Contra Horrors

[rxe]

Base coat will be U-POL Acid #8, a one pack etch primer.

Top coat will be Octacryl 2 pack car paint, matched to an original Contra clutch cover - the slightly off gray paint colour. I've got some "Stihl Orange" matched to an 090 filter cover of the right vintage.

The health warnings with the Octacryl are fierce - so I'll be wearing a positive pressure face mask and probably doing the deed outside. I need a calm, hot day. At the moment it is blowing a gale and honking down with rain. I have a dinky little touch up gun with a 330ml reservoir, so hopefully I'll get a decent finish.

Update on the piston: I've sent a mail to a company called Accralite in the UK. They say they can do anything on their web site!

 

[Dan Forsh]

Good luck with the piston. Judging by the website I think you will be talking mucho moola :jawdrop:

 

[rxe]

Yeah, I got that impression as well. I'll report back! They do specifically mention teflon coated skirts that are suitable for Nikasil, so they are clearly up for a bit of Stihl action....

 

[Saw Dr.]

I have a line on a Contra. No telling what it turns out to be. I may be in for a piston if there is a min quantity you need to buy. I was a motorcycle mechanic many moons ago, and there was someone who would make pistons custom, but there was a minimum order of 10. Arias maybe? or Wiseco? I'll look through some old books and see if I find anything.

 

[Brmorgan]

rxe, so are you just looking for a piston now, and not a crank? If so clarify exactly which one out of the above pictures you need, and any applicable measurements. I'm probably going to see my parts guy this week regarding my 090, so I could rummage through all the contra/070/090 parts boxes he has. Hopefully tomorrow, but I don't know if he'll be at his shop.

 

[rxe]

Well, Accralite got back to me quickly. For forging, their min order is 100 pistons - but at this level, they aren't a lot more expensive than Golf and the like, but almost certainly far better quality. This is because they don't have a suitable forging blank for this size, they'd have to make it. I'm seriously tempted as I reckon there is a market out there for Contra pistons, but I have to face facts, I'm a computer bloke, not a piston seller.

They can mill out of sold billet for, er, quite a lot of money , but when you consider what you'd pay for an 880 piston for example, it isn't that bad. I quite like the idea of supporting a proper engineering company - they're getting rare these days.

They have given me some more contacts of people who might have forgings of the right size in stock, so I'll chase these up first.

Brmorgan - I need a Contra 1106 piston, from the 106cc saw, so a 58mm diameter. If he has a good one, I'd be interested. All of the ones I've seen have been worn smooth. As per the pictures, it is a different beast to the 070 version.

 

[Brmorgan]

I'm not sure what you mean by "worn smooth". Like the crown is rounded over from heat/friction? Or something in the pin boss?

 

[rxe]

Only just seen this, sorry...

I'm not sure what you mean by "worn smooth".

If you look at a new piston, there are tiny ridges machined into it so that it holds oil. You can tell a worn piston because all of these ridges are worn away and the surface is smooth. (Lake taught me this, I'm not suggesting I have any jedi knowledge of my own....)

Anyway, Arias can do them, for $155 each, min order 4. That's probably expensive in the US, but in the UK, I'd pay more than that for a piston for a modern saw, so the deal is on. I'm ordering 4 - I've got 3 Contras in bits, and I'd like one spare. Anyone else want to order one?

 

[William Balaska]

I'm going to assume they need your old piston? What about the rings?

 

[Nitroman]

Only just seen this, sorry...
If you look at a new piston, there are tiny ridges machined into it so that it holds oil. You can tell a worn piston because all of these ridges are worn away and the surface is smooth. (Lake taught me this, I'm not suggesting I have any jedi knowledge of my own....)

Anyway, Arias can do them, for $155 each, min order 4. That's probably expensive in the US, but in the UK, I'd pay more than that for a piston for a modern saw, so the deal is on. I'm ordering 4 - I've got 3 Contras in bits, and I'd like one spare. Anyone else want to order one?

That's GREAT! I am happy you were able to get a deal going on the pistons. I was going to suggest finding a retired machinist who would build you one.

If that worn piston is in otherwise good condition, you can still keep it and make use of it. In the old days pistons would be "built-up" by knurling the skirt to raise the aluminum slightly. You would need the diameter of an original piston in new condition, and take that and the old piston to the machinist, they could gently knurl the skirt to bring it back into spec, or just to give you the patterns to hold oil.

 

[Saw Dr.]

I'm still waiting on my Contra to arrive. No telling if I need a piston. When are you going to place the order? If you place the order, will they ship part of it to you an part somewhere else? With a roundtrip to the UK, the cost of shipping that piston could get stupid!

 

[William Balaska]

I need a topcover for my contra, anyone have one?

 

[William Balaska]

Better yet I'm going to list my contra here in the trading post for sale $425 in running order with 150psi, unfortunately no topcover:deadhorse: yep i'm tired of looking for the cover