460 and 660 work saws double build

[046]

new port does look rough..

 

[timberwolf]

Here is the jug with some porting work done.

Port timing was not bad on the 460, just raised the exhaust a couple deg, widened it out about 4mm. Transfers were raised only what the jug was dropped and were extended back about 2mm with a fair bit of clean up work. Intake durration is increased a few deg, port widened about 2mm and squared up a little.

 

[HolmenTree]

Excellent thread here. Stihl Canada could use you timberwolf doing warranty work and rep, just be prepared to do lots of roadtrips LOL

 

[Outlaw5.0]

Likely going to take some lashes for saying this, but Stihl's quality on the cylinders has gone way down.

There are all sorts of humps and bumps, blobs of casting and ridges on the port edges. Seen beter porting in aftermarket jugs. Also on the 660 jug the porting on exhaust is about 10 deg longer than I would like to see and the plating and machieling in the top 1/8 of an inch is very poor. I'd like to be able to mill the squish and lower the jug, but plating just want allow for that. If you have any original 066 jugs hang on to them the 660's are junk in comparison.

Pics of the ports, machiening on of the pistons and final pistons. On the intake pic it's not super clear, but there is a ridge at the edge of the port about 1mm high running from one side to the other.

My factory 460 intake ports have that ridge at the bottom also, can't figure out what exactly its purpose is?.

I need to get a Fordom cable grinder, my Dremel and big air grinders are not the best tools for the job. I already burned up one cable attachment on my Dremel. Getting in the transfers is near impossible even at the bottom.

 

[timberwolf]

My factory 460 intake ports have that ridge at the bottom also, can't figure out what exactly its purpose is?.

To disrup flow and limit power. Clearly stihl has in the last year or so gone to different casting and plating on their cylinders and it does not look like a change for the better.

Here is a pic of 1st gen BB to compare I would say the after market casting is beter than new Stihl casting.

 

[Outlaw5.0]

To disrup flow and limit power. Clearly stihl has in the last year or so gone to different casting and plating on their cylinders and it does not look like a change for the better.

And charge a quite a premium for the cylinder kits!.

 

[timberwolf]

Yep don't look like they are passing the savings along to the customer.

Anyway got to work with what you got.

Here is the base being turned down.

Bored the carb out a little too and knocked off some rough edges, but forgot to snap any pics, took carb venturi out to a little over 0.7 inches.

Just need to open up the muffler and the saw is finished.

 

[epicklein22]

Hell of a thread here Timberwolf. Your work looks top notch.

Can't argue, those Stihl P&Cs aren't pretty. They are still made by Mahle correct?

 

[046]

how much are you turning down base?

fortunately I've got a old southbend lathe and milling machine at home

Yep don't look like they are passing the savings along to the customer.

Anyway got to work with what you got.

Here is the base being turned down.

Bored the carb out a little too and knocked off some rough edges, but forgot to snap any pics, took carb venturi out to a little over 0.7 inches.

Just need to open up the muffler and the saw is finished.

 

[timberwolf]

Took base gasket out and turned base down 0.028, final squish should be about .022.

Fired the saw up last night, runs well, but not real high RPM 14,200 or so, but it's a new saw so may loosen up a little yet. Might make some cuts tonight, don't know if I will be able to get video up, my internet server is kicking me off when trying to upload bigger files.

 

[Tree Sling'r]

Nice thread, TW. Always neat seeing others machining set ups. Good porting work as well. You like your 28t handpiece?

 

[046]

does shaving jug base have to done with a lathe, a milling machine do?
what's your jug holding fixture look like?

Took base gasket out and turned base down 0.028, final squish should be about .022.

 

[timberwolf]

Did not get to test saw last night, was on the cold side of -20c not counting wind.

I like the 28 handpiece, the 55 and 56 I am not so in love with, pretty much have worn out the head bearings inside a year, but thats a fair number of saws done too.

It's possible to deck a cylinder with mill, but it's very time consuming to get it clamped down level and secure. The lathe is the way to go without doubt. But without power tools, its easy enough to draw file the flat base jugs like this stihl down, then lap them to finish. I did a number of jugs that way before I picked up a lathe. Just measure all four corners and work them all down to the desired thickness.

On the lathe I just made up a selection of aluminium mandrils that fit tight to the bores, 50mm, 52mm, 54mm 56mm. Mandrils have a flat top that indexes against the squish band in the head, then hold the jug in with live center and put a bolt in trough intake and or exhaust ports to keep it from trying to turn. Takes maybe 15 min to set up and cut down a base as long as I have the right sized mandril made up. Nice thing is can do the husky jugs with clylinder extensions projecting below the deck.

http://new.arboristsite.com/attachment.php?attachmentid=84596&d=1229903924

I could snap a pic of a mandril on it's own, but pretty much it's just a flat topped plug that fits the bore on one end and gets chucked in the other.

 

[Carlyle]

I can't believe that -20C (anada) is that cold for you. I am 400 miles south and west of you and it was -16 C or 3 F here not counting the wind. I having a good feeling the guy running those saws will be in cold weather like this.
TW any idea on when you think Stihl's qualiy went south. Meaning if a guy wanted a couple more saws should I look for older than 08, etc.

Carlyle

 

[timberwolf]

It's just no fun messing with saws at -20c did not break -30 last night but it was close. Not super cold, but does not tend to stay this cold til Jan.

These were the first 08 year saws I worked on and there is a definite change. Even looking at the jugs I would guess they are a different casting alloy. They appear like they are galvanized the grain on the surface looks like frozen crystals on a frosty window. This is not like jugs I have seen as recently as 2007. Maybe lakside or some stihl experts can shed some light on whats going on... But maybe they can't talk about it.

The 460 was rough in castings but ran strong stock and has good porting numbers and lots of potential. the 660 has some troubles stock and very high porting numbers, this has got to be hurting torque. I will compare the 660 against my 5 year old 066 that is ported to about the same degree as this one will be.

 

[Outlaw5.0]

I wonder if the increased intake port timing is to bring power back due to restrictive mufflers?.

 

[timberwolf]

Finally got a couple videos of 460 up. First is stock as it came set up from stihl tuned just to 4 stroking. 7.15 seconds

Second video is ported, with a 9 pin gear. It's a bit too much for it in this sized wood, but should be ok in 8x8. 3.63 seconds so just shy of 100% faster.

With same bar and chain setup as tested stock it was cutting 4.25 so about 68% faster than stock.

I really want to see it over 100% faster so going to make a couple adjustments and open up the muffler a little more. Also It should pick up a little once broken in a bit.

Compression is sitting at 190 with 7.15 cc head volume.

http://www.youtube.com/watch?v=uRuUM6V9GEg

http://www.youtube.com/watch?v=FoiEcxZgTaM

I was hoping to load it on Santa's sleigh tonight for free shipping south, but I think it needs just a little tweaking and looking like it's going in the mail after the weekend.

Will put up a few more pics.

Going to be a week or two till I get to finish the 660, have a couple other saws I need to get running.

 

[Peacock]

So, with just porting you picked up 68%? That's pretty impressive. What kinda rpm is it running free load and in the cut?

What do figure that 660 will pick up %-wise?

Looks real good!!

Oh yeah...forgot to add....Merry Christmas!!

 

[timberwolf]

I did not check in the cut, but no load it's in the low to mid 14k range, not high RPM, but very good torque. It would have the stock 660 by a good bit.

Going to try to get a couple hours cutting and see where the saw is at for compression and RPM, then open the exhaust a little, feels I might not quite have enough blowdown on it. If opening up the exhaust does not do it the exhaust may need to come up another degree or two.

Would like to see the 660 gain at least 60%, but It's going to take some work. Think I will go back to the drawing board on this one, have 066 numbers worked out, have 066bb numbers worked out, but there is just no way as a work saw this jug can be modified to get close to those numbers.

 

[drmiller100]

just curious, why not widen the transfers over across towards above the intake????

interesting exhaust duration on the stock 460. I've never seen anything on a saw above even 165. not to be critical, but any chance you measured wrong????? That just seems wild to me.