For people who own classic cars, where do they get the gasoline necessary to run them? All you can buy these days is unleaded. Is there a specialty source of leaded gasoline for pre-conversion vehicles or do they have to do something to convert the engines to run on unleaded?
Leaded gasoline is not necessary to run classic cars. While leaded is better for performance and efficency, unleaded will still function and perfrom just fine. I own a 72 Chevy Truck as my primary vehicle and it has no trouble drinking gas… in fact, I think mine has a drinking problem.
Actually, I believe what jacquilynne is referring to is tetraethyl lead or similar substances.
One of the main uses of T-lead as a gasoline additive was for valve lubrication- it helped prevent the near-red-hot face of the valve from “welding” to the seat in the cylinder head, causing erosion.
In the efforts to phase out the lead, between 1969 and 1972, manufacturers started using hardened valve seats- usually an induction hardeneing of the iron itself, or sometimes actually pressing in a ring of a harder material like Stellite.
Owners of cars prior to that period, if they drive them regularly, need to either have hardened seats installed, install later-model cylinder heads, or use an aftermarket “lead substitute” additive to the gasoline.
I used to have a '69 Dodge Charger I used daily. I had to replace the heads on the 383 with ones off a '77 400, since in some cases, the valves had eroded into the seats by an eighth to a quarter inch.
There’s also an additive containing lead sold in car parts/accessories stores.
You can also head down to your local airport for some 100LL avgas (aviation gasoline). 100 refers to the octane and “LL” stand for “low lead,” but this is misleading – it actually has about 4 times the lead of leaded regular mogas (now no longer with us). This should make even most high-compression vintage auto engines reasonably happy.
Of course, you do well to figure out how much lead your engine really needs and use that much and no more. There are problems from too much as well as too little.
Still? I know they did back in my gearhead days, when unleaded gas was still sold alongside the other stuff. Is it still a legal product? What’s enough for a tankful go for these days?
Be careful with this one, there aren’t any road taxes on avgas.
and referring to performance… you can use 100ll in newer turbocharged, supercharged, and high compression engines… just know that you WILL kill your o2 sensors, they dont like lead.
Lead will also render your catalytic converter inoperable.
In my vintage car club, we have three sorts:
- ~55-60% are those who use lead substitute (none commercially available with actual lead anymore that I’m aware of, but maybe that’s just here)
- ~35-40% are those those who’ve installed hardened seats, etc. and run unleaded
- ~3% are those who run unleaded in their unmodified vintage cars. 1 of these in particular insists on running regular 87 octane unleaded (shudder - I just don’t get running 87 octane in a $50,000 classic corvette to save $0.15 a gallon…)
(Yes, this doesn’t necessarily add up to 100%. It’s an approximation. Deal.)
No perceptibly diff result between 1 and 2, except group 1 has to put $0.25 worth of the substitute in when they fill up.
Group 3 consists of about 10 guys (yes, this group is all men). They either basically don’t drive their car (i.e. under 100 miles a year: they’re called “trailer queens” - the cars, not the guys - and it’s not meant as a compliment…), or folks who apparently like to do valve jobs every couple years just for kicks… (This latter applies to corvette-boy mentioned above)
So out of a few hundred guys with old cars (i.e. 1965 and earlier) I know not one that uses aviation fuel or any other oddball stuff. Just lead substitute or modify the engine to use unleaded, basically.
Slight Hijack:
Were hardened valveseats put in pre-60s diesels?
:eek: And it still ran?
You can run a '71 Chevy Nova that says it needs leaded fuel on regular unleaded just fine for at least two years without having any problems. I can understand not wanting to run a $50K 'vette like that, but the Nova’s not having any trouble from the gas.
When I get my Hudson Hornet, if the engine’s in good shape when I buy it, I’ll just put additive in it when I gas up; when I rebuild the engine (as I undoubtedly will need to at some point, as I will be using a '52 Hudson as a daily driver) I will probably install the necessaries to convert to unleaded fuel and any other updates that I can do without losing the Twin-H Power.
Well, actually, I will have a mechanic (or Gun, lacking a real mechanic) do all that, as I don’t know the theory involved.
Avgas is not recommended for use in cars. Avgas and mogas are formulated differently – they have different additives. Some of those additives are good for car engines but not necessarily good for airplane engines. Same with avgas. (Some aircraft can me run on mogas, but you need to buy a Supplemental Type Certificate and follow the instructions.) If 100LL avgas has four times the amount in lead that the old leaded mogas had (and I believe this to be true), maybe it would be safe to mix 25% 100LL with mogas?
I’m having a 1966 MGB roadster restored. It has an 1,800 cc engine and the compression is 8:1 (or maybe a little more). I’ve been told that I can run it on unleaded fuel – if I don’t drive it too hard. I drove my last 1966 MGB like a sports car (this was in the early-1980s when I could still get leaded fuel). I drove my Porsche 924 and 911 like sports cars. I drive my Jeep Cherokee like a sports car. Obviously, I’m not one to take it easy on cars. So I’m having the hardened valve seats installed.
FWIW and IIRC, my last MGB did not run well on regular gas. In hot weather and especially under hard accelleration it pinged. I’ll have to run medium- or premium-grade in it.
Johnny L.A. -
My entree into the aforementioned car club is a 1959 MGA… I’ve had two B’s and a midget as well. I’m active in the local MGCC chapter. Between mine and my fellow members’ cars, I’ve probably worked on 100 MGs and a dozen or so Triumphs. I KNOW these cars… I’m pointing all this out so you’ll believe me when I tell you DO NOT run that lovely B on unleaded!!! Use additive until/unless you do have the hardened seats installed.
It’s not just a matter of “oh you’ll have to do a valve job before too long”. Unless you’ve had that sucker open, you don’t know what DPOs (Dumb Previous Owners) have done. The valve seats could be shinola already… And when they’re eroded, you’re not just screwing with the valves… Your compression is shot, you get backfire problems, cylinder pressure is blowing through that engine in ALL KINDS of places it shouldn’t be… In short, you’re stressing the entire system on an almost-40-year-old car. I’ve seen guys throw rods with no other apparent issue than running on eroded valve seats…
Sorry to rant a bit here, but it’s not like they’re making any more MGBs… Keep 'em on the road!
I * meant * to write lead substitute,but by the time I posted I saw that had been covered by another who was quicker on the trigger 
Sorry for the confusion.As to cost I think another post commented on it.And I’m definitely not a gearhead just trying to help someone who seemed to need a fix for a problem and no answer had appeared when I read the question.I’ll go back to lurking for awhile 
There seems to be a bit of confusion: Lead content does not equal octane rating.
In the case of the MBs and whatnot mentioned above- and the high-dollar Corvette- if they have a compression ratio higher than, oh, say eight and a half or nine to one, or a poorly-designed combustion chamber (or both) then you need to use higher octane fuel. The 90 or 92 octane “premium” gasoline, in other words.
Tetraethyl lead was indeed used as an octane booster back in the day, but with it’s phasing out, gasolines were reformulated to have equivalent or higher octane ratings without it.
So, if you have an older car without hardened valve seats, you need to use a lead substitute- and the only reason to do so is to control valve erosion. If you have an older car- with or without hardened seats- with a high compression ratio and/or poor combustion chamber shapes (as in the '52 Hudson flathead eight) then you need to run a higher octane fuel.
The guy with the sixties’ Corvette would likely need both- a higher octane and a lead additive. The Hudson, probably having a compression ratio barely exceeding seven or eight to one, would only need a lead substitute. The '75 Chevy Nova probably doesn’t need either one- it has factory induction-hardened seats, and a 9:1 ratio but a pretty good combustion chamber shape.
Mea Culpa:
Doc Nickel is absolutely right. My bringing up the guy who uses 87 octane was an aside, and I should have clarified it really had nothing to do with the question of using lead substitute or not…
DrLizardo: The valve seats will be done before I ever get the car back. No worries.
That’s mostly true. The British Motor Heritage Trust is making new MGB and MGB-GT bodies. You can buy them and have them shipped to New Jersey or Santa Barbara for about $6,700. Moss Motors has almost all of the parts you’ll need. Sure, you’ll have to get some parts (engine, transmission, suspension cross-piece) from donor vehicles, but you can almost make a new MGB from scratch if you want to spend the money.
Johnny:
Yeah, I know. Plus there’s always the MGF which one could import but not legally drive here (AFAIK).
I once did a rough estimate of what it would cost to build an MGA from scratch by buying from Moss. Same deal - you need a few things like much of the engine, chassis, etc. And unfortunately, unlike the MGB, the original dies for the MGA body were not preserved, so nobody’s selling anything but replacement skins, doglegs, etc. No “whole body” available… Urgh.
But even assuming you got the missing bits from a beyond-salvage donor car for free, I recall it coming out to around $60,000… Oh well.
Enjoy your B!