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Discussion Starter · #1 ·
After the rebuild of 75 Alfa 2L I'm almost ready to start engine on a run stand.
This engine is going in a Antique Midget Race Car so I need to get all bugs
out of engine before I go racing. My first picture shows a Water Temp Sender, I believe. I'm not positive because I've looked in IAP and Centerline
but can't seem to locate. Any Ideas, I would like to buy new.
Second picture shows water manifold with Rad cap and no gasket installed.
It leaks badly so I'm thinking do I really need 2 Rad Caps, (1=Radiator + 1= Manifold). Does someone sell a flat piece to go over Rad Hole on Manifold.
Would this be a good idea or should I go with 2 radiator caps and gasket?
Third Picture is run stand with Alfa almost ready to fire.
Thanks Alfa3
 

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Cool, nice setup. That sender in the head is one of them (late Spider or Alfetta), but look right by the thermostat, there's another one on the manifold. You can see it in the first picture below the brass bleed screw.
Andrew
 

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The sensor in the intake manifold as mentioned by Andrew is for the coolant temperature gauge. The sensor in the back of the head is a simple on/off thermal switch to activate a coolant temp warning light on the dash of vehicles so equipped.
 

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You got a really good reason why you are using second radiator cap set up on intake instead of a thermostat? Am I missing something I can't see clearly in those pictures?
 

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Discussion Starter · #5 ·
Water Temp Gauge?

I don't believe I need a thermostat, I was thinking I could just block off thermostat with gasket and plate over hole, then I would get rid of termostat and Radiator cap off manifold.
Does that sound reasonable?

I have a few other questions...........

1- What type of temperature gauge should I use?
2- I'm running a RML Dist, I've notived the Cap does not fit tight on body, is that typical of RML?
3- I noticed my oil pan is different then any pictures I have seen, could this be a after market oil pan?

Thanks for response's
 

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I don't believe I need a thermostat, I was thinking I could just block off thermostat with gasket and plate over hole, then I would get rid of termostat and Radiator cap off manifold.
Does that sound reasonable?
Not to me, no. I was always taught that the thermostat provides two functions:

- Regulate water temperature
- Provide flow resistance where water leaves the engine to maintain back pressure in the head and block. That back pressure, plus the radiator cap pressure, raises the boiling point of the coolant. This is important around the hot spots in the cooling system - e.g., around the exhaust valves. Deleting the thermostat can lead to coolant boiling in the hotspots, which can lead to no cooling where you need it the most.

Note that the bung you have connected to the upper outlet of the radiator is for the bypass hose - a smaller diameter flex hose that connects to the water pump. You seem to be running a 1600 water pump that excludes that connection. Not a huge issue - when you add a thermostat, you could block that smaller bung in the intake manifold, and connect the upper radiator hose to the thermostat cover. But, you definitely don't want to add a thermostat, and keep the radiator connected to that lower bung on the intake manifold!

1- What type of temperature gauge should I use?
Why not an Alfa temperature gauge? You'll know it's compatible with your sending unit.

3- I noticed my oil pan is different then any pictures I have seen, could this be a after market oil pan?
Looks like an Alfetta pan. You may have seen pictures of the "batwing" pan used on 105 model Alfas. If you want to install a batwing pan on your engine, you will need to change the oil pump pickup.
 

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Discussion Starter · #7 ·
Thanks for that info Andrew, I believe I have the waterpump hooked the way
it needs to be. I've decided to go with a SW Water Temp gauge and a metric adapter in termostat hole. I won't need warning light on my small dashboard so I'll leave senser in hole, unless I can find a plug.
I'm going to leave second Radiator Cap alone without termostat and make a gasket to see what happens. Second Radiator cap will give me a higher point in which to fill water, I may even need a expansion tank in higher location .
Thanks for all your responses I appreciate it.
 

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so no thermostat. are you going to use a electric heater to pre-heat the coolant to around 85C/185F before each start and have some sort of thermostat controlled fan to keep it there. and maybe also some sort of thrmo-controlled flap to cover the the radiator. to keep the temp in a usable range?

Seems like a lot of work. why not just use the normal thermostat and not have to have a ton of problems trying to keep the temp stable with other means, and not have to pre-heat. As it will self heat very quick with a working thermostat.
 

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Discussion Starter · #9 ·
Thermostst

Thanks for reply, I've ordered thermostat just in case, I've talked
to a few other Alfa Midget Racers and no one seems to be running one.
I didn't get a reason, so time will tell.
Thanks again
 

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No disrespect meant here but running without a stat ranks pretty darn high on the no-no list. Not only will there be increased engine wear on warm up (if the engine ever does warm up), the jetting and timing will be a constantly moving target. Not to mention risk of high load/rpm overheating caused by insufficient coolant dwell time in the radiator.
 

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It is very bad to not have a stable temp.
papajam touched on the timing and bad AFR.

but lets look at the oil
just the oil alone will be quite bad. When on the cool/side it is too thick to flow(most normal damage happens here BTW) the PSI will read good but it is not flowing much. As most will go by the bypass valve. Also the pump is very hard to turn so a lot of HP is eaten up. And there is a real risk of snapping the shaft to the oil pump.
also if the bypass can't keep up the bearings will get damaged (washed out). and the oil filter might explode.

At the right temp with the right oil, the oil PSI should be just inside the where the bypass valve opens. (at least in the power band). this is the max flow.

Now as it gets too hot the oil will get too thin and the oil PSI will drop and you might get a shear in the oil film and say bye-bye to the bearings.

So in short too cold or too hot will prevent the oil from doing its job.

At a min you will lose a lot of power and shorten the life. and worse case you kill the motor by spinning a bearing or snapping the shaft to the oil pump.

Add that to the other problems papajam touched on the mix going to hell and the timing off etc.

It is just bad new all around.
 

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Discussion Starter · #12 ·
Thanks for the responses papajam & slyalfa.
You've explained the need so I'm all in with the Thermostat.

Has anyone experienced a issue with RML Distributor cap not fitting
tight. Cap seats on top of Distributor and snaps fine it is just not a
tight fit. I'm concerned it will move around while running on dirt tracks.

Thanks again for all responses, I've learned alot.
 
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