Synthetic for flat tappet SBC

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Hi
This is my first post at BITOG, so bear with me
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I got an ’65 Impala with a 283 small block, running what I think is the stock flat tappet hydraulic cam. It probably has the original valve train and oil pump.

I don’t fancy dino oil, and I’ve never used it any vehicle I’ve owned.

Up to recently, my oil of choice for my (other) vehicles was a store branded 5W-40 synthetic. (Our equivalent to Walmart’s SuperTech)
VOA of that oil: https://bobistheoilguy.com/forums/attach...97_page_002.jpg (grey column to the right is the VOA)

I changed over to M1 0W-40 a while ago since it’s now possible to import it for a reasonable price. (Fun fact: a quart of M1 0W-40 costs 27$ (US dollars) here if bought over the counter at a regular store. Not taking into consideration the 6.2$/gal fuel price just to get to the store)

I don’t feel confortable running a flat tappet engine on the 0W-40, mostly because it’s API SN-speced. Am I wrong? Can the M1 0W-40 provide the necessary start-up protection, especially if the vehicle has been parked for a month or two?

Even though the Impala isn’t driven at low temperatures, I do need to move occasionally during the winter. It is also frequently started in the spring when the temperature is around 40°F. It is subjected to long periods of idling and cruising at idle rpm. (Long periods as in several hours at a time)

Can I use the M1 0W-40? Should I use another oil more suitable? Valvoline VR1 5W-50? I no longer care about the oil price. I just want the best possible oil for my application.

Some American brands such as Amsoil, Royal Purple, Quaker state and Pennzoil can be quite tricky to find here. But if any of those have what I need/want, I’ll find a way to buy them.

Any thoughts? Am I overthinking this?
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With 1000 ppm phosphorus and 1100 ppm zinc Mobil 1 0w40 is high on the zinc scale for a pcmo and should be enough for a flat tappet without any additional zinc additive.
You may find some diesel oils that have more more like Mobil 1 5w40 turbo diesel truck with 1300 ppm zinc but it shouldn't be necessary.
 
I think your Chevy will be just fine on 0W40.

First car oil change I ever did was in 1976, on a 1976 Impala, with a 400 SBC (flat tappet). 10w40 Dino. It ran for 200,000 miles (when rust killed it) on crummy Dino 10w40. SD, perhaps all the way up to SF.

The oil you're considering is light years ahead of that oil.

And your engine has a mild cam, with mild spring pressure, particularly if the valve train is original. So the cam lobes aren't under the heavy pressure of some flat tappet engines of that era.

Sweet car by the way! Love the '65 with its round tail lights. My cousin had a '65 rag top. It was no collector car, and slow with that two speed powerglide, but such lines....
 
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M1 0w40 or equivalent A3/B4 as well as Valvoline VR1 20w50 are good choices.

Buy what is cheaper.
 
I have had good luck with Shell Rotella T-6 5-w40 in my old buick with a super charger and tune, and some mods, it gets started and moved during the winter , and does see stop and go driving in the summer along with a few passes down the strip

it's not a v-8 but the 3800 has not complained and I have good labs back from Blackstone.
 
Can you get 15w40 dual rated diesel/gas oil? It is IDEAL for that old car.

I wouldn't run synthetic in such an old car. 50 year old oil seals and
synthetic are not a match made in heaven. Plus it's been on dino it's entire life most likely.
 
I had a '65 Impala SS 283 (2 barrel carb) back in the day-there's not a lot of valve lift or spring pressure on those old (non high performance) SB Chevy V8s-the M1 0W40 you're running is a lot better than the VI-laden 10W40 dino oil I ran then. Or, if it gets too cold, a dual rated 10W30 HDEO would be a good choice too (not sure of the ACEA spec).
 
Originally Posted By: Nickdfresh
Can you get (Euro) Valvoline MaxLife High Mileage 5W-40? It would be perfect for this application IMHO...


I have found this to work well on my 54 Plymouth flathead. Easy starts in the winter, nice oil pressure in the summer!
 
No worries on the M1 0W-40 in your old Impala - and you can extend your OCI for years unless it's your daily driver, which I doubt. Hydraulic lifter cams of that era weren't hard on oil - the solid lifter cams were a different story and even then, the M1 0W-40 should work - certainly M1 15W-50 works well. Your car would like be fine running SuperTech 10W-30 dino.
 
Som of tghouse cams were toast at 90-120K miles running high ZDp - so that doesn't help - its more about hardening/toughening and oil movement over the lobes.

A High Moly might be the ticket.

Many seals were not syn compatible. I don't know what the European Xom formulation is - is it technosynthese or Synthetic?

In USA Mobil 1 is not synthetic oil, its "alternate fact" synthetic. or semi synthetic at its best.
Nice car

I loved my brutish 67 Chevelle SS396 back in the mid 1970's.

We didn't think about oil too much. IIRC we thought 30 grade was too thin for 350HP and 20-50 maybe too thick. I think I ran American Oil Co. 10w40 in the gold and white CAN. Or Green Dino Sinclair
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15w40 is too thick unless you're frequently working it hard in fairly high temperatures. I'd be using a 10w30 in it, but the 0w40 probably performs similarly enough to do just as well. A dual rated 5w40 wouldn't be bad, either - I'd probably opt for that over the 0w40 for any increased extra extreme pressure additives it may have. However, I'm not of the belief that any flat tappet engine needs loads of extra ZDDP just to get by.

Sounds like a cool car. Pics and options?
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I had an idea for people who were familiar with ACEA oil specifications. Is ACEA E4 the kind of diesel engine oil formulated for diesels that have no DPF or SCR? If so, that may work well in a gasoline engine that needs more ZDDP.

Anyway, many people in the USA use Shell synthetic diesel 5w40 when they want a synthetic with extra ZDDP. The UOA section shows that it works well.
 
IMHO and not overthinking the application; consider a high mileage oil type, either semi synthetic or dino 5w40.
would avoid M1 products for that era motor. change 1 year or less or 5k miles or less. just my experience and opinion taken away from it.
 
All this talk and we don't know how many miles are on the engine ...

2-bbl 283 is a pretty mild motor with very modest cam lift and valve springs you can just about compress with your thumb. There is not any extreme pressure scenario there to be concerned with.

But, like all USA V8's it relies completely on splash oil or sling oil thrown off the spinning crank to lube the cam lobes. So rule number one when you start it, drive it. Get the motor to 2,000 rpm and cruise down the road. It's getting wet.

Issues that will plague you. Sitting for days at a time. Synthetics often exhibit lower surface tension by nature. That's where the 0W or 5W comes from in part. But they tend to drain off if left to sit. That does not mean there is no oil film. It just means it's thinner. And that motor wants exactly the opposite. It wants a nice robust cold oil film at start-up.

You have some really great HDEO oils in Europe. Ravenol makes some really nice fluids. I'd look there. If the motor is over 100,000 miles - I'd be looking at something like a 10W-40 semi-synthetic or Group III in that viscosity range.

Don't sweat trying to find USA oils. That motor does not care. It wants oil film (and dino is fine), it wants 1,000 PPM Zn and Ph or a bit more. It wants a good detergent package, and it wants to be driven.

The seals are old and pre-synthetic chemistry. The valve seals are as hard as rock and cracked, or missing. The generator is nearly toast (hanging off the exhaust manifold (?). The fuel pump is a big worry. As soon as it perforates the diaphragm it will be pumping gasoline into the crankcase. The oil filter base is sludged-up to beat the band (canister filter unless it's been modd'd to spin-on...). The oil screen pick-up is also half clogged ... And the cam is already gone halfway flat.

Cool morning with 10W-30 dino oil and you start the motor. Any clicking and clacking? Any ticking that is not an exhaust leak? If so, the cam is already past its prime. The cores were not that hard to start with. Typical family slow round town driving and idling didn't sling enough oil. If quiet, you can try to keep it all alive for a longer. 1,000 mile oil changes and Luiqi-Moly MOS additive will help.

Have you pulled a valve cover? What's it look like?

Things that need doing. Timing chain replacement. It is semi-dry and stretched and running with the cam at least 3* retarded ... You can change the timing chain from the front/top. If it's all dark and crusty, you need to think about when you'll replace/rebuild the motor? You can get another 30,000 miles with a new timing chain, but ...

Start looking for a good used 327 rebuild-able core. A 350 is a obvious drop-in but it's not close to period correct. You can hide a rebuilt 327 under the 283 heads and intake and it will all look correct, but run so much better
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Or, you can drive your 283 and think about rebuilding it as a marine/truck engine when the time comes. In a full sized Impala it's not much motor. Nice engine and all, but anemic ... Even the 250 cu in straight six would give it a run for it's money ...

Please add new ground side wiring. Battery (-) pinch bolt to the radiator support frame. Clean and renew the ground cable from the Neg to the motor. Solder the bolt lug to the cable to eliminate crevice corrosion. Add or replace the braided wire strap from the engine to the firewall. More grounds will mean more and better lighting, gauges, and ignition.

Have fun
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Just run a 10-40 or 10-30 Maxlife if you can get it.
Any major brand will work.
I would not use a 0w oil unless you are in very cold temps. I am not a fan of Ow oils.
 
Originally Posted By: Dallas69
I would not use a 0w oil unless you are in very cold temps. I am not a fan of Ow oils.


What happens?

I ask because I use them in all of my cars at this point. What's the risk?
 
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