Oldslincs

Are there any Rocket Olds 88 owners out there in the UK? If so, can you recommend a fuel and additive combination for my 1950 Rocket-88 four-door sedan please? It has an original engine with just over 50,000 miles on the clock. I have a re-printed owner manual with the Olds and it states that the 'Rocket Eight Cylinder Engine is designed to take full advantage of the anti-knock qualities of the best premium fuels commercially available and will not operate satisfactorily on regular gasoline'

I asked my local car-service guy and he recommended the following combination of:

• Tesco's Premium Petrol 'Momentum' with an octane rating of 99 (RON) and
• Millers VSPe, anti-knock additive, made in Yorkshire, which also raises the octane level by two points and has an anti-ethanol efffect. http://www.millersoils.co.uk/product...-multishot/624

He has a lot of experience with classic UK vehicles and track-day cars, as well as regular vehicles, but said that although the above combination has worked very well in older vehicles he's serviced, nothing beats asking owners of the vehicles themselves for their recommendation and experience, which is what I'm doing with this post. Any help would be much appreciated.

I've read lots of other posts on fuel and additive combinations for my model and year of Olds, but even where the name of the gasoline seems to be the same in the US as in the UK, I've read that the specification can differ from country to country. The brands of lead replacements are quite different, as well, as would be expected.

oldcutlass

Ron to mon rating can be 8-12 less, so your 99 can be as low as 87 in the states. Do you guys have an Octane fuel thats higher? We in the states have a 93 mon.

Oldslincs

Thanks for the info' Eric - and wow - I never knew about the difference in octane levels between different codes RON to MON. I'm on a fast learning curve on this at the moment, and a reference to this on Wikipedia confirms your forecast- as below. https://en.wikipedia.org/wiki/Octane...28R.2BM.29.2F2

Info' from Wikipedia:- Tesco Momentum available in UK: RON 99; MON 87; AKI 93

The Tesco Momentum that we get over here is equivalent to the Shell V-Power, and both are 12 points lower in Octane level on the MON scale than the RON level; the AKI being the average of the two. As far as I know, the Tesco brand at 99 RON is the highest we can get over here. What kind of Anti-Knock Index level do you feel would be needed for my Rocket Olds to run ok?

VC455

In the late 1950s, Texaco Premium had 90 octane (RON)

RON in 1950 would not have been higher than that and was probably lower.

Therefore RON of 90 would be risk-free to run in a 1950 Olds V8.

Looking at this from first principles, the compression ratio of that car is 7.25:1; it would be difficult to buy modern gas with low enough octane rating to cause pre-ignition in that engine.

Tedd Thompson

As stated above low octane will not be a problem. I run 87 in mine all the time with never a issue with ping and your engine is lower in compression than mine..... Tedd

oldcutlass

Didn't realize his compression was that low.

Oldslincs

Many thanks for your comments guys. You've put my mind at rest about the question of fuel grade. I really appreciate it. .

rustyroger

You might find your engine will be fine with the cheapest supermarket petrol (gas to most of you colonials ) you can find. Tescos or Sainsburys regular should be fine.
If you don't do many miles per year and don't have a heavy right foot you probably don't need lead additive either.
A friend ran his 1959 Cadillac for years on regular unleaded, and that had a much higher compression ratio than your engine. No problems with valve seat recession either.

Try it, if it knocks upgrade to super, but I don't think you will find any need.

Roger.

Tedd Thompson

As far as the valves lead in gas issue I have been running a engine for years (SBC) with pump gas with no problems. This is a 300 hp high compression engine. I think this problem is much over blown.... Tedd

Oldslincs

Thanks for the advice guys. I'm relieved to hear that my Olds will run on standard petrol. It's not the extra cost of super-premium fuel as such - although it can be quite a bit more expensive over here, I was more worried that even the highest grade in the UK might still cause valve seat problems and engine-knock, which could stress the engine.

Your advice is also in line with what other people are saying in other places the net, as I read more about the subject. I wasn't planning on doing any extra-long journeys or to give the engine a hard life in any way, so I know from what you and other people are saying, that's this is also going to keep the Olds happy.

Ozzie

As everyone notes, you will likely have no difficulty. You can gradually work toward lower octane. If it gets too low the engine will let you know, usually by knocking under acceleration. If it does just raise it up a bit.

stuhes

Hi Oldslincs, Nice to see that I have someone nearish to Sheffield with an olds. Mines a 49 '88' coupe.
I've often put Shell V power in mine but to be honest it runs just the same on regular. I do put lead substitute additive in, not sure what make it is but I get it from Halfords. Just a bit of insurance and peace of mind really.

Oldslincs

Well that's an amazing coincidence. I'm from Sheffield too originally. I also use lead substitute. I think it's made by the same company that make Redex upper cylinder lubricant. .Do you use Shell V Power occasionally to keep the ethanol level down a bit in your fuel? The amount of ethanol in Regular fuel is supposed to be harmful to rubber seals and diaphragms in Rochester carbs according to a few classics enthusiasts I've spoken to recently.

Could you also tell me which engine oil you use please. I've heard that Millers Classic, which is high in ZDDP, is good for our vehicles, so I might give that a go instead of the Comma Classic I've been using until now. Millers are a Yorkshire firm based in Brighouse.

rustyroger

As a rule of thumb 1200 ppm of zinc is what you need, I vote for Comma, but that's because they are based in Kent.
Of course I understand that as a Yorkshireman you would prefer Millers.
However if you email most oil companies they will tell you which oils are suitable for your needs, most companies supply oils suitable for old fashioned engines, they don't come much more old fashioned than sidevalve old American iron!.

I would guess that just about all the rubber fuel hoses have been replaced after 70 years, all petrol hose sold now is suitable for unleaded, which wasn't always the case.
I also wonder if any of the rubber in your carburettor are original, if they are you might think about replacing them anyway. Better that topping up with expensive petrol which your car won't need anyway.

Roger.

stuhes

I'm afraid I've not given ethanol much thought over the past 8 years as owner of my olds. Perhaps I should have but it it runs fine and I'm happy that it has no strange noises or oil consumption issues. I use Halfords 20-50 oil that they sell for 'older' cars. It comes in an old fashiond metal can. Does the job nicely.
If ever you are in Sheffield...

Oldslincs

Thanks for that spot-on advice about fuel and oil Roger. Much appreciated. As you say, all the rubber fuel hoses and carburettor gaskets on the vehicle have been replaced with modern components, so that's put my mind at rest knowing they're resistant to ethanol

Oldslincs

If you've had no issues with ethanol content in fuel affecting rubber components in the last 8 years, then that's good enough for me not to worry about it . Roger's post is reassuring about that as well.
As for visiting Sheffield, I might be there this Sunday at the Owls in The Park event. It's a marmite thing for Sheffielders i.e. you're going to love it if you're a blue and white, but not so if you're a red and white. My gt grandfather captained Wednesday in their early-ish successful years in FA Cup and League, so my allegiance was never in doubt - even before I was born!! If only a bit of that could happen again in my lifetime :/

stuhes

I work a couple of streets from Sheffield Wednesday's ground. Don't follow football but its all blue and white around here. I'm away this weekend unfortunately. Would have been good to show you the Olds. It is for sale at the moment. Don't you need another one to go with yours? A coupe in light blue perhaps?

rustyroger

I used to work with a guy from Sheffield down here in Dover.
He never missed a Blades match, must have cost him a fortune.

Roger.