Gas welding castiron

[Heo]

My Model A exhaust manifold had a crack.
So i tested some castiron rods for gas welding
i bought years ago
I have worked as a weldor for many years but
never tried gas welding castiron
It was more like cast in new material with the
old than welding
Had to poke around in the pudle get the slag to
float up to the surface
No problem with cracking when it cooled
why havent i tried this before
Intersting to see how it will hold up when im start
to drive it. Installed a German Ford high comp
head today going from 4.66-1to 8.5-1
They were made for running on Wood gas during
the war .Lets see if i pick up some extra horsepower

[jayb]

Did you heat up the cast iron before you welded it?  I have a local guy who's done some cast iron welding for me and he says that is important.  But maybe not so much on an exhaust manifold; certainly on a block, though...

Were you seriously running 4.6:1 compression?  That is unbelievable!

[Heo]

I usualy weld castiron with ok48.00 rods with
a.arcwelder.Just preheat and weld,1/2 inch
then hammer the weld but this time
it cracked.Old exhaust manifolds are often a pain
in the a** to weld, lots of inpurity,inbuilt tensions
from thousads of heatcycles So I thougt finaly i
 have a reason to test gaswelding. So i preheated
some Moore and welded. And with the gaswelder you heat
up so much bigger area .It worked real fine
And the weld and the area Close to the weld
was real soft when i trimed it down with a file

Yes stock model A flathead have 4.6-1 cr  guess you
can run it on kerosene.
The German head is actualy from a boat and they
swaped head beacuse it preignited on kerosene
so my father saved it from the scrapheap in the
60s sometime
Lets see how it works with 95 or 98 or if i have to
install a bigger cam

[fe66comet]

Most everything up to the 1950s was low compression. Fuel was low quality and had no additives,  our early tractors both Ford and John Deere were under 6.0:1. Also all small engines were about the same or less, a Kohler K series was under 6 also unless you had a nat gas or propane engine.

[Heo]

Tested it today warmed it up and retorqued the
head
It was like night and day incredible snappy throtlle
response much stronger on low rpm
but whats suprices me most is how quiet and smoth it idles
not much topspeed inprovment but i weld up a intake for a
1 1/2 inch S.U carb tomorow and see if it givs me some more
rpms

The exhaust manifold still holds so lets see after some more heatcycles
maby its time to weld the 4 bolt Cleveland block i bought the castiron rods for
15 years ago

[fe66comet]

I have seen cast iron repairs that are 50-75 years old still holding on blocks and heads. Manifolds tend to not last long due to warping and heat stress, even  after drilling they still crack under regular use. Just the paper clip affect, after twisting and bending so many times the integrity of the metal becomes brittle and weak.....Jon

[cjshaker]

IPS (International Performance Standards) forbid using the term "snappy throttle" in reference to a Model A 

Using that much compression in a Model A engine would make me nervous about pounding out the soft bearings with the splash lubrication on those engines.

Iron certainly wasn't the best in those days, but acceptable. If it's held this long, you will probably be ok  given the fact the engine isn't exactly breathing fire like an FE 

[fe66comet]

The hot ticket for the model a is a forged crank with shell bearings and a  balanced assembly. Also hardened valve seats and modern bronze valve guides with modern valves instead of split guides.Then you can run them on the highway no problem, we have a couple converted engines for our AA Trucks. A Offy 9.0:1 head can t hurt either.....Jon

[Heo]

IPS (International Performance Standards) forbid using the term "snappy throttle" in reference to a Model A 

Using that much compression in a Model A engine would make me nervous about pounding out the soft bearings with the splash lubrication on those engines.

Iron certainly wasn't the best in those days, but acceptable. If it's held this long, you will probably be ok  given the fact the engine isn't exactly breathing fire like an FE 

Snappier than stock then   This tread was about gas welding
cast iron ....lets see if the weld on the manifold will last

[cjshaker]

Actually, that last paragraph was meant about welding the manifolds. If it has held through a few heat cycles, there's a good chance it will be ok. What I meant was that old cast iron is hard to weld because it wasn't the best. Although by the time the Model A came out they had certainly gained a lot of knowledge over the years of the T.
Best of luck.

[Heo]

I can report that the weld on the manifold is still
fine after several heatcycles. My father had used
The model A as a Daily driver the whole summer.
but yesterday a new crack started to show on
Another Place on the manifold but the weld is still
intact
So i gues gas welding cast iron is a god metod on old
Dirty castiron
But a 80 year old xhaust manifold that started to crack
will continue to crack