How long will they last?
We have a five year replacement warranty. In normal circumstances our plugs will last 100,000 miles, depending on the condition of your engine and driving habits.

What is the price?
£17.00  each including shipping and handling. 

Can I buy Halo^TM Plug at the local parts store? Not yet.

How is the Halo^TM Plug doing in race cars?
We have reports of enhanced performance. Please note that the plug is not warrantied for racing applications.

How do I gap it?
The Halo^TM Plug is pre-gapped. Do not try to change the gap.

What improvement in MPG are you seeing?
MPG improvement of 3 (or more) miles per gallon is commonly reported.

What kind of improvement in emissions are people reporting?
Improvement has ranged from incredibly impressive to little change. Some automobiles that were unable to pass the local emission requirements have been able to do so with the Halo^TM Plug.

If I buy in bulk, will you discount the price?
Sure, email us at info@ontop.nu We will send you information.

I am a professional installer— I would like to stock/sell Halo^TM Plugs— Can we work something out to do this?
Email us with your address---we will send you information.

Do you have cross-reference guide?
Yes, Halo^TM Spark Plug cross-reference.

Do you have heat range specifications?
Yes, Halo^TM  Plug heat range specifications.

Will using Halo^TM Plugs void my automobile’s warranty?
Under the Magnuson-Moss Warranty Improvement Act, a manufacturer may not make its vehicle warranty conditional on the use of any brand of spark plug unless the manufacturer is willing to provide its product free of charge. If the consumer is told that a non-OEM brand of spark plug will void the warranty, they should request that the OEM dealer supply the OEM brand spark plugs free of charge. If they are charged for the OEM brand spark plugs under these conditions, the OEM dealer may be in violation of Federal law.

What is the guarantee?
If purchased from this site... 90 days money back. 

If you are not satisfied with the performance of your Halo^TM spark plugs, you may return them within 90 days of purchase (freight prepaid only), along with Halo's warranty claim form, for a full refund. 

Damaged, improperly installed, and/or improperly used plugs are excepted. Otherwise, see 5 year replacement warrantee.

What is the tech support number?
The Halo^TM Spark Plug, Inc. tech support line is soon coming.

What autos seem to do best with Halo?
Most Japanese and European makes of cars respond almost immediately to the Halo plug burn speed. They think this is due to the ignition control system logic, which we are told is primarily a Mitsubishi design in these types of automobiles. Chryslers have a fast learn computer which also seems to raplidly perform well.

Can you explain why some autos get great improvement in gas mileage and some don't?
With regard to the fuel demand (miles per gallon), assuming the vehicle control modules deal acceptably with the burn speed (i.e., retarding the spark advance), the autos will respond in one of two ways. They will either richen the mixture, in which case you will see improved performance, but probably little improvement in fuel economy; or the fuel demand will be lessened, in which case gas mileage will improve. Much depends on the programmed response to oxygen sensor inputs for the specific model. The oxygen sensor will always detect less oxygen with the better burn, and its response to this will determine how the vehicle reacts.

Most motors should see improved performance (this being defined as either better fuel economy or more response). This is all the Bosch Platinum +4 offers (the phrase "better performance"). Halo plugs just do it better and more pronounced.

It is uncommon, but a few GM and Ford products from about 1990 need to have the computer adaptives reset for maximal benefit from the Halo Plugs. This basically amounts to dumping the long-term memory from the computer and allowing it to reset the spark advance according to the sensor inputs. ASE mechanics will have the proper scan tools to do this. The cost depends on the mechanic. Its just a plug in the scan tool and hit a couple of commands. Our guy charges $45.00. They get good results doing the adaptive reset, and in every case the spark advance moves closer to TDC by 1 to 3 degrees.

The last word on adaptive reset. Adaptive reset is a command prompt on the diagnostic computers that the ASE mechanics will have. Most autos do not need this. Keep in mind that this is the best way to get maximum benefits quicker. Install and go will still show improvement, just sometimes not as quickly.

With so much metal protruding from the end of the spark plug into the combustion chamber, how are hot spots that would cause pre-ignition avoided on the metal electrodes? I would think that this design would lend itself to pre-ignition and maybe even melting of the electrode parts.
Good question. However, the total metal mass of our tip is actually less than a standard sidewire plug, and considerably less than multiwire plugs. Hot spots are not normally a function of total mass anyway, but are more likely to occur on sharp edges and deposits in the chamber. The tip was designed with radii (to eliminate sharp corners) to the extent possible. The sidewire plugs cannot make the same claim.

Can I order by mail or FAX?
Yes.

I don't see my auto in the on-line catalogue. How do I find the correct plug?
You may use the cross reference list if you know the current plug number. You may also email us with the question or fax.

There is not a plug for my application listed.
About 80% of auto motors are covered currently. Many non-USA autos are not listed, but we have appropriate plugs...email us with make, model, year and engine size.

Are there Halo Plugs to fit Motorcycle engines?
We do fit most Harleys, but not import motorcycles yet. All Halo Plugs at present have a 14mm thread diameter. Most non-American-made motorcycles use a different thread diameter.

Is there timing adjustment needed for small engines?
On cycles and small engines, timing normally isn't an issue because the fuel distribution systems are not as accurate. Newer bikes might be the exception.

How does Halo compare to the iridium plugs? Iridium is a step up from platinum, in that it is a tougher, better wearing metal. I think the Iridium spark plugs are quite expensive however, and the technical stuff I've read on them doesn't really talk much about anything except their increased longevity. If they are gaining horsepower, it might be because of an increased gap, which increases the spark intensity. Our material is a 95% nickel alloy that is the same as the sidewire on all other spark plugs (the iridium and platinum plugs included). Because we fire off of a different point each time, there is no need for an exotic, more expensive an less conductive metal (such as platinum) to improve the life of the plug. We do it by eliminating point firing, which is responsible for the gap degradation. The exotics only put a button of platinum or iridium on the firing surfaces, since it would be much too expensife to make the entire sidewire and center electrode out of the stuff. These metals are necessary to reduce wear when you fire from one point all the time. Not a problem for the Halo Plug.

Are your plugs safe to run with nitrous? Our plugs ignite the gas quicker than standard plugs, and with nitrous, this will be even more pronounced. If you use them with nitrous you will want to retard your spark advance to ensure that you do not create excessive cylinder pressures. Our plugs are not warranted for these types of applications. However, they will give you improved performance