Volvo - LPG spark plugs

[classicswede]

Originally Posted by hancym

Ahh! Now you've got me as I haven't had the car long enough to pull the plugs yet. Was thinking of doing it in a month or so. Could you please recommend both so I'll know what I'm after when I lift them?

The 19mm is BKR7ES and fro what I can see the longer plug was never used in the T6 so you should be able to buy them before hand

[tom-madbiker]

So what do you reckon then dai a NGK bpr 7es instead of a 5 do you think it would smooth it out a bit still a bit noisy at 70 ish

[classicswede]

BPR 7ES are plugs for the OHC engine and the thread is too long.

a 6 heat range should be enough.

[volvobaggen]

Bumping this thread.

Would there be any issues with using non-resistor spark plugs for older carburetted volvos without ECU´s? Instead of NGK BPR6ES using the BP6ES?

Theoretically this should give a better spark right?

[Joe Harding]

Originally Posted by classicswede

Hotter and Colder are not the best way of describing a plugs properties and often becomes confusing.

With LPG we are looking for a plug that will disapate heat faster than the plug normaly used with petrol. If a plug is to be run only on LPG then the plug could have an extreamly fast heat disapation without causing any problems. However a engine that runs only on LPG is very rare.

What we need is a plug that remains just hot enough to burn off any soot when running on petrol but no more.

NGK numbers and Bosch numbers go in oposite directions for how fast the plug disapates heat. NGK the higher the nuber the quicker heat is disapated. With a B20 in Toms case a 5 is perfect for 4 star, just about ok for unleaded when driven gentle but struggling with LPG. A 6 would be a much better choice but for a tweaked engine especialy on LPG a 7 or 8 would be a far better choice.

In the case of NGK with LPG you want either the same as petrol of 1 nuber higher or bosch upto 1 number lower. No need to go any further than that.

Our 1990 340 1.4 runs pretty well entirely on LPG, starting on it as well. What plug would you go for?

[volvobaggen]

Look here Joe, http://www.ngk.com.au/spark-plugs/te...-compatibility

If you have something that works fine, there is no reason to change it. Standard plug for petrol seems to be working fine for most people. Maybe slightly higher combustion temperature, but this keeps the plug from fouling up if you have a high milage engine.

[classicswede]

Originally Posted by volvobaggen

Bumping this thread.

Would there be any issues with using non-resistor spark plugs for older carburetted volvos without ECU´s? Instead of NGK BPR6ES using the BP6ES?

Theoretically this should give a better spark right?

You've got the system wrong there. The plugs you are thinking of would be BPR6E (BP6ES are short reach plugs as used in B20's)

There would be no harm in going for BPR7E plugs

[classicswede]

Originally Posted by Joe Harding

Our 1990 340 1.4 runs pretty well entirely on LPG, starting on it as well. What plug would you go for?

NGK BPR6ES plugs will be fine in the B14. As long as you are not having problems with the factory spec plugs there is no real reason to change.

[volvobaggen]

Originally Posted by classicswede

You've got the system wrong there. The plugs you are thinking of would be BPR6E (BP6ES are short reach plugs as used in B20's)

There would be no harm in going for BPR7E plugs

Sorry to drag on this code confusion, and thanks again for advice and answers. But still, I used the NGK BP7ES in the VW Golf 2 with the 1.6 L engine and it works perfectly. I don´t think it was different in size to the BPR6ES I used in the 245.

Im looking at the NGK code deciphering chart now. The only difference between BPR6ES and the BP6ES is the R, witch means resistor according to my chart. The S in the code just means standard electrode, even if this S is absent the plug has a standard electrode.

I have been reading a bit about resistors in spark plugs, and it seems very redundant and unnecessary in older vehicles already fitted with resistor ignition wires and without much delicate electronics. There should be no radio static using non-resistor spark plugs. Maybe the spark plugs failing early on lpg could also be because the resistor is degenerating?

[capt jack]

I reckon the only way to know for sure whether or not the presence of a resistor is essential would be to try it and see.

Trouble is that could be an expensive experiment!

Jack