Topic: timing chain noise......maybe

[jmac]

So after beating he hell out truck on a rough road I noticed a strange noise at low rpm during acceleration that fades at higher rpms and is intensified with strain (uphill versus flat take off).  No noise is noticed at idle or during increased rpms while in neutral....even with a stethoscope on various parts of the head.  It sounds very similar to chain going over a gear.  I was gonna pull the valve cover off this afternoon and check the gaps and and look at the timing chain.  So here are my questions:

1) Should I be able to see both guides and the tensioner from the top?
2) Should either side of the chain have slack in it?
3) If I'm looking at the front of the truck does the engine turn clockwise or counterclockwise?......this is probably obvious based on the fan blades but I haven't really looked at it yet.
4) Probably the most important question.......anybody else familiar with this sound?

[yotaneck13]

1) no you will not be able to see the tensioner from the top  you can see a lil of the guides
2)the tensioner is oil fed so when the motor is not running it will have slack on both sides
3)clockwise
4) could be valve train noise which is common among most 22re and 22r motors worst case is you bering are starting to go but could just be aa chain guise broke causing the chain to contact the side of the timing case
hope this helps

[jmac [OP]]

I'm very familiar with the valve train noise....I've had a few of these trucks.  The weird thing is this noise came on suddenly after some abusive driving leading me to believe it's not bearings or valve train "toyota tick" as I call it.

[superyota]

being that is gets worse under strain, i would be leaning towards saying it might be a rod knock.  if you have a stethiscope, get under your truck and listen for it through the side of the block or maybe the oil pan.  it would be better to catch it soon.  you  don't want it shooting out the side of the block.

[jmac [OP]]

I considered the rods, but don't think that's it either.  I know what you mean about the strain thing, but the sound in very similar to a chain on a sprocket.  I listened for that with stethoscope also before and no signs. 

I've driven it probably like 1k miles since this started (terrible I know) and it hasn't gotten any worse also.

[superyota]

stick an oil pressure guage on it and see what its running at.  this might sound far out there, but have you checked the tranny to make sure everything is good?

[emsvitil]

Are you sure it's the engine........

I had a cat converter break up inside and the rattle took me awhile to isolate to the cat converter..........

[yotaneck13]

you coulda shattered a slide if there plastic and not metal then you might be hearing the chain hitting on the bolt... drain your oil and see if plastic chunks come out or silver color which would be berings

[jmac [OP]]

Looked at the valves and chain...everything looked cool.  The tops of both guides looked okay.  Both the top gear and lower one that you can barely see looked okay.  I turned it and had my buddy watch the lower one with a light.  Valve clearance was all good....number four was a little tight on the intake but i didn't move it as it hasn't had a problem yet.

I have considered the tranny as I've heard a cranking sound come from a Nissan I trashed.......crappy Nissans.  This goes along with not hearing it when in neutral.  I rebuilt the tranny about 40k or so back....replaced 5th gear, all bearing and seals but I reused my old synchros. I got a w56 in an '81.

What about the rear end....I've never really been around a bad differential.  My rear end has popped a few times when taking off, but not very often and happened before I heard this new noise.  Also I wouldn't expect a differential to make rpm depended noises.

I will change oil over weekend and see if anything is in it.  It needs to be changed anyway.  I need to get a decent filter so I don't get that dry sound initially after cranking.

Thanks for all the suggestions.  Maybe we'll get this figured out......or I'll drive it till it breaks one.....I guess we would figure it out then too....ha ha. 

[jmac [OP]]

As for oil pressue I've got the in cab gauge and all is good there according to that gauge.

[91 super yoda]

how many miles are on the engine? and timing chain if it has been changed? I have had the chain tensioners get stuck and the chain will slap all over the place.
maybe the chain tensioner needs higher oil pressure to apply pressure to the chain, explaining why it only does it at low rpm and even more so under a load.

I have also seen broken guides that dont make noise all of the time, the chain will wear a groove in the cover and be pretty quiet sometimes. The top of the guide may be intack but the bottom gone. I personally think its in the chain.

[jmac [OP]]

I think I figured it out ........finally.  I think the tranny oil/grease was low.

I knew I had a leak that was either rear main or tranny input seal due to leaking at tranny/engine junction, but had thought it was rear main based on the oil from the drip.  Guess it was thicker than I thought.  My tranny plug was stuck in the housing pretty good and the head had been rolled pretty bad.  This is totally my fault, as I obviously overtightened during a rebuild 4+ years ago.  Had have been neglecting getting it loose as I'm a firm believer in never changing tranny grease, but last night I got it out and ran a hose in there and it's pretty low.

I need to get some more grease and a plug.  I'll confirm in a few days when I get around to filling it and putting a new plug in.

So based on this I got another question.  I rebuilt the tranny when it was in an 89, wrecked that bad boy, bought a 81, and swapped the w56 from the 89 into the 81.  I remember having a hell of a time getting the input shaft into the pilot bearing.  It was super tight and had to pull it up with the housing bolts even after getting it in the bearing.  Obviously, the input is under some stress due to alignment error.  Would this cause early failure in seal?  Does everyone have a bear of time getting the w56s into the older 22r?  Is there something that will help with this.....I can't think of anything?

Just curious that dudes gonna leak a bit longer I don't feel like pulling right now as I just did a bunch of work on some other issues I had been having with brakes, clutch, carb, and wiring.