Loud ticking 99 1.8 engine - only when warm
 

I first noticed valve ticking on low RPMs and during slow speed decel a while ago. Took it easy till I tore the engine apart, but the noise became more apparent over time.
Valve lash numbers were pretty excessive upon teardown inspection, especially on the exhaust side, with a couple as high as 0.42 mm. (MSM calls for 0.28 - 0.34 mm)

Off went the head to the machine shop, and all clearances were set to factory specs. The machinist invited me over to check everything, and we both verified the results.
I also checked all clearances on the bench in my garage, AND after I bolted the head on the engine. Everything was torqued carefully in 4 steps.

I have +1 mm nitrided Supertech valves on the intake side, and exhaust valves are +1 mm inconel Supertechs.
Supertech light double springs, titanium hats, Bill Wilner's Manganese-Bronze guides, serious porting and polishing, Japanese spec cams, new timing belt, pulley and tensioner, new seals on the head.

It took a while to assemble everything in the car, and I started it up for the first time last night.
Started great, ran pretty good (no adjustments at all, just wanted to start and do leak checks and stuff) till it started warming up.
A pretty loud ticking reared its head as the engine warmed up. Pretty much the same noise as before all this work, but a little louder.

I have a couple videos of the said noise, and it comes on pretty strong as I gently rev the engine and let it return to idle.
Once it is properly warm, it persists.

As I was watching the videos at home, I believe started hearing a bottom end noise, too. Or, I am getting really paranoid, I don't know.

I measured valve lash while the engine was good and hot, and got the following numbers (in mm):

Intake:
.23
.22
.25
.27
.26
.25
.26
.26

Exhaust:
:33
.38
.35
.35
.35-.36 (between those two, I do not have incremental feeler gauges)
.38
.36
.38

(I will also measure them cold tomorrow, once it cools overnight.)

I could be wrong, but these numbers do not look like they would cause such a ruckus to me. Moreover, the noise I'm hearing sounds like it is coming from ONE valve. A single tick.
None of the numbers above is dramatically larger than the rest to make the noise I am describing.

What do you think is happening here?

Here is the cold start with no apparent ticking.





Here it is, all warmed up and ticking:





And, here is another version, shot with a different camera with an external mono mic, to better capture the said noise.
Ticking is pretty apparent




I spoke to an experienced Mazda mechanic today. He told me he has seen two cases that are similar to mine.
One ticking case was solved once they found out one of the shims was just a tiny amount smaller in diameter than the rest, and it was moving side to side, crashing into the sides of the shim holder.
And, valve stems were shaved/cut too much in the other case, and valve keepers were standing slightly proud above the height of the stem, and were moving up and down as the cam pushed it down, causing a strange behavior and loud ticking noises.

I will know more once I disassemble the head. Machine shop owner told me to hold off till we inspect it in situ.

Please let me know what you think. Any input is greatly appreciated.

I once had a friends Tercel I swapped a junkyard engine into, ticked. I was sure it was valvetrain - turned out to be water pump (that I had replaced before putting everything in the car). Yank the belt and run it briefly?

I don't think the water pump would wait for the engine to warm up, it would just tick away as soon as the engine started.

Well, it definitely sounds like its coming from the head. I dont hear any bottom end noise there so that is one positive. It does seem to be a lot louder on decel than when the engine is revved a bit. Im sure someone like Andrew could tell you likely what the sound is since he has built a ton of engines.

Use a mechanic's stethoscope to isolate the origin of the noise. That will help narrow it down a bit.

The more I think about it, the more it sounds like a wrist pin to me.
I listened very carefully, and the noise definitely has "duller" harmonics underneath the sharp metallic tone.

On the other hand, I pulled the plug coils one by one (cops) and the noise did not go away.
My understanding is, a wrist pin knock is supposed to go away when the offending cylinder's ignition is disabled.

I also removed the water pump pulley and the belt to remove the pump and the alternator from the equation, and there's no change in the noise.
I have no other belt driven ancillaries attached to the engine.

Next step is removing the plugs and feeling the tops of the pistons with a wooden dowel while I rock the crank back and forth.
Will report back soon.

Like are you thinking one of the wrist pin retainer clips are not installed correctly?

Or, the wrist pin and/or the rod is worn, creating a clearance between the rod and the pin.
Just a theory at this point.

This motor was just built though correct? Wouldnt it be odd for it to wear so quickly? I wish you luck though sounds like youve got some money wrapped up into the engine I hope its something easily fixable.

Just had an idea..
I'll hook up the timing light to the engine to "see" the frequency of the noise.
Timing light flashes at rpm speed, because wasted spark..
If the noise is half the speed of the timing light, I could conceivably determine it is indeed from the valvetrain.
Synchronized speed of the noise and flashing would more than likely mean it is coming from downstairs.

The noise definitely matches the timing light, meaning it is NOT half speed, meaning it is NOT coming from the valvetrain, meaning I am pulling the engine right now.
Damn.

boooo that sucks man.

I got the engine really hot this time and revved it to 3500 or so...
Aaaand, #4 knocks double time when I pull the plug wire.
That pretty much confirms a sloppy wrist pin on #4.

I might just wrap some electrician's tape on that wrist pin.



I am kidding.
I shall of course repair it properly and use duct tape instead.

If you cant Duct it **** it.

What pistons and rods are you using?

I have 84 mm 9:1 JE pistons and M-Tuned rods.

Sourcing a single piston is not difficult.
I'll need a set of bearings, as well.

Aaand, I guess I found the source of the annoyance...

Presenting the culprit, in broad daylight, red handed and all.
Notice how the bushing is protruding from one side, too.



Good news is, looks like I will not have to buy a piston.
And I contacted a machine shop, where they told me the bronze bushing on the con rod is perfectly replaceable.

This is all pending a thorough measurement of engine internals with precision equipment, of course.
Or, I'll just wrap some duct tape on the wrist pin.

I remember reading a post by Savington where he said such damage is more than likely the result of foreign material(s) in the engine, which is pretty self evident by the looks of the bearings I pulled so far.
So, a maniacal cleaning of everything everywhere all over the place will ensue.

Did the machine shop you used clean all oil passages thoroughly?

I did all that.
I removed the factory installed oil gallery plugs and installed removable, threaded plugs instead.
That way, I am able to clean everything inside and out.

Hmmm, so I wonder what caused the bearing wear then? Sounds like you were pretty careful to clean out everything internally when the engine was put together.

So I dropped everything at the machine shop today. And by everything, I mean the block, crank, pistons, rods and existing bearings. Short block.

https://cimg1.ibsrv.net/gimg/www.mia...2ffa7afc92.jpg


https://cimg8.ibsrv.net/gimg/www.mia...b312141484.jpg


They gave me the good news, rod bushings are available, they had them in stock.
But, piston skirts are scuffed, so are the cylinder walls, and a hone is in order.
The machinist refuses to use existing rings in newly honed cylinders, so he will try to source a new set. Apparently, they are made to order around here.
They are practically new, but I will leave that decision to him.

I learned an interesting tidbit about bearings..
Apparently, "Taiho" is the bearing manufacturer for almost all Japanese automakers, and they have a distributor over here...
I have a friend who owns a parts business, and he sourced a set of "Made in Japan" + 0.25 mm main and rod bearings for a killer price ($30)
He gives me parts at cost, or with very minimal markup, he's pretty cool that way.
So, I will essentially be going with OEM bearings this time around.

All the machine work, including line-bore checking will take about a week, which will give me time to do some cleaning and also focus on the active hood vent project I had suspended since this noise issue started.

Just a thought:

Could this have anything to do with the deleted oil jets?
I had to delete them after a long discussion here on this forum after the engine started consuming excessive oil - roughly 1 liter every 120 miles or so.
Deleting the jets cured the oil consumption problem.

Please show pics of the bushing, that can help us here. I would think if it is a lack of oil (due to no oil jet), there would be a visible amount of damage to the bushing.

I'm sorry I did not take any close up pics of the bushing, but it really did not have any signs of oil starvation, just excessive play.

I must be the first one ever to have such a problem with M-Tuned rods...

Could this possibly be a consequence of the belt driven supercharger with added stress and harmonics on the engine internals?

I am a devout atheist.
I was called a Godless Commie as an insult once, and I really liked it, and adopted it as my username in all the internets.

IIRC Pat had oil burning issues with lightly used rings and a fresh hone on one of his engines. I'd side with your machinist as well.

Rings only break-in once. He's right to exchange for new. Especially on a forced induction build. Even if reusing pistons you replace the rings when the pistons are removed. They wear into specific patterns of micro-grooves. It's almost like fingerprints in that every one is unique.

This isn't to say that the engine won't run on used rings because it will, but they don't ever work like new again. You don't want the extra blow-by on a freshly rebuilt engine for a few dollars difference.

I dont think deleting the oil squirters would have anything to do with bushing play. There are a lot of engines that dont have oil jets and its just primarily for cooling down cast pistons so they dont assplode.

I need your input in an important matter...

We can not get exact size rings for these pistons locally.
The problem is the top ring; it's supposed to be 1 mm thick, and we can only source 1.2 mm rings.
The machinist tells me they can machine the top ring grooves to accept the 1.2 mm rings.
I am kinda hesitant, but I will give him the OK if you guys do not see a problem with this.
The rest of the rings are fine, meaning, they will be exact fit.
They will be made to order, and they have a warranty.
What do you think?

@Savington, what do you think?

Hard pass

Does that mean no?

Incidentally, I just got off the phone with JE tech support, and they told me to go for it by all means..

Sigh.

My guess was wrist pin as well after watching the video. The telltale is that the ticking goes away completely on decel.

If your piston MFG told you it's OK, then go with that. Make sure you ask them which side should have material removed (top or bottom). Ringland thickness is one of the more important aspects of piston design, so mucking with it without express approval from the piston MFG is a dangerous game.

I'd be really nervous because this is something that I've never even heard of prior to this thread, and if it goes wrong you're totally screwed and have to re-do everything

I asked about that.
They will remove equal amounts from both sides.
I was told 0.1 mm from either side will not compromise the structural integrity of the pistons.

Apparently, this is more common practice than I would have guessed around here.
They do it on all sorts of pistons, forged or not, to install custom rings.

There are some specialist shops making all sorts of custom parts for race engines.

One more question:
Crankshaft is being ground 0.25 mm. I know 0.25 mm does not go deep enough to remove the surface hardening on the crank.
Do you guys think I need to take it in to get it surface hardened anyway, or will I be opening a can of worms with such a move?

Oh, I AM really nervous.

Machining the piston for a larger ring is done in the automotive industry, although typically on large pistons that are not cheap to replace. It's possible it is done in areas where parts aren't available, but you can't put material back if it goes wrong. Sav hit one of the key aspects, in that it could possibly weaken the piston, I'm not sure how sensitive the piston is though. The second thing, is that the tolerances in the ring grooves are very important to performance. For instance, if the clearances are too tight, the piston could pinch the ring and cause a scuff. Too loose has been linked to ring breakage in the long term. I'm not saying they can't do it, but it makes me a little nervous. FYI, I design pistons and rings for a living.

If you are on a budget, lots of things can be reused in good shape. Pistons and rings, certainly. Even bearings if they are in good shape. Only stupid men reuse rings, though. Your machinist is not a stupid man.

My initial argument was simple, and not really well thought out:
I removed the pistons from a perfectly good working engine so the block could be properly cleaned, its line bore checked, etc.
The rings would be properly clocked and pistons would then be installed back in place with a ring compressor.
It was not a move borne out of cheapness, but simply a "let sleeping dogs lie" sort of an approach.
I now know better.

I am good at some things at life, but behavior of metal under stress and the intricacies involved in machining that metal to serve my needs is an area I need to gain experience in.

And, I really am thankful to this forum for everything I am learning in this respect, as well as the support this interesting bunch of crazy intelligent, cat loving boostaholics generously provide.

If you were putting the same rings in the same bores without a hone, then maybe. It still makes me nervous. The moment you re-hone the cylinders, you have fresh peaks that need to be worn down, and that means fresh rings to wear them down with. No exceptions.

Piston rings and pistons are the single most labor-intensive part of a car to replace. "While you're in there" applies in spades. There is no backup plan if you cheap out on rings and have a problem - you get to do the entire job over again from the beginning.

That's the key.
This happens to be the THIRD time I am tearing this engine apart for one reason or another since July 2012.
First time was for forged internals, and a parking attendant managed to do massive damage a couple years back, and now this wrist pin malady...

I really want to just drive and maintain this car.

Also, this turbo project turned into a monster of a job, and has been going on for almost 9 months now - doing research, sourcing parts and know how, configuring and re-configuring stuff to fit the huge turbo assembly in (had to get a new core for the radiator to chop it down by 2 Cm, I used a 30 Cm core instead of the standard 32, for example), all the air ducting, heat management, shielding, the active hood vent, electrical and vacuum circuits, new gauge setup, etc - means spending countless hours and pulling all-nighters in the garage.

I lost about 12 lbs in the past month.
So, yes. This car needs to run well for a lot of reasons.

RE: cutting the ring grooves. That's a common thing. Take your .004" off each side.