Crankshaft seal - quick easy question
 

I think when installing my crank seal, all the grease I applied to the inner lip got wiped off.

Should I redo it?

grease? you don't even need grease there. you're talking about the main seals?

Don't you need grease on the inner lip (pink circle)?
I believe there's a spring inside the seal and applies constant pressure circumferentially to the shaft. It needs a grease so it doesn't spin dry. Is this not right?

https://www.miataturbo.net/attachmen...ine=1413318647

it doesn't actually apply pressure onto the lip of the seal so there's a microscopic gap between the shaft and the seal.

I guess putting grease there is not a bad idea, but that is def not mandatory.

You'll never see grease on those things from the factory.

And what, exactly does that do? Do you plan on taking it out and greasing it every couple hundred miles?

No grease is necessary except to facilitate installation.

Quote from honda-tech:

Oil seals will machine a slight groove into the shaft it is sealing.
If you replace the seal and the oil still leaks, either the shaft needs to be machined(unlikely) or you can take the garter spring off the seal and tighten it to put a better clamp on the seal to shaft interface.
https://en.wikipedia.org/wiki/Garter_spring

Of course this all means nothing if you put the seals on dry, that would cause the seal to burn if there was no lube.

I don't hondatech bro. I'm not a bro.

Ive never put lube on seals and I've replaced more than I can quanitfy.

Just giving my opinion.

Find me an OEM bulletin that states that. I'll be impressed.

Yeah, right. Silicone or synthetic rubber will machine a steel crankshaft.

Go ahead, pull the other one.

I laughed at that too. but, it's from Honda tech, so.........not even a bit surprised

And for my next demonstration I will use a stick of butter to machine aluminum.

I used my nipples to port my wastegate

So how does a seal prevent leakage around a spinning shaft? You don't think the inward radial force of the garter spring can score the crank? Does it not hug the spinning shaft?

Serious question. I don't understand how a seal works.

its not like there is some crazy amount of oil or pressure inside there that the seal has to hold back.

the seal simply prevents oil from sloshing out

if the seal was actually pressing against the shaft, it would get worn down/out in a matter of minutes

Actually, I have seen a seal much too small forced onto a shaft wear through the inner ring, allowing the garter to score the shaft. That, however, was a one time deal, and caused by improper sizing.

The seal does "hug" the shaft, and that is how it seals. It just doesn't do it very tightly, and certainly won't mar the shaft at all in normal conditions. There are charts that I use to size the seals depending on how tight a seal I need vs. the friction/heat a tighter seal creates.

After reading about this, I believe you guys are mistaken.

Google "groove crank seal" and you'll find pages and pages where this has happened. It appears Speedy Sleeve is a product that can remedy this...or just place it in deeper. :giggle:

You guys are wrong. Seals wear shallow grooves into cam shafts and crank shafts all the time. Totally normal.

Yeah, that's actually no joke.

And the seals are oiled. If there was no oil behind it, you wouldn't need a seal. It's good practice to put a little oil on all surfaces and it'll stay lubricated until the motor makes it's own oil pressure.

you're saying there's oil pressure on the seals? not sure if serious.

I grease all cam crank seals on the inner lip during install. I also use permatex non hardening stuff on the outside, although never had a factory seal leak around the outside.

Oil vapor and splash takes care of lubrication after start up. Yes the seal touches the shaft. This is not Archimedes scroll days fellas. Yes I've personally seen seals wear groves in steel. I once ran an aluminum pulley (different application) in which the pulley made the contact with the seal. Lucky it was only a prototype pulley because the aluminum had a significant groove where the seal was riding after about 5k miles.

To answer the question, if there is some oil or grease on it, it's fine. You see some of these guys do nothing at all and have no ill effects. You are fine. Also, I've never been able to pull a crank seal without damaging so if you must redo it, buy a new seal.

Come to think of it, I've pulled seals out of the box that were pre greased.

On my accord the balance shaft seal would pop out so Honda put a retainer to prevent that from happening bc oil pressure

https://www.miataturbo.net/attachmen...ine=1414279928

I always lube crank/camshaft seal with clean motor oil.

As I understand it, it's not the seal that's machining the crank (because, yes, rubber is a lot softer than steel) but dirt and grit that get caught between the seal and the crank.

--Ian

^ yeah, that makes sense. Probably why it is not consistant on every vehicle. Dirtier oil and environment would most likely cause a deeper groove.

So much bad information in this thread...

1. There is obviously oil behind the crank seal. If there weren't, we wouldn't need the seal. (Air cooled VWs didn't have "front" crank seals, and despite a slinger plate and spiral grooves cut into the pulley, still leaked from this among many other locations.)

2. Nobody said that this oil was at full system pressure. (Looking at you here, 18psi.)

3. Still, the inside of the crankcase can, at times, be under some pressure relative to atmospheric. (Blowby much?)

Seriously, I didn't know we had so many noobs.

See post #19, 22, and 24 for some decent information.

You guys can't be serious.

1) rubber isn't gonna cut jack diddly into a forged steel crank. dirt/rocks getting in between the rubber and metal causing the groove is A COMPLETELY DIFFERENT STORY, and not in any way shape or form the same thing as the original statement.
2) yeah duhhhh....however these guys are hinting that "oil can push out the seals". which is not the case. it is there, but the seals keep it from splashing out, and just contain it inside, there is no oil pressure whatsoever behind there
3) yes, blowby gasses and all that. exactly what I was talking about. gasses pressure, but not oil pressure.

I feel like you both are trying to troll me with this retardation, and I feel like the n00bs are being completely misled. Mazda doesn't put oil or grease on the seals when installing them. So if you want to, It probably doesn't hurt and it probably helps get them in easier, but gimme a break about all this other nonsense

I have 2 genuine Mazda cam shaft seals in my garage and they both have grease on them straight out of the packet.

So do I, from Rosenthall Mazda, and they don't.....

I'm not gonna argue about it, since either way should work and be fine, my issue was with the whole "groove" and "oil pushing them out" statements.

Tomatoes, tomadoes Vlad. The seal won't scrap the crank without a little dirt, the dirt won't scrap the crank without the seal, what of it? No one here is trolling, serial.

One of my racer friends used to cut the lip off the wheel bearing seals on his race bike in order to reduce the parasitic drag it caused. The big drag reduction technique was to run aluminum shavings through the water pump (NOT on the bike at the time) until it loosened up. Really. At 12k rpm even a loose water pump ran more than enough water through the engine.

No, this type of stuff is not for everyone.