07 Boss

I thought it was weird too. I changed the plugs just to change them for this season and it was an unexpected result. It also might be that I usually run a .030 to .032 plug gap and the HT0's were at .026-.028

m05fastbackGT

Knowing that your HT0 plugs were gaped at .026-.028 was definitely more than likely the reason behind your Mustang's sputtering and backfire issues or at the very least a contributing factor anyhow..
My HT0's are gaped at .032 which is the recommended gap settings by Brenspeed for running their calibration tunes for the Saleen VI blowers.. At any rate, I would hold onto your HT0's and have them re-gaped between .030-.032 and find out if you notice any difference in which you definitely should and then keep them as either a spare or for when the time comes to replace your Brisk plugs..

The only downfall I have with the HT0's are the design of the ground strap that require a gaping tool which can be purchased through Steeda Autosports.. Otherwise I don't have any complaints towards them at all

mibo

Talking about gaps you got me thinking. HT-1's do they come pre gapped or do I gap them? Special tool needed for them?

m05fastbackGT

Both HT-1 and HT0 plugs are pre-gaped from Autolite.. Only time they require re-gaping is for forced induction and nitrous applications.. Being that your car is stock, you won't need to re-gap the HT-1 spark plugs to begin with anyhow..

mibo

Thanks for the info.

07 Boss

Well the Brisk before them were at .028. I went to Voodoo Racing to gap my Ht0's (wasn't going to buy the tool) and he also suggested the smaller gap. The were fine for 10 months and then the last couple started to act up. They looked pretty good when I took them out. I have nothing to back up my claim that I think the strap design is just not that good, but that is what I think. Back in the day when we used to have ignition problems we used to side gap our plugs to expose the spark better and it seemed to work in many cases.

07 Boss

They should come pre-gapped but it's always good to check them as your putting them in. I believe you should be at about .045 if I remember correctly. They can be a little tricky to check with a flat feeler because of the strap but I used to fit the corners of the feeler gauge in there OK.

m05fastbackGT

Were you experiencing the same issues when your plugs were gaped between .030-.032 as you said you usually have them gaped ? This is just a guess on my part, but maybe the HT0's perform better at .030-.032 rather than .026-.028 due that the HT0's have a different design construction over the Brisk plugs as in copper vs platinum.. I assume it also depends on which type of calibration tune is set up for your particular application as well..

Being that your running a whipple, your tuner may feel your car would run best with a .026-.028 plug gap over .030-.032 and once again, that's just a guess on my part.. All I know for certain, is that Brenspeed requires .032 plug gap for their Saleen VI calibration tunes, but yet JDM engineering requires .030 for their Saleen blower tunes, so again I suppose it really all depends on the calibration tuning.. However I still find how very strange that your HT0 plugs performed fine for 10 months and then a couple began acting up within a couple of months later.. You would think if the issue were the ground straps, you would notice them acting up much sooner than 10 months

Scarpi

I had the original plugs replaced with Champion one piece #7989 plugs. The car runs great and no problems.

mibo

Scarpi, how long ago and how many miles? Thanks

Lime GT

Think of it this way. How long do you plan on owning this car? Ford plugs are good for approx 60,000 miles or more. Will you ever see another plug change before selling/trading in on a newer model?

mibo

well I had the time to change out the plugs last week using the HT1's. Followed TSB and had 2 plugs break. #4 and #6. Dealer charged me $139.00 to remove both plugs and install the 2 HT1' s. No where near the cost I have read about. The HT1's were gapped between 37-40 where the oem plugs were gapped at 45. Figured a different plug means a different gap? HT1's are pre gapped right? Anyway she runs great. Thanks all.

m05fastbackGT

If you recall, your concerns/questions regarding the HT-1 spark plugs being pre-gaped were previously addressed in this thread nearly 2 months ago.. Scroll back to post # 24 and #27

mibo

I know this. What I was questioning was why there is a difference in gapping from oem to the HT1's. Being they are pre gapped why the difference

mibo

All 8 HT1's were gapped the same. None were at .45 more like .38 to .40. .40 was to small and .35 was way to big. Anyway, runs fine.

m05fastbackGT

Very good question, as you would think both OEM motorcraft and HT-1 plugs would have the same gap specs.. Might be better off contacting someone from Autolite tech support, as they should have the technical expertise to best address this issue

m05fastbackGT

If they're pre gaped between .037-.038 and your car seems to be running fine, then I wouldn't worry about it.. However I would still contact someone from Autolite tech support and find out the reason for the gap difference between the HT-1 and OEM motorcraft plugs just for your own piece of mind anyhow..

Scarpi

Sorry mibo i just noticed your question to me. I'm retired and my car is not a daily driver. But to answer your question the plugs were replaced with the Champion one piece #7989 plugs at 9427 miles in January 2011. The car now has about 22,000 miles on it today. Runs fine and no problems.