valve clatter

[Bev55]

My husband just replaced the timing belt in my automatic 4-cylinder '92 Camry. It runs great now, but a new problem has raised its ugly head, and we don't know if it has to do with him replacing the belt or not. There's a clatter which we think is coming from the valves or lifters, and it's louder when the engine is revved. We tried putting a pint of transmission fluid in the crankcase, to see if that would help, but it didn't. Someone recommended resetting the timing to what the manual recommends, so we set it to about 12. That still didn't help. He checked to see if anything fell into the crankcase when he had it open, but he didn't see anything, and he also changed the oil and filter. My husband's afraid that it's a thrown rod. Any suggestions?

Bev

[Brian R.]

Welcome to the AF!

Did he replace anything else while he had the cover off? Water pump? Cam seals? Accessory belts? Tensioner?

[jtoyotaman]

i would take the timing cover back off and check for anything suspicous, you could have gotten the belt off a notch?

Bev[/quote]

[Bev55]

Originally Posted by Brian R.

Welcome to the AF!

Did he replace anything else while he had the cover off? Water pump? Cam seals? Accessory belts? Tensioner?

Oops, my husband just corrected me in what I said--he says he didn't open the crankcase--he took the valve cover off and blew it out, then turned the crankshaft a little bit and blew it out again, just in case there was some foreign object that had fallen into the camshaft area. Also, you don't hear the noise until the car reaches about 2300 RPM, and that's when the clatter begins. If you drive slowly, you don't hear anything unusual. As of now, the compression numbers are 169, 167, 167, and 172, so, presumably, those numbers wouldn't be that high if there was a broken valve or cylinder out-of-round, or ring problems. Again, there was none of this sound before replacing the timing belt, and he just can't figure out what would cause the clattering from something as simple as changing the timing belt.

What caused him to replace the timing belt was that the car had been gradually running more and more sluggishly, so he figured it needed a new timing belt. When he took off the timing belt covers, he discovered a shredded timing belt, and upon closer inspection, found that one of the oil pump retaining bolts had come out and had fallen and wedged itself between the bottom of the lower timing cover and the path of the belt. It chewed through the inside edge of the belt, and then chewed up the steel sprocket.

The parts he replaced were the timing belt, the camshaft oil seal, the crankshaft oil seal, the oil pump "O" ring, the crankshaft sprocket, and the belt guide. (We were planning on selling the car soon, so he didn't want to replace the water pump or oil pump at this point.)

He had taken the spark plugs out, and they were out during this whole process, so it's possible that something fell into one of the chambers. He's going to hook a rubber hose up to a vacuum cleaner and vacuum out each cylinder, just in case (hoping for an easy solution to this possible disaster), hoping for a nut, bolt, or bird dropping. :-)

If nothing else, this is going to be a great opportunity to clean out the garage, before dismantling the engine...

[Bev55]

Originally Posted by jtoyotaman

i would take the timing cover back off and check for anything suspicous, you could have gotten the belt off a notch?

Bev

[/quote]

He did take the timing cover off after the noise began, but nothing suspicious could be found, unfortunately...

[Brian R.]

Does it have to be under load to make the noise? or is it only rpm-dependent?

Have you listened to the noise with the hood open and the car stationary? Pinpointing the source of the noise would be a big step forward. I was thinking it might be an accessory - PS pump or alternator. Check the PS pump fluid level. If the noise is in the head, forget what I just said.

Have you checked the oil pressure since the belt install?

Did he check the cams and oil pump shaft for thrust clearance?

Did he test the tensioner for correct tension before he reused it? Test the idler pulley for smooth turning? Might be the timing belt making the noise because of inadequate tension or nasty idler pulley bearings.

[Bev55]

Originally Posted by Brian R.

Have you listened to the noise with the hood open and the car stationary? Pinpointing the source of the noise would be a big step forward. I was thinking it might be an accessory - PS pump or alternator. Check the PS pump fluid level. If the noise is in the head, forget what I just said.

Have you checked the oil pressure since the belt install?

Did he test the tensioner for correct tension before he reused it? Might be the timing belt making the noise because of inadequate tension.

Yes, we've listened to the noise with the hood open and the car stationary. The noise is coming from either the head or even deeper. It's a solid knock, not a tapping sound.

How do you check the oil pressure? The oil pressure warning light on the dash goes out as soon as the engine is started, so that would indicate there's no problem with that.

According to the book, if you have a silver tensioner spring, which I have, you're supposed to turn the crankshaft two full revolutions, and then tighten the tensioner bolt, which is what he did. He went back in and checked the timing marks with the crankshaft timing mark at TDC. The camshaft hole is lined up with the mark, as it should be. He checked it three times.

[Brian R.]

Something I added:
Did he check the cams and oil pump shaft for thrust clearance?

[Brian R.]

Something I added:
Did he check the cams and oil pump shaft for thrust clearance? Is is possible the noise was there to some extent before you replaced the belt?

[Bev55]

He didn't hear any noise before he changed the belt. When you say the oil pump clearance, is that the end-play?

He hasn't checked the valve clearance between the camshaft lobes and the valve lifters.

[Brian R.]

Yes

[Bev55]

Originally Posted by Brian R.

Yes

No, he didn't check that, and he doesn't have a dial gauge, so he's not sure how to do that...

[Brian R.]

I meant the thrust clearance of the cams - side-to-side movement of the cams. I guess since it is a knocking noise, it is not likely to be cam thrust clearance.

By checking the tensioner, I meant the dimensional measurement on the spring in drawing #1 below.

http://i16.photobucket.com/albums/b8...lt/Timing1.jpg
http://i16.photobucket.com/albums/b8...lt/Timing2.jpg
http://i16.photobucket.com/albums/b8...lt/Timing3.jpg
http://i16.photobucket.com/albums/b8...lt/Timing4.jpg
http://i16.photobucket.com/albums/b8...lt/Timing5.jpg

[Brian R.]

For oil pressure:

[Bev55]

Originally Posted by Brian R.

I meant the thrust clearance of the cams - side-to-side movement of the cams. I guess since it is a knocking noise, it is not likely to be cam thrust clearance.

By checking the tensioner, I meant the dimensional measurement on the spring in drawing #1 below.

http://i16.photobucket.com/albums/b8...lt/Timing1.jpg
http://i16.photobucket.com/albums/b8...lt/Timing2.jpg
http://i16.photobucket.com/albums/b8...lt/Timing3.jpg
http://i16.photobucket.com/albums/b8...lt/Timing4.jpg
http://i16.photobucket.com/albums/b8...lt/Timing5.jpg

He forgot--he also replaced the spring that he had with one from Toyota, so he didn't measure it. The old spring was green, however, none of the Toyota dealers in Denver carried the green spring--they only had silver, but they said either one works.