Chainsaw Repair
Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: 1manband on February 01, 2014, 11:26:32 pm
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066 stock OEM (late) jug.
attempt to increase torque value by 40%.
can this be done without adding aluminum?
link to dyno graph of stock 1998 066 saw: http://www.dlg-test.de/pbdocs/4713.pdf
attached is a text file that shows the results of what i found.
this includes digging into the chamber and dropping the jug as modifications.
edit: note on the text file, the correct connecting rod length is 68mm. (not 64 mm). deleted and reattached the correction. (this was a two fingered typing error trying to write this up).
regards
-joe
(had to link the graph because it was to large, sorry).
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Are you contemplating modding a Saw for that torque gain? Gonna be tricky, especially with pump gas. Be an interesting project. Adam
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Stroking the two piece stihl cranks is a pain, but stroking and a smaller bore would be a good start. Using some epoxy to "tighten" up the transfers and perhaps drop them a few degrees. re-cut the squish for optimum squish velocity at target rpm. Increase compression, and use higher velocity intake/carb tract along with timing advance if the Motor will take it. small sprocket too. Who has a small engine dyno ? Be a cool project! Adam'
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Find a good older jug from before the exhaust got crazy and then cut the squish band and drop the base. You should be able to get close to 40% in cut speed change with that and then raising the transfers a little.
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its just bench racing for me adam. like the ideas. lots of work for too little gains for me.
don't know if a stroker crank would work with the same cylinder, without maybe needing a custom made piston and stroker plate or welding material onto the case. possibly putting a longer rod with the stock stroke crank, with stroker plate under the cylinder might be another idea to get the piston up.
the only other 54mm piston option i have seen requires a 13mm wrist pin, and has a shorter pin height. would not be a direct trade.
the only other physical measurements i have to compare the late oem jug to, would be an older 56mm big bore aftermarket jug. the timings and port time-areas are slightly different than the stock jug. have not taken the time to do this yet. will get around to it and post some results, to see if it is any better.
regards
-joe
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385 piston fits. You just use the piston rod bearing for that piston. 288 piston fits also. You can also put a 056 piston with the factory dome in for more compression. Lots of options. The 385 piston requires a spacer under the cylinder.
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385 piston fits. You just use the piston rod bearing for that piston. 288 piston fits also. You can also put a 056 piston with the factory dome in for more compression. Lots of options. The 385 piston requires a spacer under the cylinder.
thanks gatekeeper. will root around for the piston info of those, and work them out.
regards
-joe
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All you need is the wrist pin bearing and it fits in the rod for the 288 or 385. The 288 requires dropping the jug a lot which gets the exhaust back to a good number. The intake is a little long that way but not bad.
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do to my poor typing skills...re-check the first post. did not affect the calculations only the write up.
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did the same bench racing 066 knockoff 56mm big bore kit.
similar gain was attempted, with worse results, is attached.
same sqush band cut and cylinder dropped in this one as well.
was thinking about doing one modification at a time, so folks could see what ech step actually does or doesn't do.
next try will be playing with the transfers, to reduce blow down on both the stock and knockoff jugs.
after that..... will plug in some frankenstein pistons, stroker plates, etc. if i can find dimensional info i need on them.
regards
-joe
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All you need is the wrist pin bearing and it fits in the rod for the 288 or 385. The 288 requires dropping the jug a lot which gets the exhaust back to a good number. The intake is a little long that way but not bad.
thanks for the reply.
thinking of doing this step by step for folks to see some of the basic steps first.
like you, i'm more interested in the possibilities you have suggested. when i get done with the off the shelf stuff direct replacement parts...... will start a new thread on fitting some out of the box stuff. maybe some folks would like to see that, don't know.
regards
-joe
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It would be interesting if you could dyno it step by step also but that wouldn't be easy unless you live by Madsens or Chad in PA.
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Joe, what program are you using for the calculations?
Adam
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It would be interesting if you could dyno it step by step also but that wouldn't be easy unless you live by Madsens or Chad in PA.
agree. this 066 is just numbers. when the goal numbers cannot be achieved as in this 066 jug..... there is no way of to verify the outcome of how much actually was gained.
the bmep curve follows the torque curve in the dyno graph. knowing the factual baseline stock kW and Nm from dyno testing, makes the calculations accurate. the program is just a tool to help narrow things down.
regards
-joe
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Joe, what program are you using for the calculations?
Adam
somewhere in the "how to" section.
-joe
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can't get back in to edit my first post to put these latest text files together, and get rid of the others.
one for stock. 02/03/14
one for big bore. 02/03/14
regards
-joe
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I,ve heard that the 064 had weak cranks,
would they stand up to increased compresion?
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You won't be able to decrease the exhaust timing that much. With the stroke and rod length of this saw every 0.010" is about 1.5 deg of duration on the exhaust timing. So to go from 175-160 you need to remove around 0.1" from the squish band and the bottom of the jug. This would then raise your intake timing by around 14 deg duration which would be way too high. Also the exhaust port would probably be free porting because they are already very close to doing so stock.
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I think I had .060" cut out of the chamber and .070" off the base. It will get it back close to what you want on a mahle jug. The new KS/stihl jug ends up with 170 on intake or a little more when you get the exhaust back under 170.
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You won't be able to decrease the exhaust timing that much. With the stroke and rod length of this saw every 0.010" is about 1.5 deg of duration on the exhaust timing. So to go from 175-160 you need to remove around 0.1" from the squish band and the bottom of the jug. This would then raise your intake timing by around 14 deg duration which would be way too high. Also the exhaust port would probably be free porting because they are already very close to doing so stock.
took 2 mm = .078 inch off th squish band, and similar 2 mm off the base for a couple of reasons:
stock oem cylinder cylinder length TDC to BDC was 80.82 mm (including squish clearance). the skirt length of piston was 20.06. at BDC....80.82 - 0.5 squish - 40 stroke - 43 total piston length = -2.68
the knockoff, is way out, imo, as far as time-areas are concerned. did not pay to much attention to it after i saw the base numbers. the cylinder length was 80.64 mm on it. further time spent typing numbers into the program i will not do.
the way i see it, on the oem jug, the piston skirt extends 2.68 mm below BDC. am i thinking about this wrong?
think i have the room. the intake time-area is way too long and large. the intake floor will have be brought up to anyway to balance the ports.
the other reason is for ease of math, adding or subtracting 2.
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there is no way to get these ports to the ideal STA number goal. as i mentioned before, the program is just a tool. imo, balancing the ports is the most important idea. the port sizes and timings in the stock jug will be
balanced to approximately, to a value of 1.5 times larger than the ideal STA accross the board. ie. exh sta 1.5x ideal, trans 1.5x ideal, etc. only choice i see. cannot be made any smaller, and the height between the exh. an trans prevents this.
to get them to ideal, would require welding/replating or a sleeve pressed in. not a fight that i want to get into.
things would be much easier on a better original casting.
regards
-joe
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whats left, after already dropping the cylinder 2mm, and also cutting deck clearance (squish) 2mm....is evening out the transfers, and balancing the intake.... takes just a few minutes to do.
typing, for me is a 2 finger chore. had a couple of beverages, so its best, if i type up the results tomorrow.
regards
-joe
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Remember to measure the bottom of the exhaust port. If this becomes larger than the piston height + squish you'll be opening up the crankcase to the exhaust port (free port). The more you cut out of the squish the closer you'll get and these saws (especially AM cylinders) are know to be on the ragged edge of free porting before modification.
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good catch scarr52. i don't do this 2ST stuff anymore and its easy to forget to remember to check everything. even checks that's need to be completed before dropping the cylinder and squish cuts are planned!
remeasured everything. found a port width error. then decided to use an average port roof opening height for the slightly angled down roofs of the transfers to be more accurate.
sticking with the being more accurate theme, did my best to measure millimeters down to the 0.01 mm. note that this exceeds the accuracy of the caliper. the degree measurements were calculated from the mm measurements, and carried over to 0.01 degree. this in reality, would be impossible to get this kind of accuracy. the program calculates all values out to 0.0000001. wanted the program to not be the cause of not enough precision.
one thing to be aware of as far as the program, is concerned... accuracy in such that 0.01 degree or 0.01 mm measurements will and do change STA's. made the program 10x more accurate in calculation ability, than the university of belfast suggested. this does not mean anything however, because actual physical measurements that small cannot be made.
digressed a bit. hope if anyone got anything from that, it is to be as accurate as possible while measuring. be as consistent with port beveling as possible as well. both of these have a large effect on port opening timing and more importantly time-areas as i found out during this experiment.
in a nutshell....have enough room. will show these important steps. glad scarr brought it up.
regards
-joe
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missed what i wanted by 0.3 mm
as only luck would have it, the base gasket will add the slack needed.
regards
-joe
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When I run into a situation like Joe and miss by some tiny amount 0.3mm (0.11811) and the base gasket is used to correct for the error. I will cut a custom gasket made from 110 annealed copper precision shim stock. Very large PITA and the shim stock is stupid expensive but then I am sure the the CBGT will not change.
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066 stock OEM final design build.
disregard previous version.
went gasketless.
corrected a few measurements.
scaled each ports goal STA's to the smallest value possible.
one attached file broken up into 2 parts:
Part A - stock to base cut/deck cut
halfway down.......
Part B - where the fun starts. (not for purists).
comments appreciated.
regards
-joe
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the aftermarket 066 big bore knockoff jug is off on the exhaust.
blunder on my part, (not checking clearance beforehand), and would cause freeporting
without an excessively thick base gasket.
i'll correct this in the future, but i my opinion, the big bore jug is not as good of a
candidate for gains when compared to the stock oem jug.
regards
-joe
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the aftermarket 066 big bore knockoff jug is off on the exhaust.
blunder on my part, (not checking clearance beforehand), and would cause freeporting
without an excessively thick base gasket.
i'll correct this in the future, but i my opinion, the big bore jug is not as good of a
candidate for gains when compared to the stock oem jug.
regards
-joe
That's been the general consensus.
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Howdy,
Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg
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Howdy,
Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg
Welcome Gregg. Nice seeing you here and sharing your knowledge with us. Thanks.
Also everything here is FREE to sell if you have a online store etc. Just put your info in your sig and or where to buy online board.
All about helping folks out here freely.
Kevin
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Interesting 066 quads :o 8). Tell us more Gregg.
http://chainsawrepair.createaforum.com/index.php?action=dlattach;topic=3013.0;attach=5706;image
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Howdy,
Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg
I was wondering if these were going to be scrapped or not. You got any cylinders to demo and get the timing from?
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grande dog.... glad you are filling the need.
looks like: exhaust and intake both low and wide. nice.
exhaust roof lower on the quad. (fixed the biggest issue the dual port had). very nice.
should be a much better option. curious on the timing as well.
regards
-joe
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Howdy,
These are in development now. The cylinder molds were completed as you can see by the photo. Now we're starting in on the pistons. With the cylinders, we had the outside molds but had to create new casting cones for the inside quad loop mold. The pistons are going to be a "from scratch" type of deal. With the solid piston we're designing, it should leave lots of room for port play.
I know from being involved in these projects the biggest question is when. There is still a lot left to go on these before they're ready for prime time. If things go according to Hoyle, this cylinder will be our flagship into a line of exclusive aftermarket parts. Right now it looks like they'll be selling for about a buck and a half for cylinder kits.
I'll try to keep everybody posted on the progress as it happens.
Regards
Gregg
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thanks for all the info gregg. please do keep us posted.
regards
-joe
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That's good to hear Gregg. I would like to try one out and see if it will make more power than the later KS cylinders on the 660 or even better if you copied the port heights from the non decomp or red light cylinders.
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Howdy,
Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg
I don't like how small the primary transfer ports are and the angle of which the transfers enter the cylinder. It's going to mess with the loop scavenging efficiency.
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Howdy,
Thanks for the input. This is in the proto-type phase. I think I know how it's going to react when it actually gets strapped on to saw but, I don't know for sure. I'm going to be totally open for suggestions. I'm trying to develop products that deserve customers, and have those products stand on there own merit. It's basically the better mousetrap approach.
In the current climate of product copying, the only thing that will separate you from the heard is innovation. Realistically, you only have about a 2-3 year run on a popular product before water gets cloudy with copies. Copiers are going to copy. In recent years even the copiers are copying the other successful copiers.
Time will tell.
Regards
Gregg
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hey gregg......
is this going to be 56 mm big bore? forgot to ask.
to be clear, my previous comment was comparing the aftermarket dual trans big bore jug to the proto quad.
even though the blow down duration on the dual jug was only 25..... from what i found, the time-areas for blow down were out of proportion when comparing with the other ports. because of the too high exh roof, the blow down area was very large.
low and wide trans maybe??
wishful thinking: thick barrel flange and chamber; thick intake floor and exh roof; low and high comp piston options; unfinished as cast exh and intake ports.
regards
-joe
edit: removed some tech drivel
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Howdy,
Thanks for the input. It's going to be a standard bore.
Regards
Gregg
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gregg.......
usually seen in most other designs regarding quad transfer ports. the main ports (closest to the exhaust), are the larger ones in the pair. the secondaries (smaller in dimension) are closer to the intake and have less of an angle.
the prototypes are reversed.
looking at the exhaust roof closer.... maybe its the photo angle, but still looks high. if its going to be that high, modders may like the trans roof higher, so something can be done with it.
someone here mentioned in another thread to hit Cntrl + at the same time on keyboard to enlarge photos.
take it with a grain of salt, no offense intended.
regards
-joe
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Howdy,
Thanks for the input. This is in the proto-type phase. I think I know how it's going to react when it actually gets strapped on to saw but, I don't know for sure. I'm going to be totally open for suggestions. I'm trying to develop products that deserve customers, and have those products stand on there own merit. It's basically the better mousetrap approach.
In the current climate of product copying, the only thing that will separate you from the heard is innovation. Realistically, you only have about a 2-3 year run on a popular product before water gets cloudy with copies. Copiers are going to copy. In recent years even the copiers are copying the other successful copiers.
Time will tell.
Regards
Gregg
Well if you are open to suggestions I'd definitely keep the exhaust timing low. Probably start around the old school 066 jugs of 164-166 duration. 166 deg of duration has the roof at 1.015" with 0.020" squish.
1manband elaborated on what I was gripping about with the transfers. Since the divider is taking up space you'll have to widen the ports. Taking a mold of the Husky 395 transfers would probably be a good start.
And I'd make it a 58mm bore and stick with the stock piston design. It's light and has good flow to the transfers. Just make the skirt a little longer to keep freeport in check.
Innovation is what will set your products apart. Look at the HyWay 359 cylinder with the 357 style transfer ports (no caps). Those are great runners out of the box but I think their platting isn't the greatest.
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Howdy,
Pretty thick skinned here, so don't sweat it. Whether they are good, bad, or indifferent, all comments are welcomed.
Regards
Gregg