cosmo Kramer

Agreed for the OP, he needs to weld. The topic kind of shifted to Ad0911's issue and in his case filling them would be ok.

mark kibort

thats a great POINT!! MR know-it-all Jim? I think JB weld is not a very unusual solution here, and in my opinion,(and your right, i dont know much about this topic, but i did study strength and materials 35 years ago ) , it might be ok since its out of the fire ring.

thats what i have heard. im just trying to evaluate the risks here. and is it worth it.. i think JB weld would be very stable under the gasket material, and with no fluid around it. do you think "under the gasket" means under the fire ring or around any gasket material?

Why do you have to be such a Dxxk? !
It looks like the pitting is not at the fire ring, but under the gasket. the welding on the head, especially for the reasons mentioned about the cam carrier side not being able to be perfectly controlled.. i dont think i would take the risk. Heck, ive welded the 2 valve heads to fix a badly munched exhaust valve and port and had NO issues. But, this is such a minor problem, i dont see why epoxy cant be used. again, as you say, i dont know much about this, and i dont think you do either. i think those that have done this before should chime in.

I thought you said that filling them with expoxy is done and can be done successfully? Hey, i hope it get fixed either way. the good news is, both welding or filling should work.. leaving it alone is probably a problem.

Imo000

The OP's corrosion got under the fire ring so welding is required. The JB Weld is not suited for this case but other instances when the corrosion is clearly away from the fire ring, this could be an option to consider. Since other is the car community have done it with great success, the the results of using this (when its appropriate) are already known.

James Bailey

Just channeling my inner Kibort.... I first imagine how you might post and simply try to emulate that style, apparently with some success....Although I have gotten private messages recommending that I stop posting and responding to you in the hope that you would simply go away. Others have found it amusing for one reason or another. Jury is still out on which is the best course of action regarding posting but pretty clear about properly fixing alloy heads.

mark kibort

it sounds clear..... yes, if its around the ring.. welding best choice. Look in the mirror Jim, sometimes you say some pretty silly things and communication/dialog is impossible. just look at the KE discussion. If you have a comment, say it, dont beat around the bush. it makes for nasty dialog if we are second guessing what the heck you are talking about. you end up discussing something else that just sounds like noise to anyone else reading.