051av----parts, service...

[djmercer1]

ok, guys i need some help.....my service dealer, nor stihl have been able to help yet----but there are smart guys/gals here.


i have a stihl 051av (2986252), i think circa 1974-- ie early production run. my problem are related to the oil pump and spur sprocket:

1)the sprocket issue(s) relate to the manner in which the oil pump is driven. on my saw the spur sprocket has 2 blind holes in teeth 1 and 6(see pic), its a 7t with .404 pitch. the blind holes mate with pins in the cover plate(see pic). the replacement sprocket listed in the ipl(111-640-2007, 8t-3/8), has 2 key ways milled an appears to drive the oil pump with a oil pump worm similar to that which on a rim sprocket equiped machine(111 640 7111). anyone have this sprocket, know where to buy(and what???), how about converting to a rim setup with new worm, any ideas?

2)is related to the oil pump rubber ring. my current rubber ring(shown as old style in service manual) has an ear that plugs the taped hole(m5) in the oil pump shaft. i ordered the 'previous models' rubber ring(1111 647 9000). the replacement doesnt have the ear sealing the m5 holes. does it matter, can i plug with a loctited bolt, jb-weld...etc?

thanks

dave

 

[djmercer1]

bump, anyone have any suggestions.....

 

[martrix]

Hi DJ, looks like the new spur sprocket you ordered says 3/8" on it and not .404"?

 

[djmercer1]

Hi DJ, looks like the new spur sprocket you ordered says 3/8" on it and not .404"?
QUOTE]


yeah, i knew i ordered a 3/8-8t sprocket since the equivalant 7t-0.404(1116402001) is no longer available. ive since found another part number(11116402002, this isnt listed in the ipl) that supposedly 7t-0.404, ill have to wait to receive it to find out for sure. im more concerned with the manner in which the oil pump is driver----pins as opposed to ears on the worm. also, what about the rubber ring?

dave

 

[martrix]

Is the new rubber ring exactly the same size (length) as the old one except for not having the ear?

Post some pics of your oil pump with the new and old rubber rings.

Also post some pics of your oil pump worm.
It unscrews out counter-clockwise. You may need a new one with the drive lugs rather than the pins if you want to run that new spur sprocket.

My understanding from the manual is that the rubber rings are different to each other and cannot be interchanged between the old style and the new style pump bodys...........I may be wrong though.

 

[djmercer1]

right now the oil pump worm is still installed,----i would go to a rim setup if ii need the new worm, im trying to avoid that. my saw has a cover plate with 4 pins(2 for the spur side and 2 for the worm side) between the sprcket and the crank housing---shown on page 55 of service manual.

attached is a pic of the rubber rings laid down on the service manual showing new&old oil pumps. my saw has the old pump style. both the gas and ol tank caps have holes rather than valves. the old rubber ring measures about 13.65mm while the new one measures 14.40mm, both have nearly the same inner and outer diameters(+/- 0.5mm). i think the ring is ok fit wise, im wondering about the m5 tapped hole---does it need to be plugged? when i look at the newer style oil pump the hole is open so i think ill be ok.

i agree that the new style and old style rubber rings arent interchangable----very different shape and oil pump mockup. problem is that while i have a new 'old style' rubber ring it isnt the same as currently on my saw(it is the same as in ipl while mine is the same as in the service manual).

dave

 

[Lakeside53]

Why don't you just get the correct ring? both are still available... I wouldn't fit the wrong one.


It's a 3 day holiday weekend here, so I don't have my old tech info available to help out on the sprocket issue, but.. is the new sprocket Stihl or aftermarket?

 

[djmercer1]

Why don't you just get the correct ring? both are still available... I wouldn't fit the wrong one.


It's a 3 day holiday weekend here, so I don't have my old tech info available to help out on the sprocket issue, but.. is the new sprocket Stihl or aftermarket?

yeah, that would be easy except the one i ordered from stihl as being for my 051(for saws prior to 9945249 use 11116479000) isnt the same as the one currently on the saw even though the ipl lists its as beng the same. the difference in dimensions i can see being related to decay/wear, but the new one doesnt have the ear that blocks the m5 tapped hole for removing the oil pump assembly.

the new sprocket(11116402007) is listed in the ipl for being for saws prior to 8369699, and according to stihl should fit my saw---in the ipl it even shows a cover plate with pins for driving the oil pump worm(ipl page 10), upon recieving it this definately isnt the case.

all parts are stihl, ordered through my dealer with the help of stihl canada techs.

dave

 

[Lakeside53]

You cannot rely on serial number for ordering parts on old saws... it may have been updated during any number of prior repairs. In some cases you will also find older revisons of the parts on saws because someone bought used parts.

Be very careful with the service manual - it's only a snapshot in time... many revisions are not shown - you need to read it in conjunction with the technical information updates.

PITA, but it's the nature of working on old relics. I'm fighting similar issue on 056's right now...

 

[djmercer1]

You cannot rely on serial number for ordering parts on old saws... it may have been updated during any number of prior repairs. In some cases you will also find older revisons of the parts on saws because someone bought used parts.

Be very careful with the service manual - it's only a snapshot in time... many revisions are not shown - you need to read it in conjunction with the technical information updates.

PITA, but it's the nature of working on old relics. I'm fighting similar issue on 056's right now...

i dont think the problem isnt one of parts being updated throuh repairs(i know its posible but isnt the case with this machine), rather is that some of the the parts for my saw(1st generation which service manual is based on) havent been updated to reflect what is in the ipl(based on 2nd generation). when ordering the parts i simply tell the stihl tech the part im looking for and whats listed in the ipl and service manual and for the serial number of the saw--he does the rest.

using the sprocket for example, the ipl lists it for my saw, shows the coverplate with pins but the sprocket clearly drives the oil pump with the latter stye worm(with ears).

i guess my question would be to anyone who has replaced a sprocket that drives the oil pump with coverplate and pins is what part number to order??

dave

 

[rupedoggy]

These are .404 if you need one.

Sorry could not attach picture.

 

[martrix]

This is what you need if you want to run that new spur sprocket.

Stihl 051 Oil Pump Worm gear with lugs. (not pins)

You cant run .404" chain on that 3/8" sprocket...not sure if you need a new bar as well or not.

 

[djmercer1]

This is what you need if you want to run that new spur sprocket.

Stihl 051 Oil Pump Worm gear with lugs. (not pins)

You cant run .404" chain on that 3/8" sprocket...not sure if you need a new bar as well or not.

i had no intentions of running .404 chain on a 3.8 sprocket----i have both 3/8 and .404 bar and chain combos. i have a used tsumura hardnose bar(with used stihl .404 chain) thats about 42" and a new windsor sprocket tip thats 22"(with new stihl 3/8 chain).

if i go to replace the oil pump worm i will switch to a rim setup because i can then simply swap rims to change bar and chains combos. ideally id like to find a both .404 and 3/8 sprockets that drive the oil pump via the pin/coverplate system but thats proving to be hard. i guess that i must have the 3/8 sprocket to accompany the windsor bar because i could change the .404 chain on the hardnose bar to 3/8 and only waste a loop of chain.

as to the oil pump rubber ring, does the ear covering the m5 tapped ole rally matter, im inclined to say no upon examination of other oil pumps?

 

[martrix]

i had no intentions of running .404 chain on a 3.8 sprocket----i have both 3/8 and .404 bar and chain combos. i have a used tsumura hardnose bar(with used stihl .404 chain) thats about 42" and a new windsor sprocket tip thats 22"(with new stihl 3/8 chain).

if i go to replace the oil pump worm i will switch to a rim setup because i can then simply swap rims to change bar and chains combos. ideally id like to find a both .404 and 3/8 sprockets that drive the oil pump via the pin/coverplate system but thats proving to be hard. i guess that i must have the 3/8 sprocket to accompany the windsor bar because i could change the .404 chain on the hardnose bar to 3/8 and only waste a loop of chain.

as to the oil pump rubber ring, does the ear covering the m5 tapped ole rally matter, im inclined to say no upon examination of other oil pumps?

Yes you can change the clutch drum to accept rim sprockets as I have done this. The part numbers are in this thread.

This is a pic of the rubber ring for the new style pump body. It has 2 small notches that fit into cutouts on the pump body to keep the holes centered over the intake/outtake holes.

I am guessing that the little ear on your one servers the same purpose as the cutouts. I don't think the ear on the ring is for blocking the M5 hole. With your new ring, did it come with two little bushes that go in the holes and stop the ring moving from its position?

 

[djmercer1]

Yes you can change the clutch drum to accept rim sprockets as I have done this. The part numbers are in this thread.

This is a pic of the rubber ring for the new style pump body. It has 2 small notches that fit into cutouts on the pump body to keep the holes centered over the intake/outtake holes.

I am guessing that the little ear on your one servers the same purpose as the cutouts. I don't think the ear on the ring is for blocking the M5 hole. With your new ring, did it come with two little bushes that go in the holes and stop the ring moving from its position?

im pretty sure that the ear on the rubber ring covers the m5 tapped hole for a couple of reasons:
1)the diagram you posted in the service manual shows it installed like that
2)on my worn on there is a cut/impression from the m5 hole

my understanding is that the bushes arent necessarily to prevent the ring from rotating(but im sure theyll do that also), rather the bushes are to keep the inlet and oulet passages from closing off when the rubber ring is compressed in the oil pump bore, my new rubber ring didnt come with new bushes, but my old ones are fine.

my oil pump is identical to the old style in the image you posted from the service manual, it shows the ear covering the m5 hole pretty clearly. i think alignment to prevent rotation is achieved since the oil pump bore is keyed to accept the pump boss in one orientation only(m5 hole on top).

for changing the oil pump worm, the service manual says you need a tool to maintain the rubber seal on the worm(page 58 service manual)---is this necessary? this may be a viable option as i know for a fact stihl canada has the 3/8 rim/drum assembly and the 0.404 rim is also available. as to the oil pump, does it rotate in pump housing or is it stroked in/out to create oil flow?

 

[martrix]

im pretty sure that the ear on the rubber ring covers the m5 tapped hole for a couple of reasons:
1)the diagram you posted in the service manual shows it installed like that
2)on my worn on there is a cut/impression from the m5 hole

my understanding is that the bushes arent necessarily to prevent the ring from rotating(but im sure theyll do that also), rather the bushes are to keep the inlet and oulet passages from closing off when the rubber ring is compressed in the oil pump bore, my new rubber ring didnt come with new bushes, but my old ones are fine.

my oil pump is identical to the old style in the image you posted from the service manual, it shows the ear covering the m5 hole pretty clearly. i think alignment to prevent rotation is achieved since the oil pump bore is keyed to accept the pump boss in one orientation only(m5 hole on top).

for changing the oil pump worm, the service manual says you need a tool to maintain the rubber seal on the worm(page 58 service manual)---is this necessary? this may be a viable option as i know for a fact stihl canada has the 3/8 rim/drum assembly and the 0.404 rim is also available. as to the oil pump, does it rotate in pump housing or is it stroked in/out to create oil flow?

I have blown up the picture from the manual and it definitely looks like there is no ear to me. The impression on your old one could have been from vibrations or from when someone screwed a bolt in to it to remove the pump body.

This is from the manual: "The tapped hole in the pump body's cast boss is used only for removal and installation."
I think the little ear is just to help stop any small amount of oil that scapes the pump body from messing up the chamber.
If both your new/old rings are the same dimension except for not having the ear, then you can probably use it....

You are correct about the bushings to stop the hole from closing under compression.

Not too sure what that assembly sleeve looks like for installing a new worm gear..any one? part no# 1111 893 4600...my one easily just unscrewed by hand, but that might be because the oil seal was worn?


How the oil pump works....

 

[djmercer1]

an update....

ok guys i have an update on my 051:
1)the newer style rubber ring is fine and the ear that covers the m5 tapped hole for oil pump removal isnt necessary.
2)the type of drive on my saw(cover plate with pins) isnt supported by stihl in canada, but culd possibly get parts from other stihl divisions, i will switch to avoid trouble in future. stihl has told me that i will have to swap the worm, oil seal and cover plate to the type of worm with lugs to drive the oil pump.

i have runned the saw today and she seems fine. loads of power, spews oil to the bar and shakes the life out of the operator. where should i have the oil feed control lever for general use, what about hard use etc? i have electronic copies of both the ipl(2mb) and service manual(15mb), does anyone have the user manual in electronic format?

total cost of project:
$38 for loop of chain
$13 for oil pump rubber ring
$40 for new sprocket(havent decided on spur or rim type yet both about the same $$, suggestions are welcome)
$75 for oil pump worm, seal and cover plate

the saw is destined for a mill setup, any suggestions for using this beast(fuel mix, safety gear etc.

dave

 

[Lakeside53]

get rim... sprockets won't last, are hard on chains when they wear and are expensive to replace


Put the oiler in the midde and forget it it unless you are milling.. and if so all the way wide open (it pumps a LOT of oil and can empty the oil tank before the fuel.).