Contra/Contra-S

[rxe]

I have recently picked up a few Contras, along with what were advertised as "NOS Contra" cylinders and pistons. They weren't expensive, so I jumped at the chance of getting a new jug and piston. After all, one of my saws was bound to have a scored jug.

I unpacked my NOS items. They looked like Contra cylinders, but they were huuuuge. 66mm across huuuuuge. Hmmmm. I looked at the box and it said Contra-S. Oh, yes, the 137 cc monster saw, grand daddy of the 090. Hah, CAD rules!

They are different. The pic shows an 070 item on the right (the bottom of the Contra is identical), and the Contra-S on the left. Feel the width!

The porting is totally different, I assume that the 090 is similar:

Now I don't have an 090 in pieces to play with, but what I do know is that the Contra-S piston does not fit on a Contra case - the bolts line up, but the cylinder diameter is too big.

Can someone post a pic of an 090 case or a Contra-S case? I always thought that the cases were the same, but they seem not to be. I'd like to fit this if possible. Is it as simple as machining a Contra case to suit?

 

[SawTroll]

..... Hmmmm. I looked at the box and it said Contra-S. Oh, yes, the 137 cc monster saw, grand daddy of the 090. Hah, CAD rules!

....

Just daddy at the most, more like older brother, really.......

 

[harrygrey382]

I have recently picked up a few Contras, along with what were advertised as "NOS Contra" cylinders and pistons. They weren't expensive, so I jumped at the chance of getting a new jug and piston. After all, one of my saws was bound to have a scored jug.

I unpacked my NOS items. They looked like Contra cylinders, but they were huuuuge. 66mm across huuuuuge. Hmmmm. I looked at the box and it said Contra-S. Oh, yes, the 137 cc monster saw, grand daddy of the 090. Hah, CAD rules!

They are different. The pic shows an 070 item on the right (the bottom of the Contra is identical), and the Contra-S on the left. Feel the width!


The porting is totally different, I assume that the 090 is similar:


Now I don't have an 090 in pieces to play with, but what I do know is that the Contra-S piston does not fit on a Contra case - the bolts line up, but the cylinder diameter is too big.

Can someone post a pic of an 090 case or a Contra-S case? I always thought that the cases were the same, but they seem not to be. I'd like to fit this if possible. Is it as simple as machining a Contra case to suit?

Now that's a real man's project. Wish I could offer some advice but all I can do is watch for the moment...

 

[Bill G]

That is a VERY NICE find

Somewhere on AS is a picture of a few jugs and pistons I have with the Contra S and 090. I also have some 070 ones.

Bill

 

[rxe]

Thanks Bill! I was pretty pleased with them (there were two of them....!). Can you enlighten me on the crankcase differences? As I said, I used to think that the crankcases for all of the 1106 series saws were the same, and that the jugs were interchangeable.

 

[sILlogger]

sweet mary mother of all things holy!!! that sob is huge!!(for a chainsaw) i gotta get one of those!!!

 

[04ultra]

Hmmmmm...............I'd like to have the Big Bore 137 on my contra....

 

[Dibbs]

After a bit of trawling I found the 070, 090, Contra & Contra S Jugs.
Look for a post by "Bill G" with the attachments 58 and 66mm jugs.JPG and 58 and 6mm jugs 2.JPG

http://www.arboristsite.com/showpost.php?p=845821&postcount=25

 

[teacherman]

sweet mary mother of all things holy!!! that sob is huge!!(for a chainsaw) i gotta get one of those!!!

Neeheeheeeheeee.....lookit the Precioussss...the Precioussss is ENORMOUS!......covet...covet...drool...slobber....we must have the Precioussss.....

Maybe the 090 was actually an 009 until Raquel Welch did a Stihl commercial......:greenchainsaw:

 

[rxe]

Dibbs - had a look at those pics (Oh how I loved opening a picture called "Jugs2" at work....). They confirm what I am thinking - that the 090 and Contra-S cylinders are the same at the bottom.

You've fitted an 090 cylinder onto an 070 - did it just go straight on? The Contra-S cylinder does not fit on the Contra crankcase - the bore is too big! I need to see a Contra-S crankcase. Maybe I need to buy a Contra-S myself!

 

[Dan Forsh]

Maybe I need to buy a Contra-S myself!

Like you need any persuasion :hmm3grin2orange:

 

[Dibbs]

You've fitted an 090 cylinder onto an 070 - did it just go straight on?

Haven't just got that far yet! I'm still waiting for an 090 cylinder and piston kit to present itself, jump on it, then take it home before any of you lot slip in and claim it for yourselves!
I'm very interested in the outcome of this project of yours!
I thought it was a straightforward swap, that's why I was willing to buy an 070 and convert it at a later date.

 

[Dibbs]

rxe, your cylinder seems to be the one with a notch out of the rim. (top right type)
this kind seems to have a thicker rim than the one in the top middle which does not have the notch removed.
Does this make any difference?
What is the (outside) rim diameter of your 070 cylinder?
Does the 070 cylinder fit alright?
What is the diameter of the crankcase hole the rim is required to slot into?

 

[rxe]

OK, I did some measuring last night. I took some pics, but I don't have the camera with me.

The 070/Contra jug has an external diamter of about 67mm.
The Contra case as an internal diameter of about 67mm
So - the 070/Contra jugs fit perfectly on a Contra case.

The Contra-S jug has an external diameter of about 74mm.
So - the Contra-S jug does not fit on the Contra case. The bolts line up, but the bore diameter is too big.

This makes sense - if the 090 or Contra-S has a bore diamter of 66mm, then the jug external diameter is going to be quite a bit more than this.

So, Dibbs, the task for you is to measure the diameter of your 070 case and report back! It may be that the 070/090s are all the same with a bigger diameter - and that when they made the Contras, they made two different diameter cases. However, if your case has a 67mm diameter, you won't fit an 090 jug on it.

 

[Dibbs]

So, Dibbs, the task for you is to measure the diameter of your 070 case and report back!

Just got in from work and it's time to go to the garage already!

if your case has a 67mm diameter, you won't fit an 090 jug on it.

If the case has a 67mm diameter I can always strip her down and see a CNC man about it!

 

[Dibbs]

Opened up the 070 for the first time and found the top of the cylinder like this!

I wonder if someone changed the piston since that happened?

The bore of the cylinder is fine, as is the piston, just them dings in the head area.



Now, onward to the crackcase.

As you can see, there are two rings machined inside the crankcase, the bottom one is 67mm in diameter while the upper one is 73mm in diameter.

The depth to which the cylinder rim protrudes into the crankcase is 11.2mm, I assume the rim on the 090 cylinder does not protrude as far.

(Full dimensions will be in the next post)

 

[Dibbs]

The white block is the 070 Cylinder section and the orange block is the Crankcase.

The first pictute shows the long rim passing down as far as the bottom machined ring.
I hope the 090 cylinder rim does not go down more than 7.5mm as it would then fit into the upper machined ring in the crackcase.

 

[rxe]

Got it.

The 070/090 cases are designed to take both jugs - that extra step will take the extra large 66mm bore piston. The standard Contra case does not have the step.

Thanks for the pics. At least I can now show the machinist what I want!

Those marks are really common - I've got them in several of my eBay 070s. You're very lucky the bore is OK.

Just measured the ridge on the Contra-S jug - 6.5mm - if the 090 is the same, you'll be fine.

 

[Dibbs]

How far does the rim on the 66mm cylinder protrude?
Is it 7.5mm or less?

 

[rxe]

Stuck it in the post while you were reading it...!