I want to put a temp gauge right on the motor so I have an "accurate" reading. Any suggestions on what kind or where? (sorry, it's not a small block Chevy so I'm kinda lost! ;))
Tryin to keep cool,
Chaz
Quote from: Chaz on August 15, 2007, 09:54:59 AM
I want to put a temp gauge right on the motor so I have an "accurate" reading. Any suggestions on what kind or where? (sorry, it's not a small block Chevy so I'm kinda lost! ;))
Tryin to keep cool,
Chaz
Hi Chaz,
Like you, I want a mechanical temp gauge for the engine. I have the gauge, but it was never hooked up when the engine was rebuilt. On my 8V-71, there are three places for senders to be mounted on the passenger side (right side?) thermostat housing facing the outside (away from the engine). I haven't connected mine yet, but am in the process of finding a bushing to reduce the size down to that of the bulb.
David
Alot of coaches I have worked on over the yrs have had 2, 1 on each head or thermostat housing each! That way if you are experiencing problems, you can narrow it down to which head or radiator is likely the problem! FWIW! ;D BK ;D
Hmmmm......
The temp gauge holes (3) on my bus are on the drivers side. 2 Have single wires and 1 has 3 wires but they are all cut off. (Is the two singles for the up front gauge and indicator light?) Can I use the 3 wire sending unit spot? Or should I use one of the single wire spots?
And, should I use a mechanical or electric? The manual one will have all that excess wire/whatever. But, I want it accurate as I know the one up front isn't. (shows 210 when it's 185, I think. Checked radiator with infra-red gun)
Thanx,
Chaz
Chaz,
When you checked the radiator with a gun was it the top or bottom of the radiator.
I'm just confused about something.
I always was told mechanical is more accurate and dependable. FWIW.
Skip
Skip, that was the reason he (Jerry Lieber) checked it to see what the difference was from top to bottom. It was 185 on top and 155 on the bottom. So I guess that means the radiator was doing ok.
Chaz
Per section 6 page 3 figure 3 - GMC Coach maintenance manual X-7564 P8M4905A & P8M4108A. ???
It shows two sending units.
The top one by the square casting which is the thermostat housing is the Overheat sending unit.Item #5
The lower one is the Temperature sending unit.Item #6.
Hope this helps.
Install a "Tee" fitting and put the mechanical gauge sending unit on one side and the electrical sending unit on the other side of the "tee". ;D
Thanx Tex!!!
But I wonder what that third unit with the 3 wires coming off of it is? They are all cut off so I know it's not used.
If it's not in the book, if I took a picture of it, do you think anyone would know?
Thanx,
Chaz
Quote from: Chaz on August 15, 2007, 12:41:27 PM
Thanx Tex!!!
But I wonder what that third unit with the 3 wires coming off of it is? They are all cut off so I know it's not used.
If it's not in the book, if I took a picture of it, do you think anyone would know?
Thanx,
Chaz
Chaz please post a picture and I'm sure we can help! FWIW
;D BK ;D
Chaz, here's a pic of my t-stat housing showing where they put my mech. gauge sender (top right). I can read the mech. gauge on the engine through the vent in the rear cap (aftermarket cap). It reads about 5 deg. less than the elec. one in the dash (which makes me drive more conservatively... I like that).
HTH,
Brian B.
dont know if it helps but on my Eagle with a 6v92 the one in the head with three wires is part of the auto shut down system and is interconnected to a similar switch on the oil pressure block next to the oil pressure sender. the switches have three connections labeled C, NO, NC.
steve
1981 Eagle model 10
QuoteInstall a "Tee" fitting and put the mechanical gauge sending unit on one side and the electrical sending unit on the other side of the "tee".
Wouldn't that put the sending units out of the coolant flow and give an inaccurate reading?
Thanx Steve. I'll check that out.
Barn Owl, I was kinda wondering the same. I'm sure it would still work, but I would think the reading would be off a bit. And to the wrong side.
I think I can just go ahead and pull the 3 poled one out and use that spot. I'm just not sure about "electric or mechanical"? I would like to go mechanical, but I don't like all that excess cable or whatever you call it.
Pondering,
Chaz
a good electric gauge with clean power is about as accurate as they anything now days. does your bus have the auto shutdown? is this the original motor? if not maybe some of the cut wires are left from the swap and it was easier to cut them and leave them than fix it right. my bus had a lot of broken insulation and chaffed wires so I got fed up and ripped it all out and built a new harness based on the wiring diagram in the manual so I eleminated all the stuff that no longer is used. makes tracking things alot easier.
Steve
Thanx Steve.
Sounds like you have more patience than a buzzard or are a gluton for punishment!! ;D ;D ;D ;D That wiring thing would send me to the "nut house"!! SOONER!!!! LOLOL :D
I don't know much about the history of my bus. So i don't know what is what. But I do have a 24v system and I'm not sure how an electrical gauge will work with that.
I guess i could get around it some how, but maybe a mechanical would be easier and more accurate. ???
Thanx,
Chaz
Hey Chaz
Isspro makes electric gauges in 24 volt and are nice quality. the only problem with a mechanical gauge is that they have a capillary tube filled with fluid-glycol I think? that is not a big issue except for the length and running it that far without kinking it or having a place where it may chafe. personally I would only run a mechanical as a screw in type so that it is directly on the head without the capillary tube and use it just as a comparison to the electric dash gauge if you suspect a problem. I build performance boats and all we use are electric gauges and we beat them up pretty bad and almost never have a problem. If you go to ISSPRO's website and follow it to temp gauges the last 10 or so are 24 volt.
hope this helps.
steve
FWIW, I don't care much for the shutdown "feature" in these old MUI engines, so I disabled mine. The DD can shut down at the most inopportune time... maybe saving the engine at the potential expense of the safety of the coach and its occupants. I left the telltale lights/ sensors in place, and always watch my temp. gauges (coolant, oil, tranny oil) like a hawk, esp. during overheating/ overfueling conditions.
I'd rather be the one to decide when and where to shut down my DD.
My $0.02,
Brian B.
A mechanical gauge would not tolerate the vibration screwed directly into the engine. I have had no problem with the capillary tube gauges in the engine compartment.
MCI used to have a shutdown over ride switch available as an option. I had one bus with it factory installed and I put one on the next bus. It is very useful since you can flip the switch, drop a gear and probably get the temperature down without even stopping. This happens when you are too busy looking at the scenery instead of the temperature gauge.
Hey Chaz
I Like the mechanical also at the back. Oil & Temp.
The three wire sensor was for the auto shut down system. Use that hole for your Mechanical Guage. If you can get any of the plugs out of either of the thermostat housings that would be ok also. I like 1 in each side as previously mentioned.
I like the warning buzzer and Idiot light. Wire it with the hot leg (through fuse) to the light and buzzer, then wire the ground to standard idiot sending units for temp & oil. The sending units go to ground on low oil or high temp and complete the circuit. You can get the senders in various temps and pressures.
coil up the capillary tube on the temp guage without kinking wire tie it out of the way, It will be alright.
I like the electric up front with the warning system. The lights & buzzer realy get your attention as you are seldom watching the guages. I like the mechanical in the back to verify the accuracy of the electric.
This Just came in handy a couple of weeks ago as I glanced down @ the oil pressure guage And it was barely off 0 pounds. I shut the engine down and pulled off the road, went to the back checked the oil, all was ok, cranked the engine and the mechanical guage went right up to 25#, I hit the throttle, and the pressure went up to the normal 50#.
Had I not had that mechanical Guage(or a seperate Electric sender and guage) I would have had a very bad day, only to find the sender had gone bad.
I ran a 7 wire trailer cable from front to back that has come in handy for stuff like this.
Good luck with your installation.
Bill
I had an override switch in my freightliner and kenworth both and wondered why the busses dont seem to have them. I thought about adding one when I rewire my dash. does anyone know off hand what wires I need to add and or what switch I need? I like the auto shutdown to help when I am watching the road but I dont want it leave me dead in the water if there is an easy override.
thanks
steve
Good info!! Thanx Guys!!!
I think I will go with the mechanical and just mount it close and wrap up the excess.
All this "shut down stuff" is new to me also. I'll have to look into that in another thread. My plate is REEEEEEEEALLY full right now. I have to get all the stuff I have started, finished before the labor day weekend so I can take her up to the Auburn Auction. (Northern Indiana. It's like Barrett/Jackson but older. 5000 cars!!!) So I better focus on getting her back up and running!! ; ;D
Hey Bill!!
Good to hear from you!!! I ain't forgot about my mods for fuel and will be talking to you one day. Just not sure how soon! ??? :)
But if ya have a chance, would ya take a look at my other on-going thread? It's about Front spoiler/air dam for mileage. I'm thinking you may be able to help out in this arena also. ;)
Thanx again!!!!!!
Chaz
Chaz,
This is the one that I used: http://cgi.ebay.com/ebaymotors/_W0QQitemZ280145862295QQcmdZViewItem?hash=item280145862295 (http://cgi.ebay.com/ebaymotors/_W0QQitemZ280145862295QQcmdZViewItem?hash=item280145862295). It has a temp. and an oil pressure gauge so I won't have to bend down with a flashlight to read the oil pressure. I'll mount it on the 'ceiling' of my engine compartment where the current (dead) mechanical gauge is located. There is only about 6' of cable between the gauge and the fitting for the temp. bulb, so that shouldn't be an issue. It came with lots of adapters, but I had to get a 1" to 1/2" bushing (black iron - about $1.25) from Lowe's to mount it in the thermostat housing. It has 12 volt bulbs, but I've wiring them in series and connecting them to the engine compartment service lights. At night, I can just flip the switch on the rear control box and have lights and lighted gauges. The only question I have is about the hose fro the oil pressure gauge. I'd hate for it to become damaged and squirt oil everywhere. perhaps some 1/8" copper would be better, if it's even available. I could use 1/4" copper ice maker tubing with a reducing bushing for something more durable. Most likely, though, I'll just run the tube inside a length of windshield washer hose for a bit more protection.
David
On the boats we use aeroquip -4 pushlok hose. they have and adapter to go on the gauge. parker I think have a similar product. not the cheapest but it is good to 400 or 500 psi and will never fail in the life of the bus.
steve
David,
It is probably overkill, but when I installed my mechanical oil pressure gauge in the engine compartment, I had a local truck parts store make me a 1/4" hydraulic hose. I think it is rated for 2500 or 3000 PSI. Like you, I was concerned about that hose developing a leak and leading to a major engine problem. Jack