Re: Troubleshooting a 0.061 norvel ame

Oldenginerod Sat May 02, 2020 11:15 pm

Layback, I haven't been following this thread and have only just discovered it. Also, I have no experience with Norvels at all, but having said that, I'd like to offer a theory. I hope I don't baffle you, but I'm just thinking this through as I write.

Observing the original rubbing mark you had on your backplate, I believe the mark is too close to the centre of the backplate to be the crank pin, so the only other thing it can possibly be is the big-end of the rod. If the rod was too thick, the rub mark would be far wider, actually the same width as the big-end. If the rod was bent, the rub mark would change from inside the circle of the pin to outside the circle of the pin, so the witness mark wouldn't be a circle, rather, an elliptical shape. In the same way, if the case was machined incorrectly and the crankshaft was not running at precisely 90º to the con-rod, again the witness mark would be elliptical. Because the witness (rub) mark was consistently and evenly inside the circle of the crank pin, the only thing I can conclude is that the crank pin is bent inwards towards the centre passage of the shaft.
I had that exact problem with an OS Max .15. There was no real evidence of why it was tight, but I eventually discovered it by witnessing the crown of the piston as I rotated the crankshaft. As the piston raised and lowered in the bore, there was a noticeable rotation of the piston back and forth. Close inspection revealed a bent (and cracked) crank-pin. I found a good second hand crankshaft and bingo, no more tight spots and the engine feels much better. (Haven't run it yet.)

Hope this helps.
Rod.

franzkleber Sun May 03, 2020 5:07 am

Hi everyone.
Its a long time that I do not write on the forum (especially for my laziness!)
But this time I can't provide my personal experience on norvel engines ...it may not be the solution to your problem , but I think it's worth explaining it anyway
About a year ago I purchased a brand new in box norvel 0.074 , i only run it for fun on my test bench and everything went well from the beginning , it started easily and ran very well. Very Happy

But after about 7-8 restarts (just for fun of it!) it show a strage behavior running worse and worse.
After that in the end I could only make it run for about 2-3 seconds , it started/burst immediately and then died suddendly. Sad

After about one hour of continuous adjustments I give up unhappy and just stopped playing with it. Sad

The next day I completely disassembled the engine trying to understand the origin of the problem.
At first seems all ok but what made me suspicious was the big amount of dirty gray mixed with castor oil at the end of the shaft (between the prop bush and the engine body).
Note that I always used a small electric starter to start the engine , therefore I have always applied a slight axial force to keep the starter in contact with the propeller spinner.
The dirty gray mixed with castor oil was obviously caused by the friction between the tiny split cone in contact against the engine body.
Now we must considered two things , first the split cone is made of durall (with a hardness higher than the aluminum of the engine body) and second the engine shaft seat pass thrue without any chanfer , just a plain 90° sharp end.
After having thoroughly cleaned all the engine components I simply added a 0.2-0.3 x 45 ° chamfer with a countersinking hand tool .
After that and reassembling the engine it returned to run extremely well like brand new ! Very Happy

To make the story short it happens that especially using an electric starter you push and move back the shaft , the split cone touches the body , the friction created by the axial force combined with the rotation "coins" slightly the softer aluminium engine body removing the sharp edge and forming a tiny-small-invisible burr that narrows the diameter of the shaft bore/seat.
It is a defect that is difficult to notice because this coin/burr is almost invisible and when the prop eller is moved by hand , automatically you push the shaft back slightly away from it and so it seems that everything rotates smoothly! Huh...

But as soon as the engine starts the propeller pulls the shaft back in position towards the burr and creating the friction that causes the shaft to seize and stop!
I found the exact same defects on a brand new norvel 049 AME and on an used AP061 (although this has a bronze shaft bush) , after adding a small chamfer they all work very well. Very Happy

Obviously the definitive solution its to make the same to COX TD , add a 0.2 mm thick tiny washer between the split cone and the egine body !. Very Happy

Regards Franco Colla

akjgardner Sun May 03, 2020 6:21 am

franzkleber wrote:Hi everyone.
Its a long time that I do not write on the forum (especially for my laziness!)
But this time I can't provide my personal experience on norvel engines ...it may not be the solution to your problem , but I think it's worth explaining it anyway
About a year ago I purchased a brand new in box norvel 0.074 , i only run it for fun on my test bench and everything went well from the beginning , it started easily and ran very well.
But after about 7-8 restarts (just for fun of it!) it show a strage behavior running worse and worse.
After that in the end I could only make it run for about 2-3 seconds , it started/burst immediately and then died suddendly.
After about one hour of continuous adjustments I give up unhappy and just stopped playing with it.
The next day I completely disassembled the engine trying to understand the origin of the problem.
At first seems all ok but what made me suspicious was the big amount of dirty gray mixed with castor oil at the end of the shaft (between the prop bush and the engine body).
Note that I always used a small electric starter to start the engine , therefore I have always applied a slight axial force to keep the starter in contact with the propeller spinner.
The dirty gray mixed with castor oil was obviously caused by the friction between the tiny split cone in contact against the engine body.
Now we must considered two things , first the split cone is made of durall (with a hardness higher than the aluminum of the engine body) and second the engine shaft seat pass thrue without any chanfer , just a plain 90° sharp end.
After having thoroughly cleaned all the engine components I simply added a 0.2-0.3 x 45 ° chamfer with a countersinking hand tool .
After that and reassembling the engine it returned to run extremely well like brand new !
To make the story short it happens that especially using an electric starter you push and move back the shaft , the split cone touches the body , the friction created by the axial force combined with the rotation "coins" slightly the softer aluminium engine body removing the sharp edge and forming a tiny-small-invisible burr that narrows the diameter of the shaft bore/seat.
It is a defect that is difficult to notice because this coin/burr is almost invisible and when the prop eller is moved by hand , automatically you push the shaft back slightly away from it and so it seems that everything rotates smoothly!
But as soon as the engine starts the propeller pulls the shaft back in position towards the burr and creating the friction that causes the shaft to seize and stop!
I found the exact same defects on a brand new norvel 049 AME and on an used AP061 (although this has a bronze shaft bush) , after adding a small chamfer they all work very well.
Obviously the definitive solution its to make the same to COX TD , add a 0.2 mm thick tiny washer between the split cone and the egine body !.

Regards Franco Colla

Nice bit of trouble shooting.

Surfer_kris Sun May 03, 2020 6:28 am

I just use the springs starters Norvel made for them, no issues at all.

davidll1984 Sun May 03, 2020 9:33 am

oldenginerod is right its wat y try to explain is con rod is of set not 90' no more it hapen wit dieselised cox mod somtime con rod bent som time is crank pin broke of or bent if not hardened heat treated u can try wit new crank it wil be fine if not alredy

layback209 Sun May 03, 2020 9:42 am

Interesting, I could see that as a contributer, thanks for the feedback. I don't have a picture but on the prop side of the connector rod there is a 5mm long x 0.5mm deep ware spot.

Unfortunatly i don't have any parts for this motor. No local shops carry any anymore. If I bought it new I suspect the manufacturer would of replaced it. In my experience they have been pretty good about that stuff. I had an rc car motor shear the crank pin clean off and it was replaced under warranty which i was super surprised about. Never know if you don't ask.

Surfer_kris Sun May 03, 2020 12:46 pm

franzkleber wrote:
Now we must considered two things , first the split cone is made of durall (with a hardness higher than the aluminum of the engine body) and second the engine shaft seat pass thrue without any chanfer , just a plain 90° sharp end.
After having thoroughly cleaned all the engine components I simply added a 0.2-0.3 x 45 ° chamfer with a countersinking hand tool .
After that and reassembling the engine it returned to run extremely well like brand new !

My Norvel .074 engines do not have any split cone on them, it is a regular propdriver that engages a flat section on the crank-shaft (similar to e.g. OS engines), and yes there is a hard metal trust washer between the aluminium case and the aluminium pro-driver.

The only split cones that I have seen are on the early Norvel .049-.061 engines, but they also have the hard metal washer between the crank case and the propdriver.

I guess with a second-hand engine you can get anything, but on a new engine there should indeed be a thrust washer.

**944_Jim** Sun May 03, 2020 6:01 pm

Find Scotty68. He pops up on RCG every now and then. He did have quite a Norvel stash. We traded a bunch of stuff all last summer. Good guy to trade with. NFI.

davidll1984 Mon May 04, 2020 10:29 am

wasp is same engine wit diferent part carb and crank not the same exact part cylinder piston look the same to me only norvel use cone wasp is os style propdriver norvel carb is sort of glued in place wasp is bolted both engine is .061 tink wasp can trade part wit norvel not sure 100% can be found for les $$the norvel wil cost as norvel performing litle bether both engines piston is very tight on first start use extreme care use not over 5% sintec oil rest is castor oil compres bad sintec dont burn residu wil build inside engine to mutch result hidro lock piston sort of hope u get it run good after u find part for .061 norvel is a blast of pure power compare same size engine

Surfer_kris Mon May 04, 2020 12:14 pm

I'm struggling to follow/understand that text in terms of language, is that google translate at its best?

Only the very early Norvel engines used the split cone type and glued in carbs. It was then changed to the OS/Enya style on the pro-driver and a bolt through attachment of the carb. This was all in the pre-revlite era, and that is what the Ap wasp was trying to mimic, with a certain hit and miss approach...

On a side note, the AP wasp is prone to peeling the nickel layer on the cylinder, same plague as the OS engines...

Below is a little time-line, going from left to right. The first one is the "Steels" engine with the split cone style prop-driver, while the last engine to the right is the rev-lite version. Notably they all have the steel washer between the prop-driver and crank-case.

Troubleshooting a 0.061 norvel ame - Page 2 Img_0712

layback209 Sat Jul 18, 2020 10:48 pm

hey everyone really appreciate the feedback and suggestions. General wisdom gained from tinkering.

Here is a quick update video I put together. Unfortunately I could not get this thing to run right. It has a major flaw of somekind. Basically the connector rod is rubbing on the crank. About a 1mm deep Grove has been worn into it. Doesnt look like the rod was bent at all. I'm speculating a bit of missalignment i think a bent crank pin as suggested above really fits well. Thanks again for all the advice. I actually purchased a couple of motors off Scott. Looking forward to more builds.

Update video
https://youtu.be/2IxUH6X00Ts

I plan to upload more stuff like this when time allows feel free to subscribe if you find it interesting.

Take care, derek

sharpy01 Wed Nov 24, 2021 12:06 pm

The history of these motors is always interesting.

Sponsored content

Troubleshooting a 0.061 norvel ame