For the plastic plug in the back of the head, you slightly loosen the two bolts that hold the cap, and pry it gently. Replace with a new one and retighten the two bolts.

 

I actually just put 91 (ended up being about 25% ethanol after mixing) back in the car for the first time since I went to the 2860 and didn't see any real knock ( a couple places that were a little noisy, but nothing concerning), so if you pulled a couple degrees out you should be pretty safe.

IIRC at one point I pulled that plug and smeared it in RTV and threw it back in. There were some bits of the rubber seal that had been chewed up. I think that worked for a while but eventually I just grabbed an OEM cap from ebay or Mazda Motorsports, probably around $20 shipped. Granted... now I almost want to try 3d printing something for it. It'd probably be pretty hard to get something to hold up back there with all the heat from the exhaust though.

 

thats good to know on both points, i did just that and put some rtv around it, ill grab a new one.

new today, i forgot to put this coolant line in the proper place. I paid for it, luckily i have a whole coolant line kit and spare hoses so i just laughed it off.



HOWEVER after refilling the system and running some errands, i went to do some data collecting and pulls, just stress testing and checking things out. Keeping up with some random sportbike at around 105mph, i pulled off and checked under the hood because im obsessive, and i had pushed a very large amount of coolant out of my overflow, it was all smoking, some on my windshield, and taking the cap off the overflow shortly after driving it, i could see bubbles coming from the radiator line.

obviously as things go im sure its a headgasket sealing issue. It seems to only happen under boost, i did another small pull by my house after cleaning it up, and pushed more out. The overflow smelled not like coolant.

in a world where i practice wishful thinking, id like to believe it was just overfilled, or my radiator cap gave out. After all i cleaned the hell out of the head and block, used a good mls gasket, havent overheated, copper spray, and new headstuds torqued to 60ftlbs in stages. Who knows. I dont have a leakdown tester or coolant gas tester, ill probably grab a leakdown tester. For now im going to comp test it again, and let it idle with the cap off to see what i see!

 

I got contacts for the first time, theyre kind of horrible, i cant focus up close, and have to focus hard to see far away. Anyway, they still let me see this lovely bubble that the pressure made in the headgasket!

Supposed to be flat

Supposed to be flat

Not bad for 86 miles

This is what its supposed to be


honestly glad it made that bubble, i like knowing where things went wrong. New headgasket gets here tomorrow, going to get it cleaned up, use the straight edge to check for flatness

 

Quick work!

I've never been a fan of the spray copper stuff on headgaskets. Though I don't think that's what caused the issue here. Definitely check for flatness before going back together.

 

Like many things it doesnt have enough accurate data to be a definite yes or no, I figure it cant hurt, and will get squished out of places it doesnt need to be anyway, though the mls ones have that black stuff that seals things like that anyway... im on the fence this time.

 

Did you get the wrong headgasket or install it backwards or something?

 

not that i know of, reason for asking?

 

Couple things here.... You seem to be having a lot of carnage here... I remember elsewhere on here you had a crooked timing cover and stock balancer... The elastomer on those balancers can slip so they should always be verified.. So couple questions..

Not trying to be harsh here so please dont take the wrong way. Believe me I've broken more junk than I can shake a stick at in the last 40+ years playing with cars, boats and motorcycles, so trying to help save you some heartache if I can..

Soooo that being said...Did you ever register your balancer to true top dead center? By that I dont mean eyeballing with a screwdriver in the cylinder, but doing it properly with a piston stop and in both directions to determine true tdc?? Without doing that you really have no idea what your actually timing looks like.. Have you observed with a timing light with timing locked down to see if its advancing or retarding when it should be relatively locked and stable throughout the entire rev range? also no bad jitter (good idea to check every cylinder for jitter)? Did you ever get your lean issues sorted?? Are you positive head and block are in fact straight? If all these above issues are sorted a stock mls headgasket and good head studs should be fine for your power levels and more. You can help those stock pistons survive by being more conservative on the timing at low and mid range and ramping in hard at higher rpms. Small turbos that make peak boost before 5500 rpm combined with high timing there and below is really hard on these engines and can bend rods, break pistons and lift heads as you are finding out. A cut ring headgasket will hold more pressure than a mls gasket, but you really shouldnt need to go that route.

Also a caveat in case you ever looked up my timing map on here. I ran a lot of timing on the miata I had when I was drag racing, but it was a different animal than yours. It was very low compression, much bigger turbo and only for 6 seconds of peak boost. Also being an automatic with a loose converter allowed the engine to climb above 5500 rpm at any speed once full boost was achieved. Actually it never really saw much below 6k at full boost even if i short shifted.

At any rate I hope you get it sorted out. These little cars are a lot of fun and I'm really starting to regret selling mine.

And one last thing, be careful about trying to pull up on a modern sportbike. Just because the all look similar doesnt mean they are. A modern liter bike with a good rider can trap over 120mph in the 1/8th mile. With a swingarm, sprockets, strapped front and good tire they can also be capable of dipping into the high 5s in the 1/8 as well, with a stone stock motor no less!! Of course that takes that right rider as well.

 

im not going to take anything personally haha, im here to learn from people who have had and seen more mistakes than i have success, those are the people with valuable input and experience, and getting to *sometimes* avoid mistakes because of previous knowledgebases is a privilege . I am aware and make it known that i am not doing things “the right way” im choosing hills to die on that i think are worth the risk, and find interest in the mistakes i make and things i learn. So by all means, save me the heartache

i ended up getting a new cover, and checking tdc, but havent tried (or heard of) a piston stop.
I watched the mark with the timing fixed, but didnt rev it that way. It was static, but thats not to say it cant move during higher rpm. So ill be checking that when this is done.

the lean issues i observed were under half a tank of ethanol, and i figured out they went away when i filled up. My pump is in an odd spot, so i figure its something to get fixed later on.

the head and block i “decked” myself the first rebuild with glass and sandpaper. With a new straight edge, every single permutation tested flat, with the smallest gauge i could find. Whenever i cracked the piston, all i did was scrape off the residue and clean it, not as well as i should have probably. Ill be rechecking for flatness and flatening again, and avoiding copper spray on the mls gasket this time, along with torquing the headstuds to about 65ftlbs.

atm im running probably similar to 93 octane ignition numbers with 75% ethanol, so im sure its plenty safe, ill tune that by itself after a while.

and yeah, ive only gotten to “race” one sportbike, it was definitely a 400cc, i had no trouble winning the race, the motorcycle i kept up with this time seemed to be a similar bike. He was just trying to get away and couldnt. I like racing anything and everything. People get way too amped up with “you have to have a crazy fast drag car to race” if i line up with a kia soul or honda civic and they want to race, we’re on.

 

Just wasn't sure if coolant was supposed to be flowing through all of those passages or not. Basically I wasn't sure what I was looking at.

Iirc some people those the nb2 head gasket on to get better coolant flow and I think I've heard of head gaskets being installed backwards so I wasn't sure if that was the failure method here. I've only done the one head gasket when I rebuilt my engine so I'm not very familiar with them.

 

Yeah, I think on the nb1 and below gaskets they arent blocked, but revised for nb2's for the cooling in the last cylinder, this is off the top of my head so it could be wrong. Ive heard/remember some people using the nb1 gasket for vvt heads with reroutes, but that was a debate on which was better to run with a reroute. I dont plan on getting a reroute, so im not worried about it. Think it was just some leftover gasket i didnt clean off well enough on the head that didnt let it seal well. maybe even the copper spray being too much paired with the viton coating

 

I could be wrong, but AIUI, there are some configurations of BP blocks, HGs and heads that can cause overheating as a result of blocked cooling passages. I know of one expensive track build that used the wrong HG and needed a rebuild at the shop's expense. These engines have been around a long time, and mixing and matching means that there is scope for mismatching, and careful checking of the HG against both surfaces id needed to avoid issues.

 

There's two* head gasket layouts, 94-00, and 01-05. Mazda tweaked the design in 01-05 to force more water through the rear of the head, by blocking off some of the front coolant passages. Use a 01-05 if you don't plan on using a reroute, but you can run a reroute on both, it's just not ideal to run a reroute with the 01-05 gasket. Even the 94-00 design has some blocked passages.

While the damage to your gasket doesn't look good, I think it's a result of pushing combustion pressure into the coolant system, not a cause of the coolant pressure. If you have a properly flat and cleaned block and head, I would skip the copper spray.

*There are some aftermarket gaskets I'd consider a third design, which seem to blend the two layouts, use at your own risk.

 

Yes, I imagine it leaked into the layers of the blocked port, and into the port itself, and it kind of blew a bubble in the layers of the port, like something getting hydroformed. Pretty cool, anyway I cleaned and refinished the surfaces today, all areas checked for flatness and cant feel anything with my fingertip.
Lucky me though the headgasket got delayed, I could go days talking about my dislike for fedex.

 

A good update! I think.

got it all together, at first i had a lot of bubbling into my overflow tank. that bummed me out. I let it sit, grabbed a new rad cap, and took a breather. I went out to enjoy the car before i decided to empty the coolant on the windshield… and it never did. I had some bubbling on the 2nd drive, but on the 3rd or 4th, it had stopped. Im not sure if completely or permanently. But im happy about it. The surfaces were good and flat, though i had some pitting near the fire ring area and coolant port on the block. I assumed this was the issue to begin with or some leftover material.

during the new gasket install i forgot to put the exhaust mani gasket on before i slid the head onto it.
(i basically left it in place to avoid the 2 hour debacle of taking the hotside off the car. This was less than ideal, because it takes forever to get the hotside off, i have no room to squeeze the gasket in, and the head was already torqued. Luckily i realized if i cant move the manifold off the head, and the head off the block, move the entire block!

So after unbolting the motor mount stud and jacking the motor sideways i was able to squeeze the gasket in. Took about 15 mins.

this time around i torqued the head to 65ftlbs on the headstuds, and did a lot of cleaning. To be fair, when i saw the pitting i started making my peace with the fact that i was going to leave the car down for a good while, whilst i saved to do things right once and for all. So anything i get out of it now is a plus.

I beat the **** out of the car, and let a good friend do the same. 18.5psi pulls on some of them. After a bit of that, we stopped at his house and checked some things. My drivers side catch can had started spitting a good amount of milky oil out of the vent to atmosphere tube. I figure an lines and a pcv delete are in the plans for it. Im sure this loose ring tired bore motor has more blowby than the two tiny hose catch cans i have can keep up with. Anyone delete their pcv? Ive read its generally not a street car thing to do. Ive been over the definitive catch can thread a few times. Im jumping between both sides an line to a large vta catch can, or keeping the pcv in place and doing an AN line can on the drivers side.

the oil is still clean and coolant is still coolant colored.
no weird leaning out issues still. Had a full tank though.

i hope soon i get over the fear of just driving the car, it seems lately ive lost all trust in myself and the car, which isnt unwarranted.
I got one good vd log in 3rd today, 250~whp 17psi and what seems to be a 93 or low ethanol ignition table.
Will keep updating!

A keen eye will spot i didnt have the valves low enough before i started sanding this…

Pitting on coolant port, 3rd hole from the bottom left side under the stud hole for 1/2

i hate this vvt banjo line contraption, its a half cooked spaghetti noodle and bends, kinks, and changes its behavior anytime its observed.

 

Still holding well I think. No weird coolant bubbles. Could have been the cap, could have been the headgasket, maybe I just changed a headgasket for nothing who knows!

Anyway, im filling my drivers side catch can pretty quickly with e85 watery milky oil soup. I got completely rid off the pcv valve, just gutted an old one, capped off the intake manifold port. Now I have 2 vta cans off the vc, the hole in the inside baffles is widened, and they were put back on clean with gasket maker. No scrubbers iirc. (mostly cause i forgot to put them back in.)

for the moment to drive the car ive just been checking it often and emptying it, along with checking the oil. But im thinking of ripping the vc off and adding some baffling to slow air velocity down inside the drivers side baffle, maybe widen the baffle connection hole and or add another, then 2 10an lines to a vta dual can from both ports. I have scrubbers i might put in. Going to reseal it. I saw all sorts of things people were doing to fix issues similar to this. Im sure it has something to do with my loose ring 19psi 250k mile crack wh0re motor. Anyways, for the moment I have stock sized lines to two separate cheapo catch cans with the scrubbers inside.

On another note, I ended up getting 2 singular decent logs for virtual dyno that actually carried to redline, one got me super excited, but i dont trust it truthfully. That was around an 18psi peak that dropped to 16ish by 6k rpm. Same ignition map as the other. The lower run had more boost, and i made a small attempt at fixing the sag.




Heres the ign map ive gotten to.


definitely safe this time for e85.... right....?

im getting to a point where i am not sh1tting bricks driving the car, im trying to fix the little intricacies of the tune and dial it in as good as i can on a speedy.

they kill the car every single time a single one turns on. ive tried tons of bandaids, i really need to fix the idle up working for them, the idle up is odd for the ac and fans so I just havent wanted to delve into it and figure it out, but its getting very annoying and stressful sitting at stoplights wondering if im about to have to start the car again. Or... I could be lazy and get a fan controller/softstart module from a junkyard car... or wire the fans to their own circuit to reduce electrical draw.

 

That blue VD run definitely looks like you hit a bump or something. Just following the trend of it would make me guess it should be closer to 250 at redline. Usually dropping the smoothing will give a better idea of if a log has good data and if that looks good then turning up the smoothing will make it look like an actual dyno plot. I wish VD allowed you to use more data points. I'm not sure how it works exactly, but I've tried loading in logs with really high frequency RPM data and it never seems to improve the trace.

I'm always surprised with how much IACV duty is needed to compensate for additional loads. IIRC when AC kicks on I increase the duty like 10-15% and increase idle target by 200 RPM. I'd expect speeduino has some delay for idle up before the fans kick on, but I could be wrong. The G4x has spoiled me a bit with that kind of stuff.

Also, cat given for the flaming letters

 

It sounds like you already researched and found this, but the key with looser ring gaps is to slow the volume of the blowby air. A decent street setup is piping both sides of the VC to VTA cans, with PCV deleted. For track setups this won't work because the PCV side baffles suck and on left hand turns you'll flood oil out that side. Also, you need to enlarge the internal holes by 2-3x, these are the holes within the baffles, they are tiny and promote high air speed which carries oil and vapor into the cans more quickly. Mine was done all on the drivers side, I added more holes in the internal baffle and did to -10AN lines to a VTA can. This solved it for me. No scrubbers or anything inside.

 

but i like the higher number smh.

the idle up hasnt worked for the fans ever anyway, im going to lookup how to get it working, but so far ive just been using a lot of tricks to get it to survive the fan turning on maybe 30% of the time. When i do Ill be very happy though.
poor flaming letters are gone, at least someone got to see them.


this is good to know, i remember you mentioning you had gaps on the looser side. Im hoping mine is manageable with a good setup.