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rodm
United Kingdom
156 Posts |
 Posted - 30/05/2008 : 21:28:50
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Can anybody advise what are the best spark plugs for a standard N type for normal road use.
Preferably ones that don't break down with modern unleaded petrol?!
I imagine that this topic must have come up before, but having looked in the "search" section, I couldn't find the answer!!!!!!!!
Thanks
Rod |
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Gerhard Maier
Germany
873 Posts |
Posted - 31/05/2008 : 18:11:30
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MIKE ALLISON wrote in Safety Fast April 1995:
The plugs recommended are those recommended by the two manufacturers, except that the following points should be noted:
I. Do NOT use resistor plugs, or leads, with Magneto ignition, whatever the plug manufacturers tell you: you will destroy the windings in the magneto if you do.
Personally I will not use resistor leads at all.
2. For many of the older cars you MAY have to experiment with the actual heat range you will need for running.
3. If the engine refuses to run clean, check your distributor points gap, and reset to the recommended figure, also make sure that the points are clean and present flat surfaces to each other.
4. If your car is fitted with resistor leads, try a new set, these are often cracked internally, leading to mysterious misfires.
----------------------------NGK--------------Champion
14/40-----------------------A6----------------------D16
18/80-----------------------A6----------------------D16
Tigress----------------------A7----------------------K9
M---------------------------A6----------------------D16
M, 12/12--------------------A7----------------------K9
C, 18mm plug----------------A7----------------------K9
C, 14mm plug----------------BP7HS-------------------L82YCC
C s/c 18mm-----------------A8-----------------------K7
C s/c 14mm-----------------BP8HS-------------------L61YC
C s/c methanol--------------B10HV-------------------L55G
D---------------------------A6-----------------------D16
J1,J2------------------------BP6HS-------------------L87YC
J3---------------------------BP7HS-------------------L82YCC
J4---------------------------BP8HS-------------------L61YC
PA/PB----------------------BP6HS--------------------L87YC
QA-------------------------B10HV--------------------L55G
These recommendations assume 24psi boost, and methanol fuels but colder plugs may be needed
RA as above----------------B10HV--------------------L55G
F---------------------------A6-----------------------D16
L1/L2-----------------------BP6HS-------------------L87YC
K1/K2-----------------------BP6HS-------------------L87YC
K3--------------------------BP7HS-------------------L82YCC
This for petrol/road use, but actual plug determined by state of tune
NA,KN-----------------------BP6HS-------------------L87YC
NE--standard state of tune--BP8HV--------------------L61YC
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Bob Clare
United Kingdom
278 Posts |
Posted - 31/05/2008 : 21:26:30
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Due respect to Mike who rebuilt my Cresta NB engine, but it would never run on NGK BP6HSs and it was he who suggested using BP7HSs. Good advice!! Never missed a beat since. Mind you, he may have breathed on the engine so perhaps it's not a standard N??
Cheers.
Bob Clare
Reistrar. |
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Keith Wallace
United Kingdom
367 Posts |
Posted - 01/06/2008 : 21:03:48
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Very interesting! I have been suffering the same problem with my PB.
I had guessed that the Champion 12K ohm suppressed plug caps were too high and changed them for 5K ohm ones, better but the problem of plugs oiling up still persists. (The wife complains about interferance on the TV).
I am using the original HT coil with L87YC plugs. seems I will have to return to unsuppressed plug caps? |
Edited by - Keith Wallace on 01/06/2008 21:07:21 |
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David Allison
United Kingdom
665 Posts |
Posted - 02/06/2008 : 15:08:08
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I always use NGK BP6HS for road use and BP7HS for really hot days or if I am going to be driving the car hard.
I have tried the BP7HV but found that they oiled much easier than the older style HS style plugs.
I dont like being "Trev the rev" so I have gone back to the HS plugs.
I think that the HV might be better on an unblown engine though - I certainly used them in my Midget to great effect.
Also try the Tesco 99 octane super plus fuel - might be my imagination but the car certainly seems to run much cleaner on that!
Regards David |
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rodm
United Kingdom
156 Posts |
Posted - 03/06/2008 : 21:52:37
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Thank you all for your response, particularly to Gerhard for his missive!
I have been using (apart from some years ago Champion L 10's!),
Bosch RO 735.
I noticed nobody mentioned these. It that because they are no longer made(?), or because they are prone to breaking down as mine seem to be doing now!
It could of course be because they are possibly 20 years old!
Fortunately spark plugs from The Green Spark Plug company, still appear very good value for money!
Regards
Rod
I have just noticed that the plug is stamped "W 175 T1" on the metal base.
"RO 735" is marked on the insulation.
Rod |
Edited by - rodm on 04/06/2008 23:19:18 |
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