Leaded or unleaded?

[Chris_C]

No, agreed they don't need the lead, but they do need the extra octane that 4* had, so are only safe on Super Unleaded. Valve seats don't cope with octane, only the amount of ignition advance surely?

[volvodspec]

you'll get an octane of 96+, if you add lead to unleaded 95. the lead additive boosts the octane level slightly aswell.

therefore it's from factory spec safe to fill it up with 95 leaded without risk of detonation. but super unleaded most likely will make it run slightly smoother and make it feel a bit more powerful. a b14.4e will cope with unleaded RON 91 and will run properly but that doesn't improve fuel economy or performance:D

[S10NPH]

Thanks everyone. I will use Shell v-power which is 99 octane, and I think I'll be safe.

[Chris_C]

Sorry for turning it into a complicated reply! 99 will be fine.

[pettaw]

Hiya, if your car is model year 1980 then I suspect it'll be the B14.1E which will have the soft valve seats. Vpower is great for the octane, but I would buy a bottle of valve treatment or lead replacement additive and add that to the tank.

The octane issue is less important, because, as these cars are pre-Renix, you can adjust the timing by tweaking the dizzy round a couple of degrees to retard it, but doing that you will lose power, so if you're happy running it on V-power then I would do so and keep the timing to factory specs (about 6 degrees at idle) - might be worth checking if you've got access to a timing light in case anybody has been fiddling.

Hope that helps.

[Ride_on]

The B14.1E was in my 1980 345, but I never used it on unleaded. Volvo has been promoting low octane unleaded fuel for many years since it invented the cat, most cars do not need the lead for lubrication purposes, however according to Volvoclub the 1980 340 needs lead for this and cannot using anything else, although I guess a suitable lead replacement (with valve lubricant) should work. The lead normally coats the valve stems to prevent stem wear AFIAK.

The 340 1.4s never used high compression like the 360s so are not so susceptible to pinking, but the B14.1E has mechanical points so you can retart the ignition if needs be. You should never hear pinking, if you do, retard by 1 degree until you never hear it again.

The Volvo web site did have a list of engines and what fuel they needed, all I can remember was some 760 Turbos that needed lead lubrication, and many UK variants of the B200/B230 needed octane booster or a compression reduction as they where high compression (more torque, great for towing). The older side draft carb 360s do tend to get jet needle wear, after 130K on 98 octane unleaded my 1983 360 was refusing to adjust the mixture down enough, and tended to put out black smoke alot. The jet needle looked like a banana it had worn so much! Later types had a teflon coating.

[pettaw]

I have the list. I downloaded it from the website when it was still available, but it starts with the B14.2E

[daffodil]

all b14 cylinder heads will take unleaded....its an alluminium head with steel inserts
all that needs to be adjusted is ignition timing if it pinks
also it is only the b144e that has a renix from 83-

[pettaw]

Only after 1981/2. Early types had the softer valve seats and need protection. Lead is best but any lead replacement additive is a good option

[classicswede]

Non of the red block's need the lead for the valves etc. The only issue is with teh timing/compression and this can normaly be resolved by adjusting the timing to run on std pump unleaded. The only problems come with some of the renix systems that have to much advance to cope with the lwo octane. The only answer for those is to either use super, or change the ignition sytem/reduce teh compression ratio.

[shimon340]

hi there

Coming into this discussion a bit late but I asked a question about valve seats to a chap who used to work for Volvo BV (last project was designing the layout of the 480 engine bay)

He said (as other have said too) the B14 1E and 2E have soft valve seats and therefore need lead or a suitable lead replacement additive. B143E and 4E etc have harder valve seats and can therefore cope with unleaded fuel.

I recall volvo also offered an LPG conversion kit for the 340 which was popular in Holland. Given the info above, presumably that's the B143E onwards. I've seen UK roadtest of such a car at X reg which was around the time of the first B143E? The 2E doesnt seem to have been used for long.

I don't have it to hand now (I'm on lunch at work) but I've got a last edition version of the Volvo green book for the 340 engine. Its lists compression ratios etc and also details the B130 340 sold in Belgium. That's interesting re the info for volvo 66s below. Presumably its a lower compression version with harder valve seats. An interesting engine for a volvo 66 if you want to run on 95 unleaded with no additive.

I'll check later but I recall the B140E or B141E whichever is the earliest one, has a higher compression ratio that the B142E ....or is it the 3E?

Valve seat material determines if you need lead or lead replacement additive and compression ratio determines what octane rating the engine can handle. It also determines if you can amend the timing so as to use lower octane fuel.

The Volvo 66 with the B130 has the character of having too high compression ratio with 95 unleaded but also softer valve seats. It therefore needs lead replacement additive and octane booster.

Depending on your requirements, Castrol make both a lead replacement product (keeps Octane rating at 95) but also a lead replacement product which also contains an octane improver. This gives you 98 octane with lead replacement additive.

A car designed to run on say 95 octane can also run on higher octane fuels. however, the compression ratio (and more relevant to this discussion) the fixed ignition timing means the benefit or changes to engine running are minimal. This is a general rule but has limits but suffice to say a 95 octane running engine can run on 98 octane without amendment on detrimental outcome. However, the 95 octane ignition map means you are getting all you could from the 98 octane fuel.

Hence why running a car with fixed ignition map (ie non adjustable using knock sensor feedback), wont really be so different on 98 fuel verses the standard 95 octane. Any increases in performance or fuel consumption etc come from the better additives packages of these fuels. Hence technically true (but overall not actually!) the adverts quoting improved fuel consumption on Shell Optimax etc which are due to detergents and additives cleaning the fuel system internally hence why they say it will make even older cars run better. This is only true so long until the detergents have done their work. So the advert isnt lying, its just not the whole truth. Eventually the cleaning is done and the improvement stops....it remains static benefit. However, changing the ignition timing on the Renix (earthing one of the pins of plug B makes the map for 95 octane (sorry I forget which one but vaguely recall its pin 2 - its been a while since I did this) and making the car run on the 98 octane map and then running on 98 octane fuel makes a noticable different to engine note and performance. 95 octane on the B14 3E and 4E was a bit of a compromise.....it's a nicer engine on 98 octane with a 98 octane map.

The B14 3E and 4E have Renix units with two ignition maps, one for 95 octane and one for 98 octane.

Partly because I worked for the company that developed it, partly coz I've seen the competitor analysis research work and the lab testing for the lead replacement additive and partly coz I'm aware of the pitfalls of sodium or potassium based octane improvers I'd advise use of the Castrol lead replacement product or the lead replacement product with octane boost.

Whilst many people say "I've run it on unleaded and had no problems" this usually refers to an engine capable of running on 95 octane fuel but ignores the valve seat concern. Engines have a "lead memory". The tetra ethyl lead reacts deposits on the intake valve but also tetra ethyl lead and other lead based compounds deposit on the exhaust valve and seat. Running a soft valve seat engine/needing lead on standard unleaded will be ok for a time as these lead based deposits wear off the valve seat and face. They wear away but are then replaced by new deposits. For a time, the valve and seat will be ok but eventually once the compounds are gone the valve seat recession mechanism kicks in.......

There are also carb parts which need leaded fuel or a suitable replacement additive as well but this varies from car to car.

Tetra ethyl was originally added to improve octane rating cheaply but then manufacturers designed engines to rely on it.

I recall Andrews PV631 from 1931 runs on unleaded with no additive as it was designed originally to run on 89 octane (need to check this) and tetra ethyl lead wasnt around so valve seats were hard!

The valve seat recession is coming back now as certain newer engines have valve seats hard enough for unleaded but too soft to cope with CNG and LPG. I'm currently trying to clarify this with Volvo Car Powertrain. So far it seems the NC 5 cylinder engines (solid valve tappets) have softer valve seats than the hydraulic tappet versions they replaced. This is still unclarified at the moment though..... so far the engineer I've spoke to said he thinks it would have cost more to redesign, test and respecify the cylinder head than the cost of continuing to use the harder valve seats of the apparant original specification. Also there seems to have been N series engines designed to run on unleaded as well. Suffice to say, valve seat materials, wear and additives etc is a big research area.

also, the reduction in crankcase breather volumes in modern diesels due to emission regulations means valve seat recession is now a relevant research area for diesel engines.

I'll try to update this with B14 specs from the green book later this week

[volvosneverdie]

I hereby nominate the above post for Post Of The Month^^^

Thats some serious posting Shimon.

[Chris_C]

Hmmmm, interesting... but (theres always a but...)

The B14 3E and 4E have Renix units with two ignition maps, one for 95 octane and one for 98 octane.

Are you sure? There is no knock sensor, and no way of telling the difference between the fuel? How would the map change?

I recall Andrews PV631 from 1931 runs on unleaded with no additive as it was designed originally to run on 89 octane (need to check this) and tetra ethyl lead wasnt around so valve seats were hard!

Not sure about the PV, but the sentiment is certainly true, I know several pre lead cars that don't need it

[shimon340]

hello

I dont know off hand the octane rating required by the PV651 but I generally recall the PV444 was designed to use something like down to 85 octane. Indeed, pre-tetra ethyl lead (American company supported by General Motors and the American government at the beginning) cars are fine on unleaded as they didnt rely on lead compounds.

The mechanism of degradation of unleaded valve seats that can handle unleaded but not LPG or CNG is something I'd like to look into a bit more. Why they survive on unleaded by not LPG/CNG when it doesnt seem unleaded has any valve recession protecting additives in? Originally there was no plan to replace tetra ethyl leads valve seat protecting properties. Alternatives were only sought to replace its octane improving ability and manufacturers would need to figure out the valve seat concerns.

Re Renix, earthing one of the pins in the B plug (usually has a rubber cover in it originally) accesses the 95 octane map. No earthing and you're back on the 98 octane map. The unleaded conversion from volvo (somewhere somewhere I've got this leaflet) was basically fitting a plug and earthing lead kit to the Renix to make the car run on 95 octane.

Given their work in the USA in 1976 with Lambda Sond and catalysts (which required legislation to force unleaded fuel into production) Volvo knew unleaded was coming so you can see quite forward thinking across many models ie unleaded capable 340s from X reg which is about 1980/81 and the B14 3E. Unleaded really took off in the late 80s with new cars only being unleaded from Euro 1 legislation in 1992. 1989 was the serious phase out? Dont remember it though, I was 8!!

Wanna know why unleaded in 95 octane anyway?

I heard from some R&D guys at Shell that when it seemed likely tetra ethyl lead was going to be forced out of standard fuel due to incompatibility with catalytic converters and the rising evidence of lead deposit poisoning (plants, animals) etc the assignment they were given was to measure the octane rating of the 'standard' blend fuel but leaving out the tetra ethyl lead (TEL). Result.... 95 octane. Therefore the cheapest amendment was chosen, leave fuel as it is, just don't add the TEL....Car manufacturers then had to figure their way to use this. Wasnt 3 star petrol 95 octane anyway? But...it had TEL in it to get there from a cheaper blend of say 91 from crude.

You can get octane past 95 without lead. This is done by adding aromatic compounds hence why you can get 98 unleaded and 103 unleaded (shell special blend - big marketing for this about 2 years ago. Few filling stations took it). Its more expensive though.

Then...there's the whole debate of the carcinogenic properties and exposure risk to aromatic compounds (the replacements for TEL in terms of octane rating).

Coke recalled a batch of cola a few years ago as the CO2 they used was contaminated with benzene (a carcinogenic aromatic compound). However, one would inhale more benzene filling one's car up that from drinking this coke. Even so, it was recalled anyway.

In terms of lead replacement additives there are three main classes. Sodium based ones, potassium and phosphorus.

A little story for you. You may recall the short lived Lead Replacement Petrol in about 2001. This was the point onwards when forecourt sales of proper leaded fuel was banned. It was based on a potassium based lead replacement additive.

Volvo Cars Powertrain was accidently delivered a batch of test fuel which rather than being what they wanted, was in fact some potassium based lead replacement fuel. It ruined some research engines at Volvo and Volvo took up their concerns with the supplier. Further incidents resulted in the fuel being pulled from the market. Potassium based LRP additives arent so good. Nor are sodium ones.

The Castrol additive is the best on the market but another manufacturer might have come up with a better one since its launch in 2004. Would need to head to head testing to know for sure.

[shimon340]

from the Renix table this looks like the dual map Renix. Earth one of the pins (I think middle one) to make it run on the 95 octane map.

B14.4E = 412