efish

My Feedback: (5)

Hi, I have a Chinese made 50cc engine based around the DL50. I notice that it has a separate oil seal unit on the crankshaft between the bearings, while my DL50 doesn't.

Would it be a good idea to remove the oil seal (less friction?) and just use a quality front rubber sealed bearing (perhaps with the rear seal removed)? The stock front bearing does already have a rubber seal so I'm not quite certain what the separate oil seal is intended to do.

Thanks!

spaceworm

Removing it might void the warranty? I doubt that the added friction from the seal is significant in a 50cc engine. Good luck.

Regards, Richard

rcdude7

My Feedback: (264)

That seal is there to keep the crankcase airtight, very important on a two-stroke engine, the rubber seal on the bearing alone will not do it.

Tired Old Man

My Feedback: (1)

Loose case, poor pumping action.

efish

My Feedback: (5)

OK guys, thanks. Guess I'll leave it in place then.

Was just wondering beacuse I haven't seen one in a nitro engine and there are quite a few gas engines that do without one as well (including the DLEs).

w8ye

My Feedback: (16)

The DL-50 and DLE-55 have Ultra Seal bearings 6002 (DU) and 6003 (DU)

efish

My Feedback: (5)

Thanks W8ye! Do I understand you to mean that the Ultra Seal bearings provide a better seal as opposed to normal rubber sealed bearings?

If so, does that mean that if I can find Ultra Seal bearings of the correct size, then I could happily omit the oil seal?

After further thought, I'm not sure if its going to be wirth the bother since if I were honest, the engine has been running really well! Just took it apart to see how things looked internally; curiosity and an urge to make things better prompted this thread. On the other hand, if it ain't broke....

Thanks.

BadAzzMaxx

Using a separate is the best way to seal the crank case, Zenoah has been doing it for years and Fox also, Just do a search on how many China made engines with sealed bearing have leak problems and the bearings have to be replaced.

I would like to know the name of the engine, Seems one China engine company is ahead of the rest.

Milton

efish

My Feedback: (5)

Hi Milton, guess you have a point - I have a G-62 that just keeps ticking away and I've never even thought to open it up to take a look!

Chinese engines are a different matter for me - their low prices just means that I can afford to test a few and try to understand and sometimes improve on what's going on. I think they're great to tinker with and very affordable for learning purposes.

The engine in question is a CRRC Pro GP50R. It's a lot like a DL50 - same piston, jug, crankshaft etc but with a much nicer machined crankcase with different bearings and a separate oil seal. I actually found that while power output was very similar, the GP50R seemed (to me) to have a little less vibration. My DL50 starts easily and runs good as well, but shakes a little too much for my liking.

Mind you, my CRRC engine came with a sensor that had to be reworked (it was too recessed in its housing to pick up the magnet) and re-timed (advanced the timing a little) to get it to work properly. Only took a few minutes, but it was a little worrying when it wouldn't pop out of the box.

Funny thing - the original GP26 with a cloned Zenoah head also had a separate seal, but the latest versions have done away with this and gone with a DL like arrangement. Haven't tried it yet, but I just might soon since the the original GP26R has worked very well for me indeed.

w8ye

My Feedback: (16)

The (DU) Ultra Seal bearings have more drag than a (2RS) rubber seal bearing so you wouldn't save anything.

efish

My Feedback: (5)

Thanks W8ye, I take your point.

Thanks for the info (again).

w8ye

My Feedback: (16)

The probable savings for the manufacturer was less parts count, handling, and machining for the seal in the middle?

Antique

My Feedback: (4)

Every 3W twin and DA twin on the planet has THREE rubber seal bearings...NO seal in between...The rubber seals work just fine on every other engine they are used on, if the bearings are the NSK or NTK brand with brown seals...

w8ye

My Feedback: (16)

The brown seal type NSK bearings are the "DU" bearings with the Ultra Seals

Tired Old Man

My Feedback: (1)

Bottom line: If it ain't broke don't fix it.

aussiesteve

Ain't that a fact.
One thing I have noticed since changing from dealing with "Low purchase price" engines to "Higher purchase price" ones (which happen to be far cheaper per flying hour in the long run) is this.

When I was dealing in "low purchase price" engines. I had a seemngly never ending run of issues to deal with that were caused by one of two things
1 - The new owner "opened it up out of curiosity"
2 - The new owner didn't follow the standard instructions.

Often the problem is sorted out over the phone (but not always).

since changing to "a little higher purchase price" Engines, these issues seem to have gone away and my After Sales service calls now seem to be when the customer wants to get ahold of their next engine.

I wonder which of these reasons is the main one for this
A - The "lower purchase price" makes the customer feel braver about "fiddling" for no real reason as there is less money at stake.
B - The "slightly higher purchase price" engine is in fact a better product that needs less fiddling.
C - The "slightly higher purchase price" makes the customer more nervous about "stuffing the engine up" so they follow instructions

BadAzzMaxx

[sm=thumbup.gif]

mpascual

My Feedback: (1)

New versions of some CRRCpro engines does not have the seal beween bearings. The new GP26R comes with new and bigger rear bearing, new crankshaft and new crankcase, without the seal but with a piece of alum. tube to maintain the distance between bearings (like the DL engines).
On your GP50R you can remove the seal if you add a spacer between bearings and add a retain compound as loctite 648 , and also replace the standard bearings with NSK DU bearings.

Regards

bcchi

All very true. The two things that always scared me was. "I had the club engine expert work on my engine and he has been flying models for 60 years."

The other one is, "I overhauled the carb."

I guess there are many. Like "it is a brand new battery."

If I had time I could write a book about things model fliers have said or done. I guess 32 years was enough, I am getting Grumpy like someone else I know.

Like a guy told me - him and his buddy had cranked on this engine for three days. Asked if the engine had spark at the plug. Answer, "No it does not." What do you do?

BCCHI