How BAD is this?

[Lejon]

I purchased a TRM engine from Rick’s who ordered it from MinAir last year and did not get it installed until this June in a 1005 XCell that is about 5 years old. I broke it in as per the instructions (used Lawnboy ash less for 2 gallons) and ran it for short periods increasing load as I went.

All was well, I switched to synthetic oil and at the time, August of this year, I was running very slow head around 1300 and met some folks at the field and increased it to 1550, there was a lot of vibration, wasn't there earlier in the day, and so we set it to a slower head speed and all seemed well.

Several flights later the muffler came loose. It is a Bison aluminum muffler from many years ago. I tightened it up and several more times it backed out the bolts.

I started to get irregular runs where the engine would increase rpm once I came down to a hover. I found the lower side rail was broken and am assuming that it was the source of noise. I replaced it and all seemed well until I noticed the irregular running and even when I started it it would change rpms as happens when a car runs rough and won't idle smooth.

I took it apart and found that the gasket between the muffler and the exhaust port had vibrated until the metal inner layer was showing and had made an imprint on the flat surface of the exhaust port. I replaced it and re-installed the muffler. Went out to try it and within a minute while in a hover the muffler came loose.

My questions

I noticed that the top bolt broke off in the exhaust port... New head?

I noticed that the intake side is nice and shiny and looks like new while the exhaust side has what looks like scratches ( I am guessing that pieces of the gasket got inside and scratched that side of the piston) New Piston?

Finally where can I get replacement parts? Unless things have changed Rick’s had the engine on B/O for several months? I tried to Google TRM and only got references to the forums and Min Air.


Thanks

Lejon

[Rodney]

I am not sure but was told the TRM can only be gotten thru M/A dealers. John Garst will be the man to answer your question. Give him a day or just send him a pm or email thru the freak.

[ddavison]

Contact Toxic Al (TRM) at (toxic.al@toxicmarine.com) If you exhaust side of piston is scratched bad, sounds like too lean and possible a stuck ring. What are you needle settings, and what type of oil and fuel/oil mix ratio ?

[Lejon]

First thanks for the replies Rodney and Dave.

I am using Klotz technoplate @ approx 51.2 to 1 and I am using Coleman camping fuel.

All indications are that it is not too lean my setting are approx (after tweaking) 1 & 3/8 low and 1.5 high end.

I was able to use an easy out and drill to get the bolt out and after checking the exhaust side of the piston it seems that it is scratched but not severely and it does not appear to be any loss of compression which would indicate that the ring is still good.

I have gone back to the original muffler (can) and will test in tomorrow to see if the vibration has gone away. After that I will then contact toxic Al and see about parts and what is matched and as such needs to be ordered together.


I am hoping that it will run like before now that there are no loose parts.

BTW what plug is best at one time I was told the NGK BMR 7 A?

Thanks again

Lejon
:lol:

[broncoholic7]

Hi Lejon,


I was told the NGK BMR 7 A


I think you may have been give the wrong information and that could be one of your problems.

But...

This is the plug type that is recommended is NGK CMR-7H

[rbort]

BMR7A is the older style larger cylinder plug hole that used to go on a G23. That is the right plug, but for the older G23. You can't fit that plug in the newer G231 or G260, so get the one Mike indicated as that is the right one.

Looks like maybe slightly lean on the oil mixture 50:1 and you had a bad run one day and it scored the piston some. Remember that less oil = less protection = less margin for error = more likely to damage the engine. People love to run very little oil in hopes of more power and a smoother engine, but in reality its like playing with fire, some day you are going to get burnt! Personally I would recommend you don't go below 40:1 but its only advice. Maybe before you fix this motor you can experiment with oil ratios and needle settings to get things figured out and settled in, and once you are comfortable with everything then go ahead and rebuild the motor.

Incidentally, I was looking at Al (the guy at Hanson's) warranty statement tonight and he indicates in there that the warranty will be voided if coleman fuel is used. Though I've only used 87 octane gas, I wonder why myself (I know alot of people use that) and was thinking to give him a call and get his take on that. Maybe its the low Octane causing issues for a modified motor?

-=>Raja.

[PaulH]

Raja,

It's more likely that he won't warranty engines because Coleman fuel has an inconsistent octane rating.

I spoke with Gary Travis a few months back; he told me that one batch of camper fuel can be 50 octane and the next batch will be over 100 octane. Because it is not used for cars or home heating, it is not regulated. You never know exactly what is going into your engine when using camper fuel.

It is also possible that the low octane rating causes problems when used in a modified engine. One of the modifications is to increase the compression ratio.

[Lejon]

I emailed ToxicAl and have not heard back from him (it has only been a few days but when you are anxious it seems like an eternity) so in the mean time I will contact MinAir and see what parts are available.

I am not sure I recognize the name Gary Travis but in my humble opinion :
and I don't know much about the camper fuel processes but it would seem that regulated or not, higher octane equates to more cost and so a large variation would eat into any profit they might have.

I would thionk it reasonable that unregulated product might vary say 10 maybe 20 % which would mean if it is 50 then it might range from 40 to 60.

As for warranty I do not think it is a defect in the engine.


I tried to reset the needles and now it seems like it is all going south.

I hover at 1/2 stick and with the needles at 1 & 3/8 and the midpoint at 4 & 1/2 degrees and the engine set at 0,25,35, 60 and 100 it seems to run at about 1100 rpm (just a guess) but it is very slow head speed. If I increase the throttle curve then I get it back to normal but after a pass or two it seems to increase in rpm as if it were coming up on a pipe. Also as I test for high end settings it seems good then when I back off the climb there seems to be a sharp 20 degree turn, the motor rpms seem to drop really low and then it settles into what seems to be normal.

The only difference is the muffler which is now the large black can that comes with the engines. I noticed that it is running around 195 where it used to run around 250 with the other muffler.

Although there could be leaking where/if the ring is scratched the compression from simply pulling the cord seems the same as before.

Lejon

:arggg: :?:

[Lejon]

Wouldn't you know that as soon as I posted that I had not heard from ToxicAl I go to get a number for MinAir and there is ToxicAls email.

In real time (for anyone who may have thought I was implying that ToxicAl was not replying) his response was quick. As indicated, it was just me being overly anxious.

I know patience, but it is one of those things everybody needs and no one has time for.

Lejon

:)

[Jeff Reed]

If you get advise from Gary Travis, you can be sure that he won't steer you wrong.
I only use 87 octane (lower number = faster burn rate), 100% synt. oil @ 45-50 to 1. If you want to Know if you got good comp. get a comp tester from an auto parts store and screw it into spark plug hole (3-5 cc oil first to seal ring to cylinder wall)

[bigrcr]

It sounds as if the muffler you use (or are using) was loosening. This dramatically changes the throughput of the motor and hence the needling problems. With a muffler that is loosening up, the motor will easily lean out and score on the exhaust side.

Continue to use the stock muffler as long as it does not loosen-up on you. What concerns me is that you say the motor was running rough. The only reason it should run rough is due to it being excessively rich, or of course lean (a loose muffler will do this).

If the muffler is loosening, the motor will run lean!

Camper fuel has NO OCTANE RATING...never had and never will...It is a single chemical fuel..It is NAPHTHA..period. So, its OCTANE rating cannot change!!! :arggg: :arggg: :arggg: :arggg: :arggg: :arggg: :arggg:

No "Octane" is added to camper fuel or for that matter gasoline.

Using camper fuel in a motor with high compression can cause the motor to run hotter since the fuel burns faster..Some motors (G-62 or higher compression maybe) will not like camper fuel, but the old G-23 in any of it's configurations (G-23, G-230, G-26, G-231) like it just fine. If you live where it is 100 degree plus..OK, using camper fuel may not be best.

Using 50:1 ratio is the best thing you can do...The manufacturers require it (look at ANY yard implement manual), it provides the best protection and does not lead to problems contributed to too much oil.

Lean problems are caused by lean fuel mixture, not by lean oil mixture.

If your ring is stuck, the motor will run like crap and have little compression or will be gouging up the cylinder. Look and see if the ring "floats" up and down as you look into the exhaust port while rotating the crank back and forth.

Oh yeah, Octane rating is just that...It is a "test" to see if the fuel creates a knock at a given timing setting in a stock test engine and then the fuel is rated against that "knock" standard. The rating is an equivalency of fuel that Octane was added to years and years ago. The fuel manufacturers don't add it anymore.

Later,

[Billme]

manoman....