Spark plug diagnosis

arcturus · Mar 2nd, 2018, 14:53

My Renault 4L was running rough so I pulled the plugs to check,this is how the first one looked straight from motor. From the condition of the plug what does it say about the engine condition? A diagnosis would be interesting. BTW I will be replacing them.

Army · Mar 2nd, 2018, 16:11

Looks like you are burning a bit of oil there and that the engine works hard for a living as for things to encrust themselves and stay on - it has been getting rather hot.

mocambique-amazone · Mar 2nd, 2018, 16:12

Hey George, bad fuel!
And not enough revs, is this your short distance car?
Oil consumption?

Strange it did run with this.

check your distributor and carburetor system too.

good luck, Kay

arcturus · Mar 2nd, 2018, 16:19

Yes, it's our shopping trolley! Supermarket fuel,burns a bit of oil. Mechanic was supposed to have changed them last year. I am surprised that it was still running.

arcturus · Mar 2nd, 2018, 20:00

What's the difference between a NGK BP6HS and a BP7HS, is it heat range or reach?

c1800 · Mar 3rd, 2018, 04:25

Heat range. 7 is colder than 6.

arcturus · Mar 3rd, 2018, 09:12

Does that mean that 7 disperses any heat more rapidly and doesn't get as hot or the opposite ? I'm only doing short runs in this car, around town. Which would be best for this vehicle? Would I better changing to a 5 ?

c1800 · Mar 3rd, 2018, 16:48

7 doesn’t get as hot as 6. Some recommend 6 for normal driving, as you say, around town. Some others say 7 for spirited driving, i. e. Driving these cars “as they are meant to be driven”.

If you’re running 6 with no problems, not fouling, I’d stick with them.

ksmi · Mar 3rd, 2018, 20:43

Quote:

Originally Posted by c1800

7 doesn’t get as hot as 6. Some recommend 6 for normal driving, as you say, around town. Some others say 7 for spirited driving, i. e. Driving these cars “as they are meant to be driven”.

If you’re running 6 with no problems, not fouling, I’d stick with them.

Evening Arcturus, if the plugs are fouling,you could try a BP5HS. But you could find this leads to detonation, in theory they have a wide heat range,and so could overlap,so to speak. the 5's might not be as easy to obtain as the 6's as they are not so widely used, early Range Rovers used them long before they became Land Rovers for instance. or you could try the recommended 6's and take her for a longer,quicker run now and again?
By the way,Fiat do an oil for engines that use oil,i.e. high mileage,supposed to cure your sort of problem? can't recall what it's called,could try googling it.
Regards,Keith.

niveketak · Mar 5th, 2018, 10:32

Looks like pre-ignition to me. I had a Hillman Imp that pinked a lot for a long time because I couldn't hear it in the front was only when someone in the back said they could hear it I found plugs that from memory looked a lot like that.

Mar 2nd, 2018, 16:11	#2
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	Looks like you are burning a bit of oil there and that the engine works hard for a living as for things to encrust themselves and stay on - it has been getting rather hot. __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Mar 2nd, 2018, 16:19	#4
arcturus arcturus Last Online: Today 07:17 Join Date: Mar 2006 Location: Sagres Portugal	Yes, it's our shopping trolley! Supermarket fuel,burns a bit of oil. Mechanic was supposed to have changed them last year. I am surprised that it was still running. __________________ life's too short to drink bad wine

Mar 2nd, 2018, 20:00	#5
arcturus arcturus Last Online: Today 07:17 Join Date: Mar 2006 Location: Sagres Portugal	What's the difference between a NGK BP6HS and a BP7HS, is it heat range or reach? __________________ life's too short to drink bad wine

Mar 3rd, 2018, 09:12	#7
arcturus arcturus Last Online: Today 07:17 Join Date: Mar 2006 Location: Sagres Portugal	Does that mean that 7 disperses any heat more rapidly and doesn't get as hot or the opposite ? I'm only doing short runs in this car, around town. Which would be best for this vehicle? Would I better changing to a 5 ? __________________ life's too short to drink bad wine Last edited by arcturus; Mar 3rd, 2018 at 09:16.

Mar 2nd, 2018, 16:12	#3
mocambique-amazone Master Member Last Online: Jan 24th, 2022 17:08 Join Date: Nov 2008 Location: small village in the north of Germany	Hey George, bad fuel! And not enough revs, is this your short distance car? Oil consumption? Strange it did run with this. check your distributor and carburetor system too. good luck, Kay

Mar 3rd, 2018, 04:25	#6
c1800 Master Member Last Online: Apr 22nd, 2024 18:48 Join Date: Oct 2013 Location: Alberta	Heat range. 7 is colder than 6.

Mar 3rd, 2018, 16:48	#8
c1800 Master Member Last Online: Apr 22nd, 2024 18:48 Join Date: Oct 2013 Location: Alberta	7 doesn’t get as hot as 6. Some recommend 6 for normal driving, as you say, around town. Some others say 7 for spirited driving, i. e. Driving these cars “as they are meant to be driven”. If you’re running 6 with no problems, not fouling, I’d stick with them.

Mar 5th, 2018, 10:32	#10
niveketak 66 Amazon Last Online: Jun 14th, 2022 16:45 Join Date: Jun 2013 Location: Piegut Pluviers	Looks like pre-ignition to me. I had a Hillman Imp that pinked a lot for a long time because I couldn't hear it in the front was only when someone in the back said they could hear it I found plugs that from memory looked a lot like that.

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