marrt
Platinum Member
Thanks Kent for posting those pictures. I'm getting ready to make some modifications and, if you don't mind, will steal some of your ideas. 
Overheated Robin EH72-FI (28 hp) in PT-425 solved
- Thread starter Kent
- Start date
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MossRoad
Super Moderator
- Joined
- Aug 31, 2001
- Messages
- 58,132
- Location
- South Bend, Indiana (near)
- Tractor
- Power Trac PT425 2001 Model Year
Gotta send him a dollar for each one! :laughing:
Marks481
Platinum Member
- Joined
- May 29, 2005
- Messages
- 978
- Tractor
- Power Trac 422 (2005)
Well I just got the Robin muffler/exhaust and I gotta say that it is a very sturdy build. Not flimsy sheet metal like I expected. I guess I will have to do some surgery this weekend.
MuncyBob
Platinum Member
Looking forward to your hearing about your adventures! It will be at least until next weekend that I install the 2nd fan and probably another month or so before I get the Robin muffler.
KMA
Gold Member
I did the Robin muffler on my PT422 w/ EH72FI a few years back. I believe it helped with the heat issues, along with my other mods (re-routing fuel line, additional fan) but it's still something to worry about. The PT tub design isn't made to deal with the heat generated. I had a Subaru engine tech tell me their engines were not meant to work in the conditions seen in the PT. Here's my muffler mod:
http://www.tractorbynet.com/forums/...engine-swap-completed-pics-3.html#post3256257
Instead of hard mounting it and using flex pipe, I made a new manifold from 1" pipe and mounted it similar to the OE muffler. My engine moves quite a bit and I wasn't sure if a flex pipe would hold up over time. Let us know how it goes for you. :thumbsup:
http://www.tractorbynet.com/forums/...engine-swap-completed-pics-3.html#post3256257
Instead of hard mounting it and using flex pipe, I made a new manifold from 1" pipe and mounted it similar to the OE muffler. My engine moves quite a bit and I wasn't sure if a flex pipe would hold up over time. Let us know how it goes for you. :thumbsup:
Marks481
Platinum Member
- Joined
- May 29, 2005
- Messages
- 978
- Tractor
- Power Trac 422 (2005)
OK, I might be interested after all. The stuff I got (advertised as SS exhaust flex tubing) is not pressure tight. It is just flexible electrical metal conduit. And they sent me the wrong size (1" vs. 1.25").
Is the stuff you have pressure tight?
The Fan Control Switch (thermostat) I used was WHITE-RODGERS, Mfr. Model # 3F01-121.
Fan On Temp. (F)120
Fan Off Temp. (F)110
I bought it from Grainger Industrial Supply - MRO Products, Equipment & Tools, Item # 2E246.
Fan On Temp. (F)120
Fan Off Temp. (F)110
I bought it from Grainger Industrial Supply - MRO Products, Equipment & Tools, Item # 2E246.
jfischer
Silver Member
- Joined
- Feb 11, 2015
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- 174
- Location
- Manassas, Virginia
- Tractor
- Hustler X-One, Power Trac 425, Sold and Retired my JD318
Kent, I know this might have been asked to you before, but what were the temps on just the exhaust mod, without the fan running on the side. How much cooler running was it over the stock PT exhaust.
I wrapped my stock exhaust this last weekend, and know that the temps on the muffler itself went up from last time I measured it, so it is getting more heat out to there, but still bothers me with all the heat I can feel under there.
I guess I am just wondering if the muffler and the header is worth getting, or if just adding the fan to blow across the engine and out the exhaust side would be enough.
Did you put the stock heat shield back in behind the battery also?
I wrapped my stock exhaust this last weekend, and know that the temps on the muffler itself went up from last time I measured it, so it is getting more heat out to there, but still bothers me with all the heat I can feel under there.
I guess I am just wondering if the muffler and the header is worth getting, or if just adding the fan to blow across the engine and out the exhaust side would be enough.
Did you put the stock heat shield back in behind the battery also?
I had some temps in my original post, but didn't intend to perform a scientific study of all the possible permutations. My first attempts were to solve an alleged vapor lock problem (move the fuel pump, beef up fuel lines, use an ethanol-fixing gas additive). When those didn't help I then went for the muffler and fan fixes. Yes, the stock heat shield remains in its stock location, only now with the temp sensor disk attached to trigger the than on and off. Depending on what model year you have I think the arrangement of the major components under the hood differ. In mine in the front is the fuel tank, battery, heat shield, and then at the back, the engine.
If I were you I would just go one step at a time. Try it with just the fan + stock exhaust and see if that solves your problem. The fan is easy to add, just zip tie it to the screening. The muffler requires a bit more work for sure.
I do not have any idea about what is the "ideal" temp to run at. All I know is that with the FI engine Subaru put in a temp sensor wire that isn't on the carb engine. I had no idea I had a problem with overheating when I had the carb engine (very hot, but still running)...only when I swapped engines did the problem pop up and I had to redo the manifold/muffler and add a fan.
jfischer
Silver Member
- Joined
- Feb 11, 2015
- Messages
- 174
- Location
- Manassas, Virginia
- Tractor
- Hustler X-One, Power Trac 425, Sold and Retired my JD318
Kent, I have a 2015 of which I have put about 13 hours on it now. I am always one to try to prevent problems, and know that heat is a BIG issue. I couldn't believe on my JD how much the insulation on the firewall that seals the hood and all up makes a difference, as it pulls from the belly pan, and pushes it out the front of the tractor.
So, I wish I could put a fan on the exhaust side to pull it out, but think that will be too hot, as I have read others seemed to have tried that before. The fan seems to be the next step I should try, and is pretty cheap and easy to try. I just wish they had a bigger charging system on the machine.
I don't have any PTO attachments, and the hardest I have been working it now is digging a lot with the hoe, but can't tell a lot of difference in the heat change, other then the wrap made it keep the heat more on the exhaust header, and seemed to have brought the muffler temp up about 50 degrees. I did clean the inside of the exhaust ports on the header pipes where they welded them a bit off center before welding them, but can't tell much with that. It will soon be coming up to the first oil change, and will change over to synthetic and hope that will save the engine some.
I will test to see what the temps are on my 27hp Kawasaki in my Hustler zero turn somtime, as I know the old Onan in my JD runs pretty cool now with the way it can suck the heat out.
So, I wish I could put a fan on the exhaust side to pull it out, but think that will be too hot, as I have read others seemed to have tried that before. The fan seems to be the next step I should try, and is pretty cheap and easy to try. I just wish they had a bigger charging system on the machine.
I don't have any PTO attachments, and the hardest I have been working it now is digging a lot with the hoe, but can't tell a lot of difference in the heat change, other then the wrap made it keep the heat more on the exhaust header, and seemed to have brought the muffler temp up about 50 degrees. I did clean the inside of the exhaust ports on the header pipes where they welded them a bit off center before welding them, but can't tell much with that. It will soon be coming up to the first oil change, and will change over to synthetic and hope that will save the engine some.
I will test to see what the temps are on my 27hp Kawasaki in my Hustler zero turn somtime, as I know the old Onan in my JD runs pretty cool now with the way it can suck the heat out.
