eskiserkan

Anyone have any idea about how to set the timing on these engines ? I have 7-35 on my PT17 and i think its time to replace bearing... I searched all the web but cannot find good information. I dont want to open it without being sure how to put all the bits back correctly. There are some pictures in this thread but i couldnt completely understand. Any help will be highly appreciated.

cymaz

I've had a look, boy there is nothing!
All I can suggest is with no.1 cylinder at TDC and both valves shut, open the back take good clear close up photos. And lots of witness marks on all the main components with a scribe then take photos of that. Have 7 containers all numbered and dismantle one cylinder at a time, putting all parts in the relevant pots. Take photos as you go if you are not sure how something was positioned or angled.
if you haven't already got one, buy a magnetic tray or two....wonderful things for keeping nuts and bolts rolling off onto the floor.

Linkan2

Hello
you should have the cylinder 1 in the the top but the valves to be right at the gas exchange.

they new layers which to choose c3
look at the description I send it will be good.
they would be good if you have access to a Hydraulic press.
Lars

slskn

My Feedback: (4)

Hello Maxam, for the sake of time could you please tell me what thread you talked about on the proper setting the valves as you descrbe it, would greatly appreciate it thanks.

eskiserkan

Thanks for the information on timing setup. I mixed cool power 15% fuel with 99.9% pure methanol 50:50 for this engine. Engine run approx. two galloons but the inside is all rusted. Its the first time such thing happpens to the engines I have in my collection. I have all O.S. - Saito radials, twins, single cylinder etc. non of them prone to rust like that 7-35.

Linkan2

hi eskiserkan
I have flown 7-35 in about 12 hours did not have any problems with rust.
I press in ATF oil in the engine when coming home from the field.
during the winter, I have thicker oil, type Fuchs aero save.
always running out of fuel the engine so that nothing is left.
Lars

Maxam

My Feedback: (62)

Post # 36 is where I discuss valve adjustment. I have also discussed corrosion prevention early in the thread. I use airtool oil and allow to drain and repeat. then I run overnight with an aquarium airpump air into the engine via a lower cam follower guide and eithe venting out the carb or a removed upper cam follower. Works very well. The amount of condensate drained has been as much as a thimbleful from my 9-90! Gotta dry that water out. -Tom

slskn

My Feedback: (4)

thank you very much Tom, I am doing as you suggested and so far all winter my bearings feel very smooth, I religously turn over both of my engines at least 2 to 3 times per week just to circulate the oil on the bearings. thank you for the thread number as I am getting ready to adjust my valves for this spring, btw great job on your last project.

eskiserkan

Today I removed the back plate to have a short look... Do you have any idea about what might be happen ? For me the ring that hold the rods broken and turned my engine into a display object

slskn

My Feedback: (4)

[QUOTE=slskn;12192731]thank you very much Tom, I am doing as you suggested and so far all winter my bearings feel very smooth, I religously turn over both of my engines at least 2 to 3 times per week just to circulate the oil on the bearings. thank you for the thread number as I am getting ready to adjust my valves for this spring, btw great job on your last project.[/QUOTE got the valves done, found 3 valves on my 7-77 alittle tight, and on my 9-99, 4 were tight made adjustments hope they are ready to run.

Straightleg

Hard to say, but I can see some miscolour on the bolts for needle bearings. This indicates break down of the needle bearings, which may have caused a chain reaction.

Pete S-RCU

Hi Tom,

I have a question about what prop to use for flying on my Evo7260 radial.
I'm using a 32x12 for breakin, watching the rpm closely.
This prop is too small, I can exceed 5k at about half throttle.
The engine is going in a BUSA Stearman, weighs about 50 lbs.
What do you suggest for a flying prop?

Fulcrum2111

Hello does anyone know if the 7 35cc fits inside the seagull monocoupe 110 special? I know for sure that the saito fg33 fits fine but as the cylinder and rocker arms on the evolution engine are near to the front propeller hub than in the saito engines I am not sure as the cowl tapers in the front.

j lauria

Maxam,

Great looking model. I would like to build one. Are kits available?

John

Maxam

My Feedback: (62)

Phew! You guys are keeping me busy!
1. Eskierkan- That is quite a catastrophic failure. I can only say, send it in for a rebuild. (warranty?) I now run all my radials on at least 9% oil.
2. J. Lauria- The kit was an old S2 models from Wisconsin. Not a good kit. Much design I changed and replaced 1/2 the wood. Would not stop an experienced builder. Find a 1/4 scale House of balsa kit of the Air Camper.
3. Slskn- remember much better to be a bit loose than too tight which burns valves.
4. pete- Yep way too small. Minimum would be a 32x18 but Steve from Justprops.com had a specific recommendation.

Pete S-RCU

OK, if I use a 12x12 say on a smaller engine that I'm used too, I can pretty much know the speed of the plane.
Theoretically, one revolution is 12" of travel.
The big props seem different because of the greater travel of the larger blades.
Does the pitch still relate to speed like the smaller props, or do I need to think different with bigger props?

And another question, you say adjust the valves with a cold engine, how cold?
In other words, now the outdoor temp is in the 50's, should I bring the engine inside to say a 70 degree environment, as this would make a difference in the final adjustment?

Thanks,



4. pete- Yep way too small. Minimum would be a 32x18 but Steve from Justprops.com had a specific recommendation.[/QUOTE]

Maxam

My Feedback: (62)

Pete, pitch is pitch in terms of # regardless of diameter. The bigger the prop the lower the RPM due to tip speed which must never go supersonic or else the efficiency drops. Also as said before the pitch to diameter ratio should be at .5 or higher. There is slippage so you do not really know the planes speed unless it is aerodynamically clean. My completed Pietenpol is a slow flier but I am using an 18x12 prop which will be efficient and will fly the plane at a scale speed and a nice near scale low RPM. The real Pietenpol uses a 72x48 to a 76x51. The RPM's are under 2000 but the tip speed is high due to the greater distance travelled per rotation. Divide those # by 4 and you will see my prop is quite scale!

Fulcrum2111

Hello I got an evolution 7 35cc engine to fit a high wing aircraft with a wingspan of 80'' and a weight of 14lb and would like to know if should I:
1) keep it stock and use a large battery externally to start the engine (lower weight)
2)convert to cdi and run methanol (less fuel consumption, more power)
3)convert to gas (cheaper, no rust?)
I know there are several conversion kits for this engine to run gas or cdi ignition. I want to hand start the engine, is it possible with a external battery or do I need a spark plug? what are the advantages of eac h alternative?are the cdi conversions actually reliable? your comments and experiences are appreciated. I also want to know if converted to cdi what economy in fuel would I have and if I would get less oil residue on the aircraft.
The most important aspects for me are the no oily mess and the easy hand starting what should I do?

BobH

My Feedback: (2)

Pretty much the way to have no oil residue is to go with gas. Be advised that its an expensive option. You'll need an ignition module, pick up sensor and a different carb.
The standard engine uses a low oil content when fully broken in. Still there will be oil residue.
As Far as hand starting, once it's all broken in you can hand start the engine.

slskn

My Feedback: (4)

thanks Maxam, got the valves ajusted on my 7-77 found 3 tight valves, not real tight but just enough that the gauge would barely fit, so loosened them up a bit, found 3 on my 9 cyl. a little tight again not too tight, did not ajust since new, flew all summer, finally when I took the cowl off the Corsair, foung one plug wire off # 2 cyl. not sure how long it was off but seemed to fly well all summer, hopefully will have a little more power and run good this spring. got a new prop for my Stearman from bobs hobby shop from Toledo show a classic Falcon, makes the Stearman look even better!

Ozflyboi

Hi All,

I am new to this thread and I am an owner of Evolution 7-35 glow and 7-160 gas motors.

I have a question, with the 7-35 glow radial I have run into the problem of the push-rods dislodging in flight. I have noticed Evolution supply replacement push-rods with new style pins (ball at one end). I recall this being mentioned in an earlier post however would like to recap on this. Is the new version push-rod pins better?

I also had to replace one of the rockers and the replacement part has a different style grub screw. The grubs adjustments screws that were supplied with the motor from new are Cup End style where as the replacement appears to be a Dog Point end. Again was this done to improve engine performance and reduce the likelihood for push-rods to become dislodged/fall out?

Any help would be appreciated.

Thanks,
Steve

slskn

My Feedback: (4)

Not sure why the rods are falling out unless the adjustment is too loose, I had at one point some push rods on my 9 cyl. Fall out, but think I may have had some defective end caps because they were chipped some pics are in some very early threads, you may find, but replaced them and have not had a problem since.

Ozflyboi

Thanks for the suggestions however I have checked all the pushrods and all fine no chips on end caps.

I have located some steel grub screws with Dog Point End on ebay so hopefully will arrive soon so I can replace all the set screws and re-adjust the valve clearances.

I will let you know I go.

I am also considering converting the 7-35 to gas but will see how the motor runs once the above has been done.

So far I was unhappy with the power the motor was putting out (17x10 beila prop). Hopefully this can improve with proper valve adjustment.

Maxam

My Feedback: (62)

SLSKN; That Stearman appears to be very well built! Real treat for the eyes.
Steve, that prop is too large. Biela's are in my opinion overly thick and eat power. I would use a XOAR 17x8 prop. I bought a Moki 215 and got a Biela 32x18 prop and it loaded the engine way down compared to other brands of props of the same size. -Tom

slskn

My Feedback: (4)

Maxam, this is a 7-77, the prop I had on it was a xoar 24×10, which worked perfect, this falcon is the same size and pitch, the pic just makes it look bigger than it shows, I will check the RPM before flight and see if it has the same rpms, but hopefully it will have the same performance.