PT422 Aux cooling

[Gravy]

I've found the photos and I'll start a new thread for them.

Gravy

 

[Phils]

Just an interim update:

Although I haven't had a chance to do three hours of nonstop PTO work to truly test this modification, I made mention of the hydraulic cooling fan not coming on as it used to.

I've done a couple of hour-long jobs and investigated this further.

With the aux cooling fan I installed on, I find quite a bit of airflow coming from the hyd cooling fan even tho it's not running. ("Quite a bit" is the measurement my hand indicates when I hold it above the hyd fan... not as much as when that fan is on, but still a significant flow). In other words, the aux cooling fan is blowing enough air into the engine compartment that some of that air is passing through the hydraulic cooler and thereby keeping the fluid cooler.

I suspect Tim's cooling fan may be doing the same thing although in reverse, that is: cooler outside air being drawn through the hydraulic cooler in the reverse direction if the hyd fan isn't on. Tim -- have you noticed any difference in hyd fan operation?

After two times of hour-long PTO work there was no indication of vaporlock or overheating however the acid test won't happen for a few weeks yet.

Phil

 

[Marks481]

I haven't had a chance to do anything PTO intensive. I did run my PT422 for about an hour using my aerator (48" LIC core aerator, which is bolted to a quick attach plate, and works amazingy well), and noticed that it did seem considerably cooler, that it didn't backfire or diesel when shut off, and that the hydraulic cooler fan never came on.

I probably will have to rethink putting an exhaust fan on the left side, since it did get rather warm from the exhaust. I suspect that while it was not hot enough to melt the plastic shroud, it will shorten the lifespan of the plastic shroud on the fan and promote cracking. I most likely will relocate it to the right hand side, and still use it as an exhaust fan.

 

[Phils]

I ran the stump grinder yesterday for an hour straight and it was a warm day. That's about as hard of a use as the PT ever gets. The hyd cooler fan was running most of the time.

I let the machine idle and cool for 5 minutes before shutting down. It dieseled at shutdown. Things were hot enough that a year ago I suspect it would have died from vaporlock before the hour was up.

Next time I'll let it idle and cool longer before turning it off.

Better. Not perfect.

Phil

 

[MuncyBob]

hhmmmmmm....My PTO gets it's workout when I cut the grass. I have a lot to cut so I normally split it into two cuttings and each one is well over an hour of constant running. It will take me no more than 60 seconds to walk from the PT to the garage to retrieve the leaf blower and return to shut her down, during this time I have it in the lowest throttle setting. Shut off has not had any backfire or run-on. I did look into the gas tank last night to see if there were bubbles coming up from the bottom outlet and there was a very slow trickle. That trickle was more intense before I wrapped my fuel line with aluminum foil though. I would like to replace the fuel hose with a line that is insulated.

 

[ponytug]

Wow! If you are getting bubbles out of a gas tank vented to air, you guys have much more of a vaporlock issue than I thought. Yeah, I'd insulate the line, and I would think about aluminized foam on the tank.

Phils: Have you thought about a tank of techron or something else that might help clean out any carbon or gunk on your valves/spark plug?

All the best,

Peter

hhmmmmmm....My PTO gets it's workout when I cut the grass. I have a lot to cut so I normally split it into two cuttings and each one is well over an hour of constant running. It will take me no more than 60 seconds to walk from the PT to the garage to retrieve the leaf blower and return to shut her down, during this time I have it in the lowest throttle setting. Shut off has not had any backfire or run-on. I did look into the gas tank last night to see if there were bubbles coming up from the bottom outlet and there was a very slow trickle. That trickle was more intense before I wrapped my fuel line with aluminum foil though. I would like to replace the fuel hose with a line that is insulated.

 

[Marks481]

While running through the Robin parts manual to figure out which oil filter that I needed, I ran into a picture showing the oil filter/cooler arrangement on the EH72 (PT425 engine).

Since the engine is essentially the same, all the parts should fit... and the more cooling the better.

Does the manual picture resemble the PT425 arrangement at all?

 

[Marks481]

A picture of my side fan:

A picture of my new "dashboard", where I mounted two temperature gauges, and a buzzer and lamp wired to the engine oil pressure switch. One of the temperature gauges has the sensor mounted in the right engine oil drain plug, and the other sensor is clamped onto the inlet to the oil cooler. Someday I will work on the hydraulic oil sump drywell idea.

 

[KentT]

Nice job, Tim. I like that console idea...

 

[Marks481]

My problem now is that the oil drain plug is a straight thread, like maybe 1/4" NPSM or BSPP, and the temperature sensor that I have is 1/8" NPT (with extra collars provided to make it 1/4" NPT or larger).

1/4" NPT in a 1/4" straight thread leaks. It is obviously the same thread pitch, but it starts out very loose, and only gets tight maybe the last half-turn before the hex collar bottoms out.

Putting teflon tape on it changes nothing.

I have been unable (to my great surprise) to find a simple adaptor... 1/4"NPT (F) to 1/8" NPSM (M). Even McMaster Carr doesn't have anything like that. They have a Female BSPP to Male NPT adaptor (which is backwards to what I need, and I don't think it will work since BSPP would have 19 TPI vs 18 TPI).

I thought NPSM was the standard for hydraulic fittings, so I don't understand why adaptors are hard to come by.

Of course, it doesn't help that the holes in the back of the engine bucket barely fit my hand, and I can't turn my wrist over... my arm is almost scraped raw from messing with this.