Blowby on 184

[Wageslave645]

I just bought a used 184 Lo-Boy from my local Cub dealer, and have been getting it cleaned up and ready for mowing and occasional snow pushing use. I have almost everything working correctly on it now, but have noticed a pretty large amount of blowby from the oil breather when hot.

I added a PCV valve to the engine that took care of nearly all of the mist from the breather, but I am wondering how much blowby is still considered acceptable on this type of engine?

Other than the blowby, it seems to run quite strong for what it is. I am also seeing almost no oil consumption. I would like to see a few good years of use out of this machine before I would want to consider a rebuild, but I would do it if it became detrimental to the engine.

Thanks in advance for the advice.

[outdoors4evr]

Blowby is a "seat of the pants" measurement for whether the rings are shot. A more accurate measurement can be done with a dry and wet compression test.
Greater than 120 PSI is generally considered a good fresh engine.
95-115 is a decent working engine
Below 95 is getting in the range of needing some work. The tractor is not doing the heavy lifting it is accustomed to doing. You are having to baby it.
All these numbers are debatable, but around 65, the engine is very worn and probably isn't starting and running well and isn't doing the jobs required.

[Don McCombs]

I added a PCV valve to the engine that took care of nearly all of the mist from the breather, but I am wondering how much blowby is still considered acceptable on this type of engine?

I'd be interested in knowing how you did this. Thanks.

[outdoors4evr]

Ditto on the interest with the PCV Valve.
Even on a fresh rebuilt 184 there is some breathing that occurs through the oil filler cap. While it is not fogging oil after a rebuild, there is still a little oil that accumulates around this area from vaporized oil. A little oil does build up after a mowing season with no bath. (leading indicator of tractor abuse)

[Eugene]

SeaFoam in the fuel and engine oil. Several applications may free up the rings.

[Wageslave645]

It was actually pretty easy to add the PCV valve.

I drilled and tapped a hole in the valve access cover to add a brass fitting with a 5/16ths hose barb. From there I ran a piece of rubber line under the carb towards the front of the tractor and hose clamped a PCV valve to the end of the hose. (I am away from home, so I don't have the part number right off hand). I pulled the pipe plug from above the carburetor on the manifold and added another brass fitting with a right angle 5/16ths hose barb. I then connected another piece of hose from this barb to the other end of the PCV valve. (It looks like: Valve Cover->PCV->Intake Manifold). The valve should be oriented to be free flowing from the crankcase to the intake, and airflow should be blocked in reverse.

I tried a couple of different valves, but the bigger ones were a little too big, and caused the machine to not fully idle down and acted like a vacuum leak. This would not be an issue if the hose was plumbed in ahead of the carb instead of on the manifold, but I did not have the correct fittings to break into the hose between the carb and air cleaner at the time.

This mod is similar to what flathead Ford guys do to get rid of their road draft tubes. Hope this helps.

[Wageslave645]

The PCV number is Duralast # PCV1161DL. It is correct for a 1.0L Geo metro

[BigBill]

Soak your breather cap in kerosene. We did this on all the older cars when changing the motor oil. Do not blow it from the outside in. Clean the breather cap from the inside out.

Seafoam, frees and reseats stuck rings, lubes sticky, dry valve guides. These parts dryout from years of sitting idle.

[Wageslave645]

I have Seafoam in the crankcase now and had some in the fuel tank, but I ended up diluting it down when I refilled the tank. I cleaned the breather by soaking it in brake cleaner for a few minutes. It got a surprising amount of crap out of it, but it is clean as a whistle now.

[outdoors4evr]

Run that 184 hard and warm it up good with the seafoam. You will be amazed at the amount of junk that comes out of the crankcase when you do an oil change.

[Eugene]

I ended up diluting it down when I refilled the tank.

There is a listing of the amount of SeaFoam per gallon to add to fuel on the side of the container. When you top off the tank, add more SeaFoam to match the approximate gallons added.

[BigBill]

One can of seafoam per tank full of gas. I use one can of seafoam per crankcase. By the time I finish mowing the rpm is higher and the engine is happy, happy, happy. Once the seafoam has produced results in my engine I cut the amount back to 1/2 a can in the gas tank and crankcase.

[aparnell572]

Our 154 has a lot of blowby (on top of seal leaks). I tried several tanks of seafoam and in the oil. It didn't rectify the problem, so I just wouldn't hold my breathe that seafoam will be the cure all. Ours is supposed to be rebuilt this winter, if it does I'll be posting plenty on it.

If it's not eating/leaking oil like ours has been (2 gallons through the summer!) then you should be fine. If you are really concerned, technically burning the oil a little would wear the journals with particulate entering into the crankcase. IMO, leave it be until it becomes a problem.

[BigBill]

Seafoam isn’t a engine rebuild in a can but it can prolong it. If it clears up some of the Problem. I have two c60’s that were rebuilt and let sit for a few years. There owners passed, that should of been a warning to me, lol.