Oil for Classic Car

[cheesepuffs2]

For those of you suggesting a 50 weight: why so thick?

 

[wtd]

I run Castrol HM 10W-40 with a zinc additive in the 396 big block in my 1970 Monte Carlo.

 

[RAVL]

For those of you suggesting a 50 weight: why so thick?

Based on my experience that main bearing clearances tend to be larger on older style motors (so you need higher viscosity to ensure adequate oil pressure when the engine oil is hot, particularly at idle) and that the valve train spring tend to be stiffer due to the fact that the valves are indirectly actuated instead of directly like in more modern OHC set ups, so you want a thicker film, so to speak. Finally, The thicker oils tend to have a better additive package for these motors.

That being said, there are probably a number of good choices - this is only my experience.

HTH and good luck.

 

[sloinker]

Valvoline VR1 in the heaviest viscosity your weather/driving habits allow.

 

[addyguy]

Any HDEO 15W-40 would be perfect.
Would love to see pics of the old AMC!

 

[zray1]

FWIW, when changing back and forth with Mobil 1 15w-50 and their 0w-40 F/S I was surprised to discover the hot oil pressure was identical with both products. Using the 15w-50 is not going to be an issue any more than the 0w40 would be .

There are thousands of people using the Mobil 1 15w-50 in classics and antiques of all types, probably because Mobil 1 has a marketing campaign that is telling people the 15w-50 is made for their classics. This time they are correct. It is a good choice.

I’ve put well over 200,000 miles cumulatively on many classics using either 15w-50 or more recently, the M-1 0w-40 F/S. They just work with no drama.

 

[FordFETruck]

I've used lots of the Rotella 15W40 over the years in old flat tappet cam engines with good results. Lately started using the M1 Euro 0W40 and like it a little better, have that oil in two flat tappet cam engines, fast ramp high lobe intensity with fairly stiff springs, people usually wipe out milder cams than what I have and no issues with the M1 0W40. I appreciate the faster cranking on cold days and less lifter chatter when building oil pressure if they sit for a while.

 

[Randy_R]

10W-30 with ZDDP already in it. Brad Penn/Penn Grade 1, Driven has several, Valvoline VR1 conventional or synthetic. I ran the Brad Penn with a Comp Cams XE274H flat tappet cam, .490 lift, 230 intake, 236 exhaust duration @.50, 130# valve springs, had plenty of oil pressure and no problems. Try 5W-30 if you like. No reason to go more than 30 wt. until you try it.

 

[ka9mnx]

Based on my experience that main bearing clearances tend to be larger on older style motors (so you need higher viscosity to ensure adequate oil pressure when the engine oil is hot, particularly at idle) and that the valve train spring tend to be stiffer due to the fact that the valves are indirectly actuated instead of directly like in more modern OHC set ups, so you want a thicker film, so to speak. Finally, The thicker oils tend to have a better additive package for these motors.

That being said, there are probably a number of good choices - this is only my experience.

HTH and good luck.

What? Bearing clearances haven't changed in the last 60+ years for "normal" engines. Also, how many in-block cam engines are required to use a thicker grade oil than an overhead cam engine? With a TSB, Ford back spec'd 5w-20 (from 10w-30) oil for my 1965 designed 1993 4.9L flat tappet engine.

 

[RAVL]

As I said in my post, this is just my experience with older (not American) cars. Yours may differ. Take care.

 

[ka9mnx]

As I said in my post, this is just my experience with older (not American) cars. Yours may differ. Take care.

OH. I thought we were talking about an American made AMC engine. I didn't catch when we moved to off shore engines.

Still, your theories don't hold up.

Have a great new year.

 

[RAVL]

Respectfully, main bearing clearances can vary between different kinds of motors. I have not built motors but have helped put enough them together with our builder for our track cars that I am fairly confident of what I am talking about. Your experience may vary, and that is fine. Perhaps you are thinking I am talking about tolerances. As I said, I was simply sharing my experience.

 

[ARCOgraphite]

I don't understand your point. Are you saying GTX today isn't as suitable now as it would have been in 1978?

Just saying GTX is not bringing anything to the game more than any other conventional on the market.

Run your favourite, I'd have a 10W30 in most mild builds. VM are no good for an engine.

I miss Rotella Triple Protect multi-fleet 10W30, I wasn't happy with T5 semi last I ran it.
Then that Red bottle QS DEFY had a good run for a couple years.

Happy New Year!

 

[350Rocket]

Respectfully, main bearing clearances can vary between different kinds of motors. I have not built motors but have helped put enough them together with our builder for our track cars that I am fairly confident of what I am talking about. Your experience may vary, and that is fine. Perhaps you are thinking I am talking about tolerances. As I said, I was simply sharing my experience.

I believe that tolerances are tighter but clearances are basically the same. All it means is there could be a bigger variation in the clearances.
Which is why the myth that you can't use thicker oil than a xw20 in any newer engines is false.
An old engine could be potentially worn (especially if it was racing) but the original clearances that the engine specs is typically the same today.

 

[cheesepuffs2]

Just saying GTX is not bringing anything to the game more than any other conventional on the market.

Run your favourite, I'd have a 10W30 in most mild builds. VM are no good for an engine.

I miss Rotella Triple Protect multi-fleet 10W30, I wasn't happy with T5 semi last I ran it.
Then that Red bottle QS DEFY had a good run for a couple years.

Happy New Year!

There's no API SP conventionals though, so GTX is a synthetic blend and is better than anything that was pumped from a drum back in that engine's heyday.

 

[ARCOgraphite]

What? Bearing clearances haven't changed in the last 60+ years for "normal" engines.

Are Honda 4 pots normal? Mains clearances tend to be spec'd 0.001" tighter than mid 60's Detroit Iron.
If this was football, that would be a 50 yard loss.

Pressure lubed inset bearing have been historically clearanced based on the journal diameter and accounting how thorough the machine shop work is. Balancing, re-sizing, align boring, cap registration, oiling mods.

- Ken

 

[ARCOgraphite]

There's no API SP conventionals though, so GTX is a synthetic blend and is better than anything that was pumped from a drum back in that engine's heyday.

Right. You make my point.

I was stating that GTX is a fond memory of paper and foil cans for many when they were a kid, but the stuff in the bottle at Walmart or Pep Boys has nothing much in common - other than API grade - to your 45 year old memory of Castrol . So why the specific GTX bandwagon in this thread? Pick ANY current favourite brand.

But regardless of modern base stock quality and advanced DP, I would shy away from heavily VM laden lubricants.

Maybe look for something that comes with a good dose of MoDTC as Phosphorous is about 400ppm less.

 

[OVERKILL]

Based on my experience that main bearing clearances tend to be larger on older style motors (so you need higher viscosity to ensure adequate oil pressure when the engine oil is hot, particularly at idle)

Depends on the rebuilder. While the clearance spec range for main and rod bearings for most production engines hasn't changed much in the last 60 years (or longer) there was a tendency by a lot of shops to go a bit looser during a rebuild. Often this was also accompanied by an HV or HV/HP oil pump. It wasn't until recently that things started to shift the other way with a focus on keeping clearances tighter and with lower tolerance for deviation. @RDY4WAR can probably expound on that a bit, given his building experience.

My grandfather had a built (~425HP) Ford Y-block (312) in a marine application that was a former vintage race engine. It was freshened before install in our application (1931 Chris-Craft Cadet) and was not built loose (rotating assembly was also balanced and blueprinted). When I started looking after it, I ran M1 5W-30 in it. It spec'd a 30 grade and had good oil pressure on a 10W-30 (VWB or GTX, which is what my grandfather stocked at the cottage) or a 5W-30 despite being a 50's vintage engine.

All the old mills I remember (30's, 40's, 50's) spec'd an SAE 20, 30 or 40 depending on ambient, with, IIRC, the option for a 20W-20 if temps near freezing were anticipated (it has been many years).

and that the valve train spring tend to be stiffer due to the fact that the valves are indirectly actuated instead of directly like in more modern OHC set ups, so you want a thicker film, so to speak. Finally, The thicker oils tend to have a better additive package for these motors.

Lots of OHV engines still in production including the FCA/Stellantis HEMI and the staple of GM's fleet, the LSx series engines. The new Ford 7.3L engine is also pushrod. Many examples spec an xW-20.

Most, if not all, of the old pedestrian (non-HiPo) pushrod mills had very mild valvespring pressures and didn't rev very high. They typically ran out of steam at less than 5,000RPM and if you decided to explore beyond where they stopped making power, you'd be greeted by valve float.

The additive packages of oils in the 60's, 70's and 80's were not as advanced as they are today. And, despite the restriction imposed on phosphorous, ushered in with API SM, older oils were not necessarily higher in this AW additive, as some VOA's of vintage oils have shown.

The huge shift away from flat tappet to roller camshafts in OHV engines meant a rapidly shrinking market for FT cores and quality took a hit as a result. In many instances, lubricant choice was blamed for wiped lobes on mild aftermarket shafts when in actuality the problem was the metallurgy. Now, that's not to say that you could slap in a wild Lunati Voodoo stick with API SN GTX 5W-30 and you'd be "good to go", but for mild builds with moderate ramp rates and lobe profiles, the claim that you needed "20 billion PPM of zinc because the EPA neutered our oil" was really driven by poor quality cams, oils were an easy scapegoat.

All that said, my recommendation for older engines varies depending on how tightly they were built. An HDEO like @Astro14 noted, say a 5W-40, is typically a very safe choice if one was built a bit looser. For a stock clearance Ford Windsor, I'm a fan of Mobil 1 0W-40 (or Castrol Edge Euro 0W-40). The full-SAPS Euro additive package is far more robust than anything available on the shelf when the engine was new and there's no restriction on the AW chemistry. IMHO, some more details on the OP application are required here, as potentially either of those may be a solid option.

 

[350Rocket]

Depends on the rebuilder. While the clearance spec range for main and rod bearings for most production engines hasn't changed much in the last 60 years (or longer) there was a tendency by a lot of shops to go a bit looser during a rebuild. Often this was also accompanied by an HV or HV/HP oil pump. It wasn't until recently that things started to shift the other way with a focus on keeping clearances tighter and with lower tolerance for deviation. @RDY4WAR can probably expound on that a bit, given his building experience.

My grandfather had a built (~425HP) Ford Y-block (312) in a marine application that was a former vintage race engine. It was freshened before install in our application (1931 Chris-Craft Cadet) and was not built loose (rotating assembly was also balanced and blueprinted). When I started looking after it, I ran M1 5W-30 in it. It spec'd a 30 grade and had good oil pressure on a 10W-30 (VWB or GTX, which is what my grandfather stocked at the cottage) or a 5W-30 despite being a 50's vintage engine.

All the old mills I remember (30's, 40's, 50's) spec'd an SAE 20, 30 or 40 depending on ambient, with, IIRC, the option for a 20W-20 if temps near freezing were anticipated (it has been many years).


Lots of OHV engines still in production including the FCA/Stellantis HEMI and the staple of GM's fleet, the LSx series engines. The new Ford 7.3L engine is also pushrod. Many examples spec an xW-20.

Most, if not all, of the old pedestrian (non-HiPo) pushrod mills had very mild valvespring pressures and didn't rev very high. They typically ran out of steam at less than 5,000RPM and if you decided to explore beyond where they stopped making power, you'd be greeted by valve float.

The additive packages of oils in the 60's, 70's and 80's were not as advanced as they are today. And, despite the restriction imposed on phosphorous, ushered in with API SM, older oils were not necessarily higher in this AW additive, as some VOA's of vintage oils have shown.

The huge shift away from flat tappet to roller camshafts in OHV engines meant a rapidly shrinking market for FT cores and quality took a hit as a result. In many instances, lubricant choice was blamed for wiped lobes on mild aftermarket shafts when in actuality the problem was the metallurgy. Now, that's not to say that you could slap in a wild Lunati Voodoo stick with API SN GTX 5W-30 and you'd be "good to go", but for mild builds with moderate ramp rates and lobe profiles, the claim that you needed "20 billion PPM of zinc because the EPA neutered our oil" was really driven by poor quality cams, oils were an easy scapegoat.

All that said, my recommendation for older engines varies depending on how tightly they were built. An HDEO like @Astro14 noted, say a 5W-40, is typically a very safe choice if one was built a bit looser. For a stock clearance Ford Windsor, I'm a fan of Mobil 1 0W-40 (or Castrol Edge Euro 0W-40). The full-SAPS Euro additive package is far more robust than anything available on the shelf when the engine was new and there's no restriction on the AW chemistry. IMHO, some more details on the OP application are required here, as potentially either of those may be a solid option.

Lots of good points there. I spent a lot of time on the ( now gone) oldspower.com and realoldspower.com reading up on engine builds when I had my 455 olds which I ended up realizing I was poor and sold it since I couldn't afford to rebuild and swap it in (seller claimed it had 300k miles). My 1976 350 olds which ended up going in my 84 Cutlass in 2006 has had 130k miles put on it since then. I remember that based on reputable builders personal experiences they always recommended going on the loose side of clearance specs. Not sure how many other engines this was true for but apparently a lot of people botched Oldsmobile builds by using experience with Chevy small blocks.
I had always planned on rebuilding my olds 350 but after almost 18 years and 130k miles of perfect reliability I will not be touching it unless something fails. It has had 10 psi hot idle oil pressure for all those years and uses maybe 1qt per oil change. I wanted to at least do a cam swap one day even if I didn't rebuild it but I'm too scared of failed lifters now. I've run all kinds of oils, all synthetic, the cheapest I went with was bulk Pennzoil platinum synthetic 5w30 which would have less zddp than most of the other oils I used, but no issues so far.
Clearances on modern engines aren't inherently tighter but any old engine could have high mileage and some wear so that should be considered when choosing viscosity.

 

[cheesepuffs2]

Right. You make my point.

I was stating that GTX is a fond memory of paper and foil cans for many when they were a kid, but the stuff in the bottle at Walmart or Pep Boys has nothing much in common - other than API grade - to your 45 year old memory of Castrol . So why the specific GTX bandwagon in this thread? Pick ANY current favourite brand.

But regardless of modern base stock quality and advanced DP, I would shy away from heavily VM laden lubricants.

Maybe look for something that comes with a good dose of MoDTC as Phosphorous is about 400ppm less.

I think you're looking through this from a lens much different than I am, because I'm not old enough to have memories of GTX from 45 years ago. I'm not saying GTX based on nostalgia.

I'm recommending GTX because Mobil Super is no longer readily available, Valvoline red bottle is just off the shelf additive in base oil (Valvoline is not an innovator), and SOPUS has issues lately like the globs of additive in the Quaker State jug posted here days ago, plus recent VOAs of Platinum where the phosphorus levels were below spec, and they have massive swings in viscosity batch to batch.

Maybe those things happen with Castrol too, but I haven't seen it yet, so for now that's my go-to. I think Castrol is underrated on this forum.