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MGB-GT Leaded or unleaded - '70 GT

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Either or. Makes no big difference is my understanding. 70 models used leaded from the factory. To be correct for unleaded it needs hardened exhaust valve seats but most folks seem to think that it is not a big deal for the little we drive.
 
Some folks drive harder/more than others. I would personally upgrade to the hardened valve seats to prevent possible damage....

FWIW...YOMV
 
I've put tens of thousands of miles on my '64 MGB with unleaded Premium with no deleterious effect to the valves. Just be sure to feed it (at least) 93 octane. Most of the "Octane Boost" additives are just snake-oil, so don't bother with 'em.

If the tank is out, have it "boiled" by a radiator shop to clean it out, as you have a 50-50 shot at getting a "new" tank without a built-in LEAK from the "usual suppliers." You can have yours epoxy "linered" and be fine.
 
'70 should be a high compression engine so premium gas is pretty well a must. I get a no lead additive which is fairly easy to get in a good auto supply store (Autozone seems to be catering more for the historic car fans) supposedly this protects the valves. /ubbthreads/images/graemlins/iagree.gif
 
It doesn't matter like Doc said....those who spend all the dollars installing hardened seats aren't really accomplishing anything....you'll probably drive it like it is for several hundred thousand miles before the seats (or anything else gas related) go bad!
 
I run 93 octane in my B. One of our club members who works on these cars for a living made an interesting comment to me the other day. He said that Marathon sells the best "blend" for our cars.
 
Personally, I think that's B.S.....even if it's only "insurance", I feel better having hardened seats in my two MGCs and my 4 banger MGB. I also put them in the aluminum Buick 300 heads on the V8.

Part of my point is that it may be hard to find higher (93) octane gasoline...I recently spent 1500 miles in an MGB/GT in a weekend in two states.....and the highest octane rating we could find was 92 (once) and only 91 the rest of the times.

Octane boosters, etc...are indeed "SnakeOil" in my book as well...so go for the hardened seat. Better to be safe than sorry .... as we all know, the 1800 cylinder heads are not quite as available as they have been in the past.

FWIW...YOMV
 
My 1974 MGB had recessed valves due in part to using unleaded gas. But it showed other signs of abuse and neglect in the engine as well. It seems that if you drive the car hard, with high RPMS and high engine temps, you're going to be at higher risk for valve recession.
 
AFAIK the octane rating has little to do with how the valves wear...the lead acted as a lubricant, with the by-product of aiding combustion (effectively increasing the octane mildly). Putting higher octane gas or octane boosters would therefore NOT replace the lubricating properties of the lead unless the booster is specifically designated as a lead replacement in terms of valve protection.

FWIW, I run 98 octane (equiv. to US 93, I think), without valve lubricant additives...when it comes time to rebuild / add the supercharger :smile:)) in x thousand miles, I'll look at 'em and get back to you guys!
 
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'70 should be a high compression engine so premium gas is pretty well a must. I get a no lead additive which is fairly easy to get in a good auto supply store (Autozone seems to be catering more for the historic car fans) supposedly this protects the valves. /ubbthreads/images/graemlins/iagree.gif

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How in the world are you going to protect the valves with a "NO Lead Additive". It was the lead in leaded gasoline that added the protection for the valves. /ubbthreads/images/graemlins/confused.gif---Keoke
 
Remember " Gulf NoKnox"? It was supposed to have the higest lead content of any gas on the market. Preignition deterant. And how about Sonoco 260. Use to us it in my motor cycles. Couldn't afford to use it in my cars. Needed the money to take my girl out. Ah, those were the days. /ubbthreads/images/graemlins/rolleyes.gif PJ

PS, I forgot to say, I've been paying ever since.
 
Ha, does she know what you gave up?
 
Jack, I don't think she ever had that in mind. Do any of us poor guys ever have that consideration? I better be quiet, some of the girls might pick this up and as usual, I'll be in trouble again. /ubbthreads/images/graemlins/rolleyes.gif PJ
 
Naa, these gals here are cool. They share our pasion.
 
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'70 should be a high compression engine so premium gas is pretty well a must. I get a no lead additive which is fairly easy to get in a good auto supply store (Autozone seems to be catering more for the historic car fans) supposedly this protects the valves. /ubbthreads/images/graemlins/iagree.gif

[/ QUOTE ]

How in the world are you going to protect the valves with a "NO Lead Additive". It was the lead in leaded gasoline that added the protection for the valves. /ubbthreads/images/graemlins/confused.gif---Keoke

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Additive for "NO Lead" gas seems preety straightforward to me
 
Run unleaded and just keep an eye on the valve lash. If you get recession, the clearances will close up. The proper fix to protect against valve recession is to install hardened seats. If you don't, and you get valve recession, the fix is to (wait for it....) install hardened seats. So I say just drive it until it needs a valve job, enjoy it and don't worry! You can either pay to do the job now, or wait until it needs it.

FWIW, I've got 30,000 miles on my '69 since I bought it in 1995, with no worries. And if there was any "lead memory" effect (the idea that the seats become so impregnated with lead deposits that they're protected against wear), it was cut away when I had the valves done back in 1995 and didn't know you were supposed to have hardened seats installed....

HTH!
 
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'70 should be a high compression engine so premium gas is pretty well a must. I get a no lead additive which is fairly easy to get in a good auto supply store (Autozone seems to be catering more for the historic car fans) supposedly this protects the valves. /ubbthreads/images/graemlins/iagree.gif

[/ QUOTE ]

How in the world are you going to protect the valves with a "NO Lead Additive". It was the lead in leaded gasoline that added the protection for the valves. /ubbthreads/images/graemlins/confused.gif---Keoke

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Additive for "NO Lead" gas seems preety straightforward to me

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/ubbthreads/images/graemlins/savewave.gif
That ain't what you said. Very few additives except those for off road use only; "REAL LEAD" is one are anything but snake oil as has been said.---Keoke
 
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