Engine/Trans noise woes. Miata gurus hellp?

[xjdesertfox]

So for the past couple months, I've been trying to figure out what this noise is that my car is making. I cant really describe aside from the sound of a bearing with a pit in the race that makes a "tap tap" added in with a rattling washer.

I've tried to eliminate variables, but I just cant figure it out for the life of me.

My car is a 95, all stock drivetrain + K&N drop in filter and a Jackson racing header.

- When the sound happens. -
The sound does not occur until the motor is warm, and it seems like it happens on warmer days.

Sometimes it slightly makes the noise if i let the clutch out at around 1300 rpms. Higher rpms it does not.

In third, fourth, and fifth gear, at or above 3.5k RPMs. But not first or second.

If I climb a big hill on the freeway, it will make the noise throughout the whole pull.

- What I've tried. -

My first thought was speedo cable, I threw a new one on and it seemed to fix the problem. Until the weather got hot again.

I've removed my A/C belt and tensioner(car has no P/S) thinking it was the A/C clutch. No dice.

I've looked for any type of loose bolt/washer or the like, but it doesnt sound like its just a loose washer, theres an RPM related "tick" associated with it.






Someone mentioned clutch pilot bearing, or TOB, but I've never had one go bad so I dont know what that feels like.

You can hear the sound in this video as my car drives by. I cannot replicate the sound unless the car is under load, it does not make the sound while revving in neutral.


http://youtu.be/nJuuRlX4hSY

Is my motor gonna asplode?

[xjdesertfox]

Also, someone told me it might be detonation. I havnt checked the timing on the car, and it seems like my problem came back after putting in some 87 octane arco gas. But I topped off my tank with 3 gallons of 100 octane, and the sound did not go away.

[kung fu jesus]

would love to help, but that video isn't offering any clues. It's too short.

possible to make one from in the car? if you suspect detonation, check your timing. If you are too far advanced, 87 octane is tearing it apart. You shouldn't be at anything above 14* at idle.

[xjdesertfox]

Will try to make a video as soon as I have time. I'll grab a timing light and go to town as soon as I get a chance too.

I just drove it with the speedo unhooked, same problem so that rules the speedo cable rattle out.

Ill probably get a vid this weekend, thanks KFJ

[kung fu jesus]

If it is under load when this happens, it could very well be detonation. Check your plugs in the mean time to see if they are burnt. It could be a pulley (idler) going bad.

[atlnb]

Does sound weird. I wouldn't suspect engine though. When was the last time you changed the clutch?

[xjdesertfox]

Does sound weird. I wouldn't suspect engine though. When was the last time you changed the clutch?

I bought the car in February with 156k miles on it, "supposedly" the clutch was changed 3k miles before I bought it. When I test drove the car I tested it for slippage and it felt real good. But whatever clutch and pressure plate thats in the car doesnt feel that great.

i have an ACT stage 1 pressure plate and exedy HD friction discs sitting on a shelf collecting dust because it was given to me, but whether or not its usable is another thread altogether.

Took some pics to show you guys my plugs are unevenly colored? One side is lighter than the other. Also, I stared down the spark plug holes and my pistons look heavily carbon coated. I also discovered a leaking valve cover gasket, and a belt material covered idler.

http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0798.jpg
http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0799.jpg

My number 4 plug had this weird black burn on it?

http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0800.jpg

Idler

http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0801.jpg

Tensioner

http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0802.jpg

[kung fu jesus]

Wow. Those plugs definitely don't look right. The darker ones, especially. If you have heavy carbon build up in the combustion chamber, the carbon can heat up to the point of causing detonation, it can also raise your compression in some cases.

The idler pulley is OLD. It makes me think it is the original one. You shouldn't see pitting and discoloration on the surface like that. I changed mine, as I normally do, when I did the TB service last spring. It had 70-80k on it and still looked new.

Just my opinion, but I would still check the timing first. If I were you, I would recommend plans to "reset" the car by updating the routine maintenance. I would look into a complete TB service (timing belt, ilder pulleys, seals, hoses, coolant flush, etc.). This will help you start to pinpoint potential compounded issues and will give you a clean slate of sorts to help you get the car's performance back. Forget the clutch for now. Start with a good, thorough tune up.

I might also suggest you start running 91 octane or at least buy fuel from a GOOD source, like Chevron, Shell, or Mobile until you get the timing checked. Buy fuel with good detergents. Hell, just go BUY a timing gun, they aren't that expensive $40-50. Small price to pay for irreversible engine damage. I would probably pick up a can of Seafoam and dump it straight in the fuel tank with a full tank of fuel if you suspect heavy carbon build up.

[xjdesertfox]

I got a timing gun yesterday, those plugs only have 3k miles on them btw.

I won't be able to work on the car for awhile, I'm thinking of just buying tony pham's motor that's for sale right now. This motor also leaks all over the damn place, so at this point calculating cost, it might be cheaper and less headache to swap another motor in.

In the meantime I'm gonna drop some MMO down the spark plug holes while it sits, from my reading doing an mmo piston soak cleans the carbon off pretty damn well.

I'm running a mix of 2 gallons of 100 octane from alliance, 6 gallons of chevron 91 and the rest is arco 89 and its still pinging.

[WASABI]

I got a timing gun yesterday, those plugs only have 3k miles on them btw.

I won't be able to work on the car for awhile, I'm thinking of just buying tony pham's motor that's for sale right now. This motor also leaks all over the damn place, so at this point calculating cost, it might be cheaper and less headache to swap another motor in.

In the meantime I'm gonna drop some MMO down the spark plug holes while it sits, from my reading doing an mmo piston soak cleans the carbon off pretty damn well.

I'm running a mix of 2 gallons of 100 octane from alliance, 6 gallons of chevron 91 and the rest is arco 89 and its still pinging.

I agree that those plugs look bad, especially for only having 3k on them. Had the car been sitting before you bought it? I ask, because my idler pulley looked the same on a car I bought that had been sitting for a couple of years.

I suggest you buy a timing belt/water pump kit (that includes cam, and crank seals, new belt, water pump, pulleys, and gaskets (valve cover gasket too). Also, pick up a CAS o-ring as well (and maybe plug wires).

Once you change your timing belt, and everything else, adjust your timing, then you'll have a base to judge how you engine is really behaving. This is basic maintenance, and will more than likely fix your leak, and performance issues.

-Jim

[xjdesertfox]

I agree that those plugs look bad, especially for only having 3k on them. Had the car been sitting before you bought it? I ask, because my idler pulley looked the same on a car I bought that had been sitting for a couple of years.

I suggest you buy a timing belt/water pump kit (that includes cam, and crank seals, new belt, water pump, pulleys, and gaskets (valve cover gasket too). Also, pick up a CAS o-ring as well (and maybe plug wires).

Once you change your timing belt, and everything else, adjust your timing, then you'll have a base to judge how you engine is really behaving. This is basic maintenance, and will more than likely fix your leak, and performance issues.

-Jim

My motor is currently leaking pretty badly from the rear main. The car was indeed sitting for awhile, the previous owner said he drove it about 2k in the year prior to me purchasing it. Supposedly the previous owner changed the timing belt and water pump before it was sold to me, which I believe because my belt looks brand new, and is goodyear branded. Im guessing he just didnt replace the idler/tensioner while he was in there.

Right now I just feel I should just try and swap in a lower mileage motor which has been maintained, I have to pull the motor to change the rear main anyway right?

But if it doesnt seem financially viable to do a motor swap, I will indeed change the TB/WP/seals.

[adamvanxxx]

It is easier to pull engine and trans together but you can just drop trans and change the rear main.

But with the engine out we still had a hard time getting my buddys out.

As for the engine, without a better video there is no telling, but I would not just suspect it to blow. As stated to some tune up stuff maybe seafoam it before hand and get some carbon out. If you can try to look in those spark plug holes and see if you have any damage on the pistons.

[xjdesertfox]

Looking inside, all I could see was a ton of carbon.

Looks like I'm gonna reseal the motor and try to get it running right, the motor I wanted to buy sold.

[adamvanxxx]

Try seafoaming it and breaking some of it up?


If you can afford to taking the head off and giving it a good clean would be awesome too.

[xjdesertfox]

I would take the head off, but If I did, I know Id want to just rebuild the whole motor, I'm willing to bet my block's surface needs to be refinished if I pull the head.

I'm going to soak the pistons with MMO, then again with amsoil powerfoam. Then i'll run seafoam in the gas.

I checked the timing, and im at 12degrees BTDC. I backed it off to 10 degrees to hopefully stop the pinging for now. I think i've found the source of my pinging, I think its a combination of the carbon deposits on the pistons and running lean from my header/exhaust/intake combo. I remember pulling my plugs before I put this stuff in, and my motor wasnt detonating at the time...but it was also february so who knows.

I do plan on rebuilding this motor completely next summer when I have all the money and parts I want to put into it. So i just want to keep it running well for now. I am taking all of your guy's advice though, and I really appreciate the help.

Only reason progress has not been made yet is because its finals week next week and i've been studying.

[xjdesertfox]

UPDATE!

I have figured out the issue(s).

1) My cam sensor adjustment bolt went missing... my sensor was loose and adjusting itself as I would drive.
2) Either the person who did the belt last lined up the cam gears wrong, or the timing belt slipped, but I'm 2 teeth off on the intake side.

We discovered this today as we were doing a leakdown test on the car putting the cylinder to TDC.

So with that said, All of you guys were right. A Timing job done right will solve my issues, the detonation is purely from timing being off.

Heres a video of the miss my car is making due to the timing being off two teeth, for future reference in the community.


http://www.youtube.com/watch?v=o4NbKo0rxU8

[WASABI]

Glad to hear you found the culprits. So you must have been getting horrible lack of power too? I'm in to see the video of it all fixed and running right!

-Jim

P.S. While you are playing with the CAS, don't forget to change the o-ring.

[kung fu jesus]

Awesome!

I would treat any repairs the previous owner did as suspect.

[xjdesertfox]

Definitely, I thought my headaches from the previous owner were gone when I replaced my speedo cable that was held together with duct tape and replaced an alternator tensioner that the previous owner felt didn't need to be there.

[xjdesertfox]

Well. The saga continues. I sat down and rotated my motor with a socket. And it doesnt seem like my timing is off. Can anybody figure this out?

Heres the timing mark locations. 2nd picture is after 720* rotation.

http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0814.jpg
http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0815.jpg

I noticed when rotating my motor that air was coming out of here. Is this right?
http://i559.photobucket.com/albums/ss35/xjdesertfox/DSC_0816.jpg

Did a compression and leak down.

Compression results all dry, little change when wet.
#1 140psi
#2 150psi
#3 150pis
#4 135pis

Leakdown:

All 4 cylinders are leaking 25-40%. I cannot even fathom how this is possible. Air is coming from the intake side. No air from dipstick or exhaust side. No air coming through coolant.

Im guessing that somehow all my intake valves are fubar'd and I need a top end rebuild?

[kung fu jesus]

bad seals or guides maybe.

[xjdesertfox]

Bringing this back up. Thought I had solved the issue with a new water pump, but maybe not...

So, I did the TB/WP/Seals/coolant hoses.

Engine had not been pinging in the longest time. The motor has a "Hot ping" where if I turn on my A/C or flog the piss out of my motor in hot weather, it will ping under load.

Im guessing my engine is running hot, but I cant figure out why.

A few theories.

1) I've flushed my radiator multiple times, It STILL has a ton of corossion in it. Maybe my heat exchanger cant keep up anymore?
2) My thermostat is a non-OEM 195* T-stat, maybe its bad and not opening when it should?
3) Im running BKR5EIX-11 NGK plugs. Maybe I should go 1 Step cooler? But that doesnt make sense, why would I need to run a cooler plug than factory.
4) I do have carbon deposits on my pistons, but nothing bad. But maybe I should De-carb the pistons?

[xjdesertfox]

Also, Forgot to mention. This problem is apparent with timing set to 10-11 degrees BTDC. With timing at 14-16 degrees BTDC the pinging stops.

[kung fu jesus]

Weird. I'm trying to think this one out.

[xjdesertfox]

Also ran another leakdown test and compression test with my own tools.


#1 162psi
#2 175psi
#3 175psi
#4 165psi

~8-15% leakage from each cylinder, sounds like its coming from the intake side.

Previous tests were done with some OTC branded tools at a shop. Apparently my moroso leakdown tester and actron compression tester disagree with the shop's tools.

[Kage]

I don't mean to necromance a thread, but I've been fighting what sounds like the same noise (or pretty damn similar) that cropped up in your first video for about the past year. Did you ever manage to track it down and fix it? Or is it still making the noise after all the work you've done to it?

Thanks!

[Hyper]

Think outside box.

I once had this problem and after thinking and thinking I realize that timing was off. Why? I simply ask, then researched and learned that all 90--95.5 crank pulley are defective. The pulley itself is defective as you think the timing is right when is not. You see the damping part of the early crank pulleys wear out or so it order to set the timing properly remove the lower plastic cover and compare the TDC at the crankshaft pulley with the camshafts. If the timing mark at the crank wheel (where the timing belt moves the crankshaft) is off then crank pulley slipped and you must stamp a new mark in the crank pulley. Mazda corrected that issue in the later 1.8 models by adding a crank sensor and wheel at the crank pulley.

I am not saying that this could be your problem but looking at your two different compression test the problem seems to lie there. Flying Miata wrote an article on this for the early mazdas. Thanks to them I figured out the issue with my ride when I had the NA.

[kung fu jesus]

I'm just writing a few thoughts after re-reading this thread.

Hyper does make a good point. the rubber on the damper of the crank pulley does age and harden, so it could lead to slipping timing.
That said, you could replace the pulley with a new (or newer/fresher)one. If you did the timing belt, did you check the or replace the woodruff key? It is possible for the rounded keyway to happen on these motors, like the early b6 motors, if it was installed incorrectly.

You mention you saw carbon deposits on the pistons? If you are leaking air out the intake mani, I would suspect carbon buildup on the valves too. The carbon deposits on the pistons on in the combustion chamber can lead to detonation. Think of those carbon deposits like pieces of charcoal in a bbq grill. They start to heat up and glow. Now think of those hot pieces of carbon in the combustion chamber like ignition sources for your fuel. they can lead to pre-detonation before the piston is ready, causing knock.

Based on the pictures you posted, particularly the idler pulley, it seems this car sat a lot in a previous life. I wouldn't doubt is was neglected and no very well maintained. Aside from boreospoping the combustion chambers, pulling the head to check for carbon build up would be my inclination to solve the issue. The lazy way to maybe start to correct the issue would be sea-foaming the engine and running a fuel additive to try to beak up the carbon deposits. YMMV.