066 Magnum Big Bore Project

[BobL]

Finally got some time to put the big bore kit on my freebie 066.

Did the soft solder squish test and 0.022 and 0.024" on the opposite side. Anyone know if that is that OK?

Compression is 165 Psi using a hand held comp tester.

Just need to tidy a few cosmetic things up before giving it a run.

 

[RiverRat2]

Finally got some time to put the big bore kit on my freebie 066.

Did the soft solder squish test and 0.022 and 0.024" on the opposite side. Anyone know if that is that OK?

Compression is 165 Psi using a hand held comp tester.

Just need to tidy a few cosmetic things up before giving it a run.

That squish is good like it is ive had a 460BB that was .042,,, especially since your compression is 165..... run it!!!!!

You can always change out the gasket to get it closer later,,,, .018 is about optimal

 

[BobL]

That squish is good like it is ive had a 460BB that was .042,,, especially since your compression is 165..... run it!!!!!

You can always change out the gasket to get it closer later,,,, .018 is about optimal

Cheers RR2,

OK, I just tried it and it fired up on the 5th pull - lotsa blue smoke from the raw lube I put into the barrel. It's sunday evening here and as I live in an inner city neighborhood I couldn't really run it for more than about 10 seconds (even 10 secs will give the neighbors an excuse to have a go at me) so no tuning yet. I also need to make up a chain or adapt bars/bolts (I have mostly 078/088 bars).

Thanks again.

How do get a thinner gasket - just thin it down with a bit of wet and dry?

 

[Tzed250]

Cheers RR2,

OK, I just tried it and it fired up on the 5th pull - lotsa blue smoke from the raw lube I put into the barrel. It's sunday evening here and as I live in an inner city neighborhood I couldn't really run it for more than about 10 seconds (even 10 secs will give the neighbors an excuse to have a go at me) so no tuning yet. I also need to make up a chain or adapt bars/bolts (I have mostly 078/088 bars).

Thanks again.

How do get a thinner gasket - just thin it down with a bit of wet and dry?

.021 is fine, just run it like that. But if you did want to get it down to .018 then you could lap the base on a surface plate to get the extra .003.

To run the 3002 bars you just need spacer rings and to make sure your oil holes are lined up.

 

[BobL]

.021 is fine, just run it like that. But if you did want to get it down to .018 then you could lap the base on a surface plate to get the extra .003.

To run the 3002 bars you just need spacer rings and to make sure your oil holes are lined up.

Thanks Tzed.

I will use the spacer rings for now but will probably end up turning some new longer bar bolts like I did for my 076 so I could bolt it direct onto my mill.

Well maybe not that long, but long enough to fit onto the mill. I'll have to drill a new hole in the mill as well - shouldn't be too hard.

 

[Tzed250]

Looks like you have the situation well in hand. Let us know how the 66 runs when you get it broken in!

 

[RiverRat2]

Looks like you have the situation well in hand. Let us know how the 66 runs when you get it broken in!

Yep!!!!

Good Idea on removing metal from the cylinder base with the surface plate to get his squish to .018,,,,

 

[RiverRat2]

Cheers RR2,


How do get a thinner gasket - just thin it down with a bit of wet and dry?

You can make gaskets out of the most easy to obtain things,,,

construction paper, card board, aluminum cans,,,

Grocery bags,,,,with a coat of spraypaint,,,

But as TZed said a lapping table or a good flat piece of glass and some sand paper will remove .003 real quick!!!!! and use the stock gasket,,,,

Mays as well clean up the piston and ports while you are there,,,,:greenchainsaw:

but I would break it in stock now that it's together...:greenchainsaw:

then compare what your porting work does is all in the fun!!!!!

 

[BobL]

Thanks Guys - all good ideas.

 

[BobL]

. . . . . .
I will use the spacer rings for now but will probably end up turning some new longer bar bolts like I did for my 076 so I could bolt it direct onto my mill.
.
.
.

Got home too late to fire the 066 up but managed to turn up the longer and bigger bar bolts.

These will allow me to use my 30, 36, 42 and 60" bars on my mill.

 

[BobL]

Took the 066 to the milling yard today, found chain to fit but unfortunately the chain is not worth cutting anything with but ok to use for a basic tune. Seems to accelerate nicely and idles fine. Hopefully my roll of chain turns up this week so I can have a real go.

 

[Stihltp]

Nice work Brad!

 

[BobL]

I know you guys like pics so here are some of my BB 066 project saw - not as slick as Brads refurbs but heck it was a free saw.

Outside dog was missing so I made new Dogs from some 1/8" steel plate. Pot belly black paint and baked in a BBQ oven at 400F for a couple of hours.

Clutch cover was pretty beat up and had a couple of corrosion holes which I bogged up with JB weld. Paint is just what I had in a spray can left over from another project.

Chain and Bar are just for tuning purposes I have a good range (30, 42 and 60") of longer bars for it.

 

[blsnelling]

Good job. You should have a real runner there.

 

[BobL]

Took the BB 066 out again last Saturday with a new chain and it seemed to perform just like a new one even though I have used only about one tank of gas with it BUT this time I noticed some top end vibe that doesn't seen to be there in other 066s I've used. I have it set using a Tacho to about 12.7k rpm top end for breaking. Someone at work mentioned it could be the little end bearing is on its way out? This machine had a stuck ring and I didn't bother to change the little end bearing because it looked OK, but at this level of stress I wonder if I did the right thing?

Any thoughts much appreciated.

Cheers
BobL

 

[Lakeside53]

If the old pin looked ok, I doubt you have a bad pin bearing.

 

[blsnelling]

You're probably running way rich. Tune it properly where it's barely 4-stroking and run it. No reason to have it running that rich. I wouldn't go by the Stihl spec either since it is not a Stihl cylinder.

 

[BobL]

Thanks for the feedback guys much appreciated.

Well I decided to be cautious so I took the barrel off to see if there was anything obvious and what I saw aint pretty!

Both the piston and barrel are rubbed/scored along the side of the exhaust port. I can clearly feel the scoring or ally deposit with my finger nail on the barrel The scoring on the piston is possibly beyond recovery - I cannot believe it was running that well with this degree of damage. All this in less than one tank of mix.

I've had a look to see if it was the cylinder plating chipping off the side of the exhaust port but if it was the chips would have to be very small.

Some pics;

This one could be pretty diagnostic. It's on the side of the exhaust port. The rings look chipped but they're OK.

This shows the degree of ally rub on the cylinder wall. There looks like a small lump of metal stuck to the wall where the red arrow is.

This shows the rough casting on the inside top of the cylinder. I wonder if a piece of something broke off where those jagged bits are?

Cheers

 

[stihlboy]

ok well i took my 066 out and i feel i need a faster cutting chain. but did i mention this thing cuts like a champ? i want a full race chain can anyone help me make or buy one?? p.s. ill post a pic of my 066 soon im using it frequently so i need to clean it first

 

[blsnelling]

Thanks for the feedback guys much appreciated.

Well I decided to be cautious so I took the barrel off to see if there was anything obvious and what I saw aint pretty!

Both the piston and barrel are rubbed/scored along the side of the exhaust port. I can clearly feel the scoring or ally deposit with my finger nail on the barrel The scoring on the piston is possibly beyond recovery - I cannot believe it was running that well with this degree of damage. All this in less than one tank of mix.

I've had a look to see if it was the cylinder plating chipping off the side of the exhaust port but if it was the chips would have to be very small.

I have a few thoughts and questions.

1. Was there any breakin time before putting it on the mill?
2. Did you pressure test the saw? You may have a bad seal that caused both this and the original piston to seize. Yes, it can run well and still have a leak. I learned that the hard way.
3. What kind of fuel and lube?