CV740 ... metal shimmer in the oil, 1,500 hours

[fmorelli]

I have a CV740-0011 that is about 15 years old. Been in my possession since day one. Mobil 1 oil changes, etc. A few years ago blew a seal. I pulled the motor, regasket, updated parts. The cross hatch looked like new in the cylinders. I thought everything inside looked good. Flattened both heads on a granite calibrated stone. Mower runs great with 100 hours on it since the rebuild.

BUT ... I am seeing metal shimmer in the oil when I dump it. I just dumped oil, ran 20 hours, and now end of season dumped again to inspect. I took a video for a buddy to ask questions: https://photos.app.goo.gl/673M4EH4H4F3KmFm6

I'm assuming rod or crank bearings on their way out. Should I just pull the engine, replace rod and crank bearings with std size, and keep on trucking? (I guess I'm asking, on these mowers, is this generally ok at this stage). Assuming nothing has spun of course (which I doubt). Or ... ? Would appreciate any feedback!

 

[Scrubcadet10]

Do you have the Spec number of the engine? CV742-xxxx
No bearings on this engine, except for maybe a ball bearing in the PTO side (rarely).
What parts did you replace?

 

[bertsmobile1]

your assumptions are correct, some thing is grinding away meal
So 2 options, run it till it goes bang then blame the synthetic oil which of course means the mower should run for a million hours with no wear.
Or pull it apart right now & look for the source thus potentially saving the short block
It could need nothing more than a thrust washer between the crank & the sump or of course, the crank or cam could be wearing the bush area oval.
When you replace a seal you need to be very careful not to drive them in too deep & partially block off oil feed holes .

 

[fmorelli]

Do you have the Spec number of the engine? CV742-xxxx
No bearings on this engine, except for maybe a ball bearing in the PTO side (rarely).
What parts did you replace?

Original motor is a CV740-0011 (in a Gravely PM260Z 992047). Kohler's updated motor would be a CV742-3023.

Parts change - regasket and seals. A few external updated parts (like oil breather plate if I recall). Nothing internal was replaced.

I looked at the Kohler parts diagrams and yeah ... no rod bearings or crank bearings in the diagram. No bearing on the PTO side? It's been a couple years and I don't remember the innards any more. I did not remove the rods/pistons/crank. How does this stuff work without bearings?! lol

That leaves me head scratching on the metal. I'm a car guy so not sure how the smaller engine stuff goes - I would have guess rod or crank bearings ... but, per se, those aren't here best as I can tell? Thanks for any insights....

It runs great (don't they always before they go ka-boom?!) ... I just finished my last mow and am trying to be proactive (i.e. if I need to do something, then winter is a good time for that).

 

[bertsmobile1]

Aluminium is an excellent bearing material
Most cams run direct in the head with no bushes.
Works fine so long as the oil supply is good & the oil is clean.

 

[fmorelli]

Again I don't have experience with these motors. Is this something that can continue to run fine for a few hundred hours, or will it grenade quickly when it starts to show glitter in the oil? Thanks.

 

[Scrubcadet10]

Could get an oil analysis for $30, https://www.blackstone-labs.com/tests/standard-analysis/
They can tell you what the metals are specifically and what they may be..
FWIW, i've been using a briggs push mower with a rattle coming from what sounds like the connecting rod for about 6 years now, every mowing season for about 30 minutes each week.
here's a sample

 

[bertsmobile1]

Put it this way
That short block is $ 800
A single con rod is $ 50
There are 2 oversizes available do you should be able to run that engine for the next 50 years
Bugger the top crank or cam journals and the engine is toast .
Pulling the sump off to check will cost nothing but a lower oil seal & sump gasket .

Only you know what sort of money you have availible
I am always one for finding out the problem first then working out what you are going to do
If for instance all that has happened is the seal was driven in too far then a new seal might be the fix or a new sump cover.
Kohler have their service manuals on line
However the last time I tried to download one I was blocked but I did get one from OPE .
So download your service manual, flip through it and see if you are comfortable with what is required.

 

[andyboy]

Once a penguin went into a mower repair place with the same original problem.
The mechanic said, "It looks like you blew a seal".
The penguin replied, "No, I just had a milkshake".

 

[Ariens A19A42]

I have a CV742 that is about 15 years old. Been in my possession since day one. Mobil 1 oil changes, etc. A few years ago blew a seal. I pulled the motor, regasket, updated parts. The cross hatch looked like new in the cylinders. I thought everything inside looked good. Flattened both heads on a granite calibrated stone. Mower runs great with 100 hours on it since the rebuild.

BUT ... I am seeing metal shimmer in the oil when I dump it. I just dumped oil, ran 20 hours, and now end of season dumped again to inspect. I took a video for a buddy to ask questions: https://photos.app.goo.gl/673M4EH4H4F3KmFm6

I'm assuming rod or crank bearings on their way out. Should I just pull the engine, replace rod and crank bearings with std size, and keep on trucking? (I guess I'm asking, on these mowers, is this generally ok at this stage). Assuming nothing has spun of course (which I doubt). Or ... ? Would appreciate any feedback!

I only run Amsoil Z-ROD oil which has a high content of anti wear Zinc in it. The Zinc totally saves the cam, bearings, cylinder walls ect ect from pre mature wear. Its made for hot rods and vintage cars but I run it in all my mowers and even new cars. Even new cars. If your car or motor does not burn a lot of oil it is perfectly safe for the cars cat and smog system. Inside of all my mower motors look brand new and my cars that have 100k plus miles look brand new. They run nice and smooth and quite..