Leaded or unleaded - That's the question, Need advice on which type of fuel to use.. Options

[reineg]

Hi there, Laymen and Experts alike!

I have recently acquired a 914/4-70 with a newly built engine. Up to 2.2litre and some extra horses to boot. But now to the question:
The car has got new cylinders and pistons from Pelican Parts, but I do not know much more about the engine. So do you guys (and gals) reckon it would be safer to use modern fuel and add lead, or shall I just go for modern fuel and not add lead?

What is most detrimental to the engine; to add lead to an engine that doesn't need it, or not to add lead to an engine that requires it?

Appreciate any and all thoughts on this..

[VaccaRabite]

No one in the states adds lead.
You should be perfectly fine going unleaded. I know Europe is different, but here all the valves and such you can get are now made for unleaded fuel.

Zach

[reineg]

No one in the states adds lead.
You should be perfectly fine going unleaded. I know Europe is different, but here all the valves and such you can get are now made for unleaded fuel.

Zach

Thanks for your insights, VaccaRabite!

[914Sixer]

NON ethanol gas is my preferred choice. Burns cleaner, more horsepower, not as much carbon build up.

[GregAmy]

I can't imagine any heads rebuilt in the last 30 years needing lead (to protect the valve seats).

And I can't imagine any engine built for the street needing lead (for octane) especially when you can get 110 unleaded racing fuel (if needed). Honestly, street engines should be built to safely handle 93 octane max (91 if that's what's typically in your region).

Lead isn't pleasant stuff but it should not hurt your engine, even if it doesn't need it. But leaded fuel can have its own problems such as precipitating out if it evaporates from non-use. The photo below is the main jet stack from the Dells in my race car, photo taken earlier this month. For whatever reason (I think it was cheaper) I bought 112 Leaded at an event in June instead of 100 Unleaded, and then parked the car after the weekend. When I pulled it out the week before Memorial Day to get it ready for an event that weekend, it was running like hell...and this was why.

Ask your engine builder for minimum fuel specs, but I just don't see any rational reason to need leaded fuel these days. - GA

[930cabman]

I can't imagine any heads rebuilt in the last 30 years needing lead (to protect the valve seats).

And I can't imagine any engine built for the street needing lead (for octane) especially when you can get 110 unleaded racing fuel (if needed). Honestly, street engines should be built to safely handle 93 octane max (91 if that's what's typically in your region).

Lead isn't pleasant stuff but it should not hurt your engine, even if it doesn't need it. But leaded fuel can have its own problems such as precipitating out if it evaporates from non-use. The photo below is the main jet stack from the Dells in my race car, photo taken earlier this month. For whatever reason (I think it was cheaper) I bought 112 Leaded at an event in June instead of 100 Unleaded, and then parked the car after the weekend. When I pulled it out the week before Memorial Day to get it ready for an event that weekend, it was running like hell...and this was why.

Ask your engine builder for minimum fuel specs, but I just don't see any rational reason to need leaded fuel these days. - GA

Ouch, what happened to this main jet/holder? Probably water (IMG:style_emoticons/default/screwy.gif)

[GregAmy]

Ouch, what happened to this main jet/holder? Probably water (IMG:style_emoticons/default/screwy.gif)

It cleaned right out; the holder, jets, and air correctors are fine.

The engine ran fine when I parked it in June. And though it lives in the garage since - no significant exposure to water except maybe sitting outside with Perry's umbrella cover* if it's raining and I need the lift - I had no reason to run it so it was just pushed in and out as needed.

Best I can figure, I didn't fully drain the float bowls when I shut it down** and the fuel in the float bowl evaporated, leaving behind these precipitates, same as salt water will leave behind salt if you evaporate it. When I turned on the fuel pump it filled the bowl, mixing those solids in there, and when I fired up the engine it got sucked into the jet ports and stacks. I removed the top of the carb and there was grey lead deposits in it, and after cleaning that out I blew through the passages and more came out into the main stack ports.

I purged the rest of the tank of all that fuel, and there were no contaminates in the system. The fuel filter was clean.

Avoid the lead if at all possible.

GA

*Perry's cover does a decent job of keeping water out of the grill, but it has to be stretched tight. I'm running Sergio's GT grill and there's no water tray. Also, the air filters are using Claude's aluminum cast tops so I really don't see that there was much way for water to get into the carbs. And there was no reasonable way for water to get into the fuel cell, which is mounted in the front trunk (I didn't see any water when I purged the tank).

**At the end of a weekend I will typically turn off the fuel pump and let it idle it until it dies, using throttle to keep it running as needed. The left side carb was fine, only the right one had these precipitates. So I'm guessing the left side ran out first and the right side was not cleared out when I let it die and shut it down.

[reineg]

NON ethanol gas is my preferred choice. Burns cleaner, more horsepower, not as much carbon build up.

I believe all fuels from the pump in Sweden have 10% ethanol in them to reduce emissions.

Thanks to you all for your insights and tips.

[dr914@autoatlanta.com]

regular unleaded is just fine

Hi there, Laymen and Experts alike!

I have recently acquired a 914/4-70 with a newly built engine. Up to 2.2litre and some extra horses to boot. But now to the question:
The car has got new cylinders and pistons from Pelican Parts, but I do not know much more about the engine. So do you guys (and gals) reckon it would be safer to use modern fuel and add lead, or shall I just go for modern fuel and not add lead?

What is most detrimental to the engine; to add lead to an engine that doesn't need it, or not to add lead to an engine that requires it?

Appreciate any and all thoughts on this..

[Jamie]

I switched my stock 1.7L over 2 yrs. ago to non-ethanol when it became locally available, and "Mistress" loves it! She climbs hills now in 5th gear that before required 4th, and local fuel is 90 octane. For the past 2 Okteenerfests I used the 93 octane found in Townsend TN and she thrives on the twisty driving events even better! (IMG:style_emoticons/default/beer.gif)

[wonkipop]

Hi there, Laymen and Experts alike!

I have recently acquired a 914/4-70 with a newly built engine. Up to 2.2litre and some extra horses to boot. But now to the question:
The car has got new cylinders and pistons from Pelican Parts, but I do not know much more about the engine. So do you guys (and gals) reckon it would be safer to use modern fuel and add lead, or shall I just go for modern fuel and not add lead?

What is most detrimental to the engine; to add lead to an engine that doesn't need it, or not to add lead to an engine that requires it?

Appreciate any and all thoughts on this..

here is my take.
lead was in fuel ostensibly to prevent engine knocking. pre detonation.
it came about when manufacturers starting producing higher compression engines in the post war years.
if i am not mistaken earlier low compression engines in say the 40s, 50s and even early 60s did not need leaded fuel.
this was certainly the case in australia.
back in the 60s and 70s there were two fuels.
standard and super.
older cars with lower compression engines ran on standard.
it was lower octane and did not necessarily need or contain lead additive.
super certainly had it. in addition to being higher octane.

there is also a view that the lead additive in some way lubricated the valves or valve seats. but i think thats more of a misunderstanding.
by preventing pre detonation you got less wear on the back of the exhaust valves.

vw engines (and 914 engines) were already engineered a bit more sturdier when it came to the valve train due to being air cooled. at least that is what i have always been led to believe.

the octane requirements for the earlier engines and all the european versions is to do with the higher compression. the problem with early unleaded fuel when first introduced was they could only produce it with lower octane ratings. so they had to lower the compression ratios in the US cars. thats basically all they did with the US market cars from 73 on. lowered the CR. and of course. lowered the power.

but by the time we get to the 90s the fuel companies had formulated higher octane rated unleaded. so CR went up again.

i believe a european spec 914 with the higher compression ratios is fine to run on unleaded so long as you have the correct octane rating.
you want to avoid pre detonation is all.

remark by other poster regarding ethanol percentage formulated fuel is spot on.
you want to avoid ethanol added fuel if at all possible.

[Superhawk996]

but by the time we get to the 90s the fuel companies had formulated higher octane rated unleaded. so CR went up again.

Adding context, compression ratio went up in the 90s more as a function of OEMs being able to use knock sensors as a result of the sensors themselves becoming cheaper and the ECU processor speeds increasing.

When you can sense the onset of knock and vary timing in response, you can take more risk with compression ratio. Higher compression ratios are more fuel efficient and were better able to meet Fuel Economy regulations. They also produce more horsepower, a win for everyone.

[bkrantz]

But the challenge the OP has with a modified 2.2 liter four is what compression ratio he has. Lead additive, no, but he might need to use higher octane to run that motor hard.

[wonkipop]

but by the time we get to the 90s the fuel companies had formulated higher octane rated unleaded. so CR went up again.

Adding context, compression ratio went up in the 90s more as a function of OEMs being able to use knock sensors as a result of the sensors themselves becoming cheaper and the ECU processor speeds increasing.

When you can sense the onset of knock and vary timing in response, you can take more risk with compression ratio. Higher compression ratios are more fuel efficient and were better able to meet Fuel Economy regulations. They also produce more horsepower, a win for everyone.

very true. (IMG:style_emoticons/default/beerchug.gif)
good old computers.

[wonkipop]

But the challenge the OP has with a modified 2.2 liter four is what compression ratio he has. Lead additive, no, but he might need to use higher octane to run that motor hard.

very good point.

probably needs highest octane unleaded available.
be 98 RON in aus.
i think you guys in USA rate your octane slightly lower.

i can run my 1.8 on 91 RON here which is i think equal to 89RON usa.
i sometimes run a tank of 95 RON through it.
i don't notice any difference in performance. ha. (IMG:style_emoticons/default/biggrin.gif)
not at its low CR. (IMG:style_emoticons/default/biggrin.gif)
but i tend to do it for a highway run. figure its kinder on the engine then.
but be buggered if i ever detect any real difference.
maybe marginal fuel economy but its pretty slim difference.

i know the factory 2.0 in the USA and i think ROW ran on 95 RON.
but the european 1.8 with twin carb needed 98 RON and had that sticker.
it ran a higher compression ratio than even the 2.0 D jets.

i'd be running the OP's car on the highest octane i could get.

[reineg]

Seems you all agree on running unleaded, and I will fuel up on 98 octane, the highest commercially available gas in Sweden. Unfortunately it will contain 10% ethanol. No getting around that.

Very much appreciate all your good and speedy inputs.

Cheers,
Reine

[technicalninja]

Is leaded gas or real lead additives available in Sweden for road use?

I thought it was illegal everywhere for use in road vehicles...

Here in the USA if you want real leaded gas, you either have to by AV gas or specific race only fuel.

[Dave_Darling]

probably needs highest octane unleaded available.
be 98 RON in aus.
i think you guys in USA rate your octane slightly lower.

We use AKI, "Anti Knock Index". Also labeled "(R+M)/2". It is the average of the RON and MON octane numbers for the batch of fuel, and the number is about 4-5 points lower for the same fuel than the RON number.

Your 98 RON is about 93-94 AKI.

--DD

[wonkipop]

probably needs highest octane unleaded available.
be 98 RON in aus.
i think you guys in USA rate your octane slightly lower.

We use AKI, "Anti Knock Index". Also labeled "(R+M)/2". It is the average of the RON and MON octane numbers for the batch of fuel, and the number is about 4-5 points lower for the same fuel than the RON number.

Your 98 RON is about 93-94 AKI.

--DD

yeah that sounds right.

three grades of fuel are sold here.
91 RON 95 RON 98 RON.
all of it accords with the grade of fuel on my cars filler stickers.
mine are all euro manufactured cars.
the RS clio takes the 98. which is getting pretty xxxy in price now!!!!
the 2006 audi A3 1.8 turbo takes the 95.
the 914 takes the 91. which accords with the 91ROZ.RON sticker in the frunk.

what was the case in the USA back in the 70s.
was the fuel rated by MON back then.
i can't remember the late 80s anymore when i used to live in chicago.
what the fuel was marked as. too long ago. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

[wonkipop]

Is leaded gas or real lead additives available in Sweden for road use?

I thought it was illegal everywhere for use in road vehicles...

Here in the USA if you want real leaded gas, you either have to by AV gas or specific race only fuel.

there are additives here for older cars that used to run on leaded super (premium i think in USA speak). its not lead. its some kind of substitute. it lets those high compression engines run safely. somehow that ties into the idea that it protects the exhaust valves.
its never been entirely clear to me why thats necessary. but i know a guy that runs a couple of 60s and 70s ford falcons with original V8s and he pours it into each tank of fuel.

but lead is a big no no anywhere now in the environment.
you cant even use it for roof flashings if you were say restoring an historic building where the original flashings were once lead. particularly on 19th century slate roofs.
its just non available. non usable. banned.