Normal?

[laxeian]

My F6 to me is running spot on, pulls, drives, ticks over and starts as I feel it should but doing a daily to and fro from a course I am on at the moment I have to drive up and down a few quite long 12% and 8% hills, in gear (top) coming down the hills it backfires a few times, I’m less worried than any pedestrians that think they are getting shot at, or dispersing wildlife that think it hunting season but is this something to be concerned about? ( van not wildlife or ducking pedestrians)

 

[André4Renaults]

Back-firing is usually caused by the timing not being set properly, although there are a number of other possible reasons. I'd suggest checking the timing by checking the dwell angle, which means the points gap will be set much more accurately than it would be using feeler gauges. Once this is set properly I'd next set the timing, using a strobe lamp, which again is a bit fiddly but well worth the effort. If you're not sure how to do this, just ask!

Do these two thing s before you do anything else and see if there's an improvement before adjusting or changing anything else. It's important not to adjust more than one thing at a time, or you might become confused.

On a more "contemporary" note, your car might give you enhanced "cred wiv da kidz on da block" as your car will join the myriad exhaust-banging cars running around most neighbourhoods after 9 pm these days....

 

[malcolm]

Regular muted pops on overrun down hill are fairly normal. The fuel doesn't shut off completely and combusts in the cylinder with the exhaust valve sometimes a bit open.

A proper backfire bang would be fuel combusting in the exhaust which means the exhaust is too hot. As Andrew says that would be ignition timing retarded too far - when the engine is running the spark is firing too late and the combustion hasn't finished when the exhaust valve opens. That makes the exhaust hot enough to combust fuel. Also burns the exhaust valve.

Too advanced will make the car pink going up hill - a regular tinking noise on low throttle up hill that damages the cylinder head and pistons. The Renault 4 is sensitive to that because of the lean mixture.

A timing strobe light is a must for setting the timing as worn distributors are different static to dynamic.. I've never used anything more than feeler gauges to set the points gap. These distributors are so worn after 40 years it's worth setting them to factory specs then doing manual adjustment to back off a bit if you get pinking.

 

[laxeian]

Thanks for replies, it is the more muted pops, nothing like when driving old Commer telecom vans turning the ignition off and on to hear explosive ‘bangs’ just to really scare residents in NW London years ago.
Will check dwell and gap as suggested, its pulling really well with no adverse noises uphill, only needing changing down from top when speed drops under 60kmph uphill on the 12%, the incline is over 1km long.
Did set it it all up using all the info. from ‘tech tips’ section on forum, but do not have strobe light, but do have a freindly good old school mechanic I can ask for a bit of help with tools etc. who has helped in the past.(guy with 8 in ‘spotted’ post)

 

[malcolm]

Thanks for replies, it is the more muted pops, nothing like when driving old Commer telecom vans turning the ignition off and on to hear explosive ‘bangs’ just to really scare residents in NW London years ago.
Will check dwell and gap as suggested, its pulling really well with no adverse noises uphill, only needing changing down from top when speed drops under 60kmph uphill on the 12%, the incline is over 1km long.
Did set it it all up using all the info. from ‘tech tips’ section on forum, but do not have strobe light, but do have a freindly good old school mechanic I can ask for a bit of help with tools etc. who has helped in the past.(guy with 8 in ‘spotted’ post)

It's probably not far off. I only used to set the points up once a year or so. They do need adjustment after a while but nowhere near as bad as an MG that needs them setting up every month or so.