Stihl 028 AV Super... is it worth fixing?

[SteveoSupremo]

Update:

so got the piston, and lines in today. got the lines in only took 2 hours!!! pain in the butt!! The fuel filter is going to be an even worse pain!

anyway I think there has been a piston job on this saw before. the piston has a "C" marked on it.... if it was new I would have expected an "A"

anyway any tips for getting the P/C back together?

 

[Stihlofadeal64]

Well here is a picture after I have sanded and and ran a couple more acid baths. I can't feel any scratches with my finger or my nail.

View attachment 227193

the brown is a reflection from something.

I got the wrist pin pulled it was in kind-of tough but I got it. now to figure out the carb, get new parts, and put it together.

so I think the gas I put in was 50/1 of non stihl oil is this what I would have expected? or is there a leak in the manifold or carb?

The cylinder looks much better. Make sure you have no air leaks before you run the saw after it is put together. Otherwise you could be quickly back to "square-one."

 

[Clarkbug]

It took me about that long the first time I tried it. Definitely a learning experience. Someone here mentioned that I should use some string trimmer line, put that through the fuel tank,and feed the fuel line in that way. I havent tried it, but I might do it on the next saw I need to pull apart.

If you search a little on here, you can see the tips about using some string to get the intake manifold back through the handle. (its also in the Sthil manual, I think) If you dont have piston clamps, you can use zip ties or some people use a strip of a soda bottle. Put some oil on things and slide the jug on, feed the intake manifold through the handle, then tighten down. Dont forget to put your gasket on FIRST. Make sure you didnt get any crap in the crank case before you button it all up. Also be sure to point the piston the correct direction.

You will definitely want to be sure that you dont have an air leak, so once you button it back up, time to pressure/vac test to be sure.

 

[RiverRat2]

Another question.

How do I know if the hoses, elbows etc are bad? they are soft and pliable and I don't see any cracks.

my reason is the elbow/manifold is going to run me as much as the piston!

any thoughts?

thanks
Steve

That Cylinder looks great now,,, Good work,,,

JMHO Well for a saw that old, the new intake boot and all new hoses (fuel and impulse) are a must,,, trust me,,, it will save you much grief/time/trouble later,,, for instance a leaking impulse hose can lean you out and you would be right back where you started,, broken,,, wouldnt you feel better knowing that all those consumables are fresh and new after all the work you put into it??????

as another poster stated,,, clean all the carbon you can out of the exhaust port,,, it is not your friend,,, it is in fact the enemy,,, just be careful at the transition of the port/cylinder bore chamfering interface,,, once you get the big stuff a roll of 320 grit emory on a polish shaft drill attachment/ or die grinder/dremel works wonders and youi can clean up the casting flasing and pick up a smidge of performance in the process,,,, post pics for us as you go

if there is some flakey stuff left in the combustion chamber clean it too,,,, by hand/elbow greasen to stay out of that good bore plating you salvaged,,,

keep us posted,,,

I know you are trying to save coins but as good as that cylinder bore cleaned up,,, and oem piston kit would really be nice,,,

be sure and check the needle cage brg. on the wristpin,,, a new one is only about $8.00 and as long as the crank case bearings are snug and the seals are not leaking,,, that saw will live a very long time,,, especially with the new synthetic lubes that are now available!!!

 

[SteveoSupremo]

028_AV_Super New Pistons

So I got the new pistons from NortwoodSaw.com. it came in a much smaller box than I was expecting but hey it all fit and not an over abundance of packaging makes everyone happy!

anyway here are the pictures of the pistons!
View attachment 228200

and a picture of the old and new hoses. the new fuel line is a lot longer than the old one but I think it will work I tried to dry fit it and I think everything will work.
View attachment 228201

I'm getting a ring compressor made up and should have that put together sometime next week. assuming that I don't screw up the cylinder trying to smooth out the exhaust and intake ports.

I took a closer look at the muffler today there really isn't any room for that thing to breath!! has anyone ever run without the top cover on? what happens?

 

[SteveoSupremo]

Carb Rebuilt

WOW that was easy!

I wish pulling hoses was as easy as putting together a carb! didn't even have time to take pictures!

the carb looked pretty clean. the side with the metering diaphragm was full of saw dust. I don't think it's supposed to be that way so I cleaned it all up ran some carb cleaner through it new pin, screen, diaphrams, and gaskets.

hopefully it runs....

 

[Clarkbug]

WOW that was easy!

I wish pulling hoses was as easy as putting together a carb! didn't even have time to take pictures!

the carb looked pretty clean. the side with the metering diaphragm was full of saw dust. I don't think it's supposed to be that way so I cleaned it all up ran some carb cleaner through it new pin, screen, diaphrams, and gaskets.

hopefully it runs....

Did the old fuel line have a filter on the end of it? Make sure you put one on before you run it.

Also, dont run it without a muffler entirely, you want some resistance there. I cant explain it well enough at all, but you want a muffler.

 

[SteveoSupremo]

Yea I have the fuel filter back on. I'm sure there needs to be some back pressure. how much I don't know.

If I were to remove the spark arrester and open up the exaust port could I use some heavy duty steal wool, the really wide metal stuff not the thin sos pad type, to be a spark arrester?

do you think the steal wool would catch fire? should I use copper instead?

thanks

 

[NORMZILLA44]

How you doing Steve? Good ole saws I just sold one awihle back I traded for some wood. Funny thin it was my first carb kit, and rebuild, and I agree so easy! I had my first 028 when I was 18 I think back in early 90's.

 

[SteveoSupremo]

@NORMZILLA44 yea it was a great saw for the four hours that I was able to run it. it's too bad that I stupidly leaned it out and fried the piston....

anyway I know for next time and I learned a lot about small engines and how they run! hopefully I'm going to get this one running smoothly again so it stays running for a long time.

Steve

 

[Clarkbug]

You can open the muffler up some, but no need for any SOS type pad for a spark arrestor in there. If you dont want to run the screen you dont have to, lots of folks dont. Just dont make it too open, and you should be good.

 

[SteveoSupremo]

almost done

so yea I was all set to by some 2 cycle oil today at lunch until I saw the price tag $20 for 6 two gallon mixes! called another store and there it was less than $10 for the same stuff!

any way hopefully I'll get some so I can get this thing buttoned up and ready to go!

any tips for the first start? just set the carb to 1 and 1/4 turn from closed and give it a pull?

 

[PogoInTheWoods]

any tips for the first start? just set the carb to 1 and 1/4 turn from closed and give it a pull?

I may be way off the mark, but I think it'll probably need at least two pulls.:msp_wink:

 

[SteveoSupremo]

Update:

got the rings on, ring compressor in place, needle bearing in place, wrist pin in, copious amounts of 2 cycle oil all over the innards....

Now how do I get those darn circle clips in...

 

[SteveoSupremo]

Bump.....

anyone know how to get those circlips in that hold the wrist pin in?

 

[powerking]

I have used needlnose pliers that I have ground down...I have also used snap ring pliers with great success

 

[RiverRat2]

I use a carb adjusting screwdriver and walk it in,,, start with one end in the groove then keeping one fingertip on the clip,,, with steady pressure,,,,, on it cause if you dont hold it down,,,, and the screw driver slips off,, you wont find it!!!! LOLOL!!!

 

[H 2 H]

I use a carb adjusting screwdriver and walk it in,,, start with one end in the groove then keeping one fingertip on the clip,,, with steady pressure,,,,, on it cause if you dont hold it down,,,, and the screw driver slips off,, you wont find it!!!! LOLOL!!!

LOL

They fly thru the air with the greats of eas were they go nobody knows :hmm3grin2orange:

 

[SteveoSupremo]

back together

so I got it back together got the stupid circlips back in. pain in the kester,

got the cylinder back in went a lot easer that I thought it would... forgot the bolts that hold it on... so that took me another 30 min to fish those in there.

Manafold when in with no problems. got some pices of rubber to block the carb and the exaust for compression, and pressure / vac testing as soon as I get the head bolts tightened down.

 

[SteveoSupremo]

Compression testing... should I be worried?

So I had the exhaust closed off for pressure and vac testing but I got a compression tester from a friend and tried to test without pulling the exhaust plug first pull got me to about 75 psi and about 5 pulls later it was up just under 100.

now mind you this is the first pulls on this piston and rings, I don't hear anything wrong. The pull is jerkey ie when the piston is TDC it gets really hard otherwise it feels normal.

I'm going to remove the plug from the exhaust and give it some more pulls and see what happens. but brand new piston and ring where everything is cold what should I expect?

Steve