volvo144 B20

This car is of 1972 age and I would like to know if these cars can use unleaded petrol please any advice is most welcome

You can only run this engine on unleaded if you use a fuel additive; otherwise you'll have to have the head converted.

Huge subject much discussed on this forum.

I have a 1973 B20 and run with Millers VSP additive.

Search the forum for 'unleaded' and see the comments and read why members fal into the 'Convert it' or 'leave it alone camps'

[Mike_Brace]

I ran my Amazon on unleaded for over 60,000 miles of veryu hard driving including towing. The only modification was due to melting plugs I used the injection plugs. I also replaced the restrictive standard exhaust with a sports system so allowing the hot gases to flow away freely. I also made sure the cooling system was working at its best. Head removal showed no signs of any problems other than slight valve guide wear. An engine reconditioner said the main problem he had seen was valve and seats melting together due to the engine running too hot. I would run on straight unleaded and worry about any problems if they occur and consider head work at that stage.

Mike

[classicswede]

The B18 and B20 heads will suffer from accelerated valve guide wear when running on unleaded or lpg. The wear is caused by the side loading of the valve (pushrod engine). This wear is made worse because unleaded does not lubricate as well and LPG does not lubricate at all.

This problem can be greatly reduced by using sicone bronze alloy guides.

Hope this info helps

[pyaap]

My dad has a 1972 144 with a B20A engine and all he did was drop a Broquet fuel catalyst into the fuel tank and the car has been running perfectly on Super Unleaded eversince. That was nearly 10yrs ago and the car's never missed a beat. I've also got a relative who did precisely the same with his 240 and that's running fine too.

There is an article on the Broquet here:
http://www.volvoforums.org.uk/showth...hlight=Broquet

There is a discussion on the Broquet here:
http://www.volvoforums.org.uk/showth...hlight=Broquet

My comments are given as someone who has twice used the Broquet with great success and know others who've done the same; its not mere speculation.

[classicswede]

This is a common missunderstanding.
The broquet fuel cat is only a octane booster. They work so well on the volvo engines with unleaded because they do not need it.
The 240 engines have always run on unleaded with no problems.
What is wanted on the B18 and B20 is lubrication not higher octane.

I can see no real point in using an octane booster in a B18 or B20 engine as they run so well on normal unleaded.

Provided you do not drive your old overhead valve volvo to hard you will find no probelms running on unleaded with no more than adjusting the timing.

If you drive hard then a change of plugs and replacing the under sized exhaust with somthing more suitable to the power output is the main thing needed.

The valve guides wear if you run on 4star or unleaded, its just unleaded wears them faster.