My Alfa Romeo 33 rebuild - FIRST TIMER

[Brit01]

new rad. light as a feather and appears to have much finer fins for a bigger surface area to cool.

[WhizzMan]

That copper radiator doesn't look that bad to me on the pictures.

[Brit01]

True whizzman - not too bad - some soldering done on it to repair it after a crash.
But it does have 24 years of use.

I want to see how the aluminium compares.

[Brit01]

This weekend:

1) Head on, manifolds, carbs and all bits including new radiator.
2) Started her up and waited for the fan to kick in at about 90.
3) Let her cool down overnight.

Sunday:

1) Re-torqued head bolts (8.9 kgs)
2) Fit new bosch cap and rotor
3) Checked oil levels/water and for any leaks
4) Warmed her up and no ticking sound!! I like that.

Quick run around town to test her out. Felt good. Also radiator worked a treat.

Tomorrow I'll be doing a 60 km round trip to work and back to give her a good test.


One thing: After I cleaned up the old water sensor for the radiator it had 90/80 stamped on it.

Isn't 80 a bit low considering the thermostat opens at 86 on the engine??

Maybe I need to change the water sensor on the radiator for a higher rated one, maybe one that shuts the fan off at 82 or 84.

22mm thread and 6.3mm connections.

[WhizzMan]

4) Warmed her up and no ticking sound!! I like that.

Congratulations! Lets hope it stays that way.

Isn't 80 a bit low considering the thermostat opens at 86 on the engine??

Maybe I need to change the water sensor on the radiator for a higher rated one, maybe one that shuts the fan off at 82 or 84.

I forgot if it's on the "hot" or on the "cold" side of the radiator? If it's on the cold side, it's just fine. Remember that the radiator has to cool the coolant and if it's at 80 degrees or below after cooling, it should have cooled sufficiently for another round through the engine.

Most coolant switches are either half way, or on the cold side. You don't really have any purpose for measuring the temperature of the coolant when it just exits the engine, but you do want to make certain the radiator will cool enough, so that's what you measure and correct. ECUs tend to have a sensor on or near the thermostat, because they need the actual engine temperature to determine fuel enrichment requirements.

[Urbancamo]

Originally my car has 92/87 C switch for fan. I think that's freakin hot, engine temp rises to 100 C until fan kics in. Fan spins only short bursts, just stops engine overheating, but it won't cool down engine.
I noticed this couple years ago when driving 30C ambient temps (which might be basic temps in Uruguay, but not in Finland)

I changed the switch to Citroen one, which has two points, one 92-88 C and other 87-83 C. Citroen has 2-speed fan depending on engine temp.
Obviously used 87-83 side, which is just fine. Engine temp rises only little over 90 and it definetly cools down the engine in 80 C level.
This has M22 x 1,5 threads and 6.3 mm flat terminals too.

I have no idea why old technology engines should be run on 100C range on any situation. My car has only 0.5 bar radiator cap, many newer car uses 1 bar or more pressure in cooling system. It rises the boiling point noticeably.

Glad to hear that mighty Alfa has no more extra noises!

[Brit01]

The sensor is on the cool side so I guess that is just fine. I noticed it switched off at about 82 on the dash (the dash gauges are never 100% accurate on the Alfa anyway). Got to do some better earthing on it also as when you turn on the dash lights the gauges rise slightly.
22mm thread with 2 x 6.3 mm connectors.
I would though like to find a 87-83 C sensor with a 20mm thread.

Common issue apparently and solved by soldering a thick earth directly onto the circuit board!
(electronics were never Alfa's strong point).

Anyway gave it a good run on the highway and arrived at work with a hot engine, no ticking. Was getting paranoid a little, I could here the tappets working slightly but not ticking. Not used to not hearing a loud ticking and hearing the normal engine noise!!
Can't remember what is sounded like before the ticking appeared. Lol.

Spark felt good with new cap and rotor arm. Starts up in an instant also and with less misfires (well none in fact).

Engine was a bit unbalanced when I arrived though.
Need to get my vacuum gauges out and balance both sides again as I was adjusting the idle screws yesterday without any gauges. Must have offset them slightly. Bit of rocking going on.

Nest job is to source the left hand side cam box as this was worn also but not to such an extent to make the tappets lose too much pressure and tick.

[Brit01]

Do you know where you sourced the 87-83 sensor?

I'm looking at some sites now and there are various but in the range of 88-79. (#37340)
79 is too low as the Alfa boxer thermostat opens at 86.

88 is a good temp for the fan to start but I would like it to stop at around 82-83 as yours does.

[Urbancamo]

I ordeder my M22x1.5 sensor from local auto parts store. Intermotor part number 50091. Be careful that there is similar model available, but its rated 93-88/97-92, so higher temps. These both types are used commonly on PSA concern cars, some have this lower temp type and others have higher temp switch.

M20 threaded are pretty hard to find, M22 is more common.

[Brit01]

OK was just speaking with a fellow Alfa owner and explained things to me. Think I totally misunderstood how they work.

I just need a sensor with one rating. I have a one fan speed set up.

One that turns on at 83 degrees until the engine thermostat closes and then the fan stops.
So just a 83 rated one. Not one with 2 temp ratings.

[Urbancamo]

2-temp rating (or is it better to speak 4-temp rating?) fan switch like described earlier is used either with two fans or single fan wich uses heavy ballast resistor for lower rating. When engine heats more and rises upper reading, resistor is bypassed and fan blows at full speed.

But it can be used with singe fan with single speed easily as i use it. It works like single fan switch. Thats the reason i bought that.

[Brit01]

My wideband sensor gauge has been flashing at 20 AFR!! Thinking it was broken or something.
Checked all connections and all looks fine. I know the AFR is fine. Anything above 15 and it stumbles like c.r.a.z.y.

Just checking underneath and spotted a 1.5mm hole in the exhaust manifold about 14 inches from the cylinder head.

Can such a small hole really affect the sensor so much? Occasionally if I rev it and pump the fuel jets a lot while stationary it will fall back to 13.5 but then jump the 20 again.

I guess a new manifold will be added to the shopping list (had a 16v crossover one in mind anyway). Stainless steel this time.

[Guy Croft]

Close it up and see what happens..

G

[Brit01]

what can I close it up with? (that won't melt)

Good excuse for the wife to get a new stainless steel crossover one anyway. Lol (honey my exhaust has rusted to bits and will fall off possibly creating a great danger for our son in the car!)

[TomLouwrier]

hi Chris,

Since it's blowing a hole it's thin and rusty, so welding is probably out of the question.
Just screw in a short self-tapper, of course in theory not good for flow but hey, no worse than the average flash on the welds at the collector(s), flanges etc.
If this is a tubular thing, you may cover the hole with a jubilee-clip possibly with a piece of sheet metal under it. Something as silly as a sardine tin will do, really.

It won't hold for long but long enough for you to get another manifold and see what your AFR does.

regards
Tom