Originally Posted by clockguypete

Today I ran my new UMS radial 7-160 I received from Adrian at CH Ignitions. I put three tanks of fuel through it so far and am impressed. I did a little fine carb tuning and got these results. Prop: Sail - wood 28x12 2blade, Fuel: 91 non ethanol, Oil: Quick Silver Full Synthetic 2cycle mixed 20:1(6.4oz) per gal. ,Idle: 1000, Full throttle 5400. Same results with RC excel fuel pump connected or without. Cylinder temps 164 deg F. Transition was crisp and darn near blew my hat off even though I was slightly out of the main prop wash 😀 Was able to hand start this beast once I got a couple tanks through it and had the needles adjusted better. It sounded like it would idle all afternoon, and whenever I punched the throttle it roared to life. Midrange was smooth and clean too. Love it!

Do you have a link to the Rc excel fuel pump you are using? I am looking st a fuel pump for my Moki Radial and did not know they make one.

I got the pump from CH-ignitions.com but it is not listed on their web store. You can email Adrian and ask for one
Adrian@ch-ignitions.com or just call him (561) 927-6171

I have 25 of those fuel pumps coming, I am out at this time.
In couple weeks I should have them.

Hope the 260 runs better than the one that Horizon imported, that motor was junk, wonder why they only sell the glow models? hmmmm.....ask yourself that ?..

Originally Posted by reyn3545

I can see one improvement... they went to a standard sized prop shaft. I had to cut a 13mm center hole in the props for the older motor... makes the prop useless for anything else.

AMEN! Still junk!

When a manufacturer listens to it's customers and makes positive changes to improve a product line, I respect that effort very much. I have read through 7 years of a Moki engine thread, all 171 pages and over 4,000 entries. Many trials and tribulations, some success stories, and some failures. It is still an ever evolving process of product improvement today. My goal as one of several owners of these new engines is to simply share my honest results, and offer any helpful advise I can to others. So far I am very pleased with the way it runs, and feel it was a good investment. Peace.

Originally Posted by reyn3545

I can see one improvement... they went to a standard sized prop shaft. I had to cut a 13mm center hole in the props for the older motor... makes the prop useless for anything else.

A simple fix would be to glue a wooden dowel plug in the 13mm center, then just redrill the center to perhaps 10mm or whatever size you want. 3mm difference is not going to hurt the integrity of the prop hub, and will allow you to utilize your investments in those other props. The glued in dowel plug ends up acting like a shim, much like the various inserts used on electric motor props to accommodate various sized motor shafts. Hope this helps.

Originally Posted by jharkin

And I thought that the UMS was connected to/ or a derivative of Seidel? But I looked it up and Seidel seems to still be operating as as separate company....

From my memory, Seidel designed and made them, then moved production to UMS in India to get costs down, as Seidel are really a small engineering firm. then sold the rights to UMS and then started doing whatever it he does now. Still in radials. Evolution radials are made by UMS and you can still buy UMS branded engines direct from India. Apart from the gas engines, I think the glow versions have changed little since Seidel made them.

Originally Posted by Mokken

Hope the 260 runs better than the one that Horizon imported, that motor was junk, wonder why they only sell the glow models? hmmmm.....ask yourself that ?..

Adrian Is a stand up guy having done business with him and the quality work he does I am sure he would not sale anything that is remotely Junk.

Just like on my Saito 60 R3 I noticed a few minor drips of oil seeping out of the exhaust threaded connections. The photos show a quick and easy fix for this to prevent leaks. A permatex high temp gasket maker product would also work, but I found this to be less messy and cheaper. I have spent $9 on a tube of permatex and used a teaspoon full only to find the tube clogged up or dried out next time I went to use more. Also no pre cleaning of the threads is necessary, just wrap a couple turns and thread it back together!

A radial engine needs a good prime to start so there is a choke assembly included on the UMS gas engines. When installed in a plane, a servo can be operated from a switch on your transmitter. On the test stand I decided to make a simple mechanical assembly to set the choke while I rotate the prop around several revolutions to prime the engine. The following video illustrates what I came up with out of spare parts laying around the shop. I'm sure there are dozens of ways to do this, but here is what popped into my head on the spur of the moment.

Choke assembly for UMS radial on a test stand. (1 min 33 sec)

The UMS radials are all started and run at the factory prior to shipping for quality control, and come with a test report indicating your engines performance results. Max & Min RPM achieved, all individual cylinder temps @ max rpm. (multiply deg C x .039 to get deg F),
engine thrust (multiply kgs x 2.2 to get lbs).
I'm not sure how much run time they receive at the factory, but after running 5 tanks of fuel through mine in a rich condition, I pulled the spark plugs and cleaned them with a squirt of brake cleaner and light wire brushing.

Before starting my new 7/160cc radial, I went over the entire engine checking all screws for proper tightness, and just an overall visual inspection. I also found on page 12 of the manual a procedure for adjusting the valves so I proceeded to double check each cylinder for accuracy prior to attempting my first start. It is important to measure the valve lash at TDC (top dead center) and then rotate the prop two turns, measuring again and so on through 8 complete prop rotations, or 4 consecutive points of TDC. Repeat this same procedure for each cylinder. You may find a slight difference in each of those positions so be careful to make the valve adjustment on the tightest TDC position only. Setting the valves on a cam lobe with a slightly bigger tolerance may cause your adjustment or valve lash to be to tight or nonexistent on the position with the least tolerance. This will cause the valves not to close fully in that particular cycle. The setting should be .1mm or .004 in.

Quick video of how to lubricate your radial engine valve train. I have heard many recommendations for what oil to use including good gear oil, air tool oil, Marvel Mystery oil etc. UMS manual states quality gear oil, and this procedure should be done at the beginning of each flying day.

Radial engine valve train lubrication (0 min 58 sec)

Here are a couple earlier videos I made running the new engine.

Breaking in a new UMS 7cylinder 160cc radial engine (8 min 10 sec)

Second video shows a successful hand start after some initial needle adjustments. I figured out the little surging condition was due to a slightly lean condition on the low carb adjustment screw. I richened it up 1/8 turn and it smoothed right out with good transition to high throttle!

Hand starting and fine tuning a UMS 7cylinder 160cc radial engine. (2 min 30 sec)