Engine oil - SAE Rating for performance engines

[dlrogers]

 
Kia ora all. This'll probably be moved so pardon me if I'm posting in the wrong place, but while the going's good I'll ask the question. The engine package in my Challenger is a worked 383, not fully mind you, just the bolt ons - Headers, fairly hot cam (not sure of specs yet), 750 edlebrock and (I think dual plane) manifold. I'm wondering what SAE rating I should choose for the oil and whether to go synthetic or stay with the organic. This will be the first oil change since I imported the car from the USA about a month ago. Any help would be appreciated. Also, with the unleaded fuel we get here in NZ, should I use upper cylinder lubricant?...and what octane gas should I go for (choices are 91, 95 or 98)
Cheers
David

[kudakidd]

David, I use a 20w-50 Valvoline racing oil in my 440. The temps the engine operates in are about 40-98 degrees Farenheit. Most of the on the shelf oil have SFI/SAE recommended qualities. I'm not impressed with synthetics especially in our old school engines. Stick with the petro based oils.

A lead additive is helpful but not necessary if your mileage is 1000-3000 miles per year. and as far as octane, the 91 should be sufficient unless you've upped the factory compression ratio.

[Chryco Psycho]

I tend to disagree in that the synthetic oils are superior , I use Castrol 5-50w Syntec , just make sure the engine has at least 5000 miles on it to seat the rings before switching over

[dlrogers]

 
Thanks for that...I'll go ahead with the lube change now. All the best

David

[moparnut]

I tend to disagree in that the synthetic oils are superior , I use Castrol 5-50w Syntec , just make sure the engine has at least 5000 miles on it to seat the rings before switching over

Agreed Synthethics are better,they have stronger film strenght which will eliminate cold start up and the oil is much less likely to break down as quickly.The engine doesnt know its 30 years old,an engine is an engine,they all have steel moving parts that love to be lubricated.You can buy full Syn at Walmart in 5 quart bottle for 12 bucks,Its probably valvoline or Quaker,walmart donest have a "walmart refinery".

[matt63]

I thought 50 W oil was only used for drag racing i.e. larger bearing clearances and extreme loads

I was recently educated about the current issues with the common API oil grades. Hughes Engines has an interesting bulletin they send out with their cams.  It basically says that the newer SL/SJ/SM/EC grade oils have far less anti-wear additives than is required for flat tappet cam engines as this reduces catalytic converter contamination.  The lower zinc/phosphorous levels can cause premature wear especially in the camshaft.  They recommend an additive such as Federal Moguls Engine Lube.  Synthetic oils are not recommended for flat tappet cams.  The engine shop I have used says that they have seen many cam failures in recent years and attribute them to the lack of adequate lubrication.

I just added the Federal Mogul/Sealed Power additive to Quaker State 10w30 for my new 408 although it has a roller cam so it's probably not crucial to do this.

[Stacked440]

Im running 10.5:1 compression ratio in my 440 and the mopar recommended octane rating is 91-93.  As far as oil, dunno. most of it is climate in which you live, engine use, and preferance on brand

[jvike]

and what octane gas should I go for (choices are 91, 95 or 98)

The US/Canada uses a different Octane rating system  at the
gas pumps than most other countries.


They use the U.S. Cost of Living Council (CLC) index
which is the average of the Research Octane Number (RON) and
the Motor Octane Number (MON):


                 CLC = (RON + MON) / 2


                 RON = Research Octane number (ROZ in Germany)
                 MON = Motor Octane Number
                 CLC = U.S. Cost of Living Council


This translates to (roughly):


                91 RON = 87 CLC (Regular)
                95 RON = 91 CLC (Premium)

I don't live In the US, I put 98 on my Barracuda.

[dlrogers]

 

Thanks everybody - I appreciate the help

David