Correct fuel for my 1968 Volvo 1800S

mauro de giorgi · Feb 15th, 2012, 19:50

Hi All,

I am a new VOC member and this is the first time I use the forum. I am the happy owner of a 1968 1800S, and I would like to ask you your advice with regards to the lead additives. I understand it's a FAQ but I am still struggling to find a good answer. The question is: should I use lead additives/replacement (my volvo has its factory unmodified B18)? Or should I use V-Power petrol? Other than that, are those fuel inject & valve cleaners useful?

Thank you for your advice.

Kind regards
Mauro

classicswede · Feb 15th, 2012, 20:38

Mooved to correct section.

Most run on basic unleaded while other use an additive or have made alterations to the head.

Have a search through this section and there is pleanty of discussion on the subject.

It is only with the high compression E's that you need to increase the octane.

Volvo Canadian · Feb 16th, 2012, 01:41

Ran on regular unleaded for yonks. With my new car it is a bit higher compression and I have been running premium, but it is a lot more expensive; I'll be interested to hear if others can tell the difference. My compression is 145 all the way across (heads are shaved).

Some guys say you need the lead additive, but maybe for racing, I dunno.

tom-madbiker · Feb 16th, 2012, 07:43

i run on high octane unleaded when i run on petrol most of the time on lpg last time on petrol was about 3 months ago the compression ratio is on the high side about 9.5-1 and im running a stage 2 head and a k cam valves do not appear to be recessing at all i have not had to adjust the tappets since the rebuild

Tony Barrett · Feb 16th, 2012, 10:09

Hi Mauro,
Welcome. Additives are only needed for when you drive at maintained high speeds. When urban driving there is not a problem. Motorway type driving is when additives are needed, even then the odd one-off should not cause a problem.
The problem, is exhaust valve seat recession. I proved this to myself by driving 3000 miles, over a few weeks, at 80-85mph 130-140 kph, and adjusting the exhaust valve clearance twice in that time. Then removed the cylinder head to find considerable exhaust valve seat recession, fitted hardened sats, end of problem.
Additives are not a complete cure/preventative, but they certainly help.
Hope this helps you look forward to enjoying your Volvo.
Tony Barrett
The Old Volvo Man

Feb 15th, 2012, 19:50	#1
mauro de giorgi Junior Member Last Online: Jan 11th, 2015 18:07 Join Date: Jan 2012 Location: London	Correct fuel for my 1968 Volvo 1800S Hi All, I am a new VOC member and this is the first time I use the forum. I am the happy owner of a 1968 1800S, and I would like to ask you your advice with regards to the lead additives. I understand it's a FAQ but I am still struggling to find a good answer. The question is: should I use lead additives/replacement (my volvo has its factory unmodified B18)? Or should I use V-Power petrol? Other than that, are those fuel inject & valve cleaners useful? Thank you for your advice. Kind regards Mauro

Feb 15th, 2012, 20:38	#2
classicswede Trader Volvo in my veins Last Online: Today 21:26 Join Date: Dec 2004 Location: Anglesey	Mooved to correct section. Most run on basic unleaded while other use an additive or have made alterations to the head. Have a search through this section and there is pleanty of discussion on the subject. It is only with the high compression E's that you need to increase the octane. __________________ http://www.classicswede.org www.classicswede.co.uk

Feb 16th, 2012, 10:09	#5
Tony Barrett The Old Volvo Man Last Online: Apr 2nd, 2024 21:20 Join Date: Dec 2001 Location: london	Additive Hi Mauro, Welcome. Additives are only needed for when you drive at maintained high speeds. When urban driving there is not a problem. Motorway type driving is when additives are needed, even then the odd one-off should not cause a problem. The problem, is exhaust valve seat recession. I proved this to myself by driving 3000 miles, over a few weeks, at 80-85mph 130-140 kph, and adjusting the exhaust valve clearance twice in that time. Then removed the cylinder head to find considerable exhaust valve seat recession, fitted hardened sats, end of problem. Additives are not a complete cure/preventative, but they certainly help. Hope this helps you look forward to enjoying your Volvo. Tony Barrett The Old Volvo Man

Feb 16th, 2012, 01:41	#3
Volvo Canadian Bury me in my Volvo Last Online: Oct 18th, 2017 23:16 Join Date: Nov 2010 Location: Calgary (again!)	Ran on regular unleaded for yonks. With my new car it is a bit higher compression and I have been running premium, but it is a lot more expensive; I'll be interested to hear if others can tell the difference. My compression is 145 all the way across (heads are shaved). Some guys say you need the lead additive, but maybe for racing, I dunno.

Feb 16th, 2012, 07:43	#4
tom-madbiker Master Member Last Online: Apr 14th, 2020 21:20 Join Date: May 2010 Location: chesham	i run on high octane unleaded when i run on petrol most of the time on lpg last time on petrol was about 3 months ago the compression ratio is on the high side about 9.5-1 and im running a stage 2 head and a k cam valves do not appear to be recessing at all i have not had to adjust the tappets since the rebuild

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