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Discussion Starter #1
There are only a bazillion pages to go through to on this issue so if y'all don't mind another? :thumbup: I'm ready to lube my transmission and rear end after rebuilding. I'm looking at using Red Line 75W90 Synthetic Gear Oil or Red Line MT85 75W85 GL-4. Synthetic vs Non???? Other suggestions?
 

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Which car?

Requirements vary.

Chuck
 

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Why would a person use non-synthetic if he had a choice? Synthetic, for sure.

I have Amsoil 80W90 (GL5) in the rear end and Redline MT90 (meets GL4) in the transmission of my '65GT.

The earlier cars needed the GL4 to suit the brass synchros but at some point Alfa changed the synchro material and went to a GL5 lube. Someone out there will know the change-over date, but I think your '72 gets the later spec lube.

I've run Redline and Amsoil in my cars -Alfa and others - for many years; why not use the best stuff you can find?

While you're looking, check out Amsoil's 20W50 for old engines: AMSOIL Z-ROD 20W-50 Synthetic Motor Oil

Chuck
 

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Discussion Starter #7
So what oil would you use to break in the engine? If I'm not going to keep the oil in it that long for the first go around.........?
 

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what you suggest?
For engine break in I change the oil around 3k miles. This is about 1/3 the oil life, but when rebuilding an engine I add a ZDDP or zinc additive to my oil. 3k miles is where the additive is typically recommended to be changed. After that I am back to 12k or once per year oil changes.

I just got rebuilt transmission for my 70 1750 gtv and gentleman suggested using a non-synthetic oil for break in. Any thoughts?
Definitely the "old school" mentality. I have heard that many times with different reasoning's behind it, none of which I agree with. I think most of the logic is one will typically change oil shortly after rebuild, so why spend the extra money to dump synthetic oil down the drain. In the case of a transmissions and differentials I have never changed the oil out shortly after a rebuild. I just change them once per year as a part of my maintenance schedule. Quite honestly, if you are in the camp of break in with conventional oil and change out to synthetic; there is no harm in that either.

Its personal preference and I always use synthetic fluids whenever possible simply because conventional oils can not protect as well as synthetics.
 

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Oil type recommandations

Hi folks,

I had a longer discussion with a lubrication engineer from Castrol - my profession is Engine and Transmission Engineering, so therefore we have plenty of contact with Shell, Castrol and other oil suppliers.

The Castrol engineer gave me the following recommandation - very credible as he was talking against his own business/profit:

1. Engine: 10W40 or 20W50 is fully sufficient. Full synthetic 10W60 may kill an old engine as the detergents solve old dirt and oil carbon and such mud can plug the oil channels, leading to bearing failure - works like a heart attack or a brain stroke. Exception: If the engine was reworked and completely cleaned, synthetic 10W60 works very well

2. Transmission: GL5 is absolutely fatal to Synchros and some bearings - additives containing Phosphor and Sulfur destroy such nonferrous parts. Recommandation is a good GL4, as e.g. Castrol SMX-S

3. Rear Axle: GL5 is helpful for the hypoid bevel gear set.
For cars WITHOUT limited slip differential: Castrol Syntrax Longlife 75W-90 (former SAF-XO) GL 5
WITH LSD (2000 GTV): Castrol Syntrax Limited Slip 75W 140 (Formerly SAF-XJ 75w-140) GL5
The latter has special additives / friction modifiers to avoid NVH and durability issues of the LSD clutch plates.

Saluti

Ribolla
 

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Shell Dentax Gl1 was used in pre moly synchro Alfas.The formula in EP 80-90 Gl-5 was changed a number of years ago so it has more friction modifiers hence crunch can occur in moly gearboxes even more than in the 60's thru the 70's with the old formula.I would break in a new engine with mineral based oil with zinc for 1000 miles or so because synthetic is too viscous and the rings might not seat.Btw I use a rare in the USA, Tutela non ep 80-90 gl3, and my alfa shifts like butter.
 

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For what it's worth . . .

Some advice from long, hard-won experience.

1. Break in oil: 30wt. non-detergent w/ Rislone ZDDP additive. Period. Drive for 100 miles during break-in and then drain and replace with your choice of 20-50. Synthetic oil is "too good" and makes it harder for rings to seat. 30wt non-detergent is just right. Also, you don't need to buy expensive "break-in" oil.
Generic 30wt. oil w/zddp added will do just fine.

2. Gear lube. I won't use anything but Redline NS in my gearbox. When I changed to it, the shift effort in my expensive close-ratio gearbox was so dramatically improved it felt like a different 'box entirely. Just sayin'.
 

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Discussion Starter #20
2. Transmission: GL5 is absolutely fatal to Synchros and some bearings

Hi folks,

I had a longer discussion with a lubrication engineer from Castrol - my profession is Engine and Transmission Engineering, so therefore we have plenty of contact with Shell, Castrol and other oil suppliers.

The Castrol engineer gave me the following recommandation - very credible as he was talking against his own business/profit:

1. Engine: 10W40 or 20W50 is fully sufficient. Full synthetic 10W60 may kill an old engine as the detergents solve old dirt and oil carbon and such mud can plug the oil channels, leading to bearing failure - works like a heart attack or a brain stroke. Exception: If the engine was reworked and completely cleaned, synthetic 10W60 works very well

2. Transmission: GL5 is absolutely fatal to Synchros and some bearings - additives containing Phosphor and Sulfur destroy such nonferrous parts. Recommandation is a good GL4, as e.g. Castrol SMX-S

3. Rear Axle: GL5 is helpful for the hypoid bevel gear set.
For cars WITHOUT limited slip differential: Castrol Syntrax Longlife 75W-90 (former SAF-XO) GL 5
WITH LSD (2000 GTV): Castrol Syntrax Limited Slip 75W 140 (Formerly SAF-XJ 75w-140) GL5
The latter has special additives / friction modifiers to avoid NVH and durability issues of the LSD clutch plates.

Saluti

Ribolla
Not questioning your veracity Ribolla: I talked with an Amsoil technical advisor this a.m. who said their GL-5 transmission oils will not harm "yellow metals". Now I'm really confused:confused:
 
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