hi i'm paul brodie welcome to my shop man behind the camera that would be mitch
and we're going to talk about cylinder head fixturing today
i have four cylinder heads here and they all seem to have a problem with the exhaust port so
i would say this is one of the weak spots of the engine this is the exhaust stub i
would call it it's probably a proper name this is what goes into the exhaust port
and then the header pipe well even that's not a very good fit there this head here was in the
shed can you see how this just falls in so all the threads have gone so anyway it's got a lot
broken fins everywhere it's a pretty rough shape and there's this one here you can see
that this is stock someone's done something here i don't know what they've done but if i put in a
square there can you see how it's at an angle anyway so that's a pretty rough modification
this one here this is the head that was on the engine it's been fixed and i don't like that it's
aluminum because the exhaust has to has to clamp onto that and the exhaust is going to be a harder
metal than the soft aluminum so when there's the vibration of the motor and the bike running
this exhaust pipe is going to wear into this so don't really like that as a fix and also i noticed
this is a stock pipe can you see how i don't know how that would ever clamp it's got a really short
slot as well so you'd have to put in a shim or something like that and here's the square head
and it's been welded up and it's not quite round there's a little flat spot right
there but we're going to make up a fixture to hold this in the lathe and then i'm going to
machine this and cut it well it all depends how much metal is left in there
what i need to do is to make an oversized insert like this so that it threads in
and it never comes out so that's going to be our job for today i've made fixtures previously
we did a segment on excelsior this is an excelsior head and i made up a fixture
can you see how that bolts on mitch is gonna show you what it looks like when it's in the lathe can
can you see how it gets held in the chuck here and this is well it's the inlet port here this inlet
port is right in line with this sometimes you need to hold this in a four jaw chuck
and you and you have to dial in it's pretty hard to dial that in but you just take an
average of what you got so anyway i have made other fixtures so we're gonna make some
we're gonna make a fixture for a tiger cub head this is the oval head this is the square head
can you see how much larger it is here this is much better for cooling so oval head square head
i've got metal here i looked around my shop and i think i could make an oversized can
you see how this is a bit bigger i think i can make an oversized insert out of this
this is seamless tubing it's dom and this is the part that's going to get held into the chuck
and then i got some flat bar here and this is there's going to be a shelf that comes out
and the head is going to mount onto that maybe we need a reinforcement stop it flexing a little bit
and i got a couple allen screws you can only hold this on
one side basically because i can't put an ounce well actually i can
well anyway got some allen screws this is what's going to hold the head onto the plate
so the first thing we need to do is to make this whole round i'm just going to use a spiral roll
and my die grinder and we're going to put an inch bar into there you'll see why
oh oh there he goes okay we're in it doesn't have that much rock all right we're gonna go with that
so that's what we end up with inch half inch can you see what's going on here now
so what this does is it's holding the head where i want it to be held
and now i have to make up whatever is going to hold this no drawing no sketch
we're just going to make it so the next thing we'll do is to put that other piece of
round stock in here and and and we'll face off the end and then we'll figure out how how the
plate goes on and we have to drill some holes so that we can attach the head onto the plate
it's got a little bit of wiggle but not too bad
this is part of an old fixture some somewhere so you can see what's happening here even though this
has some size to it this plate here is only hitting maybe like half the thickness so what
we need to do i think is to take a piece of this plate and to weld it on here so that it sticks up
so that it becomes proud of the head and then we can get a weld all the way around
so i think that's the first thing we'll do we'll find a piece we can weld onto this and
we might have to make some sort of a of a counterweight or something
i don't i don't know yet so we'll we'll just figure it out as we go
i've got a c-clamp holding it down because if i put on a tack even though it's heavier
metal it can still lift up so i'm going to tack it in three spots and then do a little welding
okay we're welded
i'm leaving a little bit of room in between the fin can't get too
close so this is going to go something like that and then we want to have this out to
here basically so we're going to make a cut we'll cut right right there
i'm gonna put it almost up to the top not quite but almost up to the top there
see that there's still a little bit of play there i'm going to do some welding along here a stitch
welding it's called i don't need to weld the whole thing but i'm just going to weld a little bit
and then when i weld here depending on how much i weld
hopefully it pulls it back so let's see let's see what happens here
i think it's pretty good i think there's a there's a tiny little gap at the
at the bottom but
it's good i want to clamp this head down onto the plate and then i can go off to the drill press
and then i use these two holes here and that's where i i mock where the allen screws go see this
little thing i'm going to use this as a scriber it's out of a dental office and i'm going to
make a mark all around here but hopefully i can see
here's my and can you see what's going to happen i can only hold it right here there's no other
if if the chuck goes down anymore it's going to hit so
let's go let's go see if this will work
we have two holes marked
so let's let's take this off and drill them and tap them and then see how the head fits on
okay
i'm eyeballing here we need a right angle both ways so looks pretty good to me i got my spiral
flute tap that means i can just go straight down and i don't have to back and forth back and forth
okay
okay let's see if we have success here
okay that's pretty tight so let's put this back in the lathe now
i i know this is going to be out but let's just put it back in the lathe
and then i think next episode we're going to fix this up and we'll dial it in on the four jaw how
about that we'll just put it in the three jaw right now and see let's see what's up
see what's happening it's definitely out but that's okay because if this goes into a forge or
that all changes it's basically basically heading the right way so
what we're gonna do is we're gonna switch it on and just see if it's out of balance
won't go super fast
did you catch that so what we have to do is we have to weld on something here and have
a counterweight
that's what we need we need a counterweight now so
work on that for our episode of head fixturing we are out of time but
thanks for watching if you need some merchandise this is the promo code it's 20 off i'm placing
my order i'm gonna get some some t-shirts and some mugs thanks for watching see you next time bye you