aerocorey

Posted this recently, but I've played with it some since my first post and have a better lead on where the trouble is. My '86 22R has been making a knock/rattle/tick for a second at a time when I start the truck and on the road at high RPM when I get the throttle in just the right spot, usually about when it's time to shift. Sometimes I can get it to knock/rattle/tick steadly by finding the exact right throttle setting, but it's hard to find the sweet spot where it doesn't go away. Since I got the truck I've done the HG, the timing set (with guides and tensioner), valve clearances, plugs, wires, cap, rotor, set ignition timing...you get the idea. That sound has been a constant. I figured it could be exhaust, so I replaced the manifold. No good. Today I changed the oil to a heavier weight and added a bottle of that GUNK high mileage engine stuff. No good. I loosened the valve cover. No good. I pulled the valve cover and looked the timing set and inside of the valve cover over, both look fine. I figured while I was at the valves I'd play with the clearances to see if I could produce a change in the noise. I let the screws out half a turn, and other than making for one chattery valvetrain there was no change. When I turned the screws back in half a turn, however, the noise changed. It now ticks all the time. It ticks louder at startup and at the times when it used to tick before I messed with the valves, but it's the same noise. With everything assembled and the truck idling I used a piece of hose as a scope to probe for the noise. It's loudest when I put the hose right on the aft driver's side valve cover nut. Engine temp doesn't change anything. If I've screwed up the valve clearances is it more likely that tight clearances or loose clearances could be causing this? Could it be a shroomed adjustment screw? I'll look at it more when the sun comes up tomorrow.

bipolarandproud

Yeah , I have the same prob. From talking to people on here , We came to the conclusion that the tapping noise on my truck has something to do with the rocker arms . (there worn out or something )

This is how your supposed to check it .


http://www.autozone.com/az/cds/en_us...rInfoPages.htm

just a 22re

if you have the 22re then get used to it buddy it never goes away toyota made the 22re on a deisel style platform so when it idles its loud when you get right at the t right its loud oh and when you shift or cruse its loud to lol its just something that all 22res have no really good way around it though sorry man

just a 22re

i was joking about the desiel platform by the way just useing it for a sound check ya dig?

abecedarian

the lifting force placed on the rocker arm by the combination of camshaft and valve spring causes the arm and rocker shaft to both wear, the arm on the top and the shaft on the bottom. when you adjust the valves you compensate for this wear as well, so technically the valves aren't adjusted too loose, but when the cam releases the rocker arm, you can get the rocker shaft rattling due to the larger clearance between the rocker arm and rocker shaft. the noise can be more pronounced when the engine is cold because heat will cause things to expand and cause the clearance to shrink.
make sense?

aerocorey

Makes perfect sense. I'm used to engines with loud valvetrains, but this is a pronounced, undesireable noise which most definately needed to be isolated. Now that it's isolated, I'm confident that it's not a sign of impending component failure. I'll adjust the valves the best I can so it quiets down a little, then I'll get used to it. Thanks for the feedback fellas.

abecedarian

some people have reported good results with the noise by adjusting down to .007" intake and .010" exhaust, engine cold.

anotherjeff

Are you SURE it's not the timing chain/guides/tensioner?

abecedarian

good point!

bipolarandproud

Quote**

"Since I got the truck I've done the HG, the timing set (with guides and tensioner), valve clearances, plugs, wires, cap, rotor, set ignition timing."

Unquote**

I guess he already replaced the timing set , but I guess it's still possible .

abecedarian

/me should read more, eh?
... or maybe I read and didn't remember?

I already said what it could be- rocker shaft wear.

bipolarandproud

haha yeah , from what I've read your usually right about that kind of stuff.

abecedarian

don't ever assume I'm right. I may be informed... but like everyone else around here giving advice, I'm pulling stuff out my arse trying to answer the question with the hope it's the right thing.

bipolarandproud

lol ..I'll keep that in mind .

aerocorey

I replaced them 2 months ago and inspected them yesterday. I did buy plastic guides, but everything looked fine when i inspected it yesterday. When I scoped the engine for noise all is quiet at the timing cover. I can put the scope on the front driver side valve cover nut, it's quiet. Front passenger side nut, quiet. Rear passenger side, just a hint of the noise. Rear driver side, sounds like someone driving a metal stake into my ear. If I move the scope down further onto the head I can still hear it a little. If I move it down to the block it all but disappears.

anotherjeff

abecedarian's worn rocker shaft theory has merit. Low oil level (low oil pressure) can result in rocker shaft wear.

On a 20R, I experienced a loose valve seat on #4. It caused a very distinctive rattling/ringing sound. Drove me nuts! Finally, I pulled the head and discovered the loose seat. Another head fixed it fine.

aerocorey

Well, this is a little embarssing, but facts are facts, and the info is good for others with the same knock I have. I reset the valve clearances this morning since I messed with them last night without a feeler gauge. Turns out the noise I was getting from the back of the valvetrain was because my dumb (and buzzed ) ass ran the #4 exhaust valve out a full turn too far. Now that the valves are adjusted my original noise is once again apparent. When I did the HG I cleaned the carbon out of the cylinders and off of the head, and the ignition timing is dead on, so I hadn't considered that this could be a detonation. Just for s and giggles I pulled and plugged the vacuum advance lines and ran the engine up, no knock. Hooked vacuum back up and ran it up, knock is back. So I threw on a timing light, and it turns out that I'm detonating when the advance hits 7*. I'm also getting somewhat poor gas mileage, so it's a seafoam party and 93 octane for me from now on.

So, the moral is if you've got a mystery knock that sounds absolutely nothing like detonation it could be detonation anyhow so check it out.