Hi Troy,

I was just wondering what header you use on your 170's? On mine I have an Asano which has seem some use, hence has some carbon build up. I was only getting 8100 on a 17X12, so I cleaned out the header as best I could then tried again. Still same rpm. Tried open exhaust and it immediately jumped to 8500/8600. I should also say that running it with the pipe on or off made no difference to the rpm. The header was cleaned out pretty well and there does not seem much restriction when you blow through it but obviously it is restricting the engine by 500 rpm or so. My question is, is the Asano header too small a bore for the 170? I know other headers such as the Hatori rigid ones have a larger ID so should have less restriction. I've ordered an 822 as a replacement.

Thanks,

Angus

Angus,

I have used moth the NMP Heade from Central Hobbies and the Hatori rigid headers. They perform the same. The Hatori is a slightly heavier. The NMP header needs a slightly larger clearance to the fuse or Belly pan side.

On my Astral XXc's I have the Hatori. However on the Adventure Bipe I was able to fit the NMP header in it. I prefer the NMP header as it is easier to setup and tighten. I have run hundreds and hundreds on flights on the NMP with very little problem. The Hatori has not given quite as good of service but it has been acceptable. One of my Astrals has about 400 flights on it and I had a header replaced at about 300-350. This was not premature in my mind. However I have the NMP header that have been around for years and never a hiccup.

I have never run the Asano Headers but I know several folks that like them. I think you will get a performance increase going to the Hatori or the NMP.

500rpm in my mind is a little much, but back when I did some extensive testing I found 300rpm with the YS 160DZ switching from the OLD NMP or the CD headers to the New style NMP DZ headers. The 170 could give a similar change. To be honest I have been running 170's for about 2.5 years now and never ran one of the smaller diameter headers on it.

Troy Newman
Team YS

Troy,

Angus might have a point.

Using an internal vernier, I have measured the ID of the Hatori and Asano manifolds (both new) at 9.5 mms and 8.0 mms respectively. This means that even as new, the Asano has only 71% of the cross sectional area (CSA) of the Hatori.

However, as you infer, many top F3A pilots (including Naruke San http://www.excite.co.jp/world/englis...=JAEN&wb_dis=2) are using the Asano manifold. I would not expect them to be doing so if it caused a significant reduction in power – at least when new.

I would however expect the Asano to be considerably more prone to the effects of carbon build up than the Hatori. A 1 mm build up of carbon on the walls of each manifold would reduce the diameters of the Hatori and Asano manifolds to 7.5 mms and 6 mms respectively. At this point, the Hatori would have 62% of its original CSA compared to 56 % for the Asano. Perhaps more significantly, with this amount of carbon build up, the Asano would have 64% of the CSA of the Hatori compared to its original 71%. In a nutshell, the smaller the diameter of the manifold, the faster the effects of carbon build up will be seen.

Also, for what its worth, I have had limited success with cleaning hard carbon from the internal walls of a manifold. The sections of the pipe near the inlet and the outlet of the manifold are relatively straightforward, but the area around the inside of the bend - where the build up is likely to be at its worst - is more difficult to get at, even with chemicals and pipe cleaners. Unfortunately, the pressure that can be generated by blowing through the manifold is insufficient to give a reliable feel for the amount of restriction unless the blockage is severe.

On a separate topic, I have now read several posts and have also picked up other independent reports, where users of early production YS 170’s are experiencing problems. Typical of the issues reported are difficulty with maintaining a steady idle and instability at higher revs. I appreciate that the problems being reported may be utterly unrepresentative but I do find it slightly worrying that the problems are being reported by experienced and trustworthy users who have had many hours of trouble free running with 140 and 160 Dingos. I hope it is not the beginning of a trend!?

Regards

Bob

Thanks for the input Troy.

Bob,

I was thinking exactly the same about the CSA + trying to clean the inside is well nigh impossible. Someone told me to boil in it water with a dishwasher tab. Had nothing to loose so I boiled away for 20mins but made little difference.

I'll have a look at the NMP manifold as well.

Thanks.

Bob,

I have not experienced any issues with the 170 vs 160. I have been running test engines for over 2.5years now and it seems to my experience that they are working the same. The engines are running almost identical to my 160's about 200rpm difference at the very top end and the throttle response down low is a bit better with the 170.

I'm not a paid employee of YS or YS parts and Service so...I can just relay my experience with the prototype engines. I know there were some changes between my engines and the production engines. I have a not yet had an engine that was production with all the changes in it. I think I have all the changes just they are all not in one engine. The case was beefed up a little this would not affect performance. The crank was changed slightly to increase lubrication to the cam area. I have one engine with this new crank and it is working well I don't see a difference in performance. A change was made to connecting rod to make it more robust and provide better lunbrication channels both at the top on the wrist pin and down below on the crank pin. Again not performance related but is relalted to longevity. The case was then changed internally to accomodate this new connecting rod configuration.

There were some minor changes to the pump and I have one engine with the newer pump on it. Performance was the same as the 160pump on that same engine. Again this was a change to make the pump more robust and better longevity. The pump still works the same and has similar style of parts...its just a little different. The 170 or 160 pump work on the same engine and perform the same. For that matter the 140 pumps worked on the 160's too. I would not be surprised if the 160 pump I used was ona 140 at one time.

I just don't see much in the way of difference that could affect idle or reliability.

When the production engines come into the USA I will be going through a comparison of the 160DZ to the 170's The parts changes were to make the engine stronger mechanically not change the way it works.


Troy Newman
Team YS

Troy,

Comforting to hear.

I respect your experience and judgement.

Bob

Angus,

It might be worth trying what I use when ever I have to clean up engines.
A few years ago I used to do a lot of trading on Ebay, before evey one got in on the act, selling s/hand engines, and the best cleaner of all was automotive coolant, glycol, I think thats how you spell it.
I use the concentrat coolant, the coolant you have to add water to when you add it to your radiator, not the stuff that you pour straight in, the most common here in Australia is the green stuff.
You will also need an old electric crock pot, the one that you use to make stews in and has the ceramic / stoneware pot in it, and once you have used it, do not use it again for food processing.
Fill the crock pot with coolant, place the header in it, and switch on and walk away. Leave the crock pot setting on high as you won't boil the coolant.
The next day remove the header and let it cool, but use a pair of tongs or plyers or something as the part will be very hot.
Once cool enough to handle inspect the header, if not clean enough put it back and give it another day, the longest I ever had to cook a part was 3 days.
When clean, just rinse the part under running water, or just let it drain dry.
Coolant won't harm Alloys, brass, copper , steel or rubber, as well as bieng an excellent cleaner it's also a rust inhibitor, it won't harm the inside of your car engine, so how can it harm a model engine.
The only down side is that its fairly expensive stuff and it does deteriate with use, the more you use it the lesser cleaning job it does, and make sure you do it in a well ventilated space. IF YOU WANT A DIVORCE DO IT IN THE KITCHEN. but the bottom line is, it does work.

Will

TEAM XMAN

Hi XMANS

Do you have any experience from cleaning carbonized head assemblys using this coolant cooking method ?
I have a YS 140L head (actually from a 140DZ) that is totally messed up with carbon after using a bad batch of fuel.

Mechanical cleaning is risky, but maybe "cooking" the valves and the head in coolant will work ?

Regards
Oistein, Norway

Hi Oistein,

No I havn't actually done what you want to do but I have used it for just about eveything else, If I had a heavly carbonised head I
would fire up the crock pot and do it, so if any one out there want's to send me one I will cook it for them and post the results.

Actually Iv'e cleaned that many engines Iv'e forgotten just what I have done, but no I have not done a YS head thats heavily carbonised.
But I do know that between the crock pot and my glass bead blaster, there has never been a dirty engine I couldn't clean.

It also works extremly well on old engines total siezed up on caster and engines left out doors, I wish I had some before and after photos of some of the engines I have restored in the past.

Will

TEAM XMAN