Stihl ms 440 and 044 with 461 coil?

[Steelie90]

Need some help with coils. Working on a ms440 and 044 12mm, both need full rebuilds. P/c scored and bearings torched. Noticed both are running this 1128 1313A coil. Comes up as 461 coil?
This an acceptable swap with oe flywheel?
Are these limited coil?
Preferred coil for a ms440 or 460?

 

[Wonkydonkey]

It would seem they are ms 461 coils. Which are limited coils.

The ms 460 coil was a good coil to fit into a 461 to make it unlimited and give it a bit more ummffff.

I,m not really sure why you got two limited coils in saws that would have had unlimited coils in them originally

As you probably gathered, there are a few coils that are interchangeable, I can’t say why yours were swapped

I,m sure someone will be along shortly to help you along

 

[MG porting]

I'm guessing someone was in a hurry to get those saws going and just tossed the 461 coils on them and nice thing about the Stihl saws the 1980s and 1990s most of the coils would interchange.

 

[Steelie90]

Kind of what I was thinking, had a couple on hand and tossed them in or swapped the unlimited into there 461’s. Just wanted to make sure I wasn’t missing some curve advantage of these over the 400 1300’s . Thanks for the info

 

[Wonkydonkey]

Fyif.

Afaik.. it’s very very easy to lean seize a saw if you’re not good at tuning !! or if have an air/seal leak. The coil abeit revlimited masks these problems. Where as a non limited coil would give you a brief chance ( to a semi trained ear!.?) as in screaming to the moon. If you’re lucky ? You catch it just in time… it’s definitely harder with a Rev limited coil

 

[Steelie90]

Absolutely, little more revs on already lean conditions and things happen fast.
I wondered if this coil advance timing any from stock?
Maybe to far and cause lean/ excess heat condition?
Both saws I bought non running so can’t say for sure.

 

[Wonkydonkey]

I,m pretty sure the 461 coil would not do anything to the timing other than limit the max rpm.

I was looking at your piston pic again, it may be just old fuel or wrong fuel mix and seized, it could be a bad crank seal/air leak etc.

The only real way to get an accurate diagnosis would be to do a pressure & vacuum test. But i see your one of your cases are already in half.

If you got them both from one person, what ever it was that shagged one piston, it was repeated to the other piston. What’s the other sides of the piston look like, intake, flywheel side, pto side. ?
From the stihl diagnosis pdf. It sort of helps figure out what’s happened, i had one the other month (brushcutter) that was wrong fuel and at first I thought it was a 4 corner seizure.

So my guess is wrong fuel mix or old fuel, or wrong tuning.

Btw. What do you use the angle finder on the drill chuck for ? It in you piston pic
I’ve highlighted it here
Cheers.

 

[Steelie90]

Yep, I should have press/vac tested to confirm. Someone was itching to dive into it.
But I think you correct, bad fuel/mix maybe some water.

As to the angle finder, I use that for checking port timing. Been playing with port work or enhancing flow characteristics on my personal saws. Nothing crazy. Attached is a mocked up picture on how it attaches. Like a degree wheel just no need to set up a reference pointer.

 

[Wonkydonkey]

yes that the stihl pdf piston diagnostic thing i was on about.

The scoring on the exhaust/pto side correlates to lean tuning/ wrong old mix as the flywheel side is cooled and not scored. However the intake side being that scored, I’m not confident to say it was a lean / old mix.
So i would be making sure no pin holes in fuel lines or split intakes etc.

But as i said before, if they are from the same person/ place what ever did one it was copied to the other.

As they say…. Ask me how i know read below..

A mate said on a job, my say is getting harder to start . I asked a few questions. One was what mix/ new mix etc.. he said i topped up the fuel and added more oil…
can guess my reply …. What! You add oil to a top up…,! ..i have two cans and only add oil to the can when i add the fuel. Are you sure you added the oil after you top up the can!.?

Any way. It wasn’t the fuel in his eyes and mind.
I wasn’t going to argue so I just said. Well if it is or isn’t the fuel you will find out soon enough, when you put it in your other saw
He thought about it and dismissed it

2 days later I gets a call on the phone, my other saw is playing up…

He didn’t like that I said, well you have the answer as to why your other saw is fűcked, the only thing that they have in common is the fuel.

I fixed them both, after I made him buy 2 oem p&c kits (ms150 & ms180). i didn’t charge him for my time as he was a good mate…But I got his old cylinders and cleaned them up the mastermind way and a bit of acid.

I think he learnt from that mistake

 

[drf256]

The 440 and 044 (10/12) came with the 1300 ”dummy” coils. The 046/460 came with the coil that had start retard on it. Not really necessary to have, but a nice luxury if you are building a non-decomp saw with lots of compression.

I cant recall the number of the “smart” coil. @jacob j. @PA Dan would know IIRC. No coil can advance timing, it can’t see into the future. It can, however, retard timing at low starting rpm and then go into normal mode at a certain rpm.

The 461 came with limited coils. Most people replace them with any 1300 coil. From 024-046 should work fine. The 1122 series is where it gets really strange, with all sorts of different coils and flywheels.

 

[Steelie90]

Awesome, good info I appreciate it!
I think I have a 1309 left over from a early 046 I’ll use as well as a 1300. Just had to pickup some new lead from Stihl shop.

I have a 1122-1314 and I swore it come from a 460, maybe a late production or different flywheel combo I can’t member. Prefix had me fooled tho.