Ariel SB/1932 and SF 1931 my new project

[KenS]

Good luck, hope it works out as planned.

[paul.jameson]

The pump body is made of Mazak. It is worth Googling Mazak Rot to understand the problem fully. Fundamentally, impurities in the alloy lead to a chemical reaction which causes expansion. Eventually, the Mazak falls apart into small pieces. The 1929-32 speedo body on the left in the photo below is a classic example of Mazak Rot and explains why removing your pump body is extremely difficult. Click on the photo and enlarge to see the full horrors.

[Karol Burger]

Yes, it's a big disaster, but it's progress. At that time, they decided to use this material because of its good casting properties. The disaster only happened later. Now we've learned from previous mistakes and we're doing it better. Our new pumps no longer suffer from this defect.

https://www.arielklub.sk/inzerat-24160- ... l-SG-SF-SB

https://www.arielklub.sk/inzerat-24174- ... F6-1931-32

[Vincent.vanGinneke]

Yes Zamac, Zink, Aluminium, Magnesium, Kupfer the Dinky Toy stuff.
The surface can blow bubbels when aqua blasted, horrendous material !

[Julian Murphy]

IWhen I left college my first 'employment' was at Hornby making Hornby railways etc.

The loco chassis, wheels etc were made by diecasting Mazak.

The yield was appalling and all the scrap parts were chucked back in the pot for re-melting.

Awful material.

[Karol Burger]

the pump is out of the block. it went pretty well. We used our new tool and also heated the block sufficiently. Then I just slowly tightened the nut and with not too strong blows I pried the pump from the inside of the engine. I'm glad it's out and we didn't damage anything.

[Karol Burger]

Tomorrow I'm sending my cylinder from an Ariel SB/1932 engine for liner making and grinding. I'll use the piston that was in the engine. It's pretty well preserved. We'll modify it to 87mm. What clearance should I have for this bike? I thought they'd use 0.2mm clearance with a 87mm piston size.

[nevhunter]

Sidevalvers run pretty hot. Not worth trying too tight a fit and risk nipping up Slot to the bottom (front). I like the 3 compression rings. Nev

[KenS]

It appears as though your piston had a similar fitment/dimensional defect at the gudgeon pin area as my original VG500 piston did, causing heat seize. The new 81.8mm + .060" JP replacement clearance recommendation is .005" to .007". I had my cylinder bored to .007" to avoid any potential issues in the future and since your bore is larger, I'd consider at least .007"

[Karol Burger]

0.2 mm is 0.0078" it is approximately 0.0023 per inch of piston dimension