Rich,
I have been cryo treating gears for a while now. I have a set of tungsten treated gears in my new lower, we'll see if that helps. Right now I have about 300hrs on the gears in my old drive, so I need more power to properly test all this.
Who makes the pump that Drew uses? It looked to me like a Mallory fuel pump, but just guessing..

Dick

I asume he had a drive oil temp right? What power was he running? Maybe my 700+ hp is more than a shower can help.

Keep up the good work, your testing is great to read, is non bias, and helps us all.

As for the gears being imersed in oil, I'll agree to disagree for now. Till I'm proven wrong, and I hope you do just that... ! :-)

Isnt that the purpose of moving the sump? so the gears wouldnt be immersed in oil, thereby making them spin more freely and the oil spinning off. I'm not sure what your not getting. By creating a drain down low to pull/let the oil back, it stops the immersion and stores excess fluid in a recovery tank, where it is then sprayed directly on the gears. That's my interpretation of it.

Jeff,
The boat is a 36" Apache, with twin 850hp vortech motors. He has a gauge on the dash that tells him temp. Probe is in the top plug hole..
Broke the shower, ran it any way and when he put the shower back on.. he saw 50*. Now our water temps are only approaching 50* here.. so that helps too.

Just a guess here but :

1) As stated with the gears spinning Oil naturally wants to spin outward and away from the gears.

2) Pressure is going to try and escape via venting into the reserve bottle.

3) Not only is submeresed oil flung away from the top gear but I would guess all the airiated oil is sitting at the top too ??

Meaning poor lubrication anyways.............

4) So I would guess to see a couple gains by Mr. Gadget's set-up.

A) The gear is actually getting good clean oil and guaranteed oil

B) I think the oil temp is dropping cause it's continually being pulled from the lower case. And with the lower case being completely buried in the water your cooling is free with constant oil turn over.

Just my guess..................is all

Jon

Hi Dick,

I am looking into the Cryo process, and a few other things.. One I like is DLC, but I am not sure how it will work on the gear teeth. I know the Cryo is supposed to alter the molecular structure somewhat.

On the other hand, if the enemy is friction and wear, then maybe that should be addressed.. DLC is used on valves, cams, lifters, and other high wear, low friction desired environments.

DLC is Diamond Like Carbon in case you were wondering..

Now as far as the other things about the oil and the flinging, I'm not gonna explain centrifugal theory again..

I think you might want to ask the Cryo people if the gears become more brittle when altered, or if how the elasticity of the metal is altered... I would be curious about that as well, so if you get an answer, please let me know..

Thanks,

R

Jon,
The cooling is caused by the 2"x12" oil cooler that is in line with the pump and filter. That will hold the lube temp down to a point where the oil can do it's job under extreme conditions. When you see lube temps of 250 and higher, the protection is not very good. The filter will take the metal particles out of the equation and help protect the tapered bearings that are preloaded. I constantly find the races dented from schrapnel (sp). I also think with cooler cleaner oil, you can go longer between lube changes. Swap out a filter and put a quart in it and go again. Cut open the filter and see what is happening inside the drive.
All the parts and pieces add up in a hurry, but I do think it is worth while in certain situations. If you run for long periods or have big power, it has to help.

Dick

Very cool thread!!! I just had to chime in...

BIllet Marine has also experimented with Cryo treatments and oil coolers. I have always wanted to build a true "dry sump" Bravo but have never had the time...

I think that the idea of cool, clean oil being introduced up top would be a HUGE benefit. We developed our water cooled Billet topcap for the same reasons. (Not a drive shower, more like a cooler or heat sink...although it dumps water just like a shower)

We have showed that even a 50 degree drop in oil temperature, in the top of a Bravo, makes a huge difference in longevity. Remember, the top gear (Reverse in a R/H and drive in a L/H) is "above the oil line" Splash lubricated...
As the upper gears turn, splash lubrication of "hot, upper end oil" is really all that a Bravo can offer. (And the hottest bearings in the drive are often the pinion bearings)

Can't wait to see what comes next...
Curtis @ Billetmarine.com

Rich,
I have looked into the DLC and one company suggested a differnt process. Saying the DLC was not optimal. I currently have a set coated in their Tungsten process, which they seem to think will solve all our problems..
I have a polishing process done after the cryo. The cryo is not suppose to hurt in any way. And so far I have not seen it happen. I have probably 40 sets of upper and lower gears out and have only seen one major failure. And I have seen the same failure in several untreated gears.
One problem I think I am seeing is that the quality control of the gears from Merc, is very bad. I have been told by gear experts that their heat treat is all wrong. And the gear shape has deteriorated over the last couple of years. Gear lash is a joke nowadays, where before they were pretty good.

I hate to have to reinvent the wheel.. I would like to just sell the Imco SCX to everyone and not have to rebuild drives. That would make my life much easier..

Dick

Curtis,
I have considered draining half the oil out of my drive and trying that, but first I have to put the new drive on and run it and see how it works out. Would be neat to mount a cam inside the drive and see what is happening. I have run one with the back cap off at an idle and you can see the "natural oil flow from the lower to the pinion bearings.. Kinda cool!

If all goes well, maybe I will get brave and drain some out, at the end of the summer, see if the boat goes faster..

Dick