Welding VW heads

Croatian VW Club · Post by **Croatian VW Club** » Mon Dec 10, 2007 4:59 am

Hi guys,

I am searching for vw head welding basics,tipps.....

Does anyone have a link to an article for this subject,or pictures of someone's heads?

Need to know how to properly weld above the intakes,and inside the chamber around sparkplugs.

Where else can a VW heas be welded for strength?

I have 041 heads,so going to biger valves,I want to relocate the sparkplugs and use smaller sparkplugs.

Thanks

eugene · Post by **eugene** » Mon Dec 10, 2007 6:34 am

I will be in the same dilemma soon. There is no a lot of detailed info on this subject. Or i was no lucky to find it. I just know that the head should be preheat and cooled slowly afterwards. For the best procedure and degrees i dont know. For the most suitable filler alloy to use seems to be the something without magnesium, like the 5356 ( to avoid cracking because of high) temperatures. AlSi filler alloys probably, 4043 or 4047 or something else in the 4XXX family.

I hope somebody with experience will help to answer this question because i have no real experience hire. I saw poop up this question several times on other forums and the answers were most times missing. I also asked a german tuner and had no luck. Is probably a meter of proprietary information how somebody is doing this. The problem for us is that in my and similar countries, AC head specialists or VW AC tuners are non existent and for us lost souls, is the only way doing it, is be yourself. (Or buy something from Germany or USA, which is not so easy as it seams or so cheap as we want). Im from Slovenia, so that make us neighbors. ( If i understand your username correctly.)
Best regards

Bugfuel · Post by **Bugfuel** » Mon Dec 10, 2007 6:44 am

I have had several heads repaired and modified by a pro alu welder on his free time. Preheat and slow cooling is true, and CLEAN surfaces are absolutely critical. I prepped the heads before welding, and all he had to do was weld. 100% free of any oil or grease, and dust too. Nothing but fresh cut aluminum. Sometimes I sadblasted the area that needed welding, and after thorough cleaning he said they were fine. No problems welding. (TIG).

I think I used CRC Brakleen to wash off any oil residue and dirt.

Jan

Croatian VW Club · Post by **Croatian VW Club** » Mon Dec 10, 2007 8:32 am

eugene wrote:Im from Slovenia, so that make us neighbors. ( If i understand your username correctly.)
Best regards

Yes,that's correct.I am from Croatia/Zagreb.What part of Slovenia are you from?

I would like to invite you to the website of our Volkswagen club:

http://www.vwbuba.hr

The problem we are facing concerning the head work is the sam here in Croatia.Here are only 2 engine builders who wanted to learn how to build performance VW engines,and learned that from people who needed their engines built.Here is a small group of real enthusiasts who are seeking real knowledge,and are trying to do most of the things by themselves.

Croatian VW Club · Post by **Croatian VW Club** » Mon Dec 10, 2007 9:35 am

Bugfuel wrote:I have had several heads repaired and modified by a pro alu welder on his free time. Preheat and slow cooling is true, and CLEAN surfaces are absolutely critical. I prepped the heads before welding, and all he had to do was weld. 100% free of any oil or grease, and dust too. Nothing but fresh cut aluminum. Sometimes I sadblasted the area that needed welding, and after thorough cleaning he said they were fine. No problems welding. (TIG).

I think I used CRC Brakleen to wash off any oil residue and dirt.

Jan

So how are the heads pre-heated?To which temperatures?

Croatian VW Club · Post by **Croatian VW Club** » Tue Dec 11, 2007 5:09 am

Is it so secret,so no one would tell these secrets?

Bugfuel · Post by **Bugfuel** » Tue Dec 11, 2007 5:21 am

My guy would not tell me details, but I have seen him work. I don't want to make any guesses, I did not see it done from start to finish. Just the welding part.

Jan

eugene · Post by **eugene** » Tue Dec 11, 2007 6:13 am

Hire is some info on the subject.
http://www.shoptalkforums.com/viewtopic ... 19&start=0
You will see Len mentions the use of 4340 alloy as filler. I was wandering if it is a mistake becouse i havent heard of 4340 alu just 4340 steel alloy.

For the temps i would guess 200-250°C, (400-480°F) but it is a guess.

If i remember correctly i have read somewhere 450°F (230°C) would be OK. I would try with this. Heath it in a oven for an hour, weld it, watch to not overheat during welding and put it to cool slowly in the still hot oven. This is abouth i'm going to do it (i will left the welding to an experienced welder)

Do a serch over this and other forums and post what you have foud. Maybe somebody with experience will chime in.

Unkl Ian · Post by **Unkl Ian** » Tue Dec 11, 2007 7:25 am

Not a whole lot of specific info available,that I've found so far.

Some people recommend preheating to 400 F,
and cooling SLOWLY when finished.
If cooled to fast,the heat gets soft.

Some recommend 4043 for ports,and 5356 for seats.

Others say the heads are 356 T6 Aluminum,
so you should use 356 Aluminum filler rod.

You definitely don't want to weld on one head for too long,
and risk over heating it.Some people will weld for a few minutes,
then put the head back in the over to stabilize the temperature.
Repeat as necessary.

Definately need a big welder,with lots of amps.

eugene · Post by **eugene** » Tue Dec 11, 2007 1:18 pm

Unkl Ian wrote:
Some recommend 4043 for ports,and 5356 for seats.

Others say the heads are 356 T6 Aluminum,
so you should use 356 Aluminum filler rod.

.

Len stated not to use 5356 in the combustion chamber.

But there is probably more ways to skin this cat, as usual.

Post by **doc** » Tue Dec 11, 2007 1:40 pm

Here's the deal. There are very few people who actually have ANY experience welding and recutting vw heads. Most of the guys that have are in the business and aren't going to spend a lot of forum time teaching the rest of us. Even if they would, there would be no substitute for watching an expert do the work. It's just too precision a task, requiring professional level background skills and some substantial equipment to even make the attempt. That said, we're not talking impossible. If you have the tools and the skills (welding/machining), used vw heads are cheap to practice on.

If I was really serious about it, I think I might risk the money on a phone call to a known expert. Len is the kind of guy that might take that kind of a call. (He'll get me for this!

) I'm sure there are European expert sources, as well. Identify a couple of experts. give them a call, throw yourself on the altar of mercy and beg for help. I wouldn't be surprised if you could find someone to mentor you through your first try.

The job here is so relatively complex that sources are few world wide.

I say try it! Good luck.

doc

Rat Racing · Post by **Rat Racing** » Wed Dec 12, 2007 5:23 pm

The number is very limited that weld the heads because time is a big deal when trying to make a buck. There are a few out there but it is not a easy task to do if you don't have the equipment. If you have a tig welder and have some time with Mag or AL., it will make things easier. good luck

FITNESSFORYOUTOO · Post by **FITNESSFORYOUTOO** » Sat Dec 15, 2007 2:44 am

I used to do my own heads out at the collage aeronautics shop when I was in my 20's I remember that I heated them up to 500 degrees and welded on each one for about 3-4 min then switched heads in and out of the oven, I think I used 5356 filler rod with the tig welder. The most important thing to do with a aluminum head is let it cool very slowly and make sure you do not put too much heat on the thin areas of the head with the torch. They had a trash can full of ashes and I buried them over night, if they cool too fast they will crack. I hope this helps, if you can gas weld you can learn to tig weld pretty fast or at least I did.

John W. Kelly · Post by **John W. Kelly** » Sat Dec 15, 2007 9:08 am

FITNESSFORYOUTOO wrote: magnesium head.

Magnesium?

FITNESSFORYOUTOO · Post by **FITNESSFORYOUTOO** » Sat Dec 15, 2007 11:06 am

John W. Kelly wrote:
FITNESSFORYOUTOO wrote: magnesium head.
Magnesium?

Oops sorry it was late lol I think they have a little mag in them and the rod I used had %5 magnesium in it. It was 20 years ago so I may be wrong but the point is it is not some black magic art and anyone that can gas weld can learn to do it and save big money.