Timing chain replacement benefit

[Chai]

Replaced the timing chain after 140,000km and, my goodness, the car certainly feels more energetic.

It was last changed in 1995. Felt the engine performance decrease when leaded petrol was fully withdrawn from the market. Even had to retard the engine ignition in order to use lead replacement petrol (LRP). I recall LRP was a 95 RON fuel.
Seemed like a long time before 98 RON premium unleaded became available in the market. Guess, by that time, the timing chain had stretched, affecting valve timing and my getting used to 'normal behaviour' even when run exclusively on 98 octane.

Now, with a new timing chain and still with 98 RON, the car now feels like it was in the days of leaded petrol - zippy, more torque.

Can't provide a fuel consumption comparison just yet - as am regularly enjoying the engine during my weekend drives.

[CraigB]

that's good to know Chai. I know it is possible to measure that sort of thing, but not that expensive or hard to change a chain. Once I clear a couple of other jobs, I will put 2 3.5 engines together with fresh chains, bores, rings etc - looking forward to driving a nice crisp engine. The one in the 350sl now runs ok but I am sure it should feel crisper from other things i have heard. This will be putting its original engine back in with rebore.