Engine Heat Problem
05-24-2004, 03:34 PM
#1
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Thread Starter
Join Date: Apr 2002
Posts: 43
My temp guage has been running at half or a little more for the last several weeks So far I have done the following
Bubble Check to see if an internal seal was bad> no bubbles.
Pulled all the air conditioning parts>thought it might be blocking air to the Rad.
Flushed the Rad with CLR> Flues look good and clean.
Cleaned the Rad outside> All the fins were very clean.
Changed the Coolent > replaced with distilled water and Water Wetter, and some antifreeze.
Double Alt Pully
16 Inch Electric Fan inside of the fan shroud.
Installed an aftermarked temp guage in the water pump housing.
180 degree thermostat, with a bypass hole drilled in it.
I took the car out last night and the temp guage got up to 210, This was in less then 5 miles and sitting at one stop light.
The water pump is not leaking but could it still be bad in some way?
The car is a 79 with a SP 12a, Webber 48 carb, and RB muffler.
Could I be running the car to lean? Should I adjust the carb to more rich?
Is 210 to hot?
Thanks for any help.
Bubble Check to see if an internal seal was bad> no bubbles.
Pulled all the air conditioning parts>thought it might be blocking air to the Rad.
Flushed the Rad with CLR> Flues look good and clean.
Cleaned the Rad outside> All the fins were very clean.
Changed the Coolent > replaced with distilled water and Water Wetter, and some antifreeze.
Double Alt Pully
16 Inch Electric Fan inside of the fan shroud.
Installed an aftermarked temp guage in the water pump housing.
180 degree thermostat, with a bypass hole drilled in it.
I took the car out last night and the temp guage got up to 210, This was in less then 5 miles and sitting at one stop light.
The water pump is not leaking but could it still be bad in some way?
The car is a 79 with a SP 12a, Webber 48 carb, and RB muffler.
Could I be running the car to lean? Should I adjust the carb to more rich?
Is 210 to hot?
Thanks for any help.
05-24-2004, 09:26 PM
#2
Senior Member
Join Date: Jun 2002
Location: Arkansas
Posts: 254
Rotary engines run hot...just a fact of life 
I'm still using the factory in dash guage and it runs about half way if its freezing...about half way if its 105 outside
if you havn't replaced the radiator yet i'd advise doing so...they do tend to clog up and or rot when they get old...my 84 factory radiator i what killed my first engine
Started slowly climbing up to the red...then it would bounce back down...and eventually it quit bouncing back...replaced the radiator and it started riding about half way from then on.
as for running the car richer or leaner...My car is running EXTREMLY rich right now...so I don't think making it richer would do much good...more gas = more fire = more heat
I'd watch that radiator...cost me over 200 bucks to get a good new one here locally when I finally replaced it...but i wouldn't be cruisin around the streets without it
and...even if you can flush water thru the radiator...that doesn't mean that the rows are clear...i've worked on 2 cars where the water flowed just fine...but almost every single row was clogged with stop leak...DO NOT put stop leak in your rad unless you're asking for trouble
replaced the radiators in both of them and bam...no more overheating
I'm still using the factory in dash guage and it runs about half way if its freezing...about half way if its 105 outside
if you havn't replaced the radiator yet i'd advise doing so...they do tend to clog up and or rot when they get old...my 84 factory radiator i what killed my first engine
Started slowly climbing up to the red...then it would bounce back down...and eventually it quit bouncing back...replaced the radiator and it started riding about half way from then on.
as for running the car richer or leaner...My car is running EXTREMLY rich right now...so I don't think making it richer would do much good...more gas = more fire = more heat
I'd watch that radiator...cost me over 200 bucks to get a good new one here locally when I finally replaced it...but i wouldn't be cruisin around the streets without it
and...even if you can flush water thru the radiator...that doesn't mean that the rows are clear...i've worked on 2 cars where the water flowed just fine...but almost every single row was clogged with stop leak...DO NOT put stop leak in your rad unless you're asking for trouble
replaced the radiators in both of them and bam...no more overheating
05-25-2004, 07:10 AM
#3
to infinity & beyond, me
Join Date: Aug 2001
Location: santurce
Posts: 5,124
i always thought richer meant cooler...
also chek your oil, when was the last time u changed it?
supposedly my water pump is bad, it doesnt leak however, it just makes a lil whining noise and when it was taken out it would get stuck a bit when turned by hand.
also chek your oil, when was the last time u changed it?
supposedly my water pump is bad, it doesnt leak however, it just makes a lil whining noise and when it was taken out it would get stuck a bit when turned by hand.
05-25-2004, 07:50 AM
#4
Senior Member
Join Date: Nov 2003
Posts: 480
210 is kind of up there...You should be around 190 maybe. Just throwing this out - is your thermostat the right kind? It should have a springy thing at the bottom to block the bypass hole in the water pump.
Also water pumps are pretty reliable, but I replaced one once (not in a mazda) that had no impeller left whatsoever.
Richer does mean cooler - you can't burn the extra fuel without oxygen. The extra fuel cools it down. If you want to check your cruise mixture you might pull off the headers and look at the sleeve color, which might be more telling than the plugs.
Also water pumps are pretty reliable, but I replaced one once (not in a mazda) that had no impeller left whatsoever.
Richer does mean cooler - you can't burn the extra fuel without oxygen. The extra fuel cools it down. If you want to check your cruise mixture you might pull off the headers and look at the sleeve color, which might be more telling than the plugs.
05-25-2004, 08:23 AM
#5
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Thread Starter
Join Date: Apr 2002
Posts: 43
Originally Posted by treceb' date='May 25 2004, 12:10 PM
i always thought richer meant cooler...
also chek your oil, when was the last time u changed it?
supposedly my water pump is bad, it doesnt leak however, it just makes a lil whining noise and when it was taken out it would get stuck a bit when turned by hand.
also chek your oil, when was the last time u changed it?
supposedly my water pump is bad, it doesnt leak however, it just makes a lil whining noise and when it was taken out it would get stuck a bit when turned by hand.
05-25-2004, 08:25 AM
#6
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Thread Starter
Join Date: Apr 2002
Posts: 43
Originally Posted by 83turbo' date='May 25 2004, 12:50 PM
210 is kind of up there...You should be around 190 maybe. Just throwing this out - is your thermostat the right kind? It should have a springy thing at the bottom to block the bypass hole in the water pump.
Also water pumps are pretty reliable, but I replaced one once (not in a mazda) that had no impeller left whatsoever.
Richer does mean cooler - you can't burn the extra fuel without oxygen. The extra fuel cools it down. If you want to check your cruise mixture you might pull off the headers and look at the sleeve color, which might be more telling than the plugs.
Also water pumps are pretty reliable, but I replaced one once (not in a mazda) that had no impeller left whatsoever.
Richer does mean cooler - you can't burn the extra fuel without oxygen. The extra fuel cools it down. If you want to check your cruise mixture you might pull off the headers and look at the sleeve color, which might be more telling than the plugs.
I need to find out how to richen the Webber now.
Would you happen to have any links on how to read the plugs.
05-25-2004, 09:20 AM
#7
Senior Member
Join Date: Nov 2003
Posts: 480
I'm assuming that you are running hot in "normal" driving, ie light loads. Basically your 12A won't run very lean under those conditions (I've been playing with a wideband). Due to the late exhaust closing, you get alot of unwanted exhaust holdover to the next cycle, which hinders combustion so you wind up running a sort of rich mixture for better ignitibility. Higher loads and higher RPM can run much leaner (drive fast - save fuel).
Does the car seem to run lean? (ie driveability problems, stumbles, "scratchiness")
If your plugs are white or a little green (copper burning from the electrodes), you're lean.
The weber has idle mixture screws at the very bottom. You can alter cruise mixture by changing idle jets. Main mixture is on the main jets plugged into the bottom of the emulsion tubes. What type of weber is it?
Does the car seem to run lean? (ie driveability problems, stumbles, "scratchiness")
If your plugs are white or a little green (copper burning from the electrodes), you're lean.
The weber has idle mixture screws at the very bottom. You can alter cruise mixture by changing idle jets. Main mixture is on the main jets plugged into the bottom of the emulsion tubes. What type of weber is it?
05-25-2004, 11:32 AM
#8
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Join Date: Apr 2002
Posts: 43
48 Side Draft, Guess that makes it a DCOE?
It will stumble a bit around 1500 - 2500, But is just fine at anything above. I will try and put up a pic of it.
The only Carbs I have adjusted are on lawn mowers and my Tmaxx RC truck. Can I just give the idle jets a bit of a clockwise turn to add fuel? The idle and Main's are under the gold cap?
It will stumble a bit around 1500 - 2500, But is just fine at anything above. I will try and put up a pic of it.
The only Carbs I have adjusted are on lawn mowers and my Tmaxx RC truck. Can I just give the idle jets a bit of a clockwise turn to add fuel? The idle and Main's are under the gold cap?
05-25-2004, 03:14 PM
#10
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Join Date: Nov 2003
Posts: 480
Yes - idle and main are under the "mickey mouse hat". You can adjust the idle mixture screws (topmost in the pic) with a screwdriver, but the main and idle jets are sort of press-in things. When you remove the hat, you will see 4 screws (okay, so I'm referring to a Dell'Orto DHLA but it should be the same) - these are the jet holders. When you unscrew them, you will pull out the entire emulsion tube. Fuel jet is at the bottom, air jet is at the top - you have to pull off the jet holder to get to it if you are going to fiddle with those.
The brass screws to the left and right of "WEBER" hold the accelerator pump squirters.
I'm not sure what the others are - it's been a while.
To determine the cause of the 1500-2500 RPM hesitation, slowly tighten the idle speed adjustment screw, raising the idle. If it leans out and stalls, the idle fuel jets are too small (adjusting the screws won't help). If it continues to rev up okay, try different accelerator pump squirters. My Dell'Orto always seemed to have a problem there - I think because of the long, cold manifold.
Also I didn't see a cold start linkage in the pic. Do you have one?
The brass screws to the left and right of "WEBER" hold the accelerator pump squirters.
I'm not sure what the others are - it's been a while.
To determine the cause of the 1500-2500 RPM hesitation, slowly tighten the idle speed adjustment screw, raising the idle. If it leans out and stalls, the idle fuel jets are too small (adjusting the screws won't help). If it continues to rev up okay, try different accelerator pump squirters. My Dell'Orto always seemed to have a problem there - I think because of the long, cold manifold.
Also I didn't see a cold start linkage in the pic. Do you have one?