Blair K.

Hector we are led to believe that Saito has redesigned their inlet manifolds. I have spent considerable time on Saito engines and ive not seen different cylinder temps like john is describing without lack of fire or a poorly designed inlet manifold.

Both bottom cylinders being a couple of degrees cooler I can understand but 1&2 are hot and number 3 cold to touch doesnt suggest to me that the lower cylinders are rich.

I personally make inlet manifolds for FG33's and a engine running a stone cold number 2 cylinder on a 2 tank old engine will be within 3-6 degrees across 3 cylinders after a 20 minute manifold install.

What id give to see the inside of a the manifold on new FG60R3! Surely number 3 cylinder isn't the old number 2 ��

Cheers Blair

hpergm

Blair - I hear you.
You obviously have a lot more experience on these motors than many people, including myself.

But I also had the misfiring cylinder problem in a new glow twin (FA182TD) - which even has a twin carb (but no ignition). After a LOT of running-in and careful heat-cycling of the cylinders via continuous manual adjusting of left/right mixtures, the engine developed a well-balanced cycle and works like a little sewing machine on every throttle setting. This pointed out to me the issue of uneven ring seating in the multicylinder Saitos (one cylinder will seat-in first).

So, based on this experience I have decided to give the FG-60 the benefit of the doubt and try to balance cylinder compression within an extended break-in; after 7x 500cc tanks (3,5lt of running-in), the engine is now much better.

Much better means No. 3 firing 99-100% of the time in WOT (now gets as hot as No.1 or No.2), more than 70% of the time about half throttle and more sporadic in idle since the low needle is still rich (7.5 turns out). Max sustained rpm achieved to date is 5,4k with the High needle 4 turns out (APC 22x10). Oil is at 15:1 Klotz Regular Techniplate.

By the way, No.3 is the bottom left cylinder from the pilot's view - as per Saito instructions convention.

I will now take the engine off the stand for a good clean-up, checking and adjustment of the valve trains and checking-out the spark plugs. One thing to mention here is that No.3 has a Saito SP-2 plug (I broke the insulation of the original Chinese one upon removal ) while the others still have the RCEXl ones. As suggested in this thread, I may now actually try to swap these and check differences in behavior. The difference in the plug gaps is very noticeable between the 2 brands.

Trying to lean the engine more has indicated some bogging down, so I am now scared of going further without close temperature control of individual cylinders (in case No.1 seizes).

So, I have ordered a temperature data logger based on contact K-Type thermocouples (IRs temp guns are not accurate) and will proceed to lean the engine carefully while trying to heat-balance the cylinders out - check this out: http://www.extech.com/instruments/pr...=64&prodid=626 . Perfect fit for our purpose and not that expensive!

Heat-balancing will be via changes of engine orientation to the vertical via rolling the test stand left or right: I found this works, you can richen a cylinder by turning it towards the ground at idle - crude but effective.

I will consider the engine broken-in if:
1. It holds Max RPM (expect 6,400-6,500 with the 22x10) with even cylinder temps
2. Cylinder temp differences of more than 5% do not appear throughout the top 80% of the throttle range.
3. Changes in engine orientation of about 30-45 degrees to the vertical do not put out a cylinder at idle (I will accept some leaning/richening behavior).

I may take a video of the whole thing and post it when the time comes.

In the meantime, if someone posts a pic of the inlet for us to check what design differences were made by Saito, this would be great. I was reluctant to do this in a new engine - sorry!

Blair K.

.

In the meantime, if someone posts a pic of the inlet for us to check what design differences were made by Saito, this would be great. I was reluctant to do this in a new engine - sorry![/QUOTE]

Hi mate, I totally understand not wanting to crack it open.

None of us have all the answers but the great thing is we can learn off this forum, just now I just learned from you turning my engine stand, never thought of doing it !!!

Some interesting info, the 5 cylinder Saito FA 325R5 has a rotating impellar in the inlet to keep mixtures consistent across all cylinders, it also has bronze bushes in both little end and big bearings and its a nitro motor.
How could they get FG 33 & 84 so wrong???

Cheers Blair

slither

Just got mine! What a sweet piece of aviation machinery! Doesn't feel as heavy as I expected. Full up, supposedly 4.7lbs.

marksp

My Feedback: (9)

a gas version of the 5 cylinder radial, done right, would would sell well. Very well.

Blair K.

They can be converted, higher compression, ignition and a carby swap is all that stands in your way.

slither

Yes, but aren't there valve seat and other issues with the higher temps in the gas version? Seems like I have read something about the early gas versions having issues like that...

Blair K.

Hi Slither, I think the issues are bronze bushings which it has, ive had FG radial cylinders in my hand before and I had a good look at the valve seats and I could see no difference.

They run less compression on FG engines than Glow engines which can be achieved, I know Adrian @CH ignitions does a kit to set them up for gas.

Did you read through info I posted for your exhaust??

Cheers Blair

slither

A bad connection on the plug cap could cause misfiring, and Blair is correct on the combustion chamber dynamics... it changes under pressure.



I did... interesting approach on bending the tubing. Is this too tight to use a tubing bender? You mention the copper fatiguing... did you use soft copper tubing? What diameter tubes did you use when you did the ring?

Blair K.

Hi Slither, the problem with copper soft or hard is the heat cycles in use change its temper and sooner later that crack monster will come visit! 3 four stroke exhausts and everyone of them has cracked even if its just an elbow.

My approach to bending, Saito use 9 mm tube and I need a 7.9mm rad, never gonna happen with 0.35 mm walled tube.

My exhaust ring tube is 16.7 diameter 0.35 wall. Anyone looking to use brass on their gas engine exhaust might find this helpful, dont heat wrap a brass exhaust as it will suffer total failure, i heat wrapped one only header on a fg 33 and that one header cracked in so many places it was amazing, dont know why it just dont like the heat.

Cheers Blair

TomH

My Feedback: (4)

BK, my motor is in, just got to go pick it up, looks like it will be next Monday, or Tuesday before I can, so where do you stand on the intake mod. First thing I will do is take the back off and send you pics. Pm me with your email. Would be interested in your intake and carb. Mods
t

hpergm

Gentlemen, I would like your opinions on something.

After 3.5lt and about 3-4hrs of running-in, I took out the plugs for a clean-up.
Nos. 2 & 3 were very oily but the No.1 top cylinder was really black and dry. I then took a look at the pistons through the plug hole.
Nos.2 & 3 were clean aluminum color but No.1 was pitch black with visible thick black deposits - I became very worried about this difference.
I decided to take No.1 cylinder off. What I found is in the pics.

Anyhow, I simply used some solvent to clean everything (oily soot went away easily) and then re-assembled the lot.
No visible wear was found (even on the ring), only some difference in smothness in the lower sides of the piston skirt.
BTW, the bronze bush on the master conrod is indeed there. The small ends are also bronze bushed.

I am using Techniplate Regular (I have had it for a long time) @ 15:1 and the oily mess is huge with that one. I plan to switch to Castrol Power 1 (ex-TTS grade).
Any experience with both these oils?
What is everyone using and did you get black mess during running-in?
What about soot deposits in No.1 Vs Nos. 2 & 3??

Thanks,
Hector.

slither

These deposits are fairly normal under rich operating conditions. I would guess that a lot of it would be blown out once the break-in process is complete and the motor is running with a normal fuel-air mixture.

I had thought of rotating the engine during break-in in order to change which cylinder was at the top, and thus even things out during the process. I think rotating it will help here,as well...

Blair K.

Hi Hector, my experience with the Klotz oil was the same, rapid carbon deposit build up on pistons, valves and plugs, I went and bought Cool Power Blue and the problem stopped imediately. That Klotz oil its fine on 2 stroke but on 4 stroke radial I would not use it.

That oil cost me $40 in spark plugs, Im lost as to why the supplier here was pushing it, Cool Power Blue burns so much cleaner, trust me you'll see.

Cheers Blair

hpergm

Yes, I am too "rotating" the engine - just by leaning the test stand 30-40 degrees to left and right (see previous posts). This works.
Of course, this occurs naturally in flight, this is why Saito says "go and fly".

Thanks Blair. I have trouble obtaining Cool Power Blue over here.
I will try the Castrol and hope for the best.

johnhi

Hi Hector and Blair, thanks for the very helpfull input, I am much re-assured by your experiences, I think rotating the engine during break in in a good idea and what i wil do from now on. The oil I use is Castrol Power 1 Racing 2T Fully Synthetic 2 Stroke Motorcycle Oil 1 Litre 1L

Blair K.

Hi john, keep an eye on your plugs as the oil is cheaper than new plugs, those 1/4-32 plugs foul up easily and my experience is they dont aways let you clean them out properly.
@$20 each for genuine Saito plugs its worth making sure your oil is four stroke gas compatible as some are just bad news.

cheers Blair

hpergm

John, great; the exact same grade I will use (the gold bottle innit?). So how's your experience with this oil? What ratio are you running?

Blair - why Saito plugs? The FG-60 came with RCExl plugs which many say are better than the Saito and 50% less expensive. I happened to inadvertedly break one of the Chinese ones upon first installation (my tube wrench was misaligned and the insulation snapped like a carrot!) and had to resort to a Saito SP-2 I had in hand.

One of the things that surprised me was the difference in gap between the chinese "factory" plugs and the SP-2s (SP-2 is at the right of the pic). I think Saito realised that increasing the gap would help in avoid fouling. Also, the Saito plug has a machined tip versus a bend tip of the chinese plugs. Guess what happened when I tried to match its gap (scratch 20Eur ).

Finally, coming to think of it, the uneven cylinder temps may also be due to misfiring as you suggested in previous posts. Either the small plug gap of No.3 or the different plug body of the SP-2 may be the cuplrit(s). The body makes a difference, as the plug cap features a locking spring which goes into the groove of the hex (which is at a different distance to the top of the plug).

I will put the SP-2 in No.1( top) and see if there's a difference in operation.
A triad of RCExl 1/4-32s has also been duly ordered to replace all run-in plugs. Cost me $11 a piece.

Blair K.

Hey mate , I have not seen this before, Saito using none Saito plugs.

My experience is that cheaper none genuine plugs have a lower groove in the plug and the spring clip just doesn't hold as well.

The genuine Saito plugs definitely dont allow the lead to come off, i wonder if that may be the reason people still talking about cold cylinders.

I assumed a new Saito would have genuine plugs, I believe the Saito plugs look better made than the Chinese ones but my experiences say they work well.

Cheers Blair

marksp

My Feedback: (9)

Also amazed to hear new Saito's fitted with RCEXCL plugs. Aligns with Saito switch to RCEXCL ignitions on the gas burners.

FWIW, I'm running Redline synthetic, but with Ray English & Blair both running "Cool Power" I'm likely to switch. Wish I hadn't bought a full gallon!

Cheers

hpergm

Seems like the plug cap on this RCExl triple ingition is made just for the Chinese variety. No problem with positive locking.
It could be possible that the problem is more with the SP-2 which has a different groove geometry..
I will double check and let you know (before my wife divorces me for spending time replying in RCU on Xmas day).

slither

I will check my plugs...

captinjohn

Anyone with the Saito engines tried Red-line 2 cycle oil? Or Stihl supreme 2 cycle oil?

marksp

My Feedback: (9)

Yes, I've been running Redline Synthetic Racing 2T. Plugs look fine so far and runs well on 15:1.

Cheers

johnhi

I can't beleve I've spent all this money on a SAITO engine and they can't even supply their own brand spark plugs, I checked the price in the UK for SAITO plugs and they are £20.00UK pounds each about $30.00USD. Not good really.

I have a good mind to contact SAITO and ask why?