Author Topic: FREE PORTING PISTON Dolmar 111 & 115 family  (Read 2295 times)

0 Members and 0 Guests are viewing this topic.

Offline 660magnum

  • Global Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 6437
  • Karma: 249
  • For The Love Of Chainsaws
  • Location: NCO
FREE PORTING PISTON Dolmar 111 & 115 family
« on: April 15, 2013, 02:36:29 pm »
Converting a Dolmar 111i from a open port cylinder and non window single ring piston to a closed port Dolmar 115i closed port cylinder and a Meteor double ring window piston. 

I was in the process of converting my Dolmar 111i to a 115i with the addition of a closed port cylinder from one of my model airplane engines. I have already changed the clutch over to the wrap coil spring clutch of the 115 and changed the rim over to 3/8" X 7 pin and have a 59 DL 16" bar on it. I also put a new 3.4mm  double braid pull cord in the starter. I would like to make note here that the very last 111i's made had closed port 44mm cylinders and window pistons from the factory just like the 115i.

The cylinder is a used one that is in nice shape. It also has a Mahle single ring piston.

I originally intended to clean up a straight gassed cylinder I had but decided to use the cylinder from the model airplane engine. I bought a Meteor 44mm 2 ring window piston form the Israeli for $35 incl shipping. It has the same squish height as the OEM Mahle window piston but the Meteor is domed. It also has a short skirt. The Meteor is a nice piston except for the skirt that is about 1 1/2 mm short. As a result, it free ports about .010" about half way across the bottom of the exhaust port. Essentially just enough to say it free ports!

Some people like Neil Murphy proclaim that this small amount free porting will not hurt anything? What do you think about the free porting?

I cannot understand why Meteor pistons have the short skirts?

I also noticed that both rings of the Meteor piston come down into the intake port port but the pins do not show. On the OEM piston, the single ring also completely shows in the intake port. I would like to use the Meteor piston because it is new and has the dome and more intake timing but I don't like the two rings instead of one and I don't like the short skirt.

I can just use the OEM Mahle piston which does not free port? I like the idea that it is single ring but it is flat top.
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

Share on Facebook Share on Twitter


Offline brokenbudget

  • Nitro Hotsaw
  • *******
  • Posts: 900
  • Karma: 67
  • Location: brockville ontario canada
Re: FREE PORTING PISTON
« Reply #1 on: April 15, 2013, 02:55:18 pm »
ditch the bottom ring, throw it together and run it. .010 freeport aint gonna do anything but screw with yer head. i've had saws here with a good chunk of the skirt missing from the exhaust side (really big free port) and you wouldn't notice it while running. of course, when found, it was fixed, and you had a few beers wondering how far from fully coming apart that piston was.
when I grow up, i wanna be an adult.

Offline 660magnum

  • Global Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 6437
  • Karma: 249
  • For The Love Of Chainsaws
  • Location: NCO
Re: FREE PORTING PISTON
« Reply #2 on: April 15, 2013, 04:23:23 pm »
Thanks
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

Offline adam32

  • Piped Saw
  • *****
  • Posts: 429
  • Karma: 46
Re: FREE PORTING PISTON
« Reply #3 on: April 15, 2013, 05:50:09 pm »
How about a bit of freeport on the side of the exhaust port...?

Offline brokenbudget

  • Nitro Hotsaw
  • *******
  • Posts: 900
  • Karma: 67
  • Location: brockville ontario canada
Re: FREE PORTING PISTON
« Reply #4 on: April 15, 2013, 09:41:36 pm »
it's never a good idea to do that. bad infact. totaly different can of worms.
when I grow up, i wanna be an adult.

Offline 660magnum

  • Global Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 6437
  • Karma: 249
  • For The Love Of Chainsaws
  • Location: NCO
Re: FREE PORTING PISTON
« Reply #5 on: April 15, 2013, 10:04:31 pm »
Well, earlier in the week I had a broken tooth exactly as you did. This afternoon was my day to go to the dentist. I got there 35 min early and had to wait an hour to get in the chair where I sat for two hours. I now have a temporary tooth for a couple weeks. The dentist cut me a deal of 10% off so it was only $1147.50 for the one tooth.

Now I've got this strange thing in my mouth that I keep feeling of with my tongue.

Anyway, the Dolmar 111 with the closed port cylinder started right up and ran like it had never been apart - free porting exhaust and all.

My new 115 clutch assembly didn't work so well. It wasn't together correctly - the big sheet metal disk behind the shoes was out of position on one shoe and jammed up and wouldn't release. Snapped it together correctly and I spent some time on the clutch tonight inspecting everything and the new bell wasn't relieved correctly in the hub to drive the worm and made everything tight. The oiler did work though. Examining the old bell, there was nothing wrong with it so I just used the old bell and now everything seems fine.

Now I've got to secure what's left of the model airplane engine and the old parts.

Examining the OEM piston and closed port cylinder, all the interrelational timing factors are not thought out as well and as close on the 115 as they were on the 116S/120S/6000/6800 swap I did a couple weeks ago.
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

Offline brokenbudget

  • Nitro Hotsaw
  • *******
  • Posts: 900
  • Karma: 67
  • Location: brockville ontario canada
Re: FREE PORTING PISTON
« Reply #6 on: April 15, 2013, 11:00:25 pm »
 ;D yeah i have one of them 'temp toofs'. waiting on the infection to totaly clear up and the root to heal, or something like that. i wasn't listening as i  was enjoying the non pain at that moment :) mine has a small area where there is a little pressure point that wasn't there before, but i can live with that. pure heaven compared to before.

do the top ends from the 115 bolt on directly? never been into a 115. lots of 111's, have one myself. and it's a good saw. but you know. always looking for a little more ooomph.
when I grow up, i wanna be an adult.

Offline 660magnum

  • Global Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 6437
  • Karma: 249
  • For The Love Of Chainsaws
  • Location: NCO
Re: FREE PORTING PISTON
« Reply #7 on: April 15, 2013, 11:13:35 pm »
The 111 and the 115 are the same saw frame.

The 111 clutch had the two "U" shaped springs and the 115 had the coil spring loop. They were both two shoe designs. The last ones in that series had a 3 shoe design with the loop spring.

As a general rule the 111 was open port and the 115 was closed port.

111 came with a 15" bar 8 pin on 325 and 7 pin on 3/8"

The 115 had a 18" bar.

The closed and open port cylinders are interchangeable but the closed port piston has windows. There's no difference in the carbs, ignition or mufflers.

The Meteor piston is a window piston and will work on either cylinder.

Cylinders and pistons are no longer available at the USA distributors.

The "i" versions had Tillotson carbs.
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

Offline brokenbudget

  • Nitro Hotsaw
  • *******
  • Posts: 900
  • Karma: 67
  • Location: brockville ontario canada
Re: FREE PORTING PISTON
« Reply #8 on: April 15, 2013, 11:19:32 pm »
 >:( great. now i'm going to have to find a good 115 topend. juuuuuust great.
when I grow up, i wanna be an adult.

Offline 3000 FPS

  • Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 4469
  • Karma: 274
  • Location: Carpenter, Wyoming
Re: FREE PORTING PISTON
« Reply #9 on: April 16, 2013, 12:44:09 am »
I did not know that about the 115 being closed port and the 111 being an open port design.   I have two 111i's but have never taken the cylinders off.     Something to look out for.
PP 505, 475, 445.

 

Related Topics

  Subject / Started by Replies Last post
6 Replies
1376 Views
Last post June 01, 2016, 09:03:45 pm
by RobbinW
72 Replies
6980 Views
Last post August 30, 2015, 01:21:23 pm
by Cut4fun .
2 Replies
1180 Views
Last post December 10, 2011, 10:38:37 pm
by 660magnum
201 Replies
3797 Views
Last post October 17, 2014, 11:42:53 am
by EHP
44 Replies
1308 Views
Last post February 20, 2014, 09:06:17 pm
by aclarke
11 Replies
247 Views
Last post February 08, 2014, 11:44:49 am
by KilliansRedLeo
8 Replies
353 Views
Last post March 17, 2014, 09:07:10 am
by fordfairlane78
2 Replies
369 Views
Last post June 19, 2014, 03:32:20 pm
by farmboy
0 Replies
200 Views
Last post July 03, 2014, 12:12:12 pm
by Cut4fun .
12 Replies
337 Views
Last post January 06, 2020, 12:15:05 pm
by Cut4fun .