TR6 Plug Issue

[01cobravortech]

I know im bringing back a thread from the dead, but I have a question regarding an issue that has arose with my car after doing a pulley swap with big help from two other members on here. We put on a 2.76 pulley, snub idler and bracketr6, swapped the belt and plugs, and loaded the tune from Bob Kurgan. The plugs I am running are tr6's gapped at .028. The problem I am having is the car has a miss at around 5500 rpm under WOT. It almost feels like traction control kicks in but it is off. The car runs great other than that and very strong. It even idles just fine. Kurgan suggested I recheck the gaps and maybe close the gap some, but aren't I already running a small gap? Should I try switching plugs to say a br7ef or tr6ix? Or do you think this is a fuel/tune issue?

Good be as simple as a bad COP. I had a similar miss at higher rpms awhile back and after changing plugs found it was an issue with a COP. Man that's an awfully small gap you run on the TR6s for just a 2.76. I run the out of the box gap of .035 - .036 on my TR7ixs with just a 2.8 and she runs like a champ and idles perfectly.

 

[Spoolx]

I know im bringing back a thread from the dead, but I have a question regarding an issue that has arose with my car after doing a pulley swap with big help from two other members on here. We put on a 2.76 pulley, snub idler and bracketr6, swapped the belt and plugs, and loaded the tune from Bob Kurgan. The plugs I am running are tr6's gapped at .028. The problem I am having is the car has a miss at around 5500 rpm under WOT. It almost feels like traction control kicks in but it is off. The car runs great other than that and very strong. It even idles just fine. Kurgan suggested I recheck the gaps and maybe close the gap some, but aren't I already running a small gap? Should I try switching plugs to say a br7ef or tr6ix? Or do you think this is a fuel/tune issue?

Kurgan is pretty smart, if he suggests closign the gap a bit you should prolly do it.

 

[04cobradude]

i told him to use a FEELER GAUGE, not a $.99 gapping tool and recheck.... while he was at it, he COULD close the gap...

please dont twist my words around.

 

[SBVERT03]

Im not sure if that was directed towards me, but if so this is why I said you suggested I recheck the gaps and MAYBE close the gap some. I believe that means the same thing, no? I was in no way trying to twist your words around. And we did use a feeler gauge and I will again when I recheck them.

 

[Bdubbs]

Hmm seems like a very tight gap already, but maybe close those a little more and also buy another set of tr6's and gap those at .032 and do a comparison. Maybe datalog the two and see if anything comes up?

 

[04cobradude]

just an FYI... on my race car, we run a gap of .018.. i have tested gaps from .015-.035 and the SMALLER the gap, the cleaner the spark and the more AVG power the car made... time and time again.

 

[SBVERT03]

just an FYI... on my race car, we run a gap of .018.. i have tested gaps from .015-.035 and the SMALLER the gap, the cleaner the spark and the more AVG power the car made... time and time again.

Wow, very good to know. Im going to go recheck the gaps now, and possibly close them a bit. Its very possible a couple of my gaps could be off. Thanks for the info man. Like I said I couldn't be happier with how the car runs other than the little hesitation, but hopefully it will be an easy fix. Its a whole new beast!

 

[SBVERT03]

Well I pulled my plugs today and they were all gapped at .028. So I dropped it down to .026 and still had the cutout at 5500 rpm. So then I decided maybe the plugs were bad so I bought br7ef's and gapped them to a very tight .028 and it made no difference in the stumble. So im wondering where do I go from here?

 

[Bdubbs]

Well I pulled my plugs today and they were all gapped at .028. So I dropped it down to .026 and still had the cutout at 5500 rpm. So then I decided maybe the plugs were bad so I bought br7ef's and gapped them to a very tight .028 and it made no difference in the stumble. So im wondering where do I go from here?

TR6's are cheap, I'd still try opening it up a little bit. Won't hurt try as you've already tried a tighter gap.

 

[SBVERT03]

TR6's are cheap, I'd still try opening it up a little bit. Won't hurt try as you've already tried a tighter gap.

I thought hesitations were generally caused by too wide of a gap? I guess it couldnt hurt though...

 

[Spoolx]

Well I pulled my plugs today and they were all gapped at .028. So I dropped it down to .026 and still had the cutout at 5500 rpm. So then I decided maybe the plugs were bad so I bought br7ef's and gapped them to a very tight .028 and it made no difference in the stumble. So im wondering where do I go from here?

Why wont you just try a really tight gap? Like .020 just to see if it goes away

 

[SBVERT03]

Ok. Ill try .020, then Ill try .034 or so. That way I will have tested the whole range. After that though I'm thinking its something else.

 

[SBVERT03]

I tried a .032 gap and the hesitation is still there. Another thing to note is that the car does keep pulling after the hesitation. Its like power is cut for a second then it comes right back and the car will rev over 5500 rpm.

 

[Bdubbs]

Hmm wonder if a coil could cause this? From what I've heard though it's much easier to buy all new ones instead of trying to find just one that could possibly be bad. Any other symptoms?

 

[carguy929]

Ok so like many others I have been reading about spark plugs, gaps, good, bad, indifferent, etc etc. So after being sure to run TR6 iX, no now I am definately running just plain TR6's, but wait I could try a set of Autolites! No now I am sure that I am fing confused! So I am hoping this will help others looking for info on this.

So after about 2 weeks of reading and reading I have determined to take someones advice in this thread. I am about to have my car tuned by Tim Barth at Mr. Norms Garage so I asked him what he could recco or what he likes. I got TR6's gapped @ .032 so since they are relatively inexpensive I will be picking up a set and installing them this weekend. Along with the plugs I am upgrading to a 2.76 pulley, KB BAP, and a MafiA. This is going to be the first tune to the car since I bought it in April. Currently it has a 2.81 pulley, Afco HE, Steeda hi-flows, Steeda mufflers, and some other supporting mods and the car made 438hp and 478tq. I will post again after the car is tuned and I have some seat time. Thanks for everyone on SVTP for posting up about this so other like me car research and learn about the cars we love so much:rockon:

 

[Brutal Metal]

TR-6's gapped to .032 is right where I'm at too!

 

[carguy929]

*update*

I felt this was worth posting. The original owner of this car stated that the plugs were stock. As stated above after consulting my tuner and a couple of fellow Cobra owners that I personally know I decided on the TR6 gapped
@ .032 So upon pulling the plugs I was suprised to find TR55IX plugs! Since I am sure that the previous owner never turned a wrench on the car I guess I shouldn't have been so suprised. Anyways the plugs we all gapped between
.028 to .032???? and the all looked to have good color and no signs of anything bad. The car ran well and pulled pretty hard so hard to say if it really hurt the car performance wise. So now that I have had the TR6 plugs in for a minute I will say that the car idles better and it seems to pull a little stronger. No stumble or anything like others are experiencing. So far so good here though:rockon: She goes for the tune on Wednesday so I will post up new numbers, but I thought this was worth sharing since it is a real world experience.

 

[03 VENOM]

Just wanted to make sure: Is the part number 3689 for the tr6 IX ? Sorry if i missed it.

 

[03 VENOM]

anybody?

 

[boost4me]

Are the "disc like" looking gappers ok to use?