Corolla timing chain alignment
 

I need some smarter brains to look at this alignment setup. Car is making top end noise - especially under any load. No OBDII codes.

#1 Piston at correct TDC (not overlap TDC). Crankshaft mark on Zero

TDC timing marks (dots) on cam sprockets have perfect face to face alignment flush with top of chain cover (drawn circle in center)

Yellow links on chain are supposed to line up with upper left drawn circle on exhaust cam sprocket (left) and fat line on intake sprocket.

The chain is exactly three links past where it should be, based on install instructions but everything else lines up.

Is this "ok" or has the chain slipped? The colored links are to assist install but if it is also three links off on the crankshaft sprocket, would it matter?

Did not buy car new. Bought at 90k and there is no service life limit on the chain. 125k now. If original the factory would have put the chain on right.

http://forums.pelicanparts.com/uploa...1322688084.jpg

It doesn't matter where the links on the chain sit, the fact that they were even marked is kind of interesting. It only matters that the lower sprocket is at TDC and the marks on the CAM gears are flush with marks on the case.

If that chain has/had "slipped" you would see broken teeth and metal everywhere in most cases.

It appears to be exactly where it's supposed to be. No timing issue. If it had slipped 3 links, it likely would not run.

If I had to guess, your issue is valve adjustment. Most Corollas of that vintage (guessing 1998-2002 there) had fixed (non-adjustable, non-hydraulic) bucket shims. They were set perfectly at the factory. Over time, with heat cycle, wear, and abuse, the clearances can be too tight or too loose.

Too tight and the valves won't seat completely, causing poor idle at best or melted/burnt valves at worst. I've rebuilt or replaced several of these motors for that exact reason. You might be "catching" the symptoms before real damage is done. It's common in all Toyotas that use this family of motors (but Toyota is perfect, right?)

Too loose and they rattle with the slack. Probably not "hurting" much in the short term, but causing some accelerated wear and inefficiency.

If you check them all with a feeler, you'll find that you have some that are tight, loose, and in-spec. Measure how far out of spec they are an order the correct spec from your Toyota dealer (although they are usually cheaper at your Chevy dealer, as it's the exact same motor as the Chevy Prism).

Sound about right?

It also looks like you have lots of sludge/heat/bad oil.....

Thanks guys. Yes 2000 (forgot to post year)

Yes - actually sounds fantastic. I have the Haynes manual which is not too bad for getting me into it - it should have the valve specs.

Car is an oil sow but does not leak. Ash on plugs pretty heavy after replacing with Denso Iridium plugs maybe 10k ago. No smoke just eats it.

However, the MAIN issue is that the car is my son-at-college's car. As he gets near graduation he is home infrequently and I can't check it out. It has eaten oil pretty fast over the 30k miles and he does not stay on top of it. I have added two quarts (holds maybe 4 1/2) a couple of times which results in the heat and crap.

http://forums.pelicanparts.com/uploa...1322690549.jpg

Common problem on these starting in 98 was cracked rings, many, many engine replacement stories out there. Poor running, excessive oil consumption, all common on these sadly. One day they just die in a cloud of blue smoke.

Those motors are KNOWN for oil consumption. Toyota says 1 quart per 1000 miles is "within spec". There is an updated ring pack set available (Toyota or Hastings) that will reduce consumption. Unless you're rebuilding the motor (you might want to consider it) then you're going to have to live with it. It is quite possible from the looks of the head/cams there that you may have a secondary issue of sticking/gummed-up ring lands..... once you get it running right, try using some upper-cylinder additives, even Seafoam, to get them unstuck.

Here is Toyota's shop manual on the whole process on the 1ZZ-FE (2003 Matrix, but yours is very similar): http://madstyle1972.com/Repair/14/201lbc04/a040001.pdf

As I think of it, if it were MY car I would just rebuild the motor with the new-style (2005-up) pistons, or drill more oil return holes in the original (or o.e. style) pistons and go to the new ring packs. It really isn't that expensive, and if you have a good machine shop that you trust you don't need all new parts (it's not a race or aircraft motor).

If you don't, you'll end up buying a new catalytic converter and spending a lot of money on oil. That's if the motor doesn't blow up.

OOOO, this is cool, know anyone that's done this? How was the motor after the ring replacement, did it last? (I happen to have one of these that needs rings or a motor currently)

It would be strange - and poor design - if the cam gears rotated exactly once twice, or three times etc. for every revolution of the chain so that every time the colored links came up they were on the same gear teeth. They may line up as you described once every 10 or 15 or more rotations of the engine.

Many, many thanks. Checking valve adjustment now. Cripes, more valves than my 911.

Compression is 150 to 160 with my old as can be tester. Three are on 160 and #4 is 150.

Will report back with findings.

That's the issue. I talked to my son sort of casually about that but we only spun it three or four times. I assumed every other rotation. Given my life total of two belt replacements - in the 1980's - I never did a deep think. Thank you.

That's pretty good! You probably don't have a "broken" ring. Do you have the ability to do a leak-down test? That would really show if you have issues. Regular compression tests don't always tell the whole story.

I've had it done to a half dozen motors. It turns out great.

As long as the pistons and bores are within spec (roundness, taper, wear) then fitting the new rings really helps. Drilling additional oil "drain back" holes helps too. And cleaning the pistons (ring-lands and oil-holes) helps all on it's own.

I've also replaced pistons with stock size on good bores when the piston skirt coatings were bad.

And I've bored the block first oversize and fitted new pistons.

All have given great results. One has almost 80K miles since a ring-only job (w/ oil hole mod) and is in the normal quart-or-so between oil changes range.

Not right now - but I think I am going to gear up for it.

Here are the valve lash results

Exhaust - tolerance 10-14 thousandths. From 1 1 through 4 4

11 11 11 11 09 12 11 12

Intake- tolerance 06-10 thousandths. From 1 1 through 4 4
08 08 08 08 08 08 06 08

One lifter out of tolerance. Should not be causing the jumbled clatter under load I am hearing. A little noise at idle but under load it gets moderately scary. The idle noise quieted down after I added 2 qts this morning.

I am liking the sticking parts theory. I am off to the car parts store in a few to get a leak down tester and a valve cover set. The center rib of the gasket was like plastic it was so hard.

Agreed, you shouldn't be getting noise from those tolerances..........

Thanks again. Back in a while.

The only thing I have to add to this thread, is Damn, Eric , you are truly a walking automotive encyclopedia! How do you store all this info in your head?

He sure has put me onto a game plan.

I have the leak down tester, a couple cans of Seafoam and a new valve cover gasket.

I have a detonation theory based on crud and ash buildup. Probably should have seen a code if that happened.

First the leak down test.

Leak down test shows "low" as well as consistent across the board. Seafoam treatment in the morning.

Eric - I have two of the 3.0 Toyota's; A '92 (replaced on warranty at 75,000 miles, now weak compression on 2 cylinders) and a '99 Camry with 176,000 running perfectly. Can I PM you a question or 2? Thax