We have a baby Dolmar, but it's the wrong color. DCS401 content inside!

[oldmar]

We have a baby Dolmar, but it's the wrong color. Naughty pictures inside!

Look what the stork brought. It's a funny color for a Dolmar, and the start-y thing is way too easy to pull.





This is a very clean little 'Kita, and even with zilch compression, I couldn't pass it up. I'm told that these little guys respond very well to a muff mod, and since I've got it apart, I reckon I should lessen the 'ol squish, if there's any to be had.

It's a DCS 401, same as the Dolmar PS401. It's kinda a bad@$$ little saw- stainless muff, integrated cold-weather carb shutter, decomp, pro features abound. All but the compression feature, which is absent.

Here's where I need help- I'm no chainsaw guru, but I've seen enough lunched engine internals in my day to know what catastrophe looks like. What I see here is a fairly nice cylinder bore, with no alu transfer, and a piston that just doesn't look trashed, to my eyes. The ring is stuck in its groove about a third of the way around. There's a little bit of a ding, sorta looks like the ring was peened into the groove, but it's tiny. Can a piston sustain enough damage to freeze the ring, and still look presentable, or is the ring likely just stuck?

Option 2; is the piston trashed, and I'm just not seeing it because I'm cheap?

There's piston kits on feebay, about 30 beans, Meteor brand. Are these OK?
Is there a site sponsor who'd have the piston and ring? If I have to spend money, I'd just as soon do it through AS.

Additional non-piston-related 401 knowledge is welcomed, of course. I already know that SawTroll favors 401s over 420s, so that's covered.

Although the no-compression bit could tip him the other way.

 

[stevejr33]

They work just put one in my 044. not my first choice thoe

 

[GA_Boy]

What's that 90 degree elbow stuck in the transfer port for?

 

[bigbadbob]

My DCS340 I believe is the same bottom end. Well I opened up the exhaust, dumped the base gasket and widened the exhaust port, matched the muffler to the port, could not believe the difference. Seems like a very well made saw.

Good luck
Bob

 

[Warroad50]

What's that 90 degree elbow stuck in the transfer port for?

It's for the impulse line that goes to the carb.

 

[67L36Driver]

I.I.W.M. (if it were me) I'd get a piston w/ring and cylinder. Far too many vertical scratches. BWDIK

If you are going to hot rod an engine you should start with something in prime condition if you want an improvement over 'stock'. It's not productive to put a cam kit, headers and larger carb on something blowing smoke to begin with.

 

[GA_Boy]

those vertical lines could be aluminum deposits.

 

[grandpatractor]

A little scotchbrite pad and some elbow grease will clean that cylinder right up.

Put in a new piston and ring and do your mods. This is a good one to practice on if nothing else.:chainsawguy:

 

[oldmar]

I.I.W.M. (if it were me) I'd get a piston w/ring and cylinder. Far too many vertical scratches. BWDIK

If you are going to hot rod an engine you should start with something in prime condition if you want an improvement over 'stock'. It's not productive to put a cam kit, headers and larger carb on something blowing smoke to begin with.

I'm with you, but I'm not convinced that they're really scratches. I can't feel any variation in the surface. I think that the stuck ring is explaining the low comp so far. That said, if I can find a cylinder, I'll totally replace it.

 

[oscar4883]

Meteors are nice. I put them in about 4-5 200t's, mine included, and they get beat on pretty good. No issues so far. If the ring comes out of the groove and it is burr free and has good gap, I might be inclined to dress the ring groove on the piston and see what king of comp I got. Maybe it would be good to go. Depends on how things clean up though. A new piston is good peace of mind though.

 

[67L36Driver]

I'm with you, but I'm not convinced that they're really scratches. I can't feel any variation in the surface. I think that the stuck ring is explaining the low comp so far. That said, if I can find a cylinder, I'll totally replace it.

Yup, a ring stuck in the bottom of the groove won't allow combustion gasses to get behind it and push it against the cylinder wall. A ring also seals against the piston ring land.

 

[ran3465]

cylinder looks OK as far as i can see on my crappy laptop. If it were mine and I got a good deal on the saw I would just buy a new meteor piston and ring. Another thing I have done before is lightly work the cylinder bore in the kitchen sink full of soapy water with some wet sand paper. 30 bucks for the piston is cheap insurance.. Good luck

 

[Andyshine77]

I really don't see why the compression would be low, the P&C looks normal for a used saw. Only thing I can think of is the ring end gap is too large. Nevertheless clean the cylinder and piston up a little, throw on a new ring and see how she runs.

Meteor pistons are great BTW.

 

[oldmar]

You missed the part about the stuck ring, Andy.

But I like the part about the wear looking normal. Thanks.

 

[nmurph]

I really don't see why the compression would be low, the P&C looks normal for a used saw. Only thing I can think of is the ring end gap is too large. Nevertheless clean the cylinder and piston up a little, throw on a new ring and see how she runs.

Meteor pistons are great BTW.

yep, that cylinder doesn't look scored to me, it looks burnished. i would pull the ring and clean the groove, and then put it back together with a new ring.

 

[67L36Driver]

No matter how hard I try I can't get my fingernail in there to feel it.:hmm3grin2orange:

 

[Andyshine77]

You missed the part about the stuck ring, Andy.

But I like the part about the wear looking normal. Thanks.

Yes sir I did, yup that would do it.

Like nmurph said you should be good to go with a little cleaning. Make sure the piston crown isn't cracked or pushed down where the ring is stuck, it does it looks fine in the pics however..