Recommended spark plugs?

[drifter]

Hi - I have spent the past hour searching and have only confused myself further...

I have a '71 Series 2a with 2.25 petrol engine.

It arrived with NGK B6ES plugs in it.

I went looking amongst the various retailers here and they told me I should be using:

Champion N-9y, or
NGK BP5ES, or
Bosch WR8DC+

I have seen references here to B6ES - is that the one I should be using? They are kinda hard to find here - a wait of 2 to 3 days if I order some...

Please advise

Thanks in advance

John

[peterg1001]

The NGK web site says B6ES for 7:1 compression, and BPR5EIX for 8:1 compression, where:

B = 14mm
P = projecting insulator
R = resistor i.e. not inductive resistor
5/6 is the heat rating
E = 19mm thread
IX = induction, S = standard

The plugs in my engine are BPR6ES, which I would take to be identical to B6ES except for the projecting insulator.

The BP5ES you've had recommended are lower heat than NGK recommend, but it may not make a significant difference - someone else in the forum may be able to add to that.

The Bosch and Champion web sites are not helpful, but the NGK site says the equivalent of Champion N9Y is BP6ES and the equivalent of Bosch WR8DC is BPR5ES, which pretty well supports the original NGK recommendations but still doesn't give you an unequivocal recommendation.

Peter

[drifter]

Thanks for that. So many websites, so much 'different' info. I started to run a spreadsheet listing all the equivalents I could find for all the parts - and quickly found that some cross references were at odds with others.

*sigh*

It ain't easy :)

[JDNSW]

First thing you need to do is determine whether you have 8:1 or 7:1 compression.

On top of the head, between the rocker cover and the carburetter, there should be a square boss. If this has an 8 on it, you have 8:1, otherwise 7:1. The number may be very faint. If no number, or if the boss is not there (early 7:1 heads) you have 7:1, unless the head has been ground and not marked!

For 7:1 NGK B6ES and 8:1 BP5ES according to my information.

The original recommendation in my owners handbook was Lodge CLN-H Long reach, or in the Series 3 owners manual Champion N8 (7:1) or N12Y (8:1)

John

[drifter]

http://our-phoenix.com/vb/images/smilies/old/aok.gif thankyou John. I think it was one of your threads where I found the B6ES info.

I'll go look for that boss and, if found, scrub it (it's kinda murky under the bonnet still - well overdue for a clean - but I have only had it a few weeks)

[drifter]

Well - that was messy :)

There is a hole in my exhaust manifold. The previous owner had filled it with gunk and placed a folded bit of tin over it to stop the exhaust heating the hell out of the carby...

So - removed tin - sprayed a bit of WD40 onto the lug. Scrubbed vigorously with a wire brush and I can see an 8 sitting there - quite distinctly.

So I have an 8:1 ratio head.

I have a set of BP5ES plugs so they will get used - and the brand new set of B6ES plugs that arrived today can go in the drawer...

Having now discovered the extent of the manifold damage, may I ask - how hard is it to get one and roughly what would I expect to pay?

Thanks

John

[JDNSW]

Well - that was messy :)
............

Having now discovered the extent of the manifold damage, may I ask - how hard is it to get one and roughly what would I expect to pay?

Thanks

John

I replaced mine about five years ago (cracked). Readily available, mine came from Four Wheel Drives in Melbourne for $115. Not very difficult to do, except you can expect some of the studs to break or be missing. You will need new gaskets for the head and the intake manifold, and plan on replacing at least some of the studs, nuts and washers. The nuts on the exhaust pipe flange should be brass.

John

[drifter]

Thanks John

I have a gasket set (valve regrind set - CD770 - ex Melbourne) that I am saving until I get all the other bits I am needing and then I'll do it all in one big job. I see there is an exhaust gasket in there.

I'm a bit worried about the studs I know are going to break (ahead of time) so I'll be seeking some of those, too, as time goes by.

[LandyDude]

First thing you need to do is determine whether you have 8:1 or 7:1 compression.

On top of the head, between the rocker cover and the carburetter, there should be a square boss. If this has an 8 on it, you have 8:1, otherwise 7:1. The number may be very faint. If no number, or if the boss is not there (early 7:1 heads) you have 7:1, unless the head has been ground and not marked!



G'day John

Is this what you mean as below in the picture? Mine has "23 8R", I guess the '8' makes it a 8:1 if I understand correctly?

https://www.aulro.com/afvb/images/imported/2010/02/1233.jpg

[drifter]

I expect you meant the other John, but...

Mine has a raised bit coming off that 'bulge' under the head bolt in the centre - right out to the edge of the head by the manifold. On mine, it would cover that bit where your number is (partially).

If I were a guessing person, I would suggest that one, because the lump of metal isn't there, is a 7:1

But I will let others more knowledgeable answer it properly.

[JDNSW]

G'day John

Is this what you mean as below in the picture? Mine has "23 8R", I guess the '8' makes it a 8:1 if I understand correctly?

https://www.aulro.com/afvb/images/imported/2010/02/1233.jpg

No. This is an early 7:1 head - what you are looking for is a raised, square, boss exactly where you have marked, where the number you show is. The 8 or 7 on the boss is stamped on not cast. The cast on numbers relate to the foundry that cast the head and the batch number.

John

[LandyDude]

No. This is an early 7:1 head - what you are looking for is a raised, square, boss exactly where you have marked, where the number you show is. The 8 or 7 on the boss is stamped on not cast. The cast on numbers relate to the foundry that cast the head and the batch number.

John

Thanks John. I needed to get some new plugs and now know the compression.

I've been trying to solve a running on problem.
Checked timing and played with fuel mixture. Dizzy and carbie have been professionally reconditioned so now thinking of putting in new or possibly cooler plugs.

[JDNSW]

Thanks John. I needed to get some new plugs and now know the compression.

I've been trying to solve a running on problem.
Checked timing and played with fuel mixture. Dizzy and carbie have been professionally reconditioned so now thinking of putting in new or possibly cooler plugs.

Running on is a problem with these engines - some of the things that encourage it are need for a decoke, plugs (as you say), and probably easiest to fix, either excessive idling speed (should be around 500rpm, much lower than contemporary engines), or incorrect (retarded) ignition timing. The other thing is to allow it to idle for thirty seconds before switching off.

John

[Aaron IIA]

And the problem with running on is? Doesn't everybody turn off the engine, alight, close and lock the door, walk off, and then hear the engine stop? I have had that problem before, but only in the heat, after not idling down the engine.

Aaron.