spark plug gap

[mildewmatt]

Sorry guys, I know this has probably been asked a million times before.. but what spark plug gap should a VS V6 on gas have? Can't seem to find anything via search.

edit:they're currently gapped to 1.1mm, should i change this?

 

[Emackulation]

Sorry guys, I know this has probably been asked a million times before.. but what spark plug gap should a VS V6 on gas have? Can't seem to find anything via search.

edit:they're currently gapped to 1.1mm, should i change this?

Should be written on the passenger side strut tower sticker.

 

[ephect]

VS is 1.5mm gap

 

[Cheap6]

The standard 1.5mm gap is fine on LPG.

 

[hako]

On gas the recommendation is 1.0 or 1.1mm otherwise you can get misfiring or crossfiring - this is due to the gas mixture having a higher electrical resistance than a petrol mixture making it harder for the spark to jump the gap.

 

[digisol]

1.5mm is the stock gap, but always make it a slightly loose fitting 1.5 so the feeler gauges go in fairly easy, A tight 1.5 might be in reality 1.3 mm - 1.4 mm , never any smaller than 1.5 or it will miss and fart, lose power, idle rough, and run like a complete dog, etc.

If plugs are of correct make, heat range and gap, any miss then is generally down to faulty old leads, that is with all other things being correct.

You should have the gap shown on a sticker under the hood on the R side spring tower.

 

[hako]

1.5mm is the stock gap, but always make it a slightly loose fitting 1.5 so the feeler gauges go in fairly easy, A tight 1.5 might be in reality 1.3 mm - 1.4 mm , never any smaller than 1.5 or it will miss and fart, lose power, idle rough, and run like a complete dog, etc.

If plugs are of correct make, heat range and gap, any miss then is generally down to faulty old leads, that is with all other things being correct.

You should have the gap shown on a sticker under the hood on the R side spring tower.

He's running on gas.

 

[digisol]

Yeah I can see that, but most gas / or to be correct LPG systems can also still have the option to run on Petrol, the plug gap is set in relation to the output of the coil and other ignition components, LPG conversions don't change ignition mapping to the best of my knowledge, and why most LPG users feel virtually no difference to using std Unleaded Petrol.

To have that option of changing over back to petrol on a smaller than 1.5 gap will have dire results, it might run ? From what I have seen a different heat range plug would be sufficient to compensate for a difference in burn rate.

Then again if the entire EMU is re-mapped to run solely on LPG, that would change the entire ignition mapping making it not able to switch back, and very unlikely to even start on Petrol.

It would be then appropriate to then consult those who fit and tune only LPG, on an every day basis, and not on what is essentially a Petrol based Commodore disscussion.

 

[digisol]

Of course I could pick the top search result like this too,

THE INFLUENCE OF LPG

An engine converted from petrol to L.P.G. (liquefied petroleum gas) will cause a change in the spark plug operating conditions. Therefore, some consideration should be made on the type of spark plug being installed.

As L.P.G. has different properties to petrol it influences the spark plug operating temperature and required voltage. The extent of this influence can be seen when comparisons are made on spark plugs which were fitted in an engine using L.P.G. and petrol.

Typical results are as follows :


1. Spark Plug Temperature



Temperatures are higher with L.P.G.
compared to petrol. This occurs due
to L.P.G.'s reduced cooling effect.

2. Spark Plug Required Voltage



Required voltage increases with L.P.G.
because of the difference in the bonding
of gas particles between the two fuels.


Recommendation

To eliminate the influence of L.P.G. and to obtain optimum spark plug performance, NGK recommends:

-The use of a spark plug with one heat range colder (if possible) than that listed in the catalogue: eg, BPR6EFS-13 (L.P.G.) instead of BPR5EFS-13 (petrol) for VN 6 Cylinder Commodore.

AND

-The reduction of the electrode gap by 0.1 mm (which lowers the spark plug required voltage)


but choose not to.

 

[Immortality]

never any smaller than 1.5 or it will miss and fart, lose power, idle rough, and run like a complete dog, etc.

really. factory sticker says plug gap 1.5mm +.0/-.1 i take that to mean you can go slightly smaller but not bigger. going bigger is going to increase voltage requirement putting extra strain on the coils and leads (this you know from your stuff above). increasing the gap can be bad, on a hot day, engine under load at low rpm will cause a misfire. going to slightly smaller gap won't cause a engine to miss and fart, you might loose some mileage if the gap is greatly reduced but otherwise it should be fine.

if you have a bad idle, rough running engine and you ahve decent plugs with the correct 1.5mm gap i'd be looking else where (leads and coils as already mentioned)and maybe the fuel supply. most V6 engines these days are probably high mileage with less then ideal condition fuel injectors spray patterns etc