Oil rec for '89 Alfa Spider...

[Noey]

What say ye (and why) for my summer baby, driven short distances (although revved high). High lift cams, headers, otherwise engine stock and unopened. Been running Castrol GTX 20/50...they like 20w/50, so I'd like to stay with that weight.

 

[GSCJR]

Ok, so how about Castrol GTX 20w-50? I've read on here that they like it. Let us know.

 

[kschachn]

What's the whole "like" think you all are speaking of? What does the manual call for? I've never been a big believer in inanimate objects liking something...

 

[GSCJR]

Originally Posted By: kschachn

What's the whole "like" think you all are speaking of? What does the manual call for? I've never been a big believer in inanimate objects liking something...

Gotcha! Just regurgitating what the OP iterated. I love those questions with the answers already built into them type posts.

 

[toneydoc]

I would run me some Valvoline VR1 racing 20w50 since you like to rev her up like a racing machine. Then with that protection, you will not have to worry about racing her about town or the countryside. She will like that blue oil, she will

 

[dave1251]

Originally Posted By: Noey

What say ye (and why) for my summer baby, driven short distances (although revved high). High lift cams, headers, otherwise engine stock and unopened. Been running Castrol GTX 20/50...they like 20w/50, so I'd like to stay with that weight.

It has worked for you in the past. Why change what you do?

 

[aquariuscsm]

Stick with the GTX 20W50.

 

[CATERHAM]

One member has described the 20W-50 grade as "motor mud" which pretty much sums it up. Most high performance marques such as Porsche and Ferrari have dropped that grade (in addition to 15W-40) in favour of high VI synthetics. And these updated oil recommendations have been back dated a good 30 model years. I'd suggest you try Mobil 1 0W-40 and even that may be heavier than necessary if your oil pressure is still well above the test spec' when fully hot.

 

[xnicke]

I used to have an Alfa with the same engine. I went from Castrol 10w-60 to Mobil 0w-40. No problem at all. Still excellent oil pressure even when driving hard. For some reason, it felt like the oil consumption stopped as well.

 

[expat]

My Triumph used to (seem to) like 20w-50 until I switched to Rotella or Delvac 1300 15w-40. Which it seems to like even better, with no oil pressure loss and lower oil temps.

 

[chrisri]

This must be the first time that I agree with CATERHAM about witch grade to use . M1 0w-40 or PU 5w-40 is all you need for road use. Even in spirited driving. Nothing thicker. ONLY if you're planning some tracking you could go 10w-60. (Castrol Edge and Shell Ultra would be best). I had fifteen Italian cars in past, there's no need for anything thicker than 40 grade for on road use. Cheers.

 

[CATERHAM]

expat remember that an OP gauge is a viscosity meter so you should have seen a reduction in OP in switching to a 15W-40 at least on hot idle, if the gauge is working properly. If the oil pump by-pass setting is low, which it is on most old British engines, it's entirely possible that the engine is in by-pass mode at higher rev's on the still too heavy 15W-40. That being the case I'd suggest trying a 5W-30 like QS defy but only fill to the low level on the dip stick initially to check the OP. If your hot OP is finally correct; namely, above the test spec' but out of by-pass, then you can you op up with more of the 5W-30. On the off chance your OP is a bit low when fully hot then top up with some XW-50 or if it's still too high some defy 5W-20.

 

[expat]

Originally Posted By: CATERHAM

expat remember that an OP gauge is a viscosity meter so you should have seen a reduction in OP in switching to a 15W-40 at least on hot idle, if the gauge is working properly. If the oil pump by-pass setting is low, which it is on most old British engines, it's entirely possible that the engine is in by-pass mode at higher rev's on the still too heavy 15W-40. That being the case I'd suggest trying a 5W-30 like QS defy but only fill to the low level on the dip stick initially to check the OP. If your hot OP is finally correct; namely, above the test spec' but out of by-pass, then you can you op up with more of the 5W-30. On the off chance your OP is a bit low when fully hot then top up with some XW-50 or if it's still too high some defy 5W-20.

My hot OP did drop a little to just over 20psi at idle (800rpm) The OP bypass has been shimed to operate at just under 100psi. I use 15W-40 because I believe it may help with my solid lifters and high lift cam and double valve springs (60lbs) It's also cheap for my short oci's.

 

[NormanBuntz]

I've got an 87 Veloce. OM calls for 15w-50 (Euro spec). Many owners continue to use 20w-50, and many use 10w-40. For the last 6 years I used Kendall GT-1 High Performance 20w-50 (dino) before switching to Rotella 15w-40 for the last OC. Oil pressure readings had very little change. With the tendency of these engines to leak oil at any time, personally I would not switch to a full synthetic if it's had a steady dose of conventional. I think dino works fine in these motors.

 

[Greasymechtech]

Any UOA data proving what is best? Any stout full synth 0w40, 5w40, 5w50...! Watching obsolescence sure is fun.

 

[NormanBuntz]

Originally Posted By: Greasymechtech

Any UOA data proving what is best? Any stout full synth 0w40, 5w40, 5w50...! Watching obsolescence sure is fun.

So conventional = obsolescence? Not hardly.

 

[Clevy]

Originally Posted By: Greasymechtech

Any UOA data proving what is best? Any stout full synth 0w40, 5w40, 5w50...! Watching obsolescence sure is fun.

Do tell. How exactly is a used oil analysis going to tell whether an oil is best or not? Are you aware that used oil analysis are meant to establish trends and detect abnormalities,as well as contamination and serviceability. To use them to try and compare wear is not only a fools errand but not accurate in any way. It would cost many hundreds of thousands of dollars to test 1 oil vs another in an attempt to measure any wear differences and the only way to measure wear accurately is to measure the parts before and after. Just because a lab stated the wear metals are elevated in an engine doesn't mean much without previous data showing what wear metals that particular engine usually expels. And even then a simple particle streak can elevate metals which in reality has no bearing on actual wear. So enlighten me. How is a used oil analysis going to show one way or another what's "best"

 

[Greasymechtech]

It's data. Better than shooting in the breeze. So, where's any data proving 20w50 is so great? It's a pity when the only argument discounts UOA data compared to nothing. Too funny.

 

[expat]

Originally Posted By: Greasymechtech

It's data. Better than shooting in the breeze. So, where's any data proving 20w50 is so great? It's a pity when the only argument discounts UOA data compared to nothing. Too funny.

Well I guess when people do not have hard facts, they fall back on manufacturers recommendations and what has worked and served them well for years. The highest millage I have ever put on an engine without a rebuild was 500k, that engine was run exclusively, in Canada, on 20w-50 I DO now run lighter oils (I tend to follow manufacturers recommendations) but, I admit, I do tend to lean to the Higher viscosity side. I could turn your question around: Where is the data proving lighter oil is better?