Stihl 046 mods, porting?

[rawdog]

Hi everyone, I have a Stihl 046 that is getting low on compression 140psi. It runs and idles fine just lacking grunt. I am going to give it a birthday and speed it up a bit. I am considering a Meteor cylinder kit which I would port, but I am wondering if porting the old cylinder and adding a new piston or rings is worthwhile? The cylinder looks fine to my eye, no obvious signs of wear.
My porting jobs are simple, I usually widen the exhaust and transfers, and smooth any casting flaws. I haven't got a degree wheel and I'm a novice with regard to timing.
Any advice would be appreciated.
Thanks in advance. Mike.

 

[BonScott46]

You could try new rings and set the squish then see where you are at...

 

[CR888]

It sounds like this saw is a piston kit/new rings away from being a healthy saw again. My opinion would be to stick with a OEM Mahle cylinder whenever possible. Meteor pistons are good, you could get a Meteor piston kit and be good to go. As for porting, well you knowledge and skill level will determine that outcome. I know Stihl NZ like dealers here charge like a wounded bull when it comes to OEM cylinder kits.

 

[rawdog]

It sounds like this saw is a piston kit/new rings away from being a healthy saw again. My opinion would be to stick with a OEM Mahle cylinder whenever possible. Meteor pistons are good, you could get a Meteor piston kit and be good to go. As for porting, well you knowledge and skill level will determine that outcome. I know Stihl NZ like dealers here charge like a wounded bull when it comes to OEM cylinder kits.

You're right about the cost of Stihl parts here. I don't want to go OEM because of price. I can buy a meteor cylinder + piston kit for the price of an OEM piston. Is there an easy way to test the shape of the cylinder? Do they go "out of round"? I have heard some complaints about Meteor pistons not matching OEM cylinders properly, but I wonder if this is due to an overheated cylinder being used as a starting point.
I struggle to get good advice where I am. My local Stihl/Husky dealers are quick to dismiss anything that will lose them business.

 

[rawdog]

You could try new rings and set the squish then see where you are at...

That's probably a good place to start, would I expect to see an increase in compression immediately, or not until the rings bed in?

 

[BonScott46]

That's probably a good place to start, would I expect to see an increase in compression immediately, or not until the rings bed in?

Both. Check the wear on the piston when you have it apart, if it needs to be replaced buy an oem replacement which should be cheaper than a meteor p&c kit.

 

[BonScott46]

You're right about the cost of Stihl parts here. I don't want to go OEM because of price. I can buy a meteor cylinder + piston kit for the price of an OEM piston. Is there an easy way to test the shape of the cylinder? Do they go "out of round"? I have heard some complaints about Meteor pistons not matching OEM cylinders properly, but I wonder if this is due to an overheated cylinder being used as a starting point.
I struggle to get good advice where I am. My local Stihl/Husky dealers are quick to dismiss anything that will lose them business.

Find a member in the states to send you a piston, have them take it out if the box, should be cheaper than NZ prices.

 

[rawdog]

Find a member in the states to send you a piston, have them take it out if the box, should be cheaper than NZ prices.

Do you have a reason against using meteor pistons, or do you just prefer OEM?

 

[BonScott46]

Do you have a reason against using meteor pistons, or do you just prefer OEM?

No reason, I just figure if you can get one for a reasonable price why not? If you can get a Meteor for a reasonable price where you are at then go with it. Usually you can replace the rings on a piston once before it is too far gone. I was just suggesting the most bang for your buck with a ring swap and squish setting.

 

[rawdog]

No reason, I just figure if you can get one for a reasonable price why not? If you can get a Meteor for a reasonable price where you are at then go with it. Usually you can replace the rings on a piston once before it is too far gone. I was just suggesting the most bang for your buck with a ring swap and squish setting.

Thanks for the advice, I can get meteor pistons at a good price here, that is why I'm keen to try it. I always like to know peoples experience with a product though, that is why I asked. I'll measure the squish in the weekend, and move forward from there. I would like to port the cylinder and wake it up a bit. I'm busy this week though, I have a big old pine to cut up with my angry old 288xp...

 

[Evan]

Ohhhh yes setting squish in 020 ball park and bew rings will make an immediate improvement. Will most likely make more compression than new.

Widen intake and ex port to 75ish percent of piston diameter bump transfers towards intake if you have a tool if not dont worry.
Take the lip off the lower transfers.

This what i do ive never tried a degree wheel grind wine and dine kinda thing i never grind in a way that alters timing just widen so it can increase the amount it pumps.

Good luck and have fun with it

 

[wcorey]

Be cautious of Meteor 046 cylinders, there was recently a batch of them with some pretty obviously bad port issues, particularly the intake.
Can be cleaned up and 'adjusted' but need a lot of grinding...

If the stock cylinder bore looks reasonably clean, use it.

 

[Evan]

I have two oem 046 cylinders one is exceptional the other needs quite a lot of work to be as good i have never looked in a meteor cylinder i just know the one oem i have is dissapointing compared to my good oem not a deal breaker just my observation. Im sure if we looked in a few meteors wed see the same quality differences from batch to batc

 

[rawdog]

Ohhhh yes setting squish in 020 ball park and bew rings will make an immediate improvement. Will most likely make more compression than new.

Widen intake and ex port to 75ish percent of piston diameter bump transfers towards intake if you have a tool if not dont worry.
Take the lip off the lower transfers.

This what i do ive never tried a degree wheel grind wine and dine kinda thing i never grind in a way that alters timing just widen so it can increase the amount it pumps.

Good luck and have fun with it

Thanks Evan, have you widened the exhaust and intakes to 75% on a Stihl 046? That seems a lot to me but I admit to being overcautious. I usually go for 65% on the exhaust and smooth the intake a little, but I'm here to learn, not to give advice.

 

[rawdog]

Be cautious of Meteor 046 cylinders, there was recently a batch of them with some pretty obviously bad port issues, particularly the intake.
Can be cleaned up and 'adjusted' but need a lot of grinding...

If the stock cylinder bore looks reasonably clean, use it.

Thanks for the info. Was the port timing wrong on these meteors, or just the shape of the ports? I'm comfortable shaping ports but I don't want to adjust heights and measure timing, that is beyond me at present. I'll try to keep the factory cylinder if possible.

 

[smokey7]

75% on most saw engines would exceed the skirts to cover the port.

 

[wcorey]

Thanks for the info. Was the port timing wrong on these meteors, or just the shape of the ports? I'm comfortable shaping ports but I don't want to adjust heights and measure timing, that is beyond me at present. I'll try to keep the factory cylinder if possible.

Can’t remember all the details atm but the shape and size of the intake was the main issue. Misaligned on the boot side, also really small and very asymmetrically misshapen at the exit into the cylinder wall, was fixable though.
Also typically low intake duration and a little long on the blowdown, likely similar to many oem ones.
Just ugly and not what you’d expect from a relatively pricey name brand aftmkt kit.

I guess the newest ones are better.

 

[cgraham1]

I can buy a meteor cylinder + piston kit for the price of an OEM piston. Is there an easy way to test the shape of the cylinder? Do they go "out of round"? I have heard some complaints about Meteor pistons not matching OEM cylinders properly, but I wonder if this is due to an overheated cylinder being used as a starting point.

I have used Meteor pistons in several saws, without issue.

 

[blsnelling]

Stick with the original cylinder! Meteor piston's are fine. You won't be able to get near that wide on the ports.

 

[rawdog]

Stick with the original cylinder! Meteor piston's are fine. You won't be able to get near that wide on the ports.

Thanks Brad, how wide do you recommend for a port job on a stihl 046? I can set the squish by changing gaskets, but I don't have a degree wheel so don't want to do anything that will require timing changes.