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How to keep your Pride & Joy in tip-top condition.
#821302
Simple question....

Can a stock 4AGE series 3 16 Valve engine use unleaded petrol with zero chance of valve seat recession?

According to this site

http://www.acea.be/publications/article ... -standards
and this pdf file on that site
http://www.acea.be/uploads/publications ... BILITY.pdf
It is not compatible without a valve lubricant.

This one however says it's fine.
http://www.vea.qc.ca/vea/articles/unleaded.htm

Even the local wheels24 site says my car is fine as it is a 1990 model.
http://www.wheels24.co.za/News/Leaded-p ... e-20040702

This site however again says only compatible with valve seat additive
http://www.naamsa.co.za/unleaded/databases/index.php

Can anybody give me a definitive answer please? I just filled with unleaded for the first time as I can no longer find LRP. Car seems to be running just fine. Have done +-60km so far with no difference at all.
#821478
I'm running my 4age on unleaded. Goes fine
#821488
my chisel shape use to run on LRP then I phased it out in quantities by mixing the two in ratios until the leaded was the smaller ratio and the unleaded obviously the bigger number. I never had smoking issues or oil consumption and the engine ran fine till the car was stolen. My 89 bubble runs only on 93 unleaded fuel and now and then 95 to clean the carbon build up on the valves.
#821533
The leaded/unleaded issue mostly boils down to two critical points. the first is fairly simple, if your car has a catalytic converter, stay away from leaded/LRP.

For your application: Short answer:- Unleaded is suitable

Long Answer:-
For older cars that previously ran on leaded and switched over to LRP, the concern was that the cylinder heads are purely cast iron and fairly soft. these cars did not have hardened valve seats as the valve seats were only profiles machined into the mother material of the cylinder head. in order to protect the seat, lead was added to fuels to act as a lubricant and seat protector as the valves were made of much harder material, and without lead or similar substitute at high rpm the valves hammered and recessed the valve seats to a point were the head would eventually be beyond repair. On cast iron cylinder heads, this can be alleviated by machining and inserting hardened valve seats as we will be soon doing on our 1961 Volvo 544.

On aluminium cylinder heads, such as your 4age, these have no compatibility issues with unleaded fuel. in fact, unleaded fuel may be safer than LRP as the additives that are used to replace lead are more damaging to modern engines than using unleaded itself.
#821612
shalzn wrote:The leaded/unleaded issue mostly boils down to two critical points. the first is fairly simple, if your car has a catalytic converter, stay away from leaded/LRP.

For your application: Short answer:- Unleaded is suitable

Long Answer:-
For older cars that previously ran on leaded and switched over to LRP, the concern was that the cylinder heads are purely cast iron and fairly soft. these cars did not have hardened valve seats as the valve seats were only profiles machined into the mother material of the cylinder head. in order to protect the seat, lead was added to fuels to act as a lubricant and seat protector as the valves were made of much harder material, and without lead or similar substitute at high rpm the valves hammered and recessed the valve seats to a point were the head would eventually be beyond repair. On cast iron cylinder heads, this can be alleviated by machining and inserting hardened valve seats as we will be soon doing on our 1961 Volvo 544.

On aluminium cylinder heads, such as your 4age, these have no compatibility issues with unleaded fuel. in fact, unleaded fuel may be safer than LRP as the additives that are used to replace lead are more damaging to modern engines than using unleaded itself.

Brilliant answer. Thank you very much. :thumbright: :thumbright: :thumbright: :thumbright: :thumbright:
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