Welding heads

[jonas_linder]

I've read alot of welding on heads and most people say to stay away from welding heads... why is it so bad ?

How should you do it ?

What should you absolutely not do ?

What tig rod should be used ? I've read 4043, 5356 ?

What should be done after you welded the head ?

And lastly a shoot in the dark, how big is the spark plug angle differens betwenn a porsche2.0 head and a square2.0 head ?

[MASSIVE TYPE IV]

Len is the ultimate person to answer this question. I have seen him repair castings that were totally obliterated, melted and otherwise junk and do so perfectly!

In my experience as long as the head is welded correctly (preheated and post cooled) and the welder knows his stuff there is nothing wrong with welding heads.

Wait till you see all the welding Len is doing to the heads for the Mighty Spyder-

[jonas_linder]

Thanks for your fast replay Jake!!

Lets hope Len chims in then

[MASSIVE TYPE IV]

B TW- welding for performance gains and welding cracks/ other repairs are two different things... All the welding done to the Mighty Spyder heads are for pure performance gains- Dual plugs and heavily altered exhaust ports that don't even resemble a stock head is just the beginning of those mods.

[jonas_linder]

this is to fix my dropped seat.. is welding a no no on a seatrepair ?

Thanks for your input, I really respect your input! (even though I like to try things myself )

[dstar]

I'm not much of a welder. I can weld two pieces of metal together, but
a true welder knows MUCH more about metallurgy than I, and an experienced head machinist like Len has to be BOTH!

I think the heads are 356 alu, T6 R hardness, so if you heat
the heads over 500 degrees F, then you will have to heat treat them
to get back the strength.

Yes, I know folks have seen 500 degrees on their head temp gauges,
but then again, that is why those seats fell out later......


Len can chime in, or not, we understand the time and $$$ he has invested into his secrets.

Just remember, in heat treating the heads, it is not just bringing the heads
up to a certain temp, but how you bring the temp back DOWN, that counts
the most.

Don

[jonas_linder]

ofcourse I understand that he has a lot of money invested, but it can't hurt to ask ?!?

[MASSIVE TYPE IV]

Len has repaired those types of issues for me numerous times...

[Santas Brother]

Several years ago,I had a conversation with one of the top
engineering guys at Brownfield cylinder heads,they were one
of the early aftermarket aluminum head manufacturers for
Chevy V8s.They have since been bought up by someone else.

One of the topics of conversation was welding cylinder heads,
for repair and for modifications.He explained there were different
filler rods used for doing chambers,and ports.The rods for the
chambers and seats gave a stronger weld,but caused more distortion.

He did tell me what rods to use where,but the numbers are
long since forgotten.

[jonas_linder]

Several years ago,I had a conversation with one of the top
engineering guys at Brownfield cylinder heads,they were one
of the early aftermarket aluminum head manufacturers for
Chevy V8s.They have since been bought up by someone else.

One of the topics of conversation was welding cylinder heads,
for repair and for modifications.He explained there were different
filler rods used for doing chambers,and ports.The rods for the
chambers and seats gave a stronger weld,but caused more distortion.

He did tell me what rods to use where,but the numbers are
long since forgotten.

to bad the bill for the doctors that can make you remember is as high as the price for a new pair of heads

Good info!

[HAM Inc]

I have been welding cast aluminum for nearly 20 years now. I've experimented with different rods and spoken to numerous engineers over the years on the subject. Years ago I settled on 4340. DO NOT USE 5356 for combustion chamber welding.

Without going into specifics there are a series of steps involved in succesfully welding cast aluminum. Surface prep, pre-heating and post-cooling are very critical. Both the temp and the rate of temp rise and drop are the issues at hand here. If any of the steps are skipped or done improperly the results will be unsastifactory.

The first step is determining if the aluminum is in good enough condition to weld. My experience has been that heads that have been exposed to long term detonation are high risk and I don't even bother with them anymore. One of the quirks of T4 heads is that once they start detonating they usually toss a seat pretty quick. The upshot of this is that the detonation doesn't usually have time to ruin the casting. Carnage from dropped seats and broken valves is a bitch to repair, but welding is not a problem.

If detonation is severe enough it can contaminate the surface of the casting and this requires machining away the contaminated material. What happens is that the extreme heat causes the aluminum to expand past its point of reasonable elasticity, which opens up large pores in the surface. The high cylinder pressures associated with detonation push combustion residue into the pores. I have had to remove as deep as 4mm of material to get to clean aluminum.

Any type of welding is as much an art as science. This is doubly true of welding cast aluminum. Welding is an example of a skill that can be learned, but not taught. It takes a lot of practice. Obviously some people will master it quicker than others.
I have reached the point where I can weld net shapes that resemble the finished product, but I have been doing it for a long time. It's tough work, though. 250 amps of High-frequency A/C power while leaning over a casting that has been pre-heated to a very high temperature. The noise level is high enough to require ear plugs.
There is a reason that HIGHLY skilled cylinder head welders are hard to find. The equipment is pricey, and it takes a long time to learn. This is the reason that I charge $85.00/hour for cast welding repair and have no patience with people who think I charge to much.

[R2.0]

I used to be around a lot of very skilled welders - nuclear certified, etc. I once asked about welding aluminum, and they laughed - wouldn't touch the stuff.

$85 is a goooood deal.

[MASSIVE TYPE IV]

Its a very scientific thing and certainly an art as Len mentions.... I started welding at age 12 when the english teacher got tired of trying to read my chicken scratch and they figured out I was better off in shop classes.. To this day Tig welding aluminum is very difficult for me. The consistency of materials is a bunch of never ending variables and its so easy to contaminate the work pieces and screw everything up.

Len is the best Aluminum welder I have ever seen, and that includes the guys I was around on Navy vessels and in the aircraft world... I happily pay him 85 bucks an hour to weld on heads!

[slowtwitch]

I have a set of Len's welded heads and I have to say it's a true work of art. For the quality that was put in them, $85 per is a true bargin.

pete

[Can Drive Soon]

English teacher got tired of trying to read my chicken scratch

That's what they call my handwriting!

But I got on of those aluminum Blade scooters and somehow I managed to break on of those nice fat beads. I have heard welding aluminum is very hard also.