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Valve Timing

by eyevahn, May 6, 2015

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When I disassembled each valve I placed them in an organizer and labeled them, so I know they are correct. The only thing I can think is that I completely forgot about the washers that sit under the springs when I took the head to the machine shop. When I got it back he had placed the washers in a zip lock for me. So they were not placed back into the same spots as they were taken from. But again, the intakes were not thrown off so I don't know...

As far as the clearance measurement goes, I guess I'm still a little confused. I thought I could, with the head sitting on my work bench, torque the cams down to spec and then manually crank them with a wrench so that the lobes were pointed exactly away from the lifters to get the best measurement. So, is that not the case? How would having the head in the car with the chain attached change the clearance?

Nevermind, I reread your post and I see what you're saying. Leave them in there natural angled position. But the point of clearance is to measure at the point of closest contact outside of the lobed end which I would assume to be the opposite side...

I'll recheck them in both positions and report back. Thanks for the help.

Like I said, the lobes must point outward: \ --- / as they do in their normal position when all is assembled and properly timed.

Also, you absolutely need to have those washers installed on the springs, to protect the head and provide sufficient spring tension.

Check with him to see if he put new washers in to replace the ones in ziplock bag... The new exhaust valves may be slightly longer and/or less worn, which could easily account for the 0.010" difference. Which brand are they?

If you do need to readjust, give me your measurements to determine which thinner lifters you need. I have 2 of # 40, 3 of # 43, and 2 of # 46. They have 100,000 miles on synthetic oil, and are in excellent condition.

Thanks for the offer, dom, but I need sizes 16-30. I just ordered toyota oem valve lifters. Between the 8 new ones ordered, my clearance will ideally be 0.011-0.012 on all exhaust valves.

I've had to put my project on hold because my college schedule got really busy. Anyways, while I wait for my lifters to come in, how can I clean my exhaust manifold? The entire inside is caked with thick black carbon/burnt oil residue. I read somewhere that you can leave it submerged in water to break it up. I've also seen oven cleaner with a power washer. Any thoughts? Thanks.

If the deposits are really thick and hard - might have to sand-blast it to clean it up. Soaking in solvent or plain water + detergent, power washing generally only gets the soft surface deposits off. I've seen people use ultrasound cleaning units as well - though be tough to find one big enough to do the whole manifold. Some solvents can affect the metal itself, they work via ion exchange can actually weaken the metal. Though most of those types of solvents will also do a number of biologics - so the likelihood of getting your hands on something like that is pretty remote.

Soaking is going to be the simplest option - could try running wire brush over the tough spots first - help loosen it up and allow the liquid to penetrate it. See if that gets off enough of the deposits to look satisfactory. Could be an iterative process - scrub, soak, scrub some more, soak some more, etc. But can't argue the cost of it (almost zero - just your time).

Sandblasting - definitely the fastest way, most efficient way - depending on the media used in the blasting process. Most can be rented for fairly cheap - you just have to provide the blasting media. Stuff like bicarbonates, glass beads, plastic beads, and walnut shells will eat deposits and rust, but not really aggressive enough to eat into the metal. Something like aluminum oxide - have to be careful as it will eat a hole in the metal eventually, but will make short work of the deposits. Even a single pass is enough. I use this all the time with older machine equipment - run a degreaser first, scrape all the loose bits off first, get down to the hard deposits - then blast it. The deposits literally disappear under the media stream. Some media, like the bicarbonate ones, actually "coat" the cleaned metal, prevents it from corroding right away. Can be left on for months, then washed off with plain water to be finished as desired.

Sounds good. I may just try the soak and scrub method. Honestly though, once I soak and scrub all the loose stuff off, will it really matter if there's still a layer of carbon? Originally I was worried that without a spotless manifold it would eventually ruin the air thus the o2 sensors and catalytic converter, but is this true? Will any of that caked on carbon change the air that much to have any negative affects downstream on my exhaust?

Also, once I get the engine all assembled and ready to go, I want to make sure that it actually runs and doesn't leak or anything. But I also want to put a new exhaust on the car. My worry is if for some reason the engine blows up or becomes inoperable, I will have wasted a new exhaust. After assembling the engine could I just have the exhaust manifold on and nothing below that on the exhaust? I wouldn't have any 02 sensors connected, but would that make much difference? I would only do it to run the engine for a bit to check for leaks and sounds etc. Then after everything checks out I will install the new exhaust.

Not really - even if you got it spotless, it would start building those deposits out almost immediately. Carbon deposits breaking free and being blown downstream will not really affect the O2 sensors, as any bits that get on them will just burn off eventually.

Old school racers swore that mirror polished exhaust and rough intake promoted the best performance (quicker exhaust scavenging and good tumble for more through mixing). But that really started to make less and less of a difference with more advanced engine control systems, better fuel injection strategy, and higher engine volumetric efficiency.

Sure - you can run the engine with just the exhaust manifold on it, just be loud as hell. On a cold start, the ECM will not even look at the upstream O2 sensor, as it will start in open loop mode. Eventually it will start to adjust the air fuel mix as the engine warms a bit. For completeness - you can just run the exhaust manifold with the front pipe (the bent section) - that will allow the car to see the O2 sensor, so can run a longer test + semi-direct the exhaust gases down and under the car.

Thanks for the advice, I think that's what I'll do. I'll put it all back together, connect my exhaust manifold, leave that next bent pipe piece on, install a new O2 sensor, then fire it up.

I talked to a local muffler/exhaust shop and he said he can do the catalytic converter and that my muffler is probably still good. What do you think? Do mufflers go bad with this oil consumption issue? Also, what o2 sensors do you recommend? He says he uses denso, but his price is over $100 a piece. I can get both for $100 on

Mufflers generally don't go bad, even if the car is guzzling oil. Only thing I'd check for is the seam on the muffler - if it is heavily corroded or shows signs of opening, I'd get another muffler. Also, if you prefer a different tone/sound - now would be a good time to upgrade - get a deeper sounding muffler, while still staying legal. Up to you. On this car, the muffler is just for noise control - you have lots of flexibility if you want to change it for something else - unlike cars like the Matrix and the Scion FR-S/Subaru BRZ - their muffler is actually acts like a rear diffuser. If you remove it, you have to replace it with something of similar dimensions in the same location.

O2 sensors - I'd only recommend Denso. As for price, no reason why you couldn't pick them up from Rockauto and have him install it. No need to use their source, as they likely have their markup on it - they need to make some money too.

So I've got the camshafts torqued down. I've got the chain on the sprockets, but when the dots lineup the TDC line on the pulley is about half an inch forward from the 0 spot. Shouldn't they line up at exactly TDC 0?

They should, assuming the sprockets didn't get removed from the camshafts. Do the chain key links sit next to their reference marks on the sprockets?

Also possible that the timing mark on the pulley got borked, ie. the rubber isolated outer ring spun slightly. That's happened to me when I removed a crank pulley with an impact wrench on another project car in the past.

I'll have to pull up my copy of the FSM when I get back home - see if I can find some other information that could be helpful.

I pulled the chain off and tried again, it looks perfect now. The timing marks on both sprockets line up perfectly level with the head right as the TDC hits zero. I continued to crank to make sure the yellow marks made there way to the correct spot and they came around, both 1 link to the left of the timing marks as the other set of timing marks were level with the head, and TDC exactly zero.

I went ahead and put the valve cover on and now am in the process of putting it all back together. I've got a question though, should I replace the camshaft, crankshaft, and temperature sensors? If they test out okay with a multimeter do I assume they are okay or do I replace them since they are most likely original?

If they test OK, wiring and connector ends are not buggered up - I see no reason to replace them. There isn't any replacement interval with these components - if they are not bad, leave them be.

It has been my experience that aftermarket and OEM replacement sensors don't seem to be as long lived as the original parts - for one reason or another. Also not unusual for the replacement parts to be bad right out of the box.

Unfortunately, there isn't any preventative measures for these sensors - just replace when they go bad. Since all three of those are externally mounted - shouldn't be too bad to replacement.

Well, I am happy to report that everything has been put back together and I fired it up today for the first time. I have only driven it 20 miles so far, but it feels like a new car compared to what I was driving before this project. The funny thing is, I suspected a bad catalytic converter from the beginning but that is the only part I have not replaced. It has new denso o2 sensors, almost every part replaced was toyota oem or dnj from I did the 1zzfe oil consumption fix youtube walkthrough exactly as he did in the video. No CELs yet, but the huge hesitation issue I was having is completely gone. So here's the question, if its running perfect now, do I have a good catalytic converter even though the original CEL was cat related?

Possibly... My 2004 triggers code P0420 as soon as it misfires for any reason.

Congrats! Great to see the car back on its feet.

Only real way to find out if the catalytic converter is still good is to do a tailpipe sniffer test - actually measure the tailpipe emissions.

The P0420 code can pop up for a number of reasons, doesn't necessarily mean the cat is bad. I'd wager that in those cases, more often than not, the cat is perfectly working. The code is set when the downstream O2 sensor's waveform is too similar to the upstream's waveform, two trip logic detection on the ECM is needed before it pops the DTC. Unfortunately, lots of other things can also confuse the ECM - so this particular code is all too common on lots of cars.

Granted, catalytic converters do have a limited life span and it takes a lot to kill them off prematurely (atleast with the OEM cats). I'd just keep driving and see what the car does. Never know, the code may not comeback - problem fixed.

Update: 360 miles after the rebuild and the oil level has still not moved off the full mark. That's pretty exciting given that I would have used about 1.5-2 qts in 360 miles pre-rebuild. The car feels like it has so much more power now and runs great with a perfect idle. The only negative is that the P0420 code came back on. So now I am pretty sure I should replace the catalytic converter. Considering that the 8 months before rebuilding the engine I burned through 20-25 quarts of oil in 5000 miles, I am assuming the cat has to be bad. The downstream o2 sensor was completely black when I replaced it.

So, I am looking at and can get a walker ultra direct fit cat for $185. I am trying to save money so am considering cutting the old one off myself and using a band clamp connection to put the new one on. There are only a few local places that will weld it on for me without providing the part as well, best price I can find is $150 for labor. So $150 in labor or $10 band clamp, if possible. I've never used them so I don't know if that realistic or not. Just thinking it'd be a cheap alternative to welding. Any thoughts?

Your cat is likely just contaminated, but not worn out. Give it time to clear itself out, after a few spirited drives up and down the freeway.

I'm with dom - just reset the P0420 and keep driving the car. As long as you were using relatively modern motor oil when it was guzzling oil, the likelihood of completely killing the catalytic converter is low. Even with that high level of oil consumption. Lots of oil blenders have started to remove phosphorus from the oil's additive package - as that has shown to poison catalytic converters prematurely.

That said - that Walker replacement catalytic converter will work - just keep in mind that these aftermarket ones contain quite a bit less precious metals compared to the OEM ones - so it is not unheard of these catalytic replacements only lasting a year or so.

Don't be tempted to "wash" the catalytic converter with solvents either - regardless of what those Youtube mechanics say. That only works for a specific kind of catalytic converter and highly dependent on what the contaminant is on the cat. Most cases, that solvent will just diffuse the chemicals further into the substrate - basically killing it faster.

Okay, I may just hold off then. The 20-25 qts of oil were Mobile1 Synthetic. My only worry is whether or not the cat will cause any kind of back pressure that could harm all the work I did to the engine. I'll clear the code and drive it a bit more and see how it goes. It's still driving great. I got 36mpgs with 50/50 city/hwy on the first tank. I was getting around 32-33 pre-rebuild.

You'd know it if there was any significant amount of blockage that would lead to enough backpressure, at a level high enough to do any damage to the engine. Given the MPG you are seeing and overall driveability is good - I'd say you have nothing to worry about now.

Last time I checked - Mobil 1 Synthetic had pretty low levels of ZDDP - so little chance that even a heavy oil consuming engine will poison the catalytic converter. If you ran a "High Mileage" variant - that would be a different story, as those tend to be heavier on ZDDP. Still - even with guzzling that rate of oil (20-25 quarts) - may still not be enough to poison the catalytic converter.

I'd just drive the nuts off the car - bask in that warmth of a (now) well running engine - keep on top of fluid and filter changes, fix stuff as they break and you should be good to go.

4000 mile update:

My corolla is still running like brand new. Zero oil consumption and a ton more power than before. I highly recommend anyone with oil consumption problems with the 98-02 corollas to do the rebuild. I spent a total of around $1000 doing it myself which was about half parts, half tools. I bought a lot of toyota OEM parts, I could have saved a few hundred by going aftermarket but I had enough money set aside for the project. I plan on driving this car till the wheels fall off.

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