576xp project saw, with photos

[mbrick]

Been wanting a parts saw for a while and came across a Husqvarna 576xp (non-AT) that was advertised as 'not running'. Seemed like the bottom end was likely ok, so I bit on it. I'll detail out here the 'rebuild' process.

I pulled the spark plug to do a compression test and noticed it was missing the thread on nut for the plug wire to engage and thought no way could it be this simple. I thought maybe they just put in a junk plug for shipping. So I put in a plug I had and it fired up on the third pull. Idled and rev'd up and sounded as expected. Well that was lucky, I think.

It is the dirtiest saw I have ever seen. So, I completely disassembled except the bottom end and ran everything through the ultrasonic cleaner. Every part of it was filthy — even behind the flywheel and in the recoil area.

I noticed three of the cylinder bolts were loose, but I could tell they were not unscrewed because the heads were full of gunk that was untouched. Lots of neglect. Exhaust bolts had not been removed.

Compression is ~140psi so I will keep the piston and cylinder because I've read 140-150 when new. Rod bearing and main bearing look good to my eye. Clutch cover and recoil hub have a crack so those will get replaced along with a few other small bits like a new fuel line.

After 3 nights I got all parts cleaned. Just reinstalled the cylinder and base gasket with 1211 and I will pressure test it tomorrow after curing. Made block off plates for the exhaust and both intakes, and will pressurize it through the spark plug hole like the service manual shows because I already have a fitting.

Hoping it passes a pressure test, really don't want to have to change the crank seals..... Ok maxed out at 10 photos, tbc.

As received:


Compression:


Cylinder and crank:



So dirty:





Recoil and clutch:

 

[mbrick]

Ok I must be missing something here. The oil pump bolt holes go all the way through the case to the crank case volume. How do they seal?

One of the holes has a step next to it, so the boss on the oil pump will not sit flat against it to seal. Is there supposed to be sealer on the threads? The service manual just says tighten the two bolts to 5 Nm but no mention of sealant.

I feel like these should have been blind tapped holes...

 

[Chiknhawk]

I have built quiet a few of these I love this model they are 1lb hey then the 372 and pull a big chain and bar like it is the 372 big brother like it should love em put sealant on the threads if u dont they will leak cause a lean out problem.

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[Chiknhawk]

Do a psi/ vacuum test on it while you have the clutch and flywheel off I use the 372 oring on inside of worm gear spacer too it's probably over kill but I have built and resold a bunch with only one return that was because his son straight gassed it

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[mbrick]

I have built quiet a few of these I love this model they are 1lb hey then the 372 and pull a big chain and bar like it is the 372 big brother like it should love em put sealant on the threads if u dont they will leak cause a lean out problem.

Yes, I will pressure test in this state.

What kind of sealant do you use? Will loctite blue expand well enough and seal?

Is the 372 oring for sealing? The extra thickness does not cause issues? I'll look it up on the parts diagram.

 

[Chiknhawk]

Yes, I will pressure test in this state.

What kind of sealant do you use? Will loctite blue expand well enough and seal?

Is the 372 oring for sealing? The extra thickness does not cause issues? I'll look it up on the parts diagram.

I chanfer the spacer on lathe after zeroing it so the space is made up you dont have to use a lathe I really dont know if it helps i do know if the seal goes it can't hurt for backup i guess and i use yamabond or Honda bond type ultra gray silicone

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[mbrick]

Ok I'll try 1211, very similar to hondabond. It looks like the screws had red thread locker.

Ok I understand about the spacer and o-ring, will look at the IPL and parts more and decide if I want to do that.

 

[mbrick]

Saw passed pressure test @ 8psi for a few minutes. SO GLAD I did not need to overhaul a crank seal. Placed a parts order, build TBC once they show up...

Parts cleaned up fairly well. I need a beefier ultrasonic cleaner though and it would have been nice to drop the whole short block in.

Both the piston and cylinder say Meteor on them, but also have the Husky logo (you can see it on the cylinder below). I have not used their parts and they don't make a p&c for this saw, but I think that should speak to their quality.

 

[Chiknhawk]

Saw passed pressure test @ 8psi for a few minutes. SO GLAD I did not need to overhaul a crank seal. Placed a parts order, build TBC once they show up...

Parts cleaned up fairly well. I need a beefier ultrasonic cleaner though and it would have been nice to drop the whole short block in.

Both the piston and cylinder say Meteor on them, but also have the Husky logo (you can see it on the cylinder below). I have not used their parts and they don't make a p&c for this saw, but I think that should speak to their quality.

View attachment 727325
View attachment 727323
View attachment 727324

Nice you look to be golden if u muffler mod it you want to cut baffle out as much as u can with a carbide bit and I have got the best power buy cutting hole in lowwer right hand corner hold on I have one I just got done with unless customer picked it up I'll post pic I have tried just about every size shape direction known to man on these 575 this one really wakes it up

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[Chiknhawk]

That's the best place to put a muff mod but only draw back is it will burn wood screen it buy two slits in pipe on a x axis and slide in screen use steel ties or rivet

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[Ozhoo]

Saw passed pressure test @ 8psi for a few minutes. SO GLAD I did not need to overhaul a crank seal.

I'd highly recommend vacuum testing before you proceed. Crank seals fail first under vacuum when the lip pulls away from the crankshaft. They have to be severely buggered before they fail under pressure.

 

[Chiknhawk]

I'd highly recommend vacuum testing before you proceed. Crank seals fail first under vacuum when the lip pulls away from the crankshaft. They have to be severely buggered before they fail under pressure.

I didn't even catch that great attention to detail ozhoo I went back and payed closer atm to his set up .. good catch I agree 150% on that psi test on vacuum tells all my moto also heat in some rare cases bit have seen a couple stihl's test great sitting . Then add 110°+- buy heat gun on cyl and the leak shows its face.. it was probably over kill with the time it took to test I could have just popped seals init and been done but seeing so many other dealerships had seen and said saw was perfect and how he explained what was happening I had to narrow it for a positive outcome.. I thrive on when I hand a saw over to a customer after I have done service an repairs that when they hit the woods there is confidence that his saw will do its job as well

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[mbrick]

I'd highly recommend vacuum testing before you proceed. Crank seals fail first under vacuum when the lip pulls away from the crankshaft. They have to be severely buggered before they fail under pressure.

I see. Ok, I can do that. How much vacuum and what is an acceptable leak rate?

I've always read to pressure test two strokes. And the few saw videos I found showed huge bubbles under pressure. So I didn't think to try vacuum.

 

[Chiknhawk]

I see. Ok, I can do that. How much vacuum and what is an acceptable leak rate?

I've always read to pressure test two strokes. And the few saw videos I found showed huge bubbles under pressure. So I didn't think to try vacuum.

I look at it like a drink ...lol 7&7 if it hold both and rotate watch vac/psi guage.. this can also teach alot about the particular engine you can see at what degree on a degree wheel what is going on at certain timing in the ports as long as you have degreed the engine in ? At the time .. that is a whole other conversation keep on doing g as you are and excel

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[mbrick]

Ok, so it failed vacuum test. At 8 inHg, it starts leaking and slowly drops back down. I oiled the seal and determined it leaks from this spot on the clutch side seal. With motor oil on top it holds 12 inHg. It seems like a small leak.

Thanks Ozhoo for catching my mistake of using pressure and not vacuum.

Chiknhawk, what is your method of removal for this seal? I will make a removal tool and a press tool. Do you use something thin like the Stihl puller that slips in and pulls it out?

I see it is integrated into the bearing and not the case. P/N 505416101, $8.71.

 

[Chiknhawk]

Ok, so it failed vacuum test. At 8 inHg, it starts leaking and slowly drops back down. I oiled the seal and determined it leaks from this spot on the clutch side seal. With motor oil on top it holds 12 inHg. It seems like a small leak.

Thanks Ozhoo for catching my mistake of using pressure and not vacuum.

Chiknhawk, what is your method of removal for this seal? I will make a removal tool and a press tool. Do you use something thin like the Stihl puller that slips in and pulls it out?

I see it is integrated into the bearing and not the case. P/N 505416101, $8.71.

View attachment 727474

How much end pkay and virtical horizontal play does the crank have I bolt mine buy bar studs to a saw vise I built and puta dial indicator on sold base and play with the crank until it shows most movement it can be multiple reason bearings worn trash in between seal and shaft when they wipe out the top end they tend to pack aluminum from piston and steel from rings in bearings and seals your best bet and safest route is seals and bearing period sorry I know you dont want to hear that but it will be your best interest In the end and saw will run u a very good long service life

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[Chiknhawk]

Ok, so it failed vacuum test. At 8 inHg, it starts leaking and slowly drops back down. I oiled the seal and determined it leaks from this spot on the clutch side seal. With motor oil on top it holds 12 inHg. It seems like a small leak.

Thanks Ozhoo for catching my mistake of using pressure and not vacuum.

Chiknhawk, what is your method of removal for this seal? I will make a removal tool and a press tool. Do you use something thin like the Stihl puller that slips in and pulls it out?

I see it is integrated into the bearing and not the case. P/N 505416101, $8.71.

View attachment 727474

How much end pkay and virtical horizontal play does the crank have I bolt mine buy bar studs to a saw vise I built and puta dial indicator on sold base and play with the crank until it shows most movement it can be multiple reason bearings worn trash in between seal and shaft when they wipe out the top end they tend to pack aluminum from piston and steel from rings in bearings and seals your best bet and safest route is seals and bearing period sorry I know you dont want to hear that but it will be your best interest In the end and saw will run u a very good long service life

Sent from my SM-N960U using Tapatalk

 

[Chiknhawk]

Ok, so it failed vacuum test. At 8 inHg, it starts leaking and slowly drops back down. I oiled the seal and determined it leaks from this spot on the clutch side seal. With motor oil on top it holds 12 inHg. It seems like a small leak.

Thanks Ozhoo for catching my mistake of using pressure and not vacuum.

Chiknhawk, what is your method of removal for this seal? I will make a removal tool and a press tool. Do you use something thin like the Stihl puller that slips in and pulls it out?

I see it is integrated into the bearing and not the case. P/N 505416101, $8.71.

View attachment 727474

How much end pkay and virtical horizontal play does the crank have I bolt mine buy bar studs to a saw vise I built and puta dial indicator on sold base and play with the crank until it shows most movement it can be multiple reason bearings worn trash in between seal and shaft when they wipe out the top end they tend to pack aluminum from piston and steel from rings in bearings and seals your best bet and safest route is seals and bearing period sorry I know you dont want to hear that but it will be your best interest In the end and saw will run u a very good long service life

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[mbrick]

Have you pulled any of these seals without changing the entire bearing? Since the seal is available separately.

I don't think there is any metal debris, it is probably just old. The top end or bottom end did not shed any metal. I would like to at least pull it first and then I can also see if the plastic bearing cage is ok.

I don't have a dial indicator but I can't feel any play either direction. It feels tight. What kind of numbers do you usually see so I understand magnitude?

 

[Ozhoo]

A notched screwdriver or one of those cheap Lisle seal pullers ground down works just fine. Pull the seal and take a gander at the bearing. Hope for the best, prepare for the worst.