Port repair

[tony27]

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
 
The extra width is quite obvious here & you can see the gap I'm going to have filled in

[80-85 husky]

apparently, mismatched ports are good for turbulence...

[OverTheHill]

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.

[evo550]

..or widen the ports on the reeds to match the cylinder.

[Lozza]

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
 
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.

[tony27]

..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

[Lozza]

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

[Tomas]

"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

[djr]

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

[matcho mick]

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,

[Tomas]

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

[Mick D]

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.


And then cleaned up by my hand dye grinding in attempt to reproduce the rough Maico sand cast sort of finish


Jap dye casts are a bit more of a pain because they are an entirely different alloy composition to the Maico alloys


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

[Mick D]

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.......

[mick25]

Maicos even have a spare spot for the spare spark plugs to 

[Tomas]

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