stage 2? flathead build

[Denny]

Ouch that hurts! But all is not lost. If nothing else cracked I would just polish that area and make it look factory.

 

[jmaack]

Yeah. Maybe it'll give it some character.

 

[madprofessor]

How important is that last fin? I jb welded it.

Important for strength or for heat dissipation? JB Weld is good stuff, can add some strength where you need it. If transferring heat from point A to point B is the idea, I wouldn't have a lot of faith that it would be sufficiently metal-like as opposed to barrier-like.
First line in a HVACR educational textbook: "Refrigeration is the transfer of heat from a place where it is unwanted to a place where it is unobjectionable."
Motor cooling fins are literally refrigerating the base (the block) that they are attached to. The above statement applies the same there as to a 200-ton brine chiller. You could always stack up some solder on that pot metal to maintain metal continuity for heat transfer. If there's a way to solder strength into pot metal it would be news to me, but heat transfer? I believe so.

 

[Denny]

Can you say Muggy Weld? Look it up.

 

[jmaack]

eh. It might impact slightly. But most of the shroud still covers the area where there is still fin. I might try to braze with this but need to buy a torch.

 

[madprofessor]

Can you say Muggy Weld? Look it up.

Okay, that Muggy Weld looks like manna from Heaven if it does all it says. The Super Alloy 1 for pot metal sounds like the real deal, complete with the capacity for heat transfer. 350 degrees F. shouldn't be any problem for old head fins. The biggest deal to me is the use with Mapp gas.
The Bernzomatic torch they also advertise does both that and propane, never seen that from them before, I've always had separate torches for that. Also never seen the ignition feature that will also shut off the flame.
Was that solder stuff around 40 years ago when I was still learning, and could have made great use of it?

 

[Denny]

I would use regular oxy/acetylene torches with a welding tip, for control.

 

[madprofessor]

I would use regular oxy/acetylene torches with a welding tip, for control.

Been through 100's of R and MC bottles of oxy/acet for refrigeration-grade silver soldering (15% my favorite of course, but forced to do lots of Sil-Fos also), but unlike most techs I've ever met I was also a huge fan of it with a Type17? rosebud tip for large diameter copper, steel, brass, other stuff for common soldering, new fitwork, demolition, u-naym-it stuff.
None of the oxy/acet would be needed for that 350 degree F. that the Muggy Weld says it calls for when the (more expensive) Mapp gas cylinders can be used to get on up there, but the benefit of a small (Type17?) rosebud on oxy/acet can't be shunned, especially by me. If someone has the experience and skill with oxy/acet, then I say go that way if you already own the regulators, R and MC bottles, and associated hoses, handles, tips, tip cleaners, etc.
Otherwise, get the dual propane/Mapp gas torch wherever it's cheapest, make sure it's a swirl-type flame, like "TurboTorch" or one of those, just don't get a Mapp gas-only torch because the disposable Mapp gas cylinders cost so much more than straight propane.

 

[madprofessor]

Found that Type 17 rosebud tip I used to use for dang near everything. Curiosity about the type # made me go looking.................
Uniweld TYPE 17-30 $56.99 Rosebud Tip 1/2-6 Brazing Range | Zoro.com

 

[Denny]

Actually with oxy/acc torches I would just gas weld it with a 0 tip size. Remember aluminum does not change color when hot it just runs all over your shoes!

 

[karl]

Just my opinion , I wouldn't stick a torch that close to the head gasket surface/ cylinder.

Might do more harm than good trying to repair it, Id just leave the fin off.
Your supposed to bolt a torque plate to the block just to hone the cylinder.

 

[madprofessor]

Your supposed to bolt a torque plate to the block just to hone the cylinder.

Good idea. Wouldn't it also prevent heat distortion from 350+ degree soldering?

when hot it just runs all over your shoes!

I know the description of experience when I read it, hotfoot! Can almost see you in my gray matter right now, hopping around like a bunny.
BTW: Got both of my (wrong) shoes (sneakers) melted right off my feet. 350-degree deep-fry oil sent me to the burn unit in Gainesville for 12 days.

 

[karl]

Good idea. Wouldn't it also prevent heat distortion from 350+ degree soldering?

Maybe, but the cost of the plate and the fancy soldering rods exceeds the cost of a
good condition block that is not cracked.

So kinda a waste of time, and Im not going to heat my plate with a torch.
To me it seems like using a precision measing tool as a hammer , no?

 

[jmaack]

I'm honestly not worried about it. I'm working it out with seller. I already jb welded it and am able to pick up by the broken fin. It'll be fine as is.
Here is it mocked up still have to clean. Making sure it'll fit and going to make an exhaust. Gotta figure out starter. Can't put new style recoil on old shroud as holes dont line up. Hoping to put the new style recoil pulley in to the old style metal recoil housing. that way I can use the old style housing with the new style starter cup.

 

[madprofessor]

Can't put new style recoil on old shroud as holes dont line up. Hoping to put the new style recoil pulley in to the old style metal recoil housing. that way I can use the old style housing with the new style starter cup.

Wow. Completely lost track trying to read that. Oldnewoldnewold, I'm still confused. I'll just take it for granted that you got it and it'll work.

 

[jmaack]

Wow. Completely lost track trying to read that. Oldnewoldnewold, I'm still confused. I'll just take it for granted that you got it and it'll work.

lmao. it was hard writing it. tldr is the new style housing doesn't fit old shroud. so basically hoping to swap internals between new and old.

 

[jmaack]

Parts engine if needed. Traded the old 99cc hisun yesterday after not being able to sell for months. 1973 briggs swapped out flywheel for one without broken fins oiled up choke and yanked. It fired up but burns some oil. rings are gone.