I have noticed the coil is hot.  It is an Accel with internal 1.4 ohm resistence without ballast, which was the coil Accel called for to go with their pointless ingition if ballast resistor wasnt going to be used.  Coil is mounted in standard location over intake, with 1/2 in. spacers holding it above intake.

Intake manifold gaskets are wide open at the crossover, and they and the manifold are temporaries waiting for Mummert's release.  Thin stock phenolic spacer between intake and carb.

So what do you think is the cause in idle change?  Heating causing a change in idle mixture or an overheated coil changing its characteristics?  Idle returns to normal immediately after temp drops. 

When it goes up to say 175 I switch on the elect. fan and the engine will stay at 180 until back underway.

Leaner? 

Use your infared gun on the carburetor, hard fuel lines and fuel fillter. Mechanical fuel pump? If the engine is thumping along sort of retarded on spark - the exhaust will heat up and start "radiating" everything in the "line of sight' from the heated surfaces. Fuel pressure maybe dropping?

Mike

                                                        Michael

     And making it act rich. That's why Charlie told him to reset the idle hot. Problem is, when he does, it will be lean before it warms up. It's a tradeoff.

The cold running temp is a continuing puzzle.  The same temperatures occurred with the previous low compression engine, using a big 4 row stock 1946 new core radiator.  Put in a new engine with much higher CR, a relatively small 17X19 core alum. rad, and the same thing.  I talked to a mech. engineer/car nut about it last year.  He thought the cold temp was due to the low 7:1 or so CR.  It is now clear that wasnt right, because the CR is approx. 9.2:1.

I am lucky to have one of Franks aluminum timing covers and water pumps.  Several years ago when I was installing them, there was interference in the area of the timing cover water scraper (dont know what it should be called), and the pump impeller.  After some work clearance was achieved with a very close tolerance that could be measured in thousandths.  Perhaps the result is a super efficient, maybe too efficient pumping action, leading to cool running temps?  Sounds a little far out but nobody else has been able to explain the phenom. 

Mike

Where is the temperature sensor installed?

       That makes absolute sense. the coolant continues to absorb heat as it travels to the front of the motor. The hottest point should be at the thermostat. I can easily believe a 15 degree rise from the back to the outlet.

         Mike, I intentionally kept the impeller to the timing cover dimensions tight, but had some issues with the machine shop not locating the mounting holes in the pump/timing cover accurately. I finally had to change suppliers because of that. I hand fitted the pumps to the cover just to avoid the issue. Not sure how yours slipped through, but I apologize, you shouldn't have had to do that.   

DS rear of head right next to sender     158

DS front of head 182

PS front of head 188

Intake crossover 160

Intake water jacket 170

Water port behind thermo housing 167

Thermo housing 170

Carb body 101

Coil 122

So, as suggested by Ted and John, the water gauge is approx. 15 deg. cool due to its location.  And the rough idle doesnt start at 180, but 195 or 200 deg., which seems to make more sense. 

I'll move the sender to behind the stat when the new manifold is installed.  In the meantime the fan will get switched on earlier, and maybe that alone will take care of rough idle.  The carb and coil temps seemed good, but dont have anything to compare them to.

A couple years ago a friend checked the rear DS head & thermo housing temps, and they were virtually identical being below 160 degrees after I had driven to his house 12 miles away.  But the old engine had some weird issues.

Thanks to everyone for their help!

Mike

        I attempt to get the clearance between .020 & .030" this is an arbitrary number I chose to eliminate as much leakage between the impeller and the casting as I could. Need to keep some clearance because the impeller will grow with heat more rapidly than the timing cover. I've seen rebuilt iron pumps with over .060" that still pumped water. 

      All of the timing cover castings will show evidence of grinding. This is to remove a core to pattern mismatch. The clearance issue always seem to be at the start of the volute, which is the closest point of contact.  

       I've had this discussion with a number of folks, including some from the Classic T'Bird club. The area behind the impeller, or the size of the plenum has no effect on how the pump works. The pump works by spinning the impeller, this throws the water out of the area betweem the blades. That is replaced by more water from the supply side (the radiator). Exhausted water, after it is thrown out of the impeller, is forced into the plenum and then the engine. The only restriction to this flow should be the thermostat.

      The plate that you refer to, has only one purpose, to make money for whomever sells it. 

     Casco has a very interesting article on that plate,  Had one on my bird.. didn't work worth beans!!!  Now have large impeller, smaller pulley, clutch fan and large hole 170 thermostat--  also have A/C condensor under right front fender with elect fan. Even in parades never goes over 190.  Hope this helps!!     God bless    Eddie

     Look at the timing cover, and remember the pump was designed for the car, not the Bird. The volute and the shape is designed to direct water into the the TC passage.  

          I think that was already done to your spacer. If not then you can return it and I will or you can check the clearance yourself and let me know what's who.

Not long later came to one of the pickup points and there was a long line, the temp rose, and stall.  Couldnt start so rolled back down the hill and went in to get the cards, checked the coil and it was hot.  Immediately started on return.

I am sure it is the coil.  It is an Accel with 1.4 ohms internal resist., no ballast required.  I feel like a dumby, because this is the third of these crap coils that have been problems.  Plan to replace with a OEM unit and resistor this week.

Before the run I rechecked the valve adj. and they were all fine. 

Sounds more like vapor lock than electrical to me.

55Vickey, The first flamethrower of this number I ended up using on my 54 Ford tractor when it was first converted to 12V.  It was always hot when in use, and gave out in 1-2 years.  The second overheated and puked its oil when I left the ignition on overnight, but it was hot while in use during its short life.  My thinking was that with the Accel pointless ignition matched to one of their coils they specified in the instructions, it should be a great match this time around.

That fuel line is located in probably the hottest part of the top of the engine.  I recommend temporarily running a line on the topside of the intake and see if that makes a difference.  Even with fiberglass insulation, the heat would be trememdous under the center of the manifold.  It burns the paint off the manifolds.

I searched through this thread & didn't find what you have for a carb spacer, & what carb you are using.  I saw something about autolite, & remember from before you had planned on using a 2barrel, but think it may be relevent to find out what the application of that carb is, & what you have for a spacer/insulator. 

The carb is an autolite 2100 which originally would have been used on a Mustang SBF, 1966 if I remember right.  There is a half inch phenolic spacer between it and the intake.  This probably doesnt have any bearing, but I rotated the automatic choke spring so that the choke never is activated, always open.  Carb was newly rebuilt before installation.

Mike

I recently swapped out an old 2100 that was of 68 small block ford application that was on two different y's I've messed with over the years with a 58 holley 2300 & was surprised how much the idle through 2500 response & light to part throttle driving changed. 

The only down fall of the autolite 2100's is the fact that the idle, low & high speed air bleeds are built in to the boosters & also the carb castings.  The worst thing is there is very little information availible to properly understand what boosters with which carb produce accurate meetering with which engine, & then if you factor in the changes that occur with a 100 degree fuel bowl, & what each air bleed does or doesn't do when the carb is 100 degrees it stands to reason as to why most end up with new carbs, & or application specific remanufatured carbs. 

I rerouted the gas line so it stays well above the intake.  Also changed the coil to an OEM with ballast.

This weekend on a 60 mile run up I-5 and back, gauge temp rose to 180, as the tall climbs were made.  On return home there were three long periods of idle at 180.  Quality never deteriorated on idle.  After in the barn, checked the thermo housing temp and it was 187 with gauge at 180, maybe a couple degrees more.  The OEM coil was 147.

Soooo, the sender will remain in the stock location.  The problem looks like it is fixed on the idle.  

I tinkered around with the mainjets too, and maybe created a new issue.  The car behind me said whenever I put the foot to the throttle black smoke came out both exhausts, at highway speeds of 65-75.  So my thinking is either the jets are a tad too large, or they are on the fringe and the pump shot is excessive.   Ambient temp may have played a roll, as it was COLD the entire first leg of the trip, being about 50 degrees.  Unfortunately I was at the tail of the convoy on return, when temps outside were 95, with nobody to see what was happening.