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Discussion Starter #81
Have you looked at the spark plugs? Check the color on them, it's easy. I might be wrong, but 132 main seems bit too small for 2L.
The spark plugs looked ok to me, but I'll post a pic shortly to hear your opinion.

From what I have read, 132 is indeed too small, but could that be the cause of hot running or is it just a red herring? The temp problem exists at idle as well as at speed -- does that rule out the main jets as a possible cause of the higher temperatures I'm seeing?

@pete, no worries. I'm contemplating ordering a new shroud and mechanical fan to try your suggestion. The cost is the trouble. I'm in Canada, which means I pay through the nose for shipping. If I'm gonna pay for shipping, it feels like I may as well get a new rad, too. Mine is clearly old and, even if it's okay, it can't last forever. So following your suggestion becomes a $400 proposition. That's why I hesitate. But I may yet do just that.

Maybe I can get my hands on some carb jets locally and give that a quick try.

Or throw my hands up and bring the car to a pro. That's an option too.

I'm very grateful for all your assistance everyone. Thanks for your patience. For those who may be wondering, yes, the friggin fan is turning the right way. I'm uninformed but not stupid.
 

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looks lean to me..
 

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A lean mixture won't cause coolant temperatures to rise as the OP has posted. The t-stat should keep the coolant at the rated temperature unless the cooling system is marginal and has no further capacity.
However, the spark plugs are not showing lean in my opinion.
 

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DHLA40H (emissions model)
Corrector 180
Emulsion 7772.12
Main 132
Idle 58

Anything there that would cause high temperatures with a 2L?
Nakgtv noted the "smallish" 132 main jets and I tried to find more information regarding the 7772.12 emulsion tubes, all in the context of the emissions carburetors, but nothing conclusive was discovered.
I agree with Tom and Chas, from left to right, the first two plugs look a little lean. They reflect mixture strength right before shutdown. If the carbs spit-back at idle and idle mixture is what the plugs reflect, then the plugs look as expected. This is likely not a jetting issue but getting the carburetors synchronized and the idle mixture/volume screws set correctly.

The short answer to your question is no or unlikely. If this configuration worked fine before the head swap, it should be ok now.
 

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I edited my post- I don't believe the plugs look lean. It's difficult to actually offer an assessment because a clean cut wasn't made-there are signs of idling. But as I posted before, I doubt the mixture is the problem with coolant temperature.
 

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Heck don't waste $400 on the mechanical fan setup. My comments were all about undoing changes, to diagnose cause, not to make further changes.

Good luck. I do hope its not just because the cooling system needs burping.
Pete
 

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Discussion Starter #91
Good luck. I do hope its not just because the cooling system needs burping.
Pete
Thanks to ALL for those great comments. I'm really grateful for the time taken to help me. Thank you so much.

I didn't know that reading spark plugs requires an off-idle shutdown. I'll try that later.

The spit-back occurs on part throttle. Not WOT or idle. Not a lot of spitting at all, but a couple of pops every few minutes.

I'll work on having the carbs set up properly, but I hear you all saying it's not likely the cause of my heat problem. Message received.

Frankly, I still think improper bleeding is a likely suspect, but I've read every thread on the topic and can't identify anything I'm doing wrong. I filled up the system as prescribed using both the bleed screw on the water pump and the one on the water manifold. If I crack either of those screws now, only coolant comes out. I've rinsed and repeated that whole process three times!

It'd be so much easier if all those coolant hoses were transparent...
 

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Okay last post, really.

When you disturb an engines water system, you need to follow this procedure to burp the system (no matter what engine):
1. Fill with water, der
2. Turn heater to max hot
3. Do NOT put radiator cap on
4. Start engine and warm up, with lowish revs. If you rev the engine you may cause water to come out of radiator cap opening
5. When the thermostat opens the engine will burp and the radiator water level will drop
6. While engine is running, top up water and put radiator cap on
7. Done

Critical that the radiator cap is not installed before this is done.
Pete
 

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Well I,m going out on a limb, those plugs are way lean...yes the rad should handle it ...I still think there is a problem with the core..
 

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Jetting start point 45's

Main Jets 130
Air Correctors 200
Emulsion Tubes F9
Idler Jets 45-F-8
Pump Jets 35
Starter Jets 60 F-5
Needle Valves 200
Chokes 34 (ventures)
Auxiliary Ventures 45
Brass Floats 26
Throttle Plates 78
Intake and discharge valve-55
 

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Was the sender for the temp gauge changed at the same time as the head?
 

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I use a jewelers loupe to examine plugs; can't tell much from this distance. But I really don't think the mixture strength is the cause of your concern.
 

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I agree with Chas. The colour of brand new plugs after only 500miles is not going to determine why the cooling system is running hot, it’s a side issue (distraction).

It really feels like the system isn’t bled properly.
Take it for a fast Italian tune up with the heater on full
Redo the bleed process that PSK wrote up (it’s a good’un)

Does this model have a heater tap?

I’m empathetic to your issue, but on the positive, there is always one thing that doesn’t run right on an Alfa (new or old) - so your car is kinda good :)


(I’m chasing a rough idle in a 105 and a 1750tbi)
 
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