1954 Chevy Bel Air oil recommendation

[CATERHAM]

Originally Posted By: mrausch82
I see no reason to run 5w20.

A 20wt oil is still a 20wt oil, that hasn't changed.
Is the fact that a 20wt was the spec' oil for your Chevy back in the day not reason enough to use it?
I can understand perhaps going with a somewhat heavier oil like a 5W-30 or a HDEO 10W-30 as those grades will offer a similar start-up viscosity to the 10wt and 20wt oils of the day, but the use of a 40wt oil that was never specified under any conditions is IMO a misunderstanding of the lubrication needs of the engine.

As always, the bottom line is oil pressure and I know many older cars came with OP gauges as standard fitment. If your car doesn't have an OP gauge it's something you may want to consider installing as it enables a precise oil viscosity selection.

 

[Robenstein]

15w40 wont hurt it a bit. GM speced 40 weight oil and 30 weight oil on basically the same engines(small blocks), and many people who ran em hard ran 20w50 with no problems.

 

[Jim Allen]

I think 15W40 is too heavy but a lot depends on how tired the engine is. On a cool day, think how hard it's going to be for thar 6-volt battery to turn the engine over. If it's worn out, sure, go with the heavier oil.

Basically, I'm with Caterham in advising following the original base hot weather viscosity requirements. Just like today, they were based on bearing clearances, etc., so they still apply. I see some caveats there that would probably lead me to go 30 grade over 20 just because the bit of info I have on those old oils are that the straight 20s back then were so close to a modern 10W30 in actual viscosity. Plus I'd like to see SL levels of ZDDP in a flat tappet engine, as you would find in a HDEO CJ-4/SM 10W30.

I presume this fine old flivver has been using detergent oils. If it's had non-detergent, be careful switching it over

 

[rclint]

I would run 15w-40 or 10w-30 my local walmart carries Rotella 10w-30 now, I said for years I would use that if it were ever local, but now I have a large stash of oil I'm trying to use up before I buy anymore !!

 

[Gene K]

Does your 235 Chevy have an oil pump? I thought the manual trans version was still a "slinger" through '55.

If its a "slinger" I would stay with a thinner oil.

 

[TFB1]

Originally Posted By: Gene K
Does your 235 Chevy have an oil pump? I thought the manual trans version was still a "slinger" through '55.

If its a "slinger" I would stay with a thinner oil.


Even the "slingers" had a oil pump that fed the main bearings and pressure to the rocker arms... The rods are oiled by "dippers" on the rod caps... Of course we don't know for sure that it hasn't had a newer "full pressure" engine installed sometime in it's past... If oil pressure is around 15-20psi she's likely still a dipper, a full pressure engine should be double that...

If a straight 20 weight didn't starve the bearings at 0*F, a 5W-40 surely won't either... Unless it's recently been rebuilt, figure the thicker oil when hot gives a little more cushion for the pushin'...

BTW if cold weather operation is anticipated defiantly use a 5w-** oil, as the 6v electrical system usually will barely crank the engine fast enough to get it started...

 

[Gene K]

Originally Posted By: TFB1
Originally Posted By: Gene K
Does your 235 Chevy have an oil pump? I thought the manual trans version was still a "slinger" through '55.

If its a "slinger" I would stay with a thinner oil.


Even the "slingers" had a oil pump that fed the main bearings and pressure to the rocker arms... The rods are oiled by "dippers" on the rod caps... Of course we don't know for sure that it hasn't had a newer "full pressure" engine installed sometime in it's past... If oil pressure is around 15-20psi she's likely still a dipper, a full pressure engine should be double that...

If a straight 20 weight didn't starve the bearings at 0*F, a 5W-40 surely won't either... Unless it's recently been rebuilt, figure the thicker oil when hot gives a little more cushion for the pushin'...

BTW if cold weather operation is anticipated defiantly use a 5w-** oil, as the 6v electrical system usually will barely crank the engine fast enough to get it started...


Sorry, Brain Fade... That should have been Full Pressure Oiling instead of oil pump.

 

[mrausch82]

AFAIK it has an oil pump instead of the slinger. From what I have been told, it is the first year of that. I have a factory oil gauge and it reads pretty high on the scale. It also has an oil filter element, which I am having trouble finding locally. I have not spent much time looking as we just moved from DE to PA and the car is still in my garage in DE. I'd like to change the oil before either trailering or driving it to my friends garage for storage in Sunbury, PA... about 3 hours from where the car is now.

 

[Pop_Rivit]

A 15W-40 like Rotella will be a good choice for that engine, as would any HDEO.

Originally Posted By: Jim Allen
I think 15W40 is too heavy but a lot depends on how tired the engine is. On a cool day, think how hard it's going to be for thar 6-volt battery to turn the engine over.


I have 4 tractors that all start easily in sub zero weather with 15W-40. A well maintained 6 volt system will have no problem with 15W-40 in the coldest of weather, original specs were often straight 20 or 30 weight on the engines of that era.

 

[river_rat]

mrausch82, is this getting confusing? Making your head hurt thinking about oil?
I have the solution. Send me that beatiful old beast and let me worry about it.