Big Bore kits

[Eagle 1]

Thanks for letting me join the site, this is my first post and I have a chainsaw question. First I’ll introduce myself. I am not arborist by no means, I am retired military and a mechanic by trade.
I have an old Stihl 029 Super chainsaw that I purchased approximately 21 years ago that I use from time to time on my property cutting firewood, clearing trees etc. The saw has finally played out on me and as I suspected the piston and bore is shot. I took it to a local shop and had it looked at and they verified what I already knew. I decided I wanted to save the saw and rebuild the engine. My questions are about getting a quality big bore cylinder kit. First of all can someone recommend a quality bore kit? I found this place online and I called and talked with them.
http://www.lilredbarn.net/product-p/sbshms310-47mm.htm
Has anyone ever dealt with them?
I believe he said that these kits come from South America and that they assembled them at their shop.
Again I’m looking for quality and open for suggestions. Thanks

 

[Vintage Engine Repairs]

Hi and welcome!

Firstly, you may very well be able to save your cylinder once you’ve removed the transfer. If possible then do so as it will be far superior to the Chinese parts of your link.

To that you can just add a meteor piston, caber rings, an OEM small end bearing and a new set of crank shaft bearings from your local bearing supplier. Stihl seems to use FAG’s on their older equipment, but any of the good brands, nsk’s, skf, koyo etc are just as suitable from a bearing supplier for 3x less than Stihl.

As a mechanic you clearly know your stuff, a little 2 stroke will be a walk in the park. Though , 029’s and 039’s are rather convoluted and aren’t very conducive to working on. None the less it’s not difficult.

I’d suggest finding the issue for the damaged top end, strip it and consider re using the cylinder. If so, grab a meteor piston etc, fix the issue, give the carb a birthday with a new kit and replace all rubbers and fuel filter, make sure you do a pressure and vacuum test and she’ll probably last another 2 decades.

lots of smart and generous people on here willing to share. Welcome and best of luck with the repair!

 

[huskihl]

Someone may have an oem 039 or 390 cylinder laying around from a crushed or retired saw. I’d put up an ad for one first before going AM.

 

[Eagle 1]

Thanks for the replies, I’ll tear it down after the new year and see the damage done more closely.
I was just trying to get a heads up on a possible complete bore kit as I am betting the cylinder is probably worn as well. I kind of would prefer something new, but I agree the older stuff is better.
I’m just worried about getting something wore out that is used.
I agree that probably something in the top end caused the problem but I will know for sure once I get a look.

 

[Binthewoods]

I've been wanting to try out one of the Hyway Titanikel MS390 kits.

 

[ballisticdoughnut]

Thanks for the replies, I’ll tear it down after the new year and see the damage done more closely.
I was just trying to get a heads up on a possible complete bore kit as I am betting the cylinder is probably worn as well. I kind of would prefer something new, but I agree the older stuff is better.
I’m just worried about getting something wore out that is used.
I agree that probably something in the top end caused the problem but I will know for sure once I get a look.

I'd be willing to bet the cylinder is probably salvageable. If I were in your shoes however, I'd be looking into converting it into a 039 using good used OE parts. I'd stay away from the aftermarket stuff. Even buying new OE parts would be worth it considering you'll most likely get another 20+ years of use out of it.

 

[Eagle 1]

I'd be willing to bet the cylinder is probably salvageable. If I were in your shoes however, I'd be looking into converting it into a 039 using good used OE parts. I'd stay away from the aftermarket stuff. Even buying new OE parts would be worth it considering you'll most likely get another 20+ years of use out of it.

Just to confirm, an 029 Super uses a 46mm piston?
Does anyone have a stihl part number?
I understand that they have been discontinued.

 

[ballisticdoughnut]

Just to confirm, an 029 Super uses a 46mm piston?
Does anyone have a stihl part number?
I understand that they have been discontinued.

Now that you mention it I believe you may be correct on the piston. I know the 039 piston is NLA. Meteor makes pistons for both the 029 and 039 and they're pretty good. Only aftermarket part I'd ever consider using myself. A lot of times you can usually find OE Stihl pistons on eBay. Mite be worth a look. I'll look up some part numbers for you tomorrow when I'm at work.

 

[BrettS]

The chinese parts are sometimes ok, sometimes not. I fitted a chinese big bore cylinder (55) to my dads 51 and it's still going years later.

 

[ballisticdoughnut]

So looks like the 46mm pistons are still available, part number 1127 030 2003. 49mm piston and cylinder part number 1127 020 1213 also appears to still be available but is out of stock.

 

[Maintenance supervisor]

If your looking for Quality, I'd be inclined to purchase a pro level saw to dump oem parts $ into? All of the 029s I've run are underwhelming to say the least. Maybe look for an 036 ,ms361, or 365xp ,it'll blow your socks off and be a better investment for the OEM path.
I've used a Hyway 039 with a cross pop up piston in a 029 and its worked well .

 

[Eagle 1]

If your looking for Quality, I'd be inclined to purchase a pro level saw to dump oem parts $ into? All of the 029s I've run are underwhelming to say the least. Maybe look for an 036 ,ms361, or 365xp ,it'll blow your socks off and be a better investment for the OEM path.
I've used a Hyway 039 with a cross pop up piston in a 029 and its worked well .

I agree with what you are saying, but like I said I’m not an arborist by trade so I can’t justify needing a top of the line saw. Besides this one has always been plenty powerful enough for I use it for. In fact this is the first time I’ve ever had a single problem with it. I did get lucky and find an OEM stihl piston at a very good price on eBay. So hopefully the cylinder will be salvageable and I will be able to save the saw.
Thanks for all the input.

 

[ericm979]

Two problems with the big bore kits: Vibration and ports. Even the stock size Chinese pistons are significantly thicker and heavier than OEM. The big bore ones are even heavier. So you'll feel more vibration. When they make a big bore cylinder the ports are the same in the casting. They just machine the cylinder hole bigger. So the transfer port angles are not as good and the ports are undersized for the displacement. Which means you'll get less power out of it than you think.

 

[Maintenance supervisor]

The 660 aftermarket pistons are lighter .

 

[Wood Doctor]

The chinese parts are sometimes ok, sometimes not. I fitted a chinese big bore cylinder (55) to my dad's 51 and it's still going years later.

I did that four years ago to a Husky 51 and a tree service company bought it. They wanted a 20" bar, so I installed that and believe it or not, it pulls it OK in a commercial environment, which is usually devastating. Compression is still good. As I look back, I never should have sold it.

 

[ballisticdoughnut]

I agree with what you are saying, but like I said I’m not an arborist by trade so I can’t justify needing a top of the line saw. Besides this one has always been plenty powerful enough for I use it for. In fact this is the first time I’ve ever had a single problem with it. I did get lucky and find an OEM stihl piston at a very good price on eBay. So hopefully the cylinder will be salvageable and I will be able to save the saw.
Thanks for all the input.

There was a OEM 029 piston on eBay a few days ago.

 

[Eagle 1]

I just wanted to update on my post. I did buy a new stihl piston on eBay and I was able to use my original factory cylinder. While it was tore apart I did replace both crankshaft bearings and seals as well as the rod needle bearing. Along with a new carburetor and a good cleaning the saw is good as new and hopefully will last me another 22 years and by then I will be to old to use it anymore. Lol. Thanks for everyone’s help.