scmedic

Hi Folks,

I'm looking for help diagnosing a noisy 22re. Here is the background info:

I have a pretty loud tapping / clicking noise that sounds like a very poorly adjusted valve or maybe a bad rod bearing.

The noise is worse when running cold but doesn't go away completely when warmed to operating temp.

I've adjusted the valves several times (0.008", 0.012" hot) and no significant change in the noise. I've done my own valves many times in the past with no problems so I'm pretty sure the adjustment is OK.

Cylinder compression is 172 160 171 170

Based on the compression numbers and the fact that there is no change with valve adjustment, I'm thinking it's a rod bearing in the #2 cylinder.

Any thoughts one way or the other?

BTW this is on an 85 4runner, 230K on the clock.

Thanks for any advice!

scmedic

Couple more pieces of information I just thought of:

1) Engine power seems to be fine...

2) It *sounds* like the tapping is coming from the top end of the engine.

3) Recently put new exhaust (everything from the manifold back), no obvious leaks.

rdharper

I'd be tempted to learn how to do a leakdown test, as I understand that you can quite easily tell the difference between valve, rings or HG. Given that you've got one low cyclinder, it would be useful to know which is the problem.

As to the noise, you've said it sounds like its from the topside... maybe a weak valve spring? Also causing lower compression? Had one break on me, it was on the #2 cylinder, exhaust valve. Replaced the spring, everything is quite again, mileage is back where it should be. Also, it made an ever louder ticking before it broke. Was about to reset the valves, when it broke. Did no other damage as far as I can tell. That was a year ago.

scmedic

Richard

Thanks for the inforamtion. The leakdown test is a good idea - I'll look into getting one done.

How did you find the broken valve spring? was it visible with with the valve covers off? I had a good look at the rocker arms, valve stems, etc yesterday and didn't notice a broken spring but then again I didn't think to look for a broken spring.

rdharper

It was just what you'd iimagine a broken spring would look like. And it was visible with the valve cover off.

Also, the cylinder was effectively not functioning, as the exhaust valve did not open enough to run properly.

I mentioned this case as the initial symptoms (before the break) sounded like your case. The ticking got louder over a few months. When it broke I figured it was a broken exhaust spring, as that is the one that gets hot. 200K+ miles at the time, so it is not unreasonable that the springs were "worked" by the heat and number of cycles on it.

Wish I'd done a leakdown test myself, as I'd be curious as to what it said prior to the broken spring. In any event, the good news was that when it did break, it was inexpensive to fix, and no other damage. I got some help from others here as to how to replace one spring without taking the rocker assebly off.

At the risk of bringing some scorn from some of the better mechanics and purists, I also drove it home (the wife was in town with it) after thinking hard about it. I thought about removing the #2 sparkplug, but ended up not doing it. The distance was 12 miles, with the last 1.5 miles first and second gear type running. So apparently I was lucky for, as I said, the truck purrs like a kitten. No coolant loss, no heating problems, and mpg as good as its ever been. Lucky I was.

One more thing. Not sure how a "weak" spring would explain a 10lb loss of compression in one cyclinder. But there must have been some slack somewhere, maybe dynamically, to cause the somewhat strong ticking sound.

surfersr5

I had the same problem but the mechanic I go to told me that its normal sound. Meaning, it's something to do with catalictic converter.

scmedic

Thanks for all the help. I took the 4runner by the local Toyota guru (Yarnell's) today for an opinion. After listening to it, they confirmed my worst fears and said they are sure it's a rod knock.

Now I've got to figure out if it's the wrist pin or the crankshaft bearing. If I'm lucky I'll be able to get away with just dropping the pan and swapping a crankshaft bearing....

If it's the wrist pin I'm asuming I'll have to at least pull the head to get the piston out - does anyone know of a way to get the wrist pin out from under the engine?