My Alfa Romeo 33 rebuild - FIRST TIMER

[Brit01]

The aging and inherent inaccuracy of thermo-switches will make the stamping on the outside totally irrelevant within a year after placement.

Do you know if the inaccuracy and aging tends to swing to the switch opening at a higher temperature than stamped or lower? Maybe there is no consistency and it could swing either way.

Just curious.

[Brit01]

I think I might try the Castrol TWS 10W/60 after I have changed the small ends and run it in more with Valvoline semi.

I've spoken with various Alfa boxer owners who use 10w/60 for daily use and are very happy with oil pressure and the general running of the parts.

[TomLouwrier]

Not much running in to do with just the small ends renewed.
Fill it up with your favourite oil and be happy.

regards
Tom

[Brit01]

mm just confirmed that the oil temp of the boxer runs at about 85-90.

10w/60 will be too thick I believe at 90. 10-15 degrees will make a big difference in viscosity no?
May not lubricate the mains properly if it becomes too thick.

The Castrol was designed specifically for the BMW M series which run hotter hence requiring this special oil.

24.4 viscosity at 100 degrees the 60 oil states.
18.5 or close to that with the 50 oil.

But when do the polymers start activating to thicken up the oil?
What will the viscosity be at 85-90?

whizzman: you are the whizz with oils it appears.

What would be ideal is to get an accurate oil temp sensor and gauge, maybe take it from the oil sump or from the filter(sandwich plate possible with connections for the pressure outlet also)? But that's another project.



Maybe 300v I will try first. 15W/50.

[Brit01]

Wonderful !!!
Just researching into Mann and fram filters and the trustworthy garages that fitted my filters put the wrong ones on!!

I specifically asked for ones with anti-drain valves. 'yes yes of course you see these have. all of ours do sir! '

Now they put a Mann W712/53 on and a Fram PH5548.
Both DO NOT have an anti-drain valve and also a bypass valve pressure of 2.5 bar!!!


The ones I need are W712/16 or PH9732.
Anti-drain valve and bypass of 1 bar.

The current Coopers Fiamm I need to check the serial number on it.

But for sure tomorrow I'm returning to the garages to ask for the Correct ones.

Good job my engine is clean due to the bypass valve and hope I haven't done any damage at start up. In the last month of break in I have always started it up carefully. But still...not pleased. Luckily I found out now and not 5000 kms later.

[WhizzMan]

If it's too thick at 90 degrees, how would your engine turn when cold? Too thick is only measured when cold, not when on temperature.

Anti-drain valves are nice, but substantial damage in a flat four in just a few hundred kilometers is very unlikely. Every time you start your engine, it takes a little longer before oil pressure at the bearings is good, very important, but once it's running, the valve has no more function.

[Brit01]

Too thick is only measured when cold, not when on temperature.

mmm not sure if I agree with you here whizzman sorry in regards to when the oil is hot. Yes it's crystal about the Winter value of oils, we all know that but..

50 oil at 100 degrees has a viscosity index of around 18
60 oil around 24

10 or 15 degrees below 100 degrees it's viscosity maybe be substantially greater and have these consequences,
Lower BHP
Increase Fuel Consumption
Increase heat in the engine
Increase wear

BUT I will look into this with the oil makers to see the viscosity at 85 degrees just know (not to disagree with you) wink.
Opie recommend 10W/40 for the 1.7 boxer.

Please feel free to correct me if I'm wrong.

Why has BMW formulated TWS 10w/60 specifically for M series? Possibly because the engines run at 100 degrees normally and need the 60 oil but engines that run at 85 the 60 oil will be much thicker.

In regards to the polymers that thicken the oil this is not clear to me when they do kick in and thicken the stuff.


Would be interesting to see some scientific information/graphs about the polymers and how they work/action in relation to temperature.

[Brit01]

The film shear strength is interesting also:

MOTUL 4100 Turbolight 10W-40 4,200 kg/cm ²
MOTUL 4100 power 15W-50 4,800 kg/cm ²
MOTUL 6100 synergy 5W-40 5,200 kg/cm ²
Castrol Formula R-S 10W-60 6,800 kg/cm ²
Castrol TWS 10W-60 17,800 kg/cm ²
MOTUL 300V Le Mans 15W-60 22,000 kg/cm ²

300v has a higher strength than the Castrol and significantly higher than Motul semi oils.

Is this an important consideration in the choice of an oil? I would say so.

HTHS - High temperature High shear A relatively new oil test/specification, the oil is subjected to high temperature 150C and is mechanically sheared at 1 x 10^6 per second.

Mobil 1 0W40 HTHS 3.6

Castrol RS 10w-60 HTHS 3.7

Castrol RS 0w-40 HTHS 3.7

Silkolene PRO S 5w-40 HTHS 4.07

Motul 300V 10w-40 HTHS 4.19

Motul 300V 5w-40 HTHS 4.51

Redline 5w40 HTHS 4.6

Redline 10W40 HTHS 4.7

Mobil 1 15w-50 HTHS 5.11

Silkolene PRO S 10w-50 HTHS 5.11

Silkolene PRO R 15w-50 HTHS 5.23

Motul 300V 15w-50 HTHS 5.33

Redline 15W50 HTHS 5.8

[Brit01]

I found a better oil filter today, 30 mm longer and with an anti-drain valve. More appropriate for the Alfa 1.7.
The original for the 33 has 2 anti-drain valves. 1 is better than nothing and at 100 mm long more surface area to filter.
Good.

[Brit01]

Every day I see people start their cars in the morning by revving them high while stone cold and then zooming off. I cringe when I see that. Poor small ends and the rest.

Just found out also that the filters I've been provided with have a metric thread M20.
But the Alfa connection is 3/4-16 UNF.

I imagine just a small amount of hot oil seeps between the thread, between the unfiltered and filtered oil but not affecting the oil pressure.

I have a list of the appropriate filters with imperial threads now. The search is on.

[Brit01]

I'm not too convinced with the INA tappets. Very lightweight yes but I get a rattle on start up each time which goes away after 7-10secs.

Never had this on the OE tappets, even with the damaged ones!!!

Maybe the INA tappets do not have an anti-drain or are just not good on the flat 4 engine perhaps.

Considering changing them for OE tappets.

[WhizzMan]

Are you sure it's tappet rattle and not bearing rattle?

[Brit01]

Are you sure it's tappet rattle and not bearing rattle?

Could this be the small ends rattling as we were discussing?

Before the oil reaches them they could rattle like this? Then click slightly when hot and idling.

I'm unfamiliar with certain sounds so yes I could be wrong.

(and when I removed 4 of them a while back and tested their compression they were all very stiff and did not leak oil easily so you may well be right).

[WhizzMan]

If I remember correctly, small ends on the Alfa boxers aren't pressure lubricated. If it's bearings, it will be cam bearings, big ends or main bearings.

Even if it's tappets, it can be a nominal situation. There will always be at least one valve that is partially opened when the engine is not running. Leaving it open for the entire evening and night will slowly make the oil in the tappet go away. it will take a few seconds for that tappet to pump up again, once the engine is running.

I'd try and not assume anything and start replacing parts without verifying they are actually broken. These engines in general are good for 100,000 km easy, most do double before falling apart. If you fix the small ends and do an inspection on the rest, you should be just fine if you don't find any other problems during the inspection.

[Brit01]

If you fix the small ends and do an inspection on the rest, you should be just fine if you don't find any other problems during the inspection.

Yes that's the plan so far ( and plastigauge all the bearings as I didn't have this before). Although I will be changing the left cam box as the original did have lateral wear same as the right one which as you know I replaced already.


But I do want to collect some spares parts, engines block gaskets and crank seals, also some new OE tappets just in case I need to replace them in that moment during my holiday. After I won't have the time to strip the engine down again for a long time.

These parts are not easy to get here so to have a box of spares is always good IMO and can always be used by another fellow Alfa friend here in Uruguay as we have a small club and forum here and always looking for older Alfa parts.

Thanks

Chris