Tracking a early 1.8 head...
 

I just did my first track day yesterday at Lime Rock Park. The car ran well although I did overheat a bit during one session. Ran at 7psi on a T25 all day. I did not install my coolant reroute yet because I didnt get a chance to re-do some IC pipes.

I am running the 6 spd on the stock 4.01 rear so I spent a lot of the course above 7000 RPM instead of shifting into 5th before a braking zone. On my drive home I noticed a rattle above 3000 rpm. I am assuming its just the HLA's crapping out. Who tracks the non-solid lifter heads? Do you have some serious trouble with the lifters? I am going to change my oil and hope/pray that the oil A) is clean & B) is enough to solve the issue.

Other than that my mechanical failures were:

1) bad gas cap that got me pulled off the track one run. I ended up making a tampon with rags around the gas cap for the rest of the day

2) slight overheating. Need re-route.

3) Snapped ground wire causing some electrical issues with the headlights.

4) Manifold gasket failure. Big surprise there :loser: need moar inconel

Generally if you let it cool enough the HLAs will get the oil they want. Even during a drive home the oil is hot and thin. That ---- does not like to cool down.

How's your ducting? That's a bigger help for cooling than the reroute.

Ducting is mainly stock. Cxracing intercooler is in front of the cxracing radiator. Stock under tray is still on. No inner fenders.

I am a bit worried because it is silent at cold start but only makes noise when warm and above 3000. I hope it's not a bearing. I'll try to change the oil this week. Until then she will sit.

That's weird behavior. How many miles on the head?

But yeah, might want to do basic track turbo Miata upgrades before putting money into it. You know. Inconel, reroute, ducting. Oil cooler couldn't hurt.

Yeah. When I built the motor (stock other than rods) my focus was on a fun street car... now I have been putting all my money into wheels, tires, brakes, & suspension and I am finding my inferior engine setup is now the weak spot again. I have a custom re-route I made but isn't installed. I need a catch can, inconel, oil cooler, and ducting asap.

I won't know until I change the oil but I think its a bearing on its way out. The head was cleaned/ decked with new valve seals about 20k ago, but other than that it is as it has been since day 1 (141k). The motor has a stock oil pump, stock pistons, M-tuned rods. About 20k on it. Was originally a budget build to get me back on the road after I bent a rod.

Well, even if your head is on the way out, a used 99-00 head isn't that much. Overheating definitely wouldn't help a bearing or a head though. Would have recommended installing the reroute before the trackday, tbh.

I planned on it... right up until I had to replace my suspension the week before, move into a new apartment, and rebuild my brothers wrx engine. LOL.

When I say overheated I mean the needle moved to past the half way mark. It wasn't pegged...and I came into the pits that lap and let it cool down before I went back out.

Hopefully I will get a chance to change the oil this week and see whats up.

I have HLAs. Your noise is opposite the noise that HLAs generally make, and that does not give me the warm fuzzies at the moment.

My noise seems to be counterintuitive to what HLAs do. I think I have a spun bearing. I plan on looking into it this weekend.

The intercooler needs to be set far enough back from the mouth of the bumper opening to allow lots of air to go around it or you will overheat. You cannot block the mouth opening too much with it. These guys taught me that and it solved my problem.

Can you explain with pics? Here is my front...

https://www.miataturbo.net/attachmen...ine=1340117919

https://www.miataturbo.net/attachmen...ine=1340117919

EDIT.. I am adding hood louvers soon and better ducting between the IC and Rad

After a track session I notice a little tick or roughness from the engine. Not audible on the cooldown lap with my helmet on, but very noticeable when I pop the hood in the paddock. It's probably the HLAs but sounds different than the typical HLA cold startup noise before they get pumped up. Sounds nice and smooth again once the oil cools. I've done 20+ track days on an untouched 94 motor, experienced this about every session, and the motor is still fine as far as I'm aware.

I was seeing 225-230*F coolant on my naturally aspirated car before the coolant reroute. That's slightly over the half way point on the stock dash gauge and just too damn hot. Oil temps were around 245*F. Probably a decent estimate of how hot you were running.

It's difficult to know if the sound you describe is what I hear from mine, but you don't necessarily need to panic over the motor's health just yet. Have a used oil analysis done and go from there. It's cheap and will tell you how the oil is holding up and if your bearings or other engine metals are seeing abnormal wear.

How many inches of space do you have between the top front edge of the intercooler and the steel crossmember that runs across the top inside of the mouth opening? Two inches of space was not enough for my car but three and a half solved the problem. We are trying to let more air go over and around the intercooler and through the radiator instead of forcing it all through the intercooler first. Plenty still goes through the intercooler but the radiator needs more volume than can readily pass through the intercooler alone.

WWhat oil do you run? My car does the same thing. Does anyone think there would be a benefit to running a 20w-50 oil at these temps?

Contrary to popular belief, I think 280*f+ is too hot for engine oil so I say you "need" an oil cooler for naturally aspirated Miatas on the track, and I saw this in OK in October. This and an oil that stays thick when hot will keep the HLA noise away. When I had the 1.6, the 0w30 Mobile1 worked well and I had no lifter ticking, You all know which oil I'd use today due to price/performance. When I start tracking my daily, I'll run blue-bottle Rotella and change it every 7000 miles.

Ordered a blackstone kit.

My guess is rod bearing. The piston will start tapping the head as a rod bearing develops a lot of slop, the result is it sounds like a lifter.

Bob

The difference (in general) is the frequency, cam related stuff bangs about 8 times/second at 1000rpm, crank/rod stuff twice as often.
500 bpm vs 1000 for the DJs :)

In general, since noise can be produced in so many ways (twice per revolution, every other time, two different things alternating, ...).

I've been running M1 0W40 pretty much since I got the car in 07. The first fill was M1 10W30 but it didn't like to get into the lifters quickly at startup on cooler mornings (more of an annoyance than a performance issue). So I searched around and some m.netters reported less or no HLA tick with the 0W40, and more importantly the UOA results on BITOG suggested it held up to track use pretty well. This was before Rotella T6 existed, and now that my stash of cheaply bought 0W40 is used up I have acquired a couple jugs of the T6 and will switch to that at the next oil change based on UOA results posted by others on this forum and elsewhere. However, the next time the car sees a road course it will have a built bottom end, no HLAs, and an oil cooler, so I won't be able to offer much meaningful comparison between the two oils with respect to the hot track noise.

It might help the track abuse noise to run a little higher viscosity, but my car is also (mostly) a street car and doesn't spend a big % of its hours running that hot. Given my use I don't think I'd ever put 20W50 in it. I need something that holds up to track days but that also flows well enough at cold startup on 30-40*F autumn mornings. I'd rather run 0/5W40 and an oil cooler than use a 20W50.

OK here is a quick video. It was quiet until the engine got fully up to temperature.



Ill be draining the oil tomorrow and checking for pretty gold flakes