Doppelgänger

iTrader: (12)

OK, I have not had a chance to take my bitch to the track since doing the reroute late last year. Before that, I never had an issue...even at Flyin' Miata's track day at high altitude on a 90*+ day.

So.

Yesterday I went to a small track (Little Talladega...aka Talladega Grand Prix for those of you in the Southeast). On my first session I was fine for the first 5-6 laps. Then I got this strange ignition cut issue. Started at higher RPMs at 10+psi and it quickly worked it's way down to going into any boost above 3,500 RPM. Came in, pulled the plugs and they looked "ok" at best. Color was light grey/brown on the ceramic and electrode with some buildup and the flat "ring" around the bottom of the plug was BLACK. BTW- using plugs NGK #BCPR7ES. So I knocked the tip with some sand paper to take the build up off and eyed the gap and threw them back in. Next session...same thing. 4-5 laps of WOT goodness followed by a progressively worsening ignition breakup. Ran to the parts store to try some new plugs (NGK #BKRE6ES). I couldn't find anything with 7 or 8 in the number indicating heat range, so I got the 6s because the electrode was about the same length and the ceramic insulation was the same thickness. Back to the track. Same thing again.
Temp gauge stayed about 2 needle-widths below half (a little lower than it usually is in city driving as I was running the heat while on track.

So my thoughts- It was found that Mazda re-designed the headgasket for 01+ (remember mine is a 2002) which promotes flow from the front of the block to the back, up to the head and out the front. Obviously with the reroute, coolant is going to the back of the block, up to the head and out the back.....leaving the front of the head with little to no coolant flow...possibly.

Could this cause cylinder temps to skyrocket and cause a misfire/ignition failure? Would going to heat range 8 plugs have helped?

I do plan on modifying the reroute to accomodate the original waterneck and t-stat back onto the front of the engine and adding a T fitting to the radiator hose to allow the head to flow coolant out the front and back...and which ever is hotter will flow more as it's t-stat opens.

Thoughts?

BarbyCar

iTrader: (1)

I was lapping last week with a Mazdaspeed (04 I think) with the big enchilada. He had the reroute and both T-stats in place. He mentioned the same head gasket issue and that this fixed it.

Doppelgänger

iTrader: (12)

Was the owner saying the it had any issues on the track with the reroute before adding the front t-stat back? (It wasn't QQQQs car was it?)

GeneSplicer

iTrader: (14)

So did you have to change your tires along with the plugs? TGRP eats tires like crazy, which is why I rarely go there...
So dies the cut start happening on the straights coming out of a turn? I had a fuel issue at Barber last weekend. Haven't nailed it down but know it's a fuel issue with sucking vapor into pump whith 4gal still in the tank and going through #5 combined with possibe vapor locking due to a bad cap. But my car just stalled out.
I would think if you were having det probs in #1, that plug would tell the story.

Doppelgänger

iTrader: (12)

All 4 plugs looked good, no detonation. Tank was above 3/4 so I know it wasn't a fuel starvation issue.

I was running Kumho V710s and since my sessions were so short due to the technical issues, no wear even occured....though when it was running fine, the car was feeling superb. Heard they clocked me at a 1:10 early in the day...when I was just crusing around there.

BarbyCar

iTrader: (1)

IIFC, yes he had issues. Unless QQQQ lives in Ottawa, Canada then no. I'll see if my guy is on miataturbo and have him post here or I'll ask and get info for you.

steelrat

So the commentary about that situation....

01+ head gasket changes how everything flows to 3&4.... as a result with just the regular old coolant re-route, the #1 cylinder gets hot the same way the #4 does normally.

So the "fix" was using two thermostats. One on the back of the head (or with the Mtuned reroute inline) and one in the stock location -- requiring a "T" just before the rad to link the system.

Discussions at the track were discussing whether the pressure would cause any reverse flow, or static conditions, but either way, the rad should be the low pressure point, so it could cause the flow to head that way. Even if the stats opened at different times.

However, the guy was still having heat issues, so I believe the resolution was to do the standard "flashing" upgrade.....

Dave,

Doppelgänger

iTrader: (12)

What kinda of issues were being seen? Ones like mine with ignition cutting out or a general overheating issue?

The reason I suspect more and more that it was some kind of cylinder temperature issues is because the car had cooled down a lot between sessions AND on the street I cannot replicate the issue/symptom as I cannot drive the car hard enough. Also, I did go out and do some drifting a couple of weeks ago on a warm sunny day, pushing the car hard in 2nd and 3rd gear (aka asking a lot of the engine and turbo) and didn't have any issues then...and we all know that doing several minutes of WOT drifting creates a lot of heat with less airflow over the front of the car compared to being on track). But on my way home,I had the a/c going, a 250lb passenger and a trailer loaded to the gills..probably 500lb total weight behind the car and I did a 5th gear pull and had the ignition cut issues for just a moment as I was getting off the interstate...and since the rest of my drive home was slow, it didn't happen again.

JayL

iTrader: (12)

What gap do you run the plugs at?

Doppelgänger

iTrader: (12)

.035"

JayL

iTrader: (12)

I'd be willing to guess that gap might just be too big for what your coils are putting out or even one of the coils is just weak. I bet if you closed the gap it would be fine.

steelrat

I don't think there were any ignition issues, just high temps.....

Dave,

hustler

iTrader: (6)

Savington and I don't have this problem with a single t-stat. Try cutting the gap down a bit, make sure you have good ground connections, put dielectric grease on the connections, and check plug wires, and get BKR7E plugs.

If your plugs don't show detonation, then I doubt you have a misfire. My plugs are always brown on the electrode and black on the base, that happens at 12:1 AFR. I recently went through this and it was a bad plug.

schmoo

DropTopDrifter, Is that you? It's schmoo. I messed up my own name when I registered.

No fuel cut or other issues for me at the track, just really freakin' hot water temps.

I did the Tee fitting like QQQQ with two T-stats.

Doppelgänger

iTrader: (12)

See, what baffles me is that I have had gap issues and bad plug issues. Though this current problem feels like either one of those, I put new plugs in with a gap I know works and nothing changed. Previous issues were there all the time....not come-and-go like this one.

I will be getting a new set of the BCPR7ES plugs though.

It just really sucks that I cannot replicate the symptoms on the street.

JayL

iTrader: (12)

I bet you can replicate this on a dyno. What's the gap that you know works?

jimj64

Hustler, are you and Savington using the coolant re-route? I assume you have an '01+ seeing as those years seem to be the issue here? I have the M-tuned kit but haven't installed it yet. This is the first thing I've seen regarding the change in head gaskets on the '01+ Miata's.

Jim

jimj64

This is kinda from left field, but what your describing sounds very similar to a problem I was having on my car. The ECU was throwing a cam position sensor error. At first it was just cutting out as you described, I changed plugs and it went away (and so did the error code), but kept coming back after a while. After testing the wiring to the cam sensor, and buying two cam semsors, I checked the crank position sensor (thanks to some comments on this forum) and found that the wiring to the crank sensor was sitting loose right behind one of the pulleys and intermittanly rubbing the backside of the pulley. The pulley had rubbed through the insulation and most of the way through one of the wires. I assume what was happening is that the exposed wire was shorting the sensor when it would rub the pulley

Jim

Doppelgänger

iTrader: (12)

You know, come to think of it, I've heard from other people having issues with cam sensors on 01+ cars when they get particularly hot since it's right on the side of the valve cover. Dunno if those sensors just die or degrade though...but I wouldn't mind taking a look at both the cam can crank sensors.

Jay- I've run up to .040" gap before and found .042"+ started getting misfires. So I've been running .035 for awhile with no issues. But why would plug gap cause a steady decline in performance after x:xx time..multiple times?

Splitime

iTrader: (24)

TDGP is kinda fun for what it is. I had a friend dukes of hazzard it out of turn two... missed the tires and other fence... jumped the ditch and almost made it to the train levy thing. Pulled the front end out with a come-along strap and then drove the TYPE RRRRRRRRrrr all the way back to Chicago.