OzVMX Forum
Clubroom => Tech Talk => Topic started by: tony27 on December 13, 2016, 05:18:03 am
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I picked up a cylinder out of the states for my CZ a couple of months ago which has the boost ports added to run a big DH reed valve which I already have
When I put the reed block & cylinder next to each other I found the the intakes had been opened out about 5mm on each side & are that amount wider than the reed block which definitely won't allow that amount of opening up to match
I'm considering having the ports welded up a bit as well as the gap between the manifold mount & next fin filled in as my modified Falta cylinder has then getting the mount machined flat & matching the port width & reed block to each other
What are peoples thoughts on this or any other suggestions
(http://i788.photobucket.com/albums/yy166/tony27_photo/CZ%20981%20random%20stuff/Southbay%20cylinders/74%20reed%20cylinder%20over%20width%20ports_zpsgznpbkuy.jpg) (http://s788.photobucket.com/user/tony27_photo/media/CZ%20981%20random%20stuff/Southbay%20cylinders/74%20reed%20cylinder%20over%20width%20ports_zpsgznpbkuy.jpg.html)
The extra width is quite obvious here & you can see the gap I'm going to have filled in
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apparently, mismatched ports are good for turbulence...
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probably not a sensible response Tony but looks like it'll seal all round--just not by much at the top & suppose bottom, so you know me--[don't do what i do]--just bolt it on & see how it goes!!, as sounds like a lot of expense & work welding & machining. Maybe you're pointing out it isn't going to seal top & bottom? or too close for comfort. looks ok down the side & middle.
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..or widen the ports on the reeds to match the cylinder.
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I picked up a cylinder out of the states for my CZ a couple of months ago which has the boost ports added to run a big DH reed valve which I already have
When I put the reed block & cylinder next to each other I found the the intakes had been opened out about 5mm on each side & are that amount wider than the reed block which definitely won't allow that amount of opening up to match
I'm considering having the ports welded up a bit as well as the gap between the manifold mount & next fin filled in as my modified Falta cylinder has then getting the mount machined flat & matching the port width & reed block to each other
What are peoples thoughts on this or any other suggestions
(http://i788.photobucket.com/albums/yy166/tony27_photo/CZ%20981%20random%20stuff/Southbay%20cylinders/74%20reed%20cylinder%20over%20width%20ports_zpsgznpbkuy.jpg) (http://s788.photobucket.com/user/tony27_photo/media/CZ%20981%20random%20stuff/Southbay%20cylinders/74%20reed%20cylinder%20over%20width%20ports_zpsgznpbkuy.jpg.html)
The extra width is quite obvious here & you can see the gap I'm going to have filled in
Won't make 0.01hp difference if you leave it as is or fill it. If you want to fill it JB Weld or Liquid Steel is the go. With a reed valve engine the reed is the restriction.
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..or widen the ports on the reeds to match the cylinder.
5mm per side is wider than the outside of the reed block.
I've got no idea what someone was thinking when they did this, the Falta cylinder I own had the heights altered to DH's specifications & the gap between the fin & port filled as there actually isn't much width to seal with & they do have a reputation of being prone to air leaks because of that
Never been keen on using something like JB weld on intake ports due to the possibility of it coming loose
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Never been keen on using something like JB weld on intake ports due to the possibility of it coming loose
Where it turns to powder under combustion pressure and temperature , like anything if the surface is rough and with areas to key onto it sticks like shit to a blanket. Have had JB last in cylinders for 5years easy. Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust
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"Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust"
And you may end up with an air leak and your motor may shit itself. Clean it well, Tig weld it and match it to your reed block. Bog is for plasterers :)
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if you TIG weld this how far into the port would you be welding ?
if you were going to weld up close to the liner distortion could be a problem, as piston clearances are very small a few thou of distortion could be too much
if you only weld near the mounting face even this would need machining flat again
there is nothing to loose by bolting it together as it is and seeing how it performs
also if that barrel is sand cast they don't always weld nicely due to some sand getting into the casting
whatever you decide I hope it works out for you
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KISS ,see where the blocks chamferred on the inside edges,just chamfer the outers to match (if you can) & bolt the forking thing together,& see what it does, :P
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if you TIG weld this how far into the port would you be welding ?
if you were going to weld up close to the liner distortion could be a problem, as piston clearances are very small a few thou of distortion could be too much
if you only weld near the mounting face even this would need machining flat again
there is nothing to loose by bolting it together as it is and seeing how it performs
also if that barrel is sand cast they don't always weld nicely due to some sand getting into the casting
whatever you decide I hope it works out for you
Would weld walls (top and botom mainly)thick enough to be happy with sealing surface.
Yes cas aluminium is not easy to weld but not impossible.
Yes it has to be machined after welding. Would do this anyway just to get flat sealing surface.
Or just bolt the reed block on and hope it does not leak :)
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With Respect ;)
It makes nine tenths of sweet FA difference for weldability and/or ease of it has very little to do with whether it is Sand cast, dye cast, extruded, rolled of forged Aluminium.
We are not talking Aluminium once it has other elements added we are talking Aluminium alloys now and how pure it was to start with before they started adding to it.
It is what has been added and in what amounts that mainly determines its level of welding suitability and to be fabricated and/or repaired by welding.
Example; any Tom Dick or Harry can weld Maico aluminium alloy sand castings, because they are just so pure compared to anything Japanese. They are just so easy.
(http://i677.photobucket.com/albums/vv132/mc125mick/74440MAICO002_zpsf2289cfb.jpg~original)
And then cleaned up by my hand dye grinding in attempt to reproduce the rough Maico sand cast sort of finish
(http://i677.photobucket.com/albums/vv132/mc125mick/74440MAICO003_zpsbc4eb635.jpg~original)
Jap dye casts are a bit more of a pain because they are an entirely different alloy composition to the Maico alloys
(http://i677.photobucket.com/albums/vv132/mc125mick/GLENNPICKERING.jpg~original)
Indeed, I have invented/developed a process of oxy welding cracked fins back on Maicos when straightening them.
A bit of mucking about, but very doable because of their quality of Aluminium alloy
And if I didn't tell you it had been done,,,,,? well you would not find where at first glance :)
(http://i677.photobucket.com/albums/vv132/mc125mick/ROYGAIZE051_zps829c5dc1.jpg~original)
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I would just bolt that reed box straight on,,,,welll I probably wouldn't actually, but its not going to make much of a difference the way it is. Maybe more a bit latter, time the great leveller. Don't waste it, bolt it straight on.......
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Maicos even have a spare spot for the spare spark plugs to ;D
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There is lots of places that can do this job tony27. Depends on your location. RK Engenering in Victoria was mentioned in a post here somewhere. Realy nice work there. I think that you can even post your cylinder to them if you can not find anybody local that can do the welding and machining for you. I am sure they will be able to help. Would not be suprised if comunist CZ used some pot metal for their cylinders but I am sure it is weldable :) Good luck
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Mick D, "with respect" as you say, this thread is about welding a CZ barrel not a Maico barrel ,
and yes we all know the difference between pure aluminium and aluminium alloys ,
I doubt the alloy used in the CZ is exactly the same as Maico or any other manufacturer so you wont know how it welds until you try.
when selecting an alloy to use for a casting I don't know if weldability is considered by the manufacturer or not, but I doubt it
many aluminium alloys are not recommended to be welded but we all ignore that when repairing or modifying old bike parts, sometimes they weld up nicely, sometimes it gets messy.
would you please explain the new welding process you say you have invented ?
I am always interested in new inventions but I haven't got a Maico, will it work on other bikes ?
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a mate stripped his sump plug on his new 85 kdx 200 (years ago) and in getting it welded up, the cases peeled apart and it looked like half a coke can was layered in the cases. Kawasaki stumped up some new cases.
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a mate stripped his sump plug on his new 85 kdx 200 (years ago) and in getting it welded up, the cases peeled apart and it looked like half a coke can was layered in the cases. Kawasaki stumped up some new cases.
That doesn't surprise me Husky Man,,, none of that Jap stuff seems to be up to Maico Quality ;D
They even bought a few to spy on and still could come close ::) guess that's what happens when you cut corners :-*
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Mick D, "with respect" as you say, this thread is about welding a CZ barrel not a Maico barrel ,
and yes we all know the difference between pure aluminium and aluminium alloys ,
I doubt the alloy used in the CZ is exactly the same as Maico or any other manufacturer so you wont know how it welds until you try.
when selecting an alloy to use for a casting I don't know if weldability is considered by the manufacturer or not, but I doubt it
many aluminium alloys are not recommended to be welded but we all ignore that when repairing or modifying old bike parts, sometimes they weld up nicely, sometimes it gets messy.
No, no ;D Pretty obvious that I was clearly responding to the comments about "Castings being more difficult to weld",,,which is a total load of bolocks ::)
Welding aluminium alloys ease or degree of difficulty mostly depends upon the composition of the parent metal!
would you please explain the new welding process you say you have invented ?
I am always interested in new inventions but I haven't got a Maico, will it work on other bikes ?
I just bought some new "maintenance repair items" for this process last week, still some more on the way
(http://i677.photobucket.com/albums/vv132/mc125mick/20161214_212636_zpsdvcdwp8h.jpg~original)
I can already replace them near "flawlessly". Maicos are easy because the Radial fin configuration allows better access than tight parallel fins. It is a pain to have to remove upper of lower fins to access the one that needs to be replaced or repaired. I was able to get in tight and replace the last Maico one without removing anything above or below with the tools I developed. I want to try a Parallel alloy fin next without removing above or below for access :)
I will post before and after and maybe in between pics,,,,soon I am hoping, but it is gingle bells time and I am in jingle bells mode until the new year ;D
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you say
No, no, Have :)
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mick D, if you are going to quote me then quote the words I actually wrote don't make things up
I did not say - "castings are difficult to weld"
I actually said - " if that barrel is SAND CAST they don't always weld nicely due to some SAND getting into the casting"
try reading properly first before commenting
moulding sand can sometimes mix with the liquid metal if the pouring speed is too fast or the sand is weak/thin in places, this is not a problem until one day you decide to weld the casting and hit an area where there is some contamination, over a 25 year period I have had many sand cast aluminium parts welded and every decent welder I have been too has mentioned this potential problem
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mick D, if you are going to quote me then quote the words I actually wrote don't make things up
I did not say - "castings are difficult to weld"
I actually said - " if that barrel is SAND CAST they don't always weld nicely due to some SAND getting into the casting"
try reading properly first before commenting
Who said I was quoting you? Well? At least your self inflating
DH
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Make things up, F--- y-- DH
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Well come on, show me where I was quoting you when I made that first post! come on DH
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would you please explain the new welding process you say you have invented ?
What would be the point in that?
over a 25 year period I have had many sand cast aluminium parts welded and every decent welder I have been too has mentioned this potential problem
According to you,,,you wouldn't even be able to apply it? would you? so what would you do with my intellectual property? dispute it with nothing more than so called "here say" ability? because you are unable to weld yourself? DH
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question - what would I do with your intellectual property ?
answer - nothing, you don't seem to have any
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would you please explain the new welding process you say you have invented ?
What would be the point in that?
over a 25 year period I have had many sand cast aluminium parts welded and every decent welder I have been too has mentioned this potential problem
According to you,,,you wouldn't even be able to apply it? would you? so what would you do with my intellectual property? dispute it with nothing more than so called "here say" ability? because you are unable to weld yourself? DH
its a bit hard to understand you here , are you trying to say the 10+ qualified welders who have mentioned potential sand contamination in sand castings to me are all wrong ?
and that this is just "here say" ?
is that what you are trying to say , because that's how it comes across ?
you also say "because you are unable to weld yourself "?
I can weld fine with MIG, TIG, ARC, Oxy , but I choose to delegate some sand casting repairs to other people
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I have been told by a (very good) welder the jap al. castings have a lot of zinc in them which makes the metal flow better during the casting process. When he welds them he takes his time "burning off" impurities, whether from the initial casting or later contamination. All done with a water cooled tig torch.
He crack tests afterwards as well. Also has a mini torch for ports/ valve pockets etc.
For sure every manufacturer has their own blend for castings
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The welding will probably get done by the engine rebuild guys who bored the cylinder for me. They did some welding & machining on another cylinder for me a while ago & made a good job of it
I don't plan on getting full depth of the port welded, just 1 or runs(5-10mm) wide to allow me to taper from the sealing surface back to the rest of the port.
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Personally, Tony, I'd be backing away from the welding right about now.
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"Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust"
And you may end up with an air leak and your motor may shit itself. Clean it well, Tig weld it and match it to your reed block. Bog is for plasterers :)
Proving that old saying correct "Its better to be thought a fool than opening your mouth and removing the doubt".
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Ya have My attention
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Jap cases have a very high percentage of Silicon. Forms as Black slag in the weld. Have to keep grinding it out. Very time consuming.
Example early Honda XR and KX sump plugs. Stripped or Ripped out. Ask Gavin Cosway how hard they are to weld. Must of Done Hundreds of them.
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"Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust"
And you may end up with an air leak and your motor may shit itself. Clean it well, Tig weld it and match it to your reed block. Bog is for plasterers :)
Proving that old saying correct "Its better to be thought a fool than opening your mouth and removing the doubt".
Have you read that somwhere dude? Nobody seem to take your idea of boging parts seriously Mr. I know everything hahaha ha
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Jap cases have a very high percentage of Silicon. Forms as Black slag in the weld. Have to keep grinding it out. Very time consuming.
Example early Honda XR and KX sump plugs. Stripped or Ripped out. Ask Gavin Cosway how hard they are to weld. Must of Done Hundreds of them.
Yep Ive had the same problem! also the Suzuki t250 do the same, the trick is to get a weld run onto the parent metal then go back (after a clean ) and weld to the previous pass (weld) stop most of the porosity and drop out, with a lot less oxidisation
And yes there are guite a few additives in the old Jap castings to help it flow and get that nice smooth finish, Oh yer use the right series rod for the job and set for cleaning (we had fun working this stuff out lol)
oh yer heat the job right up to burn the oil out of the pours before welding
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oh yer heat the job right up to burn the oil out of the pours before welding
I always boil any engine parts that have been subjected to oil in a big drum, topping up with fresh water regularly until no more oil floats to the surface. Clean with acetone, S/S wire brush then a couple of dummy runs (no filler rod) with the weld width biased all the way to cleaning. Another hit with the wire brush, weld width back to normal, and good to go.
Oh yeah, and leave the Devcon on the shelf where it's supposed to be...
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oh yer heat the job right up to burn the oil out of the pours before welding
I always boil any engine parts that have been subjected to oil in a big drum, topping up with fresh water regularly until no more oil floats to the surface. Clean with acetone, S/S wire brush then a couple of dummy runs (no filler rod) with the weld width biased all the way to cleaning. Another hit with the wire brush, weld width back to normal, and good to go.
Oh yeah, and leave the Devcon on the shelf where it's supposed to be...
I like the boil the bits, will definatley go down that path, oh and thanx for mentioning the acetone (forgot to mention that)
some cases be prepared to just go in and get that weld on the parent metal in one /the first pass, just so much inclusion and porosity, but get that first pass (weld) then keep welding off of that (like I said only some old covers ie Suzuki T250) cheers