Foaming oil P-YB in my Ariens 7hp Techumpseh

[GhostFlame]

I didn't know this would be a problem.

Last year I put P-YB 10w-40 in my engine. I couldn't remember the speced weight. Well it started running really lousy (surging rpm). Blowing a ton of oil out the reed valve. so I replaced the reed valve, in the process I found the head gasket had blew out, so I fixed that this summer. I had some of the 10w-40 left over so, that's what went in when I was done with the head gasket.

This morning thinking I'm ready yo go for the winter. I start it up the engine is running lousy again. I look at the reed valve and it is blowing foamed oil out the breather. I shut it down and decided it was time to read the manual.

It says in Bold letters, "DO NOT USE 10w-40 oil. summer 30w, winter 5w-30 dino or 0w-30 synthetic". Then I google foaming oil and I found an article that said Synthetic doesn't foam as much if any compared to dino.

I get down a qt of Mobil1 0w-30, drained the old oil and it was very foamy coming out. Put in 19 ozs of 0-30.
I start it up it is running smoother, the breather is puking less after about 5 minutes it stopped puking completly.
I had no idea oil grade could have f-ed-up an engine so badly but, here's the proof.

 

[johnnydc]

I have a Craftsman with the 5hp The-crumb-sah and been using VWB 5w30 since new. I never noticed that. I will keep an eye on that.

 

[GhostFlame]

Originally Posted By: johnnydc
I have a Craftsman with the 5hp The-crumb-sah and been using VWB 5w30 since new. I never noticed that. I will keep an eye on that.


The 5w-30 is fine that's what I was putting in it for the last 24 of 25 years. 10w-40 is what they specifically say not to put in. I just thought in a splash pan, oil is oil... what could go wrong? apparently more than I thought

 

[SS1970chrysler]

Originally Posted By: GhostFlame
Originally Posted By: johnnydc
I have a Craftsman with the 5hp The-crumb-sah and been using VWB 5w30 since new. I never noticed that. I will keep an eye on that.


The 5w-30 is fine that's what I was putting in it for the last 24 of 25 years. 10w-40 is what they specifically say not to put in. I just thought in a splash pan, oil is oil... what could go wrong? apparently more than I thought

 

[Doog]

Originally Posted By: GhostFlame
I didn't know this would be a problem.

Last year I put P-YB 10w-40 in my engine. .

I shut it down and decided it was time to read the manual.

It says in Bold letters, "DO NOT USE 10w-40 oil.

I had no idea oil grade could have f-ed-up an engine so badly


Wow, I can't understand what could have possibly gone wrong...

 

[boraticus]

I find that unusual. Wonder why 10W40 would be so different to cause an issue with that particular engine.

I'm using 10W40 Formula Shell in a Kawasaki powered riding mower and in a Honda powered riding mower. Both are running just fine. No problems with the oil whatsoever.

 

[engineerscott]

If it was me and the manufacturer said not to use a specific grade of oil, then I wouldn't use that grade. The other thing that might be going on is that you may have overfilled the crankcase. That can definitely cause foaming.

 

[boraticus]

"The other thing that might be going on is that you may have overfilled the crankcase. That can definitely cause foaming."

When he said it was puking oil out the crankcase vent, that was my initial thoughts. Too much oil in the crankcase would cause that.

I've heard of oil foaming in super high revving motorcycle engines but never in a low tech lump like an old Tecumseh engine???

My vote goes to oil overfill.

 

[JimPghPA]

If you google "Amsoil vs Mobil 1 motorcycle oil" there is a section where they rate the oils by how much they foam.

Apparently viscosity is not necessarily the cause of foaming, because some oils in the 50 Wt range still score a 1 on foaming, and M1 V twin 20W-50 is one of them.

So foaming probably is more about the formulation of the oil, and also if the engine had too much oil in it.

Makes me glad I chose M1 V twin 20W-50 as the oil that I keep two bottles of for running the genset on the hottest days of summer for powering the whole house AC, though I will continue to use GC for anything below 80F.

 

[GhostFlame]

Originally Posted By: Doog
Originally Posted By: GhostFlame
I didn't know this would be a problem.

Last year I put P-YB 10w-40 in my engine. .

I shut it down and decided it was time to read the manual.

It says in Bold letters, "DO NOT USE 10w-40 oil.

I had no idea oil grade could have f-ed-up an engine so badly


Wow, I can't understand what could have possibly gone wrong...

The point that I was trying to make was that after 20+ yrs of using the 5-30. I didn't remembr that the manual says don't use 10-40. I had the PYB 10-40 on the shelf and figured oil is oil especially for this little engine.

I did not overfill the crankcase. I have a measuring cup with 19 ozs measured on the side(that I used last summer to fill the pan). I checked it. yesterday, before I started and it was half way up the safe range.

As soon as I put in the 0-30 Mobil-1 it stopped foaming. Don't ask me

 

[JimPghPA]

From what I have learned here on BITOG, and also from the few small engines I have, there are probably several reasons why the manual for your 7 HP Tecumseh engine on a snow-blower would say "do not use 10W-40".

1) it is an engine on equipment that will be ran in cold weather and therefore you are better off with a thinner oil
2) non synthetic 10W-40 were known for causing sludge when they first came out
3) non synthetic 10W-40 are made with a 10W base stock and when enough viscosity enhancers are used to provide the 40 speck they have a greater tendency to shear and become too thin in rough service engine like an air cooled engine

It is not worth the effort of the experiment, but I would bet that the “M1 4t Racing 10W-40” you listed in your signature would not foam up, and for that matter “M1 V twin 20W-50” would also not foam up.

Take a look at the google site I listed and you will see that there are significant differences in the foaming rating of different oils.

BTW, thanks for letting everyone know that PYB 10W-40 is one of the oils that we can expect to foam big time if used in OPE.

 

[1 FMF]

what is PYB ?

 

[engineerscott]

Originally Posted By: 1 FMF
what is PYB ?


Pennzoil Yellow Bottle, i.e. Pennzoil's conventional motor oil. It's a very good conventional motor oil.

 

[RF Overlord]

Wait...this is a 25 year-old machine and the owner's manual listed 0W-30 synthetic as acceptable? I didn't think that grade even existed that long ago.