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ZZ502/502 and Oil Weight

32K views 15 replies 7 participants last post by  69-CHVL 
#1 ·
What weight oil are you guys using in your 502's 10w/40 or 20w/50?

Thanks...........
 
#7 ·
Thanks for the replies guys..............

Well, I have my manual and GM states to use 5W30 synthetic racing oil after the break-in. I have not used synthetic in my 502 at this time and my concerns are........

Can I expect oil seal leaks from using synthetic?

5W30 seems very light weight compared to my other big blocks.

It seems that a lot of people like Mobil1, is this the best out there?

What other brands of synthetic are considered racing fluid?

What mileage intervals do you guy use with synthetic?

Tall or short oil filter with synthetic?

I plan on changing the oil and filter on mine this week/weekend.

Your thoughts are welcome and thanks.
 
#8 ·
We'll, all of the GM info is a little suspect to be honest, seem like they dont have their act together with alot of things (suprise!).

For example, they state that initial timing should be set at 4*, total 26* - yeah right! I couldnt even get my motor to run with the 4*. But, some other info from GM says to run 36* total :confused:

Looks like the manual/info provided has specs listed for a run-of-the-mill truck 454 motor, which leads me to believe that the 5w-30 is also incorrect. I did run the 5w-30 for a couple of years and didnt notice and difference. Maybe their tolerances are tighter l:).

Bottom line, you cant go wrong with a 10w-30/40 dino oil, I even ran 20w-50 but I had high oil pressure and it took a while for it to settle down. I would think it just beats on the oil pump/dizzy a little more than necessary.
 
#10 ·
Keep in mind. Conventional oil has heat activted (heat responsive) thickeners. So, the hotter the oil, the thicker it gets. Synthetic is non-responsive (not as responsive) to operating temperature. One major problem with conventional oil is that in race situations (ie. drag racing), the oil is very thin at start up in a cold motor. For guys that have a oil temp gauge installed, they can get it to proper oil temp and proper viscosity. For the average guy, it's a crap shoot.

For comparison, I just did an oil change. Went from 10/30 conv to that prior mentioned mix of 10/30 & 20/50 synthetic (only had two qts of 10/30 synth here, hence the added 20/50). Oil pressure went from approx 30# hot to 50# hot at idle. Odds are, I don't need the 20/50. Can tell you, the valve train is a lot quieter with the 20/50 in there.
 
#13 ·
Good article I read the same one. When we put 5W30 in the last 502 it idled around 10-15 psi oil pressure. So we put 10W30 in it didn't make a difference. As soon as you touched the gas the gauge flew up to 40 psi. The only problem I have run into is the 4 quart pan. There is not enough volume if you plan on racing it. I have installed a handful of ZZ502's they have all worked flawless. The one best investment is the Moroso oil pan, that way you can re-use the windage tray and the oil control is alot better. The article read that 10W40 would make it better, I agree.

Dave
 
#16 ·
I think that article's suggestion that 15-17 psi oil pressure is good - really isnt so good. My 454HO, which is basically the same shortblock as the 502, generates about 22-25psi at an 800rpm idle fully heated up, and 45psi at a 1500rpm cruise, close to 60 at 2000 rpm cruise. These motors have either a high volume pump or a high pressure spring.
 
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