Fuel, no lead or additive ?

[jojomiamia]

Hi guys,

I am running my 402 with 95 fuel without lead or additive, there is no need to add a lead substitue ?

Thanks

['68OrangeSunshine]

Originally Posted by jojomiamia

Hi guys,

I am running my 402 with 95 fuel without lead or additive, there is no need to add a lead substitue ?

Thanks

Do you have hardened valve seats or stellite valves? If so you can run lead-free no problem,
If you're worried try the additive until you know what alloy your valves are made of.

Used to be a auto parts resto company called the Paddock, that sold RealLead by the quart. It was an additive that contained n-tetra-ethel lead in solution.
The 15 year-old rebuild on my '68 292 L6 ran like a song. The one time I added a quart of this wonder stuff to a 20 gallon tank, I got a ticket out in the sticks for speeding. I didn't feel that I was going that fast, my engine ran so smoothe. Sadly the Paddock went out of business, probably hounded there by EPA lawsuits.
Big Blocks like premium.
I used to have a 454 V8 in a '67 K/10 Suburban. That beast liked hi test, 91 octane ''Premium''. it would run sick on regular [87 oct]. It also had a drinking problem: 8 highway, 6 city.

[jojomiamia]

Thanks for your reply,

Frankly I don't know if valves seat have been hardened, as I bought the truck few months ago with no trace of such invoice in the historic.

But the engine is running fine.

And I don't know how to figure out.

['68OrangeSunshine]

If it runs well I wouldn't mess with it. Just change oil every 2500 miles or so. I like Valvoline 30 weight, and 20w50 weight in the winter.
A compression test would tell you the condition of the valves and rings, but not necessarily their composition. If it ain't broke, then don't fix it.
Maybe the ''dress date'' stamped into the machined pad on the top of the crankcase
could tell you the day of assembly, the plant it was built at, and sometimes special applications, but I don't remember where they are on a BBC.
Also if rebuilt, some machinists mill off the factory numbers and may add their own for inventory control.
What vehicle are you running with a Chevy big block in Paris? I thought they outlawed old muscle cars and trucks.

[special-K]

The best way to find out if it still has stellite valves or hardened seats is use no additive. You'll know when it starts smoking on start-up after sitting and will verify when heads are removed to do a new hardened valves. If you want to avoid pulling the heads, take a chance on using additive when you didn't need to.

[jojomiamia]

Thanks mates,

Runing the bbc on a 1972 C20, and the fun part is I can cross Paris even during limitation days due to pollution, as it's a collector, no rules for them ;-)

Changed the gas tank yesterday, wh wife brought it direct from LA, I love this truck !!

[special-K]

That's a good wife! I'm sure the others are as glad as I am to hear you are enjoying your big block Chevy in France. I would love to be in France and see that going down the road.

[jojomiamia]

Thanks, but the main issue is for parts, shipping costs or custom fees are just out of understanding. Better to go to LA directly.

The good side is I think we are not more than maybe 5 or 10 to have that kind of car in France, funny…

[davepl]

That's plenty of octane, more than enough. I don't think you will run into problems with the lack of lead unless you were towing in the mountains, for example, where the exhaust valve gets really hot.

When it comes time to rebuild mine, I always put hardened seats in them. But I never proactively take one out of commission just to add hardened seats. Hope that makes sense!

I have hardened seats in my 402 now but it ran for 20 years without them without incident.

[jojomiamia]

Great feedback, I am happy to read this news.

Just affraid to break a part so far away from US warehouse

[Old_Gold]

Pretty cool to think of your truck in the streets of Paris!
On the seats, and some of the others can correct me if I'm wrong, but I was thinking that all engines 1972 and later would have been built with hardened valve seats. If the engine is original, it may be ok.
Anyone else familiar with when they changed?

[special-K]

The whole no-lead thing came along after '72. Cats went on light trucks in '75.

I did my '71 Custom Camper when it started smoking when starting after sitting. It was time for a timing chain too

[El Dorado Jim]

Originally Posted by special-K

The best way to find out if it still has stellite valves is use no additive. You'll know when it starts smoking on start-up after sitting and will verify when heads are removed to do a new hardened valves. If you want to avoid pulling the heads, take a chance on using additive when you didn't need to.

x2 run the additive if you arent sure,,..

[LongBox]

It's my understanding that the lead in old gasoline acted as a kind of cushion/lubricant on the valves and stems. When lead was phased out of gasoline, there was an opinion that older engines, designed and built for leaded fuel, would have to have hardened valve seats installed in order to avoid wear and damage with unleaded fuel.

It turned out that old engines that were not run hard, did not suffer nearly as much seat and valve damage as was first feared, and the reason is that the damage is much more likely to occur if the valves and seats are really hot, as they can be under severe hard use.

So, if it's running fine now, and you don't plan on thrashing the beast, I'd just run it, and keep tabs on the compression over time.

[special-K]

Figure these trucks were run hard on the hiway with no overdrive and a 70 mph speed limit. Younger people think their truck is going to blow up running 70 mph because the newer vehicles they are used to run the freeways at 30% lower RPMs. I've had quite a few end up needing a no-lead head job due to running no-lead through original engines. I've ended up doing total rebuilds on some because the miles were too high to put tight heads on an old bottom end. This was once the trucks were around 15-20 years old

[1972RedNeck]

Originally Posted by davepl

That's plenty of octane, more than enough.

IIRC, European octane ratings are different than ours.