PT422 Aux cooling

[Phils]

Ok, I've installed an electric fan to help cool the exhaust manifold and gas tank area. Hopefully this will finally and completely eliminate vaporlock problems, including running hot because of the lean condition. Might stop the "pop" or run-on when shutting down as both those problems are a consequence of the lean hot running condition.

I put a toggle switch with a condom on the rear of the engine cover/cage. On the dash would be more convenient but would necessitate a relay and much more wiring (as per Woodlandfarm's suggestion). This was easy and quick and has the shortest run to 12V at the starter solanoid. The fan is a Hayden 10" and fit perfectly. My cost was $70 for the fan, but with a fuseholder, switch, and switch condom the bill was about $80.

Also, although I have to dismount to turn it on or off, I'll only turn it on when it's a situation where I'll be working the machine hard for long periods with the PTO (mowing, stump grinding).

It'll be a few weeks until I will know if this solves the problems completely and will post in this thread when I feel the problem is solved completely.

Phil

 

[duane]

Phils,

Nice job. Is it pushing or pulling air. I'm not sure what would be best. My only thought is that if you are pushing air in, will it tend to send the heat up into the hydraulic cooler?

Duane

 

[Barryh]

Ok, I've installed an electric fan to help cool the exhaust manifold and gas tank area. Hopefully this will finally and completely eliminate vaporlock problems, including running hot because of the lean condition. Might stop the "pop" or run-on when shutting down as both those problems are a consequence of the lean hot running condition.

I put a toggle switch with a condom on the rear of the engine cover/cage. On the dash would be more convenient but would necessitate a relay and much more wiring (as per Woodlandfarm's suggestion). This was easy and quick and has the shortest run to 12V at the starter solanoid. The fan is a Hayden 10" and fit perfectly. My cost was $70 for the fan, but with a fuseholder, switch, and switch condom the bill was about $80.

Also, although I have to dismount to turn it on or off, I'll only turn it on when it's a situation where I'll be working the machine hard for long periods with the PTO (mowing, stump grinding).

It'll be a few weeks until I will know if this solves the problems completely and will post in this thread when I feel the problem is solved completely.

Phil

Good job, I'm very curious to see how this works out, since I want to do the same thing. Keep us posted on your finds.

 

[tracdoc]

Very slick installation, Phil. I haven't been on the forum much of late, and I am frustrated that you are still experiencing the vapor lock problem, despite all you have already done. Any additional airflow into that "hotbox" compartment should be a big help.

On Duane's question, I would think that the relative merits of air inflow vs. air exhaust might be a function of the unit airflow volume (CFM) of each of the two fans. For example, if the top fan, which blows air IN to cool the hydraulic radiator, has a higher CFM than the side fan, I would guess that it would not matter much which way the side fan moves air. Blowing in, it would blow across and out the opposite side. Exhausting, it would remove the hot air charge that has just passed over the hydraulic radiator. Now if the CFM of your side fan is greater than that of the top fan, I would think that having the side fan operating in exhaust mode would "assist" the top fan by sucking out the hot air charge. Blowing in, I could see where it might work against the efficiency of the top fan action. Some "artificial smoke' like dry ice chunk in water, might definitively tell you what's going on and which is the best flow direction for the side fan.

Please keep us posted.

 

[RegL]

Top fan blows out.

 

[toy]

I have been wandering about if you or your family was affected by the vt tragedy. Prayerfully not that was a bad thing. As you know it snowed the day I got the mower and I also had day surgery a few days later so I never got to try the mower out for a while but when I did I really liked it, even though I now don't have a flower left in the yard got to do some replanting. Just kidding about the flowers. I haven't tilted it up to check the blades for sharpness yet but when I aligned the blades up for you to use the forks to load it they seemed sharp from the apearance of the mower I assume that that asumption is correct isn' t it? If so I will wait a little later in the year to check them. I don't seem to be too hard on mower blades I put a new set on my sears craftsman lgt the other day . I have used those blades for since 1990 and I can still touch them up and keep them for a spare set. Some of the neighbours around here change blades about every year or so, I've never understood why they don't mark the spots where they are hitting obsticales and either get them out of their way or at least mow around them and get that area with a push mower or a weed eater one or the other. This is the first year that I have put new plugs in it also, hope the pt can hold up that long.

 

[ponytug]

Dear Phil,

Looks factory new!

Have you thought about putting a little extra insulation on the fuel line and/or fuel tank to keep it from getting heated up in the first place? Often something as simple as wrapping the fuel line with a second fuel hose (split lengthwise and cable tied on) is enough to keep the fuel cool enough not to vapor lock. Or a piece of shiny aluminium between the tank and the rest of the engine compartment? I used some of the anti-sweat foil surfaced foam pipe tape on one vehicle to keep things cool.
Vapor lock is a pretty common problem on some older carburetor vehicles, e.g. VW bugs, etc. Usually, it is part design failure (gas line too close to the engine) and part operational (hot day, clogged fuel filter or non-venting gas cap instead of a venting one.) I used to work on a ranch where it routinely got up over 115, so we had a few tricks to keep things running.

I hope that your fan solves your problem!

All the best,

Peter

 

[Phils]

Have you thought about putting a little extra insulation on the fuel line and/or fuel tank to keep it from getting heated up in the first place? Often something as simple as wrapping the fuel line with a second fuel hose (split lengthwise and cable tied on) is enough to keep the fuel cool enough not to vapor lock. Or a piece of shiny aluminium between the tank and the rest of the engine compartment? I used some of the anti-sweat foil surfaced foam pipe tape on one vehicle to keep things cool.
Vapor lock is a pretty common problem on some older carburetor vehicles, e.g. VW bugs, etc. Usually, it is part design failure (gas line too close to the engine) and part operational (hot day, clogged fuel filter or non-venting gas cap instead of a venting one.) I used to work on a ranch where it routinely got up over 115, so we had a few tricks to keep things running./QUOTE]

Thanks for the tips Ponytug.

Insulating the fuel lines was one of the first things I tried. Helped, didn't solve the problem (it would take LONGER before shutdown from VL). Tried insulating with the foil covered insulation sheeting next. Still would die from VL after long, hard and hot usage. Never tried insulating the gas tank as it didn't occur to me it could contribute to the problem until this last time when the level was low and refilling the tank seemed to help. (One inch of gas left, engine started surging from VL, dumped in a couple of gallons and the surging stopped). I SHOULD have been measuring temps of the tank. But then... I SHOULD have bought Microsoft stock 20 years ago too.

I moved the fuel lines from the left hotter side of the engine to the right cooler side by installing an electric pump (the mechanical pump is mounted on the left side just inches from the exhaust muffler. That helped and I haven't had the engine shut down from VL since. However, it's still running hot and because of the electric pump I can hear whether it's pumping vapor or liquid.

Because it is still so hot and there is vapor in the lines, the engine is running lean and therefore hotter than it should be. I run synthetic so I don't worry about seizing anything, but this still can't be good for engine life.

Taking a short break in the middle of stump grinding or mowing will result in vapor in the lines but I can still start and run because of the electric pump.

This added fan is a pusher and blows through three areas: across the back of the fuel tank and out the other side, across the exhaust manifold and out the other side, and across and above the baffle which may supply somewhat cooler air for the hydraulic cooler.

I've also discovered that I can reach the toggle switch from the seat but it's a stretch.

It's gonna be weeks until I have a free day to mow or grind stumps... dang, but the calendar is filling in fast! A nice warm day and a few hours with the PTO going will either confirm that THIS is the final solution or ....

Provided this does solve my problem, I believe I MIGHT have been able to skip the electric pump/ re-routed hose idea. I'm not going to undo that modification but mention that for anyone else chasing this situation.

Phil

 

[Marks481]

You inspired me to add a fan to the side of my PT422. I went with a SPAL 7.5" exhaust fan (same brand and size as the top fan). I mounted it on the same side as the muffler... hopefully it will keep things cooler by drawing the air across the heat shield and outside of the engine. I just connected it to the same connections as the top fan, so it comes on as soon as you turn the key on.

$62 from Jaycorp was the best price that I found.
JayCorp Technologies - SPAL 7.5" Slim Fan

It should be interesting to see if the alternator has any problems keeping up with the extra 6 amp load.

On a parallel note, has anybody added oil temperature gages to their PT? I did a search here on TBN, but didn't come up with much. It is unfortunate that PT didn't think that I would be willing to pay a couple hundred more to get the quad gage like the T12+ series.

Anybody know the brand of this quad gage, or a source for it? Other then an aircraft supply store, which is the only place that I have seen quad gages.

 

[tracdoc]

Hi there TOY,

I don't want to hijack Phils thread here, so I'll PM you on the stuff you asked...

 

[Phils]

Great idea, Tim!

It seems that the stock fan (like you used) moves more air than the one I installed. I make that call after using my hand to accurately measure air flow from each. This weekend I was wondering if using a second stock PT fan might've been a better idea, if for no other reason than having a "spare" fan onboard. Better that it costs less too!

I did SOME PT work this weekend but not the extended three-hour-with-PTO days that caused vaporlock to present its ugly little self. For the longest continous period (maybe 1 hour) I ran the aux fan. The only thing I noticed was that the hydraulic fan never came on and it usually would have in that time with the work I was doing.

On whether to push or pull air, one consideration I had was that locating a plastic fan assembly above and near that hot muffler and exhaust could shorten the life of or even damage that fan. This could happen after you've shut the PT off because the hot muffler would continue to radiate heat. Your's is a smaller diameter tho, and my larger diameter fan would've mounted closer to that exhaust than what you should have been able to do.

I may consider rewiring mine provided it HAS solved my VL problem. Having it on whenever the ignition is on may be the best plan. That eliminates having to think about it. Now I turn the aux fan on when I anticipate longer and hotter.

This weekend I also gave thought to adding two automotive relays in a "latching" setup triggered by the hydraulic fan. That is... when the hydraulic fan turns on, the aux fan would too. But when the hyd fan turned off, the aux fan would remain running until the key was turned off.

So keep us posted Tim on your results.

Phil

 

[BobRip]

Great idea, Tim!


I did SOME PT work this weekend but not the extended three-hour-with-PTO days that caused vaporlock to present its ugly little self. For the longest continous period (maybe 1 hour) I ran the aux fan. The only thing I noticed was that the hydraulic fan never came on and it usually would have in that time with the work I was doing.


Phil

Phil, I would be a little concerned that the PT hydraulic fan did not come on. The air flow that you created is cooling the fan thermal switch, but it may not be cooling the hydraulic fluid as much. Can you check the fluid temperature and see how it is doing. You might want to have both fans come on from the fan switch if that does not overload that switch. Of course I am not sure this is a problem, just one of my usual paranoid concerns. You could also wrap some insulation around the fan thermal switch so that it more closely thermally couples to the hydraulic fluid. I think this is a better idea.

 

[Phils]

BobRip,

Good idea on wrapping the hydraulic oil thermal switch. Possibly I hadn't worked the PT long and hard enough, possibly the extra cooling air actually contributed some to hydraulic cooling, and possibly the thermal readings are skewed from the extra cooling air.

I will be monitoring closely. I don't imagine "too cool" is a problem normal to PT.

Phil

 

[Marks481]

the top fan works off of a thermoswitch that is just clamped onto the outside of the hydraulic piping. It is believable that if you are not using the PTO, that the engine compartment temperature rather then the hydraulic oil temperature is triggering the thermal switch.

The downside of the 7.5 amp fan is that it is noisy (although probably not noticeable with PT at full throttle). I will keep you all informed if the exhaust starts melting the plastic shroud.

The PT422 temperature just makes me nervous; after extended PTO ops I generally get a backfire and a bit of "dieseling" after I shut down... anything that drops the overall temperature should help. Strangely enough, I have not had any problems with vapor lock.

Temperature monitoring would be nice; I bough two 2" oil temp gauges to mount on the vertical section of the center tunnel.

Any suggestions on where/how to mount the sending units? Eventually, I will mount one in the hydraulic tank, but that will have to wait until the first drain interval when the tank is empty. Until then, I will probably clamp the sending unit to the side of a metal hydraulic fitting and wrap it in insulation.

Location for the engine oil temp sender is the harder choice.

Of interest, Spal makes a PWM fan controller, which will ramp one fans speed from 50% to 100% based upon user selected temperature, and control another fan with a relay. Not cheap, but it woul be an option which would not be much more expensive then putting in a relay. My theory is that the PT runs hot enough that pulling air across the exhuast manifold is a good idea regardless of engine temp.
JayCorp Technologies - SPAL Programmable Fan Controller

 

[Phils]

the top fan works off of a thermoswitch that is just clamped onto the outside of the hydraulic piping. It is believable that if you are not using the PTO, that the engine compartment temperature rather then the hydraulic oil temperature is triggering the thermal switch.

The downside of the 7.5 amp fan is that it is noisy (although probably not noticeable with PT at full throttle). I will keep you all informed if the exhaust starts melting the plastic shroud.

The PT422 temperature just makes me nervous; after extended PTO ops I generally get a backfire and a bit of "dieseling" after I shut down... anything that drops the overall temperature should help. Strangely enough, I have not had any problems with vapor lock.

Temperature monitoring would be nice; I bough two 2" oil temp gauges to mount on the vertical section of the center tunnel.

Any suggestions on where/how to mount the sending units? Eventually, I will mount one in the hydraulic tank, but that will have to wait until the first drain interval when the tank is empty. Until then, I will probably clamp the sending unit to the side of a metal hydraulic fitting and wrap it in insulation.

Location for the engine oil temp sender is the harder choice.

Of interest, Spal makes a PWM fan controller, which will ramp one fans speed from 50% to 100% based upon user selected temperature, and control another fan with a relay. Not cheap, but it woul be an option which would not be much more expensive then putting in a relay. My theory is that the PT runs hot enough that pulling air across the exhuast manifold is a good idea regardless of engine temp.
JayCorp Technologies - SPAL Programmable Fan Controller

That controller would be a good answer. Just leaving it on like your's is probably better though, because of the KISS philosophy. And keeping it simple is what will probably stop me from installing those relays.

The dieseling and backfire result from running hot. As the engine heat increases, the gas starts to turn to vapor but not so much that it kills the engine. But it makes the engine run lean, which causes the engine to run hotter. Which makes the gas vaporize more, which makes the engine run leaner, which makes it run hotter, which will cause dieseling and backfires at shutdown. Rather a vicious spiral.

Also contributing to the backfire "pop" is IMO the exhaust "manifold".... that is, some sections of square tubing welded to a couple of pieces of round tubing, and feeding a box with baffles. Hot spots develop in the "manifold" when the engine is running hot, then at shutdown those hotspots ignite the air/fuel mixture that's present in the exhaust stream because the spark plugs were turned 'off'.

It all relates to heat and I am confident that you and I won't be having the problem anymore!

Putting oil temp gauges where you describe is a good idea. Aren't there some unused bungs in the hydraulic tank? When the oil is cool, it'd be easy enough (I'm imagining here) to install a sender in the tank by pulling the plug and putting the sender in quickly, thereby letting very little oil out? Or am I imagining the extra bungs?

Phil

 

[Gravy]

I also thought the backfiring was due to the funky square exhaust system. I was really disappointed when my adaptation of the Robin side-mount exhaust system with the round tubing manifold made no difference. Oh well, at least it's not quite as obnoxiously noisy.

Gravy

 

[ponytug]

Um... I'm a rank amateur here, but I'm with Phil on this one. When you shut off the ignition, all you shutoff is the sparkplugs. If you have a hot spot in the engine (the plug itself, a valve, a bit of carbon), you always get run on from a carburetor equipped engine. Fuel injection engines are a different story (no fuel). As Phil points out, what one wants to do here is get the engine cool enough before you turn it off. That way there won't be any internal part of the engine hot enough to diesel on. Besides, if the engine is cooler, the oil and the engine will last longer, but that's a whole 'nother thread.

Of course, you could get fancy and have the engine, and the headers sent off for coating to insulate/conduct the heat. But it does seem like overkill in a tractor engine.

As far as mounting the senders, getting a good thermal bonding is all you need; just use a pipe clamp around the metal nut on a non-swivel hydraulic hose, and put a wrap or two of neoprene pipe tape on top. It will read the oil temperature accurately, just with a slight lag. Don't tighten the pipe clamp too hard or you'll break the sender.

For those of you that didn't buy the sender, you can get a cheap electric BBQ thermomenter and pipe clamp it to a metal fitting. You have to replace the AAA periodically, but most come with alarms- assuming that you can hear it over the engine. The price is right; you can often find them on sale for less than $20.

All the best,

Peter

I also thought the backfiring was due to the funky square exhaust system. I was really disappointed when my adaptation of the Robin side-mount exhaust system with the round tubing manifold made no difference. Oh well, at least it's not quite as obnoxiously noisy.

Gravy

 

[kmaz]

I also thought the backfiring was due to the funky square exhaust system. I was really disappointed when my adaptation of the Robin side-mount exhaust system with the round tubing manifold made no difference. Oh well, at least it's not quite as obnoxiously noisy.

Gravy

Hey Gravy, I too was interested in the robin side mount exaust. Sorry to hear you weren't happy with it. You dont happen to have any picteres of that do you?
Kris

 

[Gravy]

I do have photos. I'll try to post some soon.

Gravy

 

[MossRoad]

I do have photos. I'll try to post some soon.

Gravy

Woo Hoooo!!! We love photos!