In putting my 350 back togather I couldn't recall the orintation of my crank seal, i've since found a picture as to the way it was when I removed it. The seal says INSIDE on the flat side of it or black in the pictures, some on the chat board suggested that the open side of the seal or green as it looks should go towards the inside of motor (( Internal Combustion Engine ? )) or towards the crank. There is a spacer that goes in side the seal with an o-ring, Randy at Ody Savlage said to put the oring towards the crank, and the flat part of the seal towards the crank. The manual isn't much help. I'm posting a picture of when I tore it down, and I guess I did document it, just didn't catch it the first time.

Charlie

That goes against all the seal installations I have seen and my industrial training for installing
seals, the part with the long side of the seal or the side with the most surface area always
goes towards the side with the most pressure, air pressure or fluid pressure puts
force on the surface area of the seal and forces it tighter against the shaft.

Was the reason why your Engine went poofkaboon becuase it sucked air?
Was the seal installed wrong the last time now you have found the problem?

I have no idea, and like you I would think it should have been the other way. Funny part is that the seal says INSIDE on the flat part that is inside and according to Randy at Oddy Salvage the way it is shown in the pic is correct. So I don't know at this point. I wish I had a difinitive answer as now is the time to make it right, not a big deal to pull it out at this point.

cs

I can take a look at the drawings at work but I don’t go back till Tuesday. The ‘inside’ mark may not be relevant, often the seals and bearings are off the shelf items and we typically ignore the makers instructions (we test to see what works, often reinventing the wheel (FYI round wheels seam to work better)).

Thanks Lee, It is a Honda Seal kit from Honda if that makes any differance. Also the one that came out was marked inside as well (and was facing inside).

The plot thickens....

Well I looked into my pic archive and have pics of before and after.

I was the first person into my Engine since it was built at the factory.
So that seal is in correctly. At least in the before pics. :)

Sorry csheldon I should have looked the other night while in chat.

MassOdy

Thanks Mass
That settles it in my mind. I guess that "INSIDE" was there for a reason.

I really appreciate it. Now to figure out why the works tightenedup when I cinched down the balancer nut, it was free moving before that. Now that I've tightened it, it still turns easy just doesn't free spin like it did.

Charlie

I still say that is wrong I will wait to see what Lee says, The guy that rebuild Toymans
Pilot Engine installed his seal the way you have shown in the pics and it would not pass
the pressure test .

http://pilotodyssey.com/PO/viewtopi ... light=seal

If that is the right way I would like to know what is different with that seal so it will
seal when pressure is applied to the other side, can someone take a clear detail picture or
scan of the seal on both sides so I can see it or save the old seals and send them
to me? back when racing the 250's was popular that was one of the tricks the races
use to use to stuff the bottom end of the 250 Engine, install the seals backwards,
they would seal for a few races then leak so they would change them between race
weekends, seem like alot of work to me but some guys felt it was worth the effort to
shrink the crankcase volume another few ounces.

In the end we will have a difinitive answer. I've heard from several that the way to install is per pics (or INSIDE) facing in. But we shall see. Good discussions is what it is all about and getting it right.

cs

i have old seals and bearings I can send.

How you know "inside" is not facing "inside" the balancer case their something
telling you "inside" means "inside" the crank case?

Can you take detail pics or scans of both sides of the seal for all I know
the design is the same on both sides and its just offset on one side.

FYI pictures of the seal the way it came from Honda means nothing to me
Honda sent out hundreds of 400EX's with BOTH brake pads on one side of
the disc, YES INSTALLED WRONG, years ago they shipped out a bunch of
CR125's with the pistons installed backwards YES INSTALLED WRONG I am
sure a old Honda mechanic could give you more examples of the factory
assembly being WRONG so what the monkey did at the factory really means
nothing to me looking at the orignal design drawings IMO is the way to go....
Hurry up Lee heh

Your right it is good conversation that is how you exract the most and get more
wheels turning and spitting out more ideas, snowball effect..

In the service manual on page 8-9 3rd pic down they show a O ring and a collar
do they mate up with part of the seal ?


Here is a new one on me...

Page 8-1 "Fill the cavity between the double lips of the crankshaft oil seals with
gasoline resistant grease"

What grease is resistant to gas?

The pics are not the best camera was too close and it is getting dark. You can see the ridge that holds the spacer in place.

Yea, I have heard some even better stories than that.



Hoser this is sounding like the meaning of ‘yes’ when talking to the Japanese. In a culturally induced stupor they don’t want to tell you no as that would embarrass the person they are talking to. So you notice that they say yes to mean yes and yes to mean no. So is it the inside or not?



Ha! Years ago we almost had big problems when a note on a drawing was translated ‘apply fat to aid assembly’. The intent was to use oil not soap to assemble a rubber hose on to a fitting. Soap could get in to a valve and gum it up when the water evaporated out but oil would be OK. However the Japanese word used implied whale oil and could be interpreted as blubber (the word was an archaic use, not that we are killing whales to make cars today). The assembly guys had no idea of what it was talking about and they used the soap for mounting tires. Competent translation is everything.

So it would be ok to use any grease on hand for the seals?

You know their is "soap" or "soaps" in grease don't you?

I have heard from several different Engine builders to use white lithium marine grease on the seals. That is what I have been using for quite some time and it seems to work well with good results. I believe the grease is applied to aid in sealing but is mostly used to make sure the seal stays lubricated during break in as opposed to being installed dry. If installed dry they wear quicker and are much more likely to fail.

I just tore down one of my spare 350 Engine bottom ends for the 418CC project. It has never been apart before(non-rebent lock washer tabs, hard factory gaskets and red locktite). It also has the seal in question in backwards. I did notice the seal on the alternator was sticking out about 1/8 inch where it was contacting the recessed area of the back of the stator mounting plate. I pressed lightly on it and it popped back in where it belongs(fully seated).

My question is this.... Is it possible that there was a design error with the depth of that recess? That could have easily allowed the gasket to pop partially out when it became a little hard, thus allowing the oil/gas venting into that area and into the starters. This motor (( Internal Combustion Engine ? )) had alot of black oil in that area too. I may put something between them to keep it from popping out again when I reassemble.

I can post some pictures if you like to see what I am talking about. Maybe I should have just started another thread.

Gary

Post pics I am not sure I follow you.

Is it possible that a Engine backfire pushed the seal out?

Every 350 I have ever taken apart had that seal installed the same way as in the pics above. That is the way they came from the factory (with the inside out or outside in or whatever you want to call it) . I always put them back in the same way they came out and never even thought much about it after that. If you guys are in question, I can verify that is the way they came. What I don't know is what happens if you install it the other way?

Bill, I am talking about the "leaky" seal on the otherside of the crank(alternator side). My other side(counter-balance) seal is installed like everyone elses and I do agree with Hoser that it should be installed the other way.

Here are the pictures of the alternator side seal area.

I wish I had a good set of depth guages so I could actually see what it adds up to. About 1/8" too much. LOL I bet this has been the leaking oil problem for all these years.

Thanks for keeping the topic alive guys this is great info and confirmation for me as I went ahead and installed them hoping it wasn't in foolish ambition on my part. I'm going to hold off on the balancer gears and stator until I leak test it on the bench, then I'll button it all up.

Charlie

Your a smart man Charlie!

I'm sorry, I should have been more specific. I was only commenting on the balancer seal that was in question. I was not referring to anything on the ignition side of the Engine. I have always reinstalled the seals in same orientation that they came out, and it always worked just fine. I guess I was chicken to try it any other way I figured Honda Knows Best and their must be a reason it came that way. If you guys find out otherwise, I would like to be the first to know.

Nothing to appologize for Bill, its very hard to offend me, LOL. I agree with you, normally, everything goes back in the way it comes out, but in this case-- why would you have one seal facing in and one facing away from the crank. Somethings fishy in Denmark! Seals, with the open area in the compression area gain grip by the expanding pressure pinning the walls outward( if that makes sense). I am a rocket scientist, ya know--LOL.

I like the white lithium grease idea too. I usually use 2 stroke oil to lube things during reassembly but I am sure the grease with help lube thing alot longer during break-in. Nice, Thanks

Gary

When I go back and carefully take a look at that seal orientation again, it occurred to me that it might be installed in that direction to help stuff the crank case and reduce the crankcase volume by that little bit. Maybe if it is installed the other direction (non-factory orientation) it would allow more air volume to build up in that area and create pressure against seal outward, more so than if installed the other direction. Perhaps the extra air volume could build pressure against the seal. Maybe some sort of boundary layer around the bearing at speed allows to much pressure to build up on that seal due to heat expansion and so that is why they installed it in the orientation they did from the factory. Or in the event of a backfire there is not a cavity there for crankcase pressure to build and press against the seal (worst case scenario). Also gravity would tend to drain residual balancer oil away from the seal when installed with factory orientation. Other than that, I can see no other reasons. I guess only the engineers could tell us why it really came that way, but I have questioned it before myself and decided to go with what they knew, and it worked out OK. I'm not sure I described what I'm thinking clearly, but hopefully you guys get the drift.