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angel
Enthusiast
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There has been some more discuss about this in the past...
My own experience with 845s is: About 90.000 kms with 95 RON unleaded (of varying quality, must I admit, it's usual here), never used any additive. Head is "late" type (with pushrod guides cast in, not separate bronze tubes), skimmed 0,50mm (total) after one gasket failure and one engine rebuild.
I have been checking valve clearances every 10.000 kms, and they were never found to be closing (either stayed the same or widened very slightly), which is absolutely normal. Some open road/maximum load trips, but not too much. Mostly driven in hot weather (35 to 40 deg. Celsius ambient temperature common here in the summer).
I never noticed signs of valve seat recession, both when chcking valve clearances and when I overhauled the head, where the exhaust valves and seats needed only to be ground in with paste, absolutely no need for seat recutting or valve regrinding.
I also never noticed exhaust valve gaps closing on any other customer's 845, that I know it's using unleaded.
I have also talked with people from Germany in the past (where unleaded has been available since mid-80s), and their conclusions are the same: the "small" engines are 100% unleaded compatible. Personally, I would not bother about using additives or LRP on these engines.
As for 1108, I don't have enough experience, i have covered only about 5000 kms with the Jogging and have not checked valve clearances yet.
My own experience with 845s is: About 90.000 kms with 95 RON unleaded (of varying quality, must I admit, it's usual here), never used any additive. Head is "late" type (with pushrod guides cast in, not separate bronze tubes), skimmed 0,50mm (total) after one gasket failure and one engine rebuild.
I have been checking valve clearances every 10.000 kms, and they were never found to be closing (either stayed the same or widened very slightly), which is absolutely normal. Some open road/maximum load trips, but not too much. Mostly driven in hot weather (35 to 40 deg. Celsius ambient temperature common here in the summer).
I never noticed signs of valve seat recession, both when chcking valve clearances and when I overhauled the head, where the exhaust valves and seats needed only to be ground in with paste, absolutely no need for seat recutting or valve regrinding.
I also never noticed exhaust valve gaps closing on any other customer's 845, that I know it's using unleaded.
I have also talked with people from Germany in the past (where unleaded has been available since mid-80s), and their conclusions are the same: the "small" engines are 100% unleaded compatible. Personally, I would not bother about using additives or LRP on these engines.
As for 1108, I don't have enough experience, i have covered only about 5000 kms with the Jogging and have not checked valve clearances yet.
malcolm
& Clementine the Cat
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I'd agree with that. I'll run 750cc or 850cc engines without any additive. The lovely Ornella made it back from the south of France with no additive, and I made a few 600km trips to college and back in my younger days in an 850 with no problems. Even 6000km to Slovakia and back flat out all the way was no trouble without additive.
1108 and 956 do need additive for long motorway journeys. The same 600km trips to college burned valves in an 1108, and a 5000km trip to the south of Spain and back had the car idling on 3 cylinders. On both occasions I needed to remove the cylinder head to replace valves and valve seats.
For running around locally in an 1108 I don't use additive. For long motorway journeys I do use additive for the convenience of not having to take the engine apart after 3000 miles. But that's only the 1108 engines (956 are the same). 750s and 850s are fine without additive.
1108 and 956 do need additive for long motorway journeys. The same 600km trips to college burned valves in an 1108, and a 5000km trip to the south of Spain and back had the car idling on 3 cylinders. On both occasions I needed to remove the cylinder head to replace valves and valve seats.
For running around locally in an 1108 I don't use additive. For long motorway journeys I do use additive for the convenience of not having to take the engine apart after 3000 miles. But that's only the 1108 engines (956 are the same). 750s and 850s are fine without additive.
Cornish4
Le Dazzleur
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Point taken angel, it's not uncommon I think with a lot of classic cars, that the earlier examples seem more durable, and later in production manufacturers cut corners to save money, and sometimes use slightly inferior materials. They think the customers won't notice, and most times they don't. It's when the cars get into the hands of enthusiasts that these problems come to light. All part of the fun of owning a classic car. Just read your posting too Malcolm, us with 1108 engined cars take note, and thanks for the advice.
angel
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Even though our beloved R4s were cheap cars, I think that material quality is very high. Renault cut costs from equipment, finishing and interior but made no compromises in mechanicals because they had to last for many years of abuse. Valve seats, cylinder liners/piston rings, torsion bars, suspension bushes, electric components are good examples.
Compare them with British or German cars of the time...Better still, if you make the comparison with any modern "ecobox" you would be heavily disappointed when you notice that some things are going one or two steps backwards in the automotive industry...
Compare them with British or German cars of the time...Better still, if you make the comparison with any modern "ecobox" you would be heavily disappointed when you notice that some things are going one or two steps backwards in the automotive industry...
Late comment on this thread. There seems to be some consensus on here that at least for the 'larger' engines, using an additive for long or fast journeys is a good idea. When I see 4's for sale on leboncoin with 200,000km done, I wonder if they've ever had any additive in their life. I get the impression some French drivers of 4's have never heard of additives...
