stihl 045 super question about cylinder and piston

[mesquitey]

Hi - i'm new on the site, and
wonder if anyone could help me. I have a Stihl 045 AV Super electronic (that is what the plate on the top reads). I've owned the saw for over twenty years, used to make a living cutting firewood with it,
love that saw - but haven't used it for a long time till i recently started using it with a carving bar for roughing out sculptures. After about a month of occasional use (I have two smaller saws) the 045 got
hard to start, progressively worse till wouldn't run at all, did a compression test and got 60 - so figure it needs a new piston and rings at least. tore it down and the cylinder appears ok, but i'm used to car
cylinders so not sure what to look for - no scoring on cylinder i can see, little bit on the piston near bottom edge, but i can feel an edge in the cylinder with my fingernail on one side where the sides of the
piston were, so i suppose that means the cylinder may be worn out too.

My question is this - it appears there were at least two different size piston/cylinder combos with that saw, 52mm and 54mm, 54 being the main one.

My cylinder is stamped MAHLE 52ZN12 followed by what looks like 11 with a horizontal slash through the 11, or else a crude H, and a small A1 above those markings. When i measure the cylinder, it appears to be 54mm instead of 52(measures 2.12", and the piston is marked 54L41 above the wrist pin hole on the inside, and what looks like R011 below the wrist pin hole.

Should i look for a 54mm piston /cylinder combo for it, or 52, or does it really matter, and would anyone know where i could get either or have one or the other they would like to sell. i'm thinking 54 but I
can't find much on ebay, looked on all the sellers
sites also that have stihl stuff, one old cruddy looking cylinder and maybe two or three aftermarket pistons, no aftermarket cylinders except for 066. will those work? they don't look the same in pics.

thanks in advance for any help, i sure would like to get this beast running again, its a heavy sucker but it sure does have some guts, or used to anyway.
-reply to mesquitey / tucson

 

[hotshot]

045 Supers

Welcome aboard, you have one of my favorite saws.

I've seen that 52 series casting number on some 54mm Supers cylinder bases, but the 52 code was usually followed by
some plus signs. Your 2.120" piston measurement confirms it. Measure the piston skirt diameter at the very bottom, it should be 2.122" or more. When the skirts get worn down, the saws start spitting gas mixture back out of the carb when idling, as they don't seal off the intake port very well. Makes a mess of the air filter too.

54mm bore was the standard size for all the Supers, but 60-80 psi is way low for cold compression. Sounds like
it needs a new piston w/ a set of rings, jug gasket, and new crank seals to freshen it up. Can you post bore pictures?
New stock saws had around 145# to 155 # compression. I have decked some cylinder bases & ran gasketless to get 0.020" squish, & ended up with 175# cold cranking compression. I've never seen anything close to 195# that someone mentioned on an earlier 056 Super thread (same P & C) w/o turning a pop up piston. Looks like the combustion chamber would be too large to get over 180. Anyway, at 175# it makes hard on your elbow to crank it up without an ElastoStart type cord, but they do run like a scalded cat when compression is that high.

Episan and Meteor both make a good AM 045/056 piston, but the 54mm OEMs are recommended & occasionally for sale on Flea-Bay. Don't buy the India or Taiwan products for any price, they wear out too fast.

 

[Officer's Match]

Reminds me I gotta' dig into my old 045 Super Electronic.

 

[cbfarmall]

I've seen alot of the 045s (and 031s for that matter) with a mesh screen filter. OK for big particles, but lets little stuff thru rather easily. Anyway, the artist formerly known as Lakeside53 always said that 045s and 056s were known for badly wearing the intake side of the piston skirt due to ingestion. Probably the aft location of the airbox had as much to do with this as the filter.

Should be enough of these junkers out there to find a good top end. The real problem with this series are the ignitions.

Chris B.

 

[mesquitey]

thanks for all that great information

Welcome aboard, you have one of my favorite saws.

I've seen that 52 series casting number on some 54mm Supers cylinder bases, but the 52 code was usually followed by
some plus signs. Your 2.120" piston measurement confirms it. Measure the piston skirt diameter at the very bottom, it should be 2.122" or more. When the skirts get worn down, the saws start spitting gas mixture back out of the carb when idling, as they don't seal off the intake port very well. Makes a mess of the air filter too.

54mm bore was the standard size for all the Supers, but 60-80 psi is way low for cold compression. Sounds like
it needs a new piston w/ a set of rings, jug gasket, and new crank seals to freshen it up. Can you post bore pictures?
New stock saws had around 145# to 155 # compression. I have decked some cylinder bases & ran gasketless to get 0.020" squish, & ended up with 175# cold cranking compression. I've never seen anything close to 195# that someone mentioned on an earlier 056 Super thread (same P & C) w/o turning a pop up piston. Looks like the combustion chamber would be too large to get over 180. Anyway, at 175# it makes hard on your elbow to crank it up without an ElastoStart type cord, but they do run like a scalded cat when compression is that high.

Episan and Meteor both make a good AM 045/056 piston, but the 54mm OEMs are recommended & occasionally for sale on Flea-Bay. Don't buy the India or Taiwan products for any price, they wear out too fast.

thanks hotshot. you got it right about the skirt wearing down, and also about it spitting gas, the air filter had been running dirty for a while, and i just thought i hadn't cleaned it good, then it would be dirty again, i didn't realize what was going on, but that must have been it. i'll take some shots of the bore and piston tomorrow, i been out of town for the past week, which is why i didn't answer your post sooner.

i've got a line on a new OEM 54 cyl if i can get it for the right price, so that may solve that part of the problem, just need to find a piston and ring set - i don't know how to tell on fleabay where they are from, if they are india or taiwan parts or not - there are some from a place in canada marked MB chainsaw salvage, are those any good, or do you know the sellers of the ones you mention that are good AM?

since i'm just using the saw now for carving it doesn't get the sort of workout it used to when i made a living cutting firewood with it - i just use it to rough out big stuff and then use a couple of smaller,
lighter saws for most of the work - so its really just an occasional use saw anymore, so i probably don't need quite as high end a fix as it would if it was day to day working saw, but still, being such a good
piece of stihl, i don't want to insult it by putting in junk parts.

it did have some compression in the past though, cause it did used to be a pain in the elbow and elsewhere to pull, i may have to find out what these elasto start cords are about too.

thanks again for your help, i'll try to get some shots of it tomorrow.

mesquitey

 

[pioneerguy600]

You can ask any seller on eBay where their products are made or the name of the manufacturer, that would be better than guessing at where they came from. I have bought many parts from the Canadian seller you mentioned and they will quikly reply to any questions I ask of them.

 

[hotshot]

OEM Piston

I would keep hunting for an original Stihl/Mahle piston, much better in the long run.

I had to send the imported MB piston back for refund, as the wrist pin bearing pocket was 0.060" or 1.5mm
too wide when compared to the Stihl OEMs, and it didn't have the smooth side machined flats (were simple
"as cast" surfaces) that the OEM pistons have.

Nominal new OEM 045/056 pistons bearing pockets were 0.580-0.585" on sampling six or seven over
the years. I don't see how it could ever keep the con rod centered like that, and would have allowed the
rod's big end to contact or rub the crank flats. Even looked for 13mm ID shims or thrust washers before I
returned the piston, but came up empty.

For an occasional use saw, or for a saw that you're going to give to your brother-in-law, that may be
have been fine.

Meteor makes a good 54mm replacement aftermarket piston, and Episan follows them in ranking IMHO.

 

[jdemaris]

Hi - i'm new on the site, and
wonder if anyone could help me. I have a Stihl 045 AV Super electronic (that is what the plate on the top reads). My question is this - it appears there were at least two different size piston/cylinder combos with that saw, 52mm and 54mm, 54 being the main one.

I was a Stihl mechanic back when the 045 Super was new. All that I've ever seen or repaired used a 55 mm setup. Basically the 045 Super is the same saw as the 056 and 056 Super (not magnum or whatever). Granted it got pretty confusing with all of Stihl's "supers", "IIs", Magnums", etc. 041 Super was 74 ccs. 045 was 75 cc. 045 Super was 87 ccs. 056 was 81 ccs in early versions and then 87 ccs. 056 Super was 87 ccs. 056 Magnum and 056 Magnum II were 94 ccs.

I've had my 041 Super and 045 Super saws since new. The 041 Super not a great saw. My 041 gear drive even worse. But the 045 Super is probably the best saw I've ever owned. I cut a lot of hardwood, ever summer and fall for over 20 years without even changing a spark plug. Just had to put on a few new sprockets. My only complaint is that it should of had a compression release.

Last year, I burnt it up. Made a really dumb mistake. I blame it on the new ear protectors with radio. I was cutting a big hard maple and the saw started bogging down. I thought it was running rich so I turned down the main jet. Then went back to cutting and siezed it up. Ends up the real problem was I'd hit a honey bee nest. The wax and water made the saw bog down, NOT a rich mixture. If I'd taken off those ear protectors, I would not have made that goof.

I went to Ebay and found a 54 mm piston easily. The jug-wall was fine. So, I fixed it and a month later the electronic module went bad. Stihl USA in Virginia Beach told me no replacement parts available anywhere on the planet. So I replaced the 045 Super with a new 64 cc Makita/Dolmar.

Later, I found out that saw dealers in Germany carry new modules. They are made in Italy by Ducati. So, $120 later I had my 045 Super running again. Still runs great, but my 64 cc Dolmar is pretty much just as fast and lighter. So I keep a 30" bar on my Stihl and only use it on the huge stuff.

 

[mesquitey]

pics of cyl and piston

here's some pics of the 045 piston and cyl from my saw, i figure the piston is shot for sure, but cyl's seem hard to come by, especially one in decent condition, so if anyone can tell from these shots if it looks
like i can use this one and just get a new piston, pin and ring set, that i can probably find an AM, will look for meteor. also, if anyone can tell by those markings on the bottom of the cly if it is the 54mm - i am going to pick up a digital calipers later today and will get the measurments off the jug and the piston, but just by putting the piston in the cyl with the skirt in first i can tell it has some play. don't know if you can see from these pics, but there is discoloration / lighter area right below the intake inside the cyl, should i somehow hone or otherwise treat the inside of the cyl with something (muriatic wash) before
putting it back together if i am using the same cyl with AM piston? thanks.

 

[jdemaris]

there is discoloration / lighter area right below the intake inside the cyl, should i somehow hone or otherwise treat the inside of the cyl with something (muriatic wash) before
putting it back together if i am using the same cyl with AM piston? thanks.

I bought a Golf 54 mm piston for my 045 Super. I paid $37 and that was few years ago. They are on Ebay right now for even less. Quality seemed fine to me and I've used the saw a lot since. No problems.

045 056 chainsaw piston kit GOLF - fits 056 54mm SUPER | eBay

I've put new pistons in Stihl jugs there looked much worse then that and they worked fine. That's one good thing I can say about the Mahle process. The cylinder-wall is amazingly durable. The only thing you won't get with aftermarket is a letter-graded piston - but even when that saw was fairly - the graded pistons were available from Stihl either. They just sold one generic piston to fit all grades. If you can find a way to put light cross-hatch marks in the cylinder, it will help with break-in. A three-jaw or bead hone will work fine if run the correct speed.

I'll try to look in to my jug and see if I can read the number. Regardless, I'm pretty sure there was only one size used on the 045 Super.

 

[jdemaris]

Update

here's some pics of the 045 piston and cyl from my saw,

I just went out and looked at my jug and my old piston. It is marked 54ZN9 W3. Same with an 056 jug I have. Note also that the original 54 mm piston from my 045 Super is clearly marked "54L41" on the inside between the piston pin and inner-skirt. Sounds like your jug is a 52 mm from an 045 non-super. There are new Golf 52 mm pistons for sale also on Ebay.

By the way, in your photo of the inside of the jug. Is that just discoloration by the port or is the chrome actually worn off? Can you still see the original cross-hatch marks?

 

[mesquitey]

piston and cyl, 045 super

I just went out and looked at my jug and my old piston. It is marked 54ZN9 W3. Same with an 056 jug I have. Note also that the original 54 mm piston from my 045 Super is clearly marked "54L41" on the inside between the piston pin and inner-skirt. Sounds like your jug is a 52 mm from an 045 non-super. There are new Golf 52 mm pistons for sale also on Ebay.

By the way, in your photo of the inside of the jug. Is that just discoloration by the port or is the chrome actually worn off? Can you still see the original cross-hatch marks?

Thanks Jdmaris. i think mine is a 54mm jug even though it says 52, cause my piston is also clearly marked the same as yours on the inside - 54L41. Hotshot said up above that some of the 045 super jugs
were marked 52 even though they were 54, usually they had a bunch of plus signs up above the number, mine has two plus signs after it, but once i pick up that calipers tonight I will know for sure.

The discoloration may be the chrome has worn off or it may be more like a deposit, its hard for me to tell, i can't really see much cross hatching on either it or the shiny part, but when i run my finger over it
almost feels more like a deposit than something missing - but i think someone wrote that crap can get past the air filter and come in the intake, which from the looks of things had been going on for a while.

guess i can order one of those pistons (thanks for the link), put it in the old jug, and see what my compression is - if its upwards of 130 or so, i'm probably good to go. thanks again for the link to the
golf pistons, all i was finding was some taiwan ones.

 

[jockeydeuce]

A 52ZN12 Mahle cylinder is 52mm.....For sure!!

Your pics of the bore aren't good enough for me to see the upper portion of the bore, but on the intake side, your nikasil lining in that cylinder is worn right through to the aluminum.....That cylinder isn't long for the world no matter what, unfortunately.:msp_sad:

 

[jdemaris]

The discoloration may be the chrome has worn off or it may be more like a deposit, its hard for me to tell, i can't really see much cross hatching on either it or the shiny part, but when i run my finger over it

I guess the cylinder numbers could just mean it was a casting originally meant for a 52 MM 045, but got bored out to 54 MM for use in a Super. Maybe early production. It would not make any sense for any 045 Super not to be bigger then a plain 045. There would be nothing "super" about it.

I'd just try to scratch that discolored area with a metal srcibe. If the chrome is actually worn off, it will be soft and scratch easy. If it doesn't, it's nothing to worry about. As explained to me by a Stihl salesman/rep around 1968 (when we first started selling Stihl), the Mahl process impregnates the aluminum cylinder . . . i.e. it's not just thin plating like many other saws had at that time. It must be true since I've seen the chrome peel off many other make jugs, but never on a Stihl.

On a sidenote- another rep in the 1960s told me that the Stihl jugs were made in West Germany but the pistons were made for Stihl in Japan. True or not - who the heck knows? I do know that it's only the German stuff where I've ever come across letter-graded pistons. I just had a diesel V8 apart out of a 1982 Chevy pickup truck and all those pistons are marked "Mahle" and are letter-graded.

 

[mesquitey]

A 52ZN12 Mahle cylinder is 52mm.....For sure!!

Your pics of the bore aren't good enough for me to see the upper portion of the bore, but on the intake side, your nikasil lining in that cylinder is worn right through to the aluminum.....That cylinder isn't long for the world no matter what, unfortunately.:msp_sad:

i wondered if that was what it was, its going on on the other side too, not as bad, but there's a bit of it both above and below the exhaust opening. new or even decent used 54mm jugs seem almost
impossible to come by, whereas 52mm are easier, so maybe i should just get a 52mm piston/jug AM kit, instead of trying to re-use this cylinder. if it is 54 as the piston says, i suppose i'll lose some power,
i'll know better once i get an exact measure on it.

 

[jockeydeuce]

i wondered if that was what it was, its going on on the other side too, not as bad, but there's a bit of it both above and below the exhaust opening. new or even decent used 54mm jugs seem almost
impossible to come by, whereas 52mm are easier, so maybe i should just get a 52mm piston/jug AM kit, instead of trying to re-use this cylinder. if it is 54 as the piston says, i suppose i'll lose some power,
i'll know better once i get an exact measure on it.

Measure it to confirm, but it's a 52mm for sure......I sent you a PM.

 

[jdemaris]

. new or even decent used 54mm jugs seem almost
impossible to come by, whereas 52mm are easier, so maybe i should just get a 52mm piston/jug AM kit, instead of trying to re-use this cylinder.

Just scatch the area in question and see if it's soft of not. If not soft, don't worry about it.
I've got a good used jug from a 54 mm saw (056).

As to size? 2mm is over 1/16" and pretty easy to measure, even with just a ruler.

 

[mesquitey]

Just scatch the area in question and see if it's soft of not. If not soft, don't worry about it.
I've got a good used jug from a 54 mm saw (056).

As to size? 2mm is over 1/16" and pretty easy to measure, even with just a ruler.

with a ruler i get 2 and 1/8 inches, within about a 32nd, and looking up the conversion, 2.12 is very close to 54, so that's what i figured it was. the piston is easier to measure at the skirt, and also 2 and 1/8.
haven't tried the scratch test yet, i don't want to score it, but i guess the chrome coating is hard enough that won't happen. will try it lightly.

 

[jdemaris]

with a ruler i get 2 and 1/8 inches, within about a 32nd, and looking up the conversion, 2.12 is very close to 54, so that's what i figured it was. the piston is easier to measure at the skirt, and also 2 and 1/8.
haven't tried the scratch test yet, i don't want to score it, but i guess the chrome coating is hard enough that won't happen. will try it lightly.

You're not going to scratch it if it's any good.

 

[jdemaris]

with a ruler i get 2 and 1/8 inches, within about a 32nd, and looking up the conversion, 2.12 is very close to 54, so that's what i figured it was. the piston is easier to measure at the skirt, and also 2 and 1/8.
haven't tried the scratch test yet, i don't want to score it, but i guess the chrome coating is hard enough that won't happen. will try it lightly.

I've got a 52 mm from an 045 and a 54 mm piston from a 045 Super - both sitting on a ruler. 52 mm bottom skirt clearly measures 2 1/16 th. the 54 mm skirt is 2 1/8" on the nose. No mike needed.

I also noticed that the jug marked 54ZN9 also has a long row of plus marks above. Five of them.