Frustrated

[SHOYAY]

That totally sounds like a bottom end bearing, heard from inside the passenger compartment. You first video shows the sound lessening when the engine is unloaded between shifts. Sorry.

It can sound like it is coming from elsewhere, a recent thread saw the owner opening the top and front, only to finally find the spun rod bearing. The tick of a rod bearing is transmitted into the rod and piston, and into the crank. You need to roll it up on ramps and get near the oil pan to not be deceived.

Cam chain tensioner sounds like you'd expect a belt slapping around to sound. A valve that shot out a shim, making a cam tap, or is wedged, hitting on the piston carbon that could also sound like that are long shots. These wouldn't care how much gas you gave the engine.

(The flappy slappy of an ATX timing tensioner is a sound I also hope not to hear again...)

A wishful far in left field is you got terrible octane gas or mixed with diesel, and a high compression cylinder from carbon etc, along with a bad knock sensor...and maybe slipped a timing belt tooth or poor injector.

I'd be surprised and bummed if it was rod bearings especially with only 10k on rebuild.
I used a stethoscope on it tonight and oil pan and bottom of motor sounded quiet for any of that noise, mostly heard it at top towards the front of the rear valve cover and block.
I've had a couple people mentioned TOB.
Bad injector?! Hmmm ... I am having severe running and idling problems with it, hence what this original post started out for... Could injector make that noise and also cause my idling and running problem at the same time?!

 

[SHOYAY]

Also, maybe a stupid question, but if I wanted to just check valve lash without pulling shims (don't have the tools currently) I can do that, just check the clearance? I thought I read that you have to pull the shims after checking clearance, which makes no sense to me when just checking, especially cause it's only has 10k on it

 

[NoSlo]

Also, maybe a stupid question, but if I wanted to just check valve lash without pulling shims (don't have the tools currently) I can do that, just check the clearance? I thought I read that you have to pull the shims after checking clearance, which makes no sense to me when just checking, especially cause it's only has 10k on it

You don't have to pull a single shim to check. Last top 60K a month ago all my car got was valve cover gaskets, spark plugs and seals, and a new clean intake, because all the valves were good, the wires tested good, and the car is not being put back the hands of someone incapable.

You can just take off the intake and valve covers (and the regulators and fuel lines from the rail if you want to be practical, don't lose copper gaskets), and use a fine, wide, and long feeler set to inspect gaps are in the specified range when the cam lobe is opposite the valve. Make sure the feeler set has these ranges, either with USA or metric.



It would take a huge problem, like a missing shim, to make that much tick. I would open the bottom before the top after you've ordered a plastigauge kit and another rod bearing. Torque caps to 26, then 36ft-lb. If you didn't use a torque wrench before, then all new bolts to replace the loose or stretched ones...

The last paragraph I wrote was imagining causes of octane knock, it would take impossible circumstances for pre-ignition to sound like that, especially on a cold engine, but a lean cylinder would be a contributing factor. The KOER cylinder balance test would reveal an underperforming cylinder.

 

[blk\blk90]

The TOB going bad will rattle in neutral, foot off the clutch. Then when you're slipping the clutch it rattles with engine speed and disappears as it engages until it's gone at 100% engagement. Then it decides to destroy itself at 7000 rpm in second on they way to visit your mom.

 

[SHOYAY]

I already have the the intake off and I'm gonna pull the valve covers tonight and check valve clearances and check the cam tensioners. If all looks good I'll put back together.
It'll surprise me if I have to go after rod bearings when they only have 10k on them and no noise heard from them bottom end when using a stethoscope while running.

 

[SHOYAY]

Here's a vid and any noise it makes while idling and revving.

 

[sperold]

It does sound like a rod bearing. However, you don't usually have high oil pressure if it is. The oil light is usually on at an idle when the bearing or bearings get loose. And it is set at something like 3 pounds pressure.

You do have an oil pressure light and an added gauge?

These engines are low pressure, high volume oil systems.

The rod bearings can be checked with the engine in the car, and it will not take an experienced eye to find the rod causing that much noise. If it is a rod bearing at all.

If you have time, you could send a sample to Blackburn labs and see if there is a lot of copper in the analysis.

You could also swap the oil out for one that is quite a bit more viscose (like 20 W 40) to see if the noise stops at least on start up and cold idle. Might not be a great idea to leave it in though if your oil pressure is high.

The engines are not really know for wrist pin noise, or cracked piston noise or missing side skirt noise, but your high oil pressure means you have to look at all possibilities.

I hope there is more simple explanation for the noise. Good luck on this issue.

And with the intake off, it would be a good time to look at your PCM to see the condition of the connector.

 

[SHOYAY]

There really is no noise on start up at all....blows me away that it could be a rod bearing with only 10k on it. Oil pressure is @60 start up idle and 20-25 hot idle. Yes I have both mechanical and idiot oil pressure gauges.
If is rod bearings, how come I can't hear anything on bottom end with a stethoscope?

 

[NoSlo]

Here's a vid and any noise it makes while idling and revving.

That gives a bit more of a chain tensioner sound at least, it has a bit of that hollow valve cover sound. If it were one, you'll wish it was a bearing when you try to find one.

 

[SHOYAY]

That gives a bit more of a chain tensioner sound at least, it has a bit of that hollow valve cover sound. If it were one, you'll wish it was a bearing when you try to find one.

I have a 94mtx parts car with a good running 3.0
What's best way to tell if they're worn past good use?

 

[NoSlo]

I have a 94mtx parts car with a good running 3.0
What's best way to tell if they're worn past good use?

There's no documented procedure or specification about chain tensioners, so you can just tell by how deep the groove from the chain is worn in the plastic. Somewhere close to plastic being worn to metal they will run out of travel. They wear much less than you'd expect.

They also might not tension well or become stuck, the more likely culprit. If I recall, some of the action is from oil pressure inside, like an ATX timing tensioner, not because they have their own oil passages. Without tension, the opposite side of the chain may get slack between lobe pulses and be able to hit the tensioner chain cover. You can examine the outside of the chain for any sign of contact.

If the chain has stretched, then the loop of chain they tension may grow longer to where it can contact something inside. Any touching should be unlikely but evident. Again, no procedure, but one could attempt to measure that the timing marks on the sprockets are at exactly 180 degrees, or if instead the trailing sprocket is lagging behind in timing from chain stretch. You'd have to be careful to only turn the engine forward, and find a place where the cams tension the straight side of the chain.

 

[SHOYAY]

There's no documented procedure or specification about chain tensioners, so you can just tell by how deep the groove from the chain is worn in the plastic. Somewhere close to plastic being worn to metal they will run out of travel. They wear much less than you'd expect.

They also might not tension well or become stuck, the more likely culprit. If I recall, some of the action is from oil pressure inside, like an ATX timing tensioner, not because they have their own oil passages. Without tension, the opposite side of the chain may get slack between lobe pulses and be able to hit the tensioner chain cover. You can examine the outside of the chain for any sign of contact.

If the chain has stretched, then the loop of chain they tension may grow longer to where it can contact something inside. Any touching should be unlikely but evident. Again, no procedure, but one could attempt to measure that the timing marks on the sprockets are at exactly 180 degrees, or if instead the trailing sprocket is lagging behind in timing from chain stretch. You'd have to be careful to only turn the engine forward, and find a place where the cams tension the straight side of the chain.

Can tensioner be changed without major engine surgery?

 

[NoSlo]

Can tensioner be changed without major engine surgery?

Nope. You've got to take off the timing belt and cogs, then remove all the caps to lift the chain end. Then replace all the cam seals.



It is much better to diagnose and rectify the actual problem, rather than throwing parts at something (and charging customers for your ineptitude, like "professional" mechanics).

 

[SHOYAY]

Well I'm f'd for a while. It's the rear timing chain tensioner. The chain is hanging down in the housing as you can see in the picture. Looking down in at the cap doesn't look very grooved on the edges of the plastic, but noticed that the plunger part of the tensioner isn't extended downward much, and I can push it down with some pressure and tighten the chain. The chain makes the noise I've been hearing when I rattle it in the housing where it's hanging, metal against metal. Is there supposed to be anything within the housing, ie plastic or anything?

 

[NoSlo]

Well I'm f'd for a while. It's the rear timing chain tensioner. The chain is hanging down in the housing as you can see in the picture. Looking down in at the cap doesn't look very grooved on the edges of the plastic, but noticed that the plunger part of the tensioner isn't extended downward much, and I can push it down with some pressure and tighten the chain. The chain makes the noise I've been hearing when I rattle it in the housing where it's hanging, metal against metal. Is there supposed to be anything within the housing, ie plastic or anything?

I don't know why they have the chain cover guide boxes, except to make noise to alert you.

On the plus side, you've figured out the no-tool way to change out-of-adjustment valve shims, and will have uncovered the valves if you have another 12 hours to do valve stem seals.

 

[SHOYAY]

I don't know why they have the chain cover guide boxes, except to make noise to alert you.

On the plus side, you've figured out the no-tool way to change out-of-adjustment valve shims, and will have uncovered the valves if you have another 12 hours to do valve stem seals.

Is there a guide to help and with torque specs so I can just change out the tensioner?
Is there any way to get a tensioner un-sticky aside from replacement?
And someone told me that can just unbolt cam sprockets and tensioner bolts and change it over without removing the cam and/or timing belt.

 

[NoSlo]

Is there a guide to help and with torque specs so I can just change out the tensioner?
Is there any way to get a tensioner un-sticky aside from replacement?
And someone told me that can just unbolt cam sprockets and tensioner bolts and change it over without removing the cam and/or timing belt.

The challenge with unbolting the sprockets in the car:

- you have very little clearance inside the head to be able to move the sprockets off the cam; you'll have to rotate cams to expose the second bolt. If you do get a sprocket off the end, then it still will be kind of stuck in there. I don't know if you'll be able to manipulate them around enough to get the back tensioner out without having attempted it that way.
- once you have removed a sprocket, the camshafts will be free to spin whatever direction relieves the cam pressure, giving you a challenge to put them back on, especially with a new tensioner that is working on the chain.
- then oops, you lost a bolt down an oil passage...

There is a jig in the SHO Rotunda kit that locks the two camshafts in the correct position, which would make this easier to try. Otherwise to get a sprocket back on the dowel and centered to bolt it up is at least going to take a helper to work two wrenches on the cams (to keep one in position and turn the other), while you try not to skip a tooth (paint some non-permanent alignment marks to both the sprockets and chain for reassembly).

The back side tensioner is kind of stuck below and between the sprockets. Fortunately, you may just need to unbolt one cam, then rotate the other (so in effect you are "rotating" both) so you can lift the unbolted cam high enough to weasel the tensioner out from between the two. Still, the front timing belt cogs have to come off to remove the back of the timing cover to be able to lift a cam, you've done all the work at that point to do cam seals too, so it's barely more to uncap the second one.

Here's a thread where you can read one of the other dangers - don't torque oily cap bolts to full strength.

https://shoforum.com/index.php?threads/camshaft-bolts.134533/

The SHO engine book is also linked in a message there; you can see starting page 89 the procedure is: install sprockets to cams, align chain, put tensioner in between, put them all in the head. Torque specs at the end of the book.