Pretty sure I'm driving on borrowed time, what should I do?
 

So I've just been enjoying my new (to me) miata, but I think I see trouble ahead. Usually when I start the car the engine is noisy and knocks quite a bit, but usually it just goes away as soon as the oil pressure goes up. At first I thought it was just noisy lifters, but now I'm not so convinced. As time went on, it would stay noisy at startup for longer periods... turns out it was burning oil at a fair clip and the oil was getting below the low level. So I just made sure to top it off every once in a while until it was time for an oil change.

I just changed the oil a week ago for the second time since I bought it. Ended up having to use mostly 5w-30 synth 'cause it was all I had lying around, except for the maybe 1.25qts of 10w. Put in a Bosch filter after realizing the store brand filter I bought may have been complete crap... and from now on have decided to use either PureOne or Mobil1/K&N.

Now, I was just driving it today, and it's noisy again! While it did eventually fade a little before driving, today it actually knocked while driving (for maybe the first 2-3 minutes). The knock got louder with more throttle, but eventually seemed to fade away.

Parked, came back out in 30 minutes, started it up and noisy again, knocking a little for another 2-3 minutes then seemed to fade away. Then while dropping off my gf it got noisy again for 3-4 minutes WITHOUT even turning the car off!

Long story short, I'm pretty sure I'm driving on borrowed time, since I think a bearing died or is dying. I'm 90% sure the prev owner tracked the car, and I'm sure me driving it with low oil, and now with lighter oil is only making things worse.

Now I'm not sure what to do... I'm only a simple shadetree mechanic. I cut my teeth on a DSM which I owned for more than 5 years, but never even got so far as to install a clutch let alone pull/install an engine or even rebuild an engine. I did all the basic maintenance (plugs, wires, adjust timing, fuel filter, pcv, rad hoses, thermostat, coolant temp sensor, etc.), free mods, upgraded the turbo, installed an exhaust, fixed boost leaks, installed a boost controller and turned up the wick by tuning for a low knock count with my datalogger.

I don't feel at all comfortable replacing my miata's engine myself- not to mention I don't have a hoist, engine stand, trans jack, or the space in my garage to do the work.

So if I'm not willing to do the work, I'm not sure what I should do? Get another used engine swapped in w/out having them re-install the turbo (so I can do it myself to become more familiar with it and save some $$), try finding a place that can install another engine and re-install the turbo kit, or maybe find a place that will take out the current engine to rebuild it and re-install everything?

Any suggestions are welcome...

Welcome to the site driver70, thanks for joining up!

Welcome to the site driver70

The first thing I would do is install an oil pressure gauge and see what's actually going on.

My '92, as an example, was noisy as hell. Lifters. I tried a few different oils, and found that Mobil1 0w40 was the least bad, but even at that I never had to write down the mileage when I changed the oil- the car would let me know when it was time to change it by the noise.

Looking online at the local auto parts stores, I'm not even sure what type of pressure gauge to buy. I assume a compression tester wouldn't work, maybe a fuel pressure tester with adapters to plug it into the oil pressure sensor bung?

Do you know anyone that could give you a hand with maintenance or an engine swap?

Well, I do know 1 guy who would most likely have all the tools and the experience to do an engine swap. He's a car nut, and loves buying cars to fix up, then make them go fast, then after he gets bored with it sells it to make more $ to buy his next project. I know he's had a turbo'd miata before and built and used MS to tune it.

He used to rent from my girlfriend, and I managed his property. He's since bought a house so I don't see him any more. Truth be told though, he'd probably enjoy working on my car with me 'cause he loves working on cars.

Hey driver, welcome to the forum. The description of the sound your experiencing could be a bit better. For ex I had a na supra many years ago and it got rod knock. Sounded like a slight rattle at first around 4k rpm and eventually got louder and moved down the rev range. It got to the Point that it knocked at idle. A vid may help with diagnosing the car too.

Long story short I swapped the motor myself, all I had ever done to a car before was, bolt ons, suspension, etc....little stuff. With the factory service manual at hand I swapped the motor and changed the clutch out. Just take your time and label everything possible.

Thanks for the vote of confidence Advancedspecv. I'm starting to think a swap might be the way to go. When I work on my cars I always just use the shop manuals and follow whatever steps they list. I suppose an engine swap is the same thing, just on a bigger scale. I'm thinking I just won't worry about whatever damage is lurking inside my engine, and if/when it goes just plan on getting another used engine.

As of now, I've been topping it off when needed, and the previous owner's mechanic said to use Mobil1 High Mileage. So, I went and got some of that and ever since I topped it off with maybe a qt of that stuff, it's been pretty quiet at startup. I can still hear a ticking noise that'll probably get worse with time, but I'll enjoy every mile I can squeeze out of it...

You should be able to find all manner of cheap mechanical oil pressure gauges- some intended for handheld use, others for dashboard mounting. Sunpro seems to be a popular brand at the lower end of the price scale, and is adequate for our needs here.

The simple solution would be to purchase a cheap "dashboard" gauge and simply affix it to the outside of the windshield with goose tape.

Examples:
http://www.summitracing.com/parts/SUM-G2934/
http://www.summitracing.com/parts/SUN-CP7977/


The oil pressure sender hole in your block is threaded 1/8" BSP, which is sufficiently similar to 1/8" NPT that you can install an NPT plug into the hole without damaging anything if you are careful. (1/8 BSP is 28 TPI as opposed to 27 TPI for NPT, however you're not going to need much thread depth engaged, so the risk of damage is small, especially with a brass plug.)

Thanks for the part reference and sender threading! I never knew you could get some of those gauges for so cheap. I figured $60 would be the cheapest but I was waaay off on that one.

I don't have any goose tape though so I'll just have to use duck tape. The only trick is mounting it so it doesn't get in the way of the windshield washers... but, I'm sure it'll be better than getting a new a-pillar gauge pod.

Well, I'm assuming this will be a very temporary thing, so it won't matter of the wipers are blocked.

The point is just to verify whether or not you have adequate oil pressure when the engine is running at load and at normal operating temp. Once you have that answer, the gauge can come out.

Yeah, I was totally kidding, I'd probably end up making it a permanent gauge... I'd already be doing all the work and paying for all the parts, it might as well just stay there. No sense in throwing away that money, time, and effort. Not sure where I'd end up mounting it as it's already kind of a pain looking into corners with the boost gauge in the way.

Besides, this will give me an excuse to put in an Amsoil bypass filter that I bought for a previous car I owned but never got around to installing. I'll be in there anyway, and there might be a slight chance in hell the bypass filter will prolong an untimely death.

After I first heard this noise at startup, I started doing some research and am almost convinced that the issue is just noisy lifters. More research into how to cure noisy lifters led me to use auto-rx.

I've got a high mileage motor with 170k+ right now, but I've completed the first clean and rinse stages and am now ~500 miles into the second clean cycle. The noise at startup is fairly regular now, usually quiets down to 10-20% within a minute, then seems to go away after the engine's warm. I read that sometimes the noise gets worse before it gets better, but I'm hoping it'll all but go away after I'm done with the treatment. I think some people have used different weight oils to help eliminate the noise, but I don't remember which weights worked best so I'll have to look that up again.

Anyways, just thought an update was in order.

My '92 had ferociously loud lifters. I never used any of the fancy treatments, I just found by trial and error that it seemed to like Mobil1 0w40 (the original mix, never tried any of the newer ones.)

ugh. you're one of those "changing the oil will fix compressed lifters that arent in constant contact with the lopes" sort of guy? I wouldn't have taken you for one of them Joe.

All I can tell you is that once I found the right oil, the engine in that car would run quietly for 2-3,000 miles until it got dirty again.

Mock if you will, but it worked.

I will mock you! and i will quote myself:

Buy whatever is cheap and change it every 3000-3500 miles and you're good to go. It's the sludge blocking the tiny oil passages that contributes to the noise. I did a flush 3 or 4 years ago, and use cheap oil, and it's never been a problem.

Driver, you'd be surprised at how crazy loud lifters can get. I had tick a long time ago that was the standard moderate annoyance but got it to go away after switching to synthetic (go figure Brain. Previous owner ran dino). Anyway I thought I knew lifter tick pretty well.

One day after driving appx 200 meters, my car ran sluggish, made crazy loud knocking sounds with RPM, and ran and sounded like a diesel. Shut the thing off and was like WTF. I thought the engine was toast from rod knock or spent bearings after seeing the oil level well below the low mark from more oil burning than usual (only 2000 mi highway and an autox).

I had my buddy tow me home thinking there's no way this sound is lifters and preparing for engine work. After some research, I simply did an engine flush and oil change and the rough knocking sound went down to a tick which faded away to normal silent running. I was dumbstruck. Hopefully I'll find the video I took to demonstrate how loud it was before fixing.

Try that gauge out like Joe said. Hope this is the case for you.