'90-'97 Owners: Check Your Engine Valve Clearances

[monarch]

'90-'97 owners with more than 60,000 miles should consider heeding the advice of your owners manual to check the engine's valve clearances every 60,000 miles to maintain optimum engine power, fuel economy, durability smoothness and quietness. Today I checked a '94 LS400 engine (not my own) with 146,000 miles that had never had the valve clearances checked. Here's what I found:

INTAKE VALVES: Factory specs call for a clearance of .006-.010". On 14 of the 16 intake valves I found the clearances ranged between .007 and .009" (good), but 2 of the intake valves had a clearance of .010" which was only marginally within specs.

EXHAUST VALVES: Factory specs call for a clearance of .010-.014". One of the 16 exhaust valves had a clearance of .012" which was perfect. One valve had a clearance of .013" which was still within specs. Four of the valves had a clearance of .014" which was only marginally within specs. Six of the valves had a clearance of .015" which was slightly too loose. Four of the valves had a clearance of .016" which was substantially too loose.

My next project is to check and adjust the valve clearances on my own '91 LS400 engine. I hope to create a tutorial for this task and give it to Lexls for him to post on his outstanding website (if Lexls wants it).

[SRK]

The dealer routine for checking valve clearances is a listening check - if the valves are excessively noisy then they open up the engine. One or two thousandths of an inch makes no difference at all, and I wouldn't worry about it. If the valves got a bit tight, that may pose a problem, but two thousandths loose? Not a problem.

[monarch]

The dealer routine for checking valve clearances is a listening check - if the valves are excessively noisy then they open up the engine.  One or two thousandths of an inch makes no difference at all, and I wouldn't worry about it.  If the valves got a bit tight, that may pose a problem, but two thousandths loose?  Not a problem.

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I have over a million miles worth of Toyota driving experience (various models and engines) and have consistently found "One or two thousandths of an inch " out of spec valve clearance has a noticable adverse impact on engine power, fuel economy, smoothness, quietness and durability.

Owners who wish to maintain ideal valve clearances have a big problem, however: finding a dealer or mechanic who is caring and meticulous enough to do an accurate job of valve clearance adjusting. Why? Because the majority have a "one or two thousandths of an inch out of spec makes no difference at all" attitude. One solution is to provide tutorials so interested owners can learn how to do their own precise valve clearance adjusting.

[jzz30]

i checked mine at 120k and all was within spec.

[PK_Lex]

how do you check the valve clearances?

[Shadow]

how do you check the valve clearances?

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Filler gauge would do it.

[SRK]

As far as I know, adjusting the valves on the early 1UZ-FE requires removing the camshafts. That's a big job. Time consuming. As the acceptable RANGE is .004 in, having a valve out of spec, larger, by .002 is not so bad. Any mechanic who would insist on spending five or six hundred dollars to adjust a few valves that are so close to the limit, borders on unethical behaviour. Of course, if for whatever reason, an owner insists on this, then a mechanic should go ahead and do the work, with the proviso that any time one opens up an engine that far other items may break, or need replacing.

If one were to dismantle any Lexus V-8 that had say, more than 200k miles on it, one would fine cylinder wall taper, ring end gaps, valve guide play, that would be outside factory spec. And yet engines of that mileage don't burn oil, or display any symptoms at all. But the specs say........

So the "Princess and the Pea" syndrome begins. Moderated with the old adage "If it ain't broke, don't fix it".

I have been rebuilding engines for over thirty years. Maserati to VW, Volvo to Ford, Lotus to Mazda - and even a Toyota or two....and two thousandths is nothing to worry about - or spend huge dollars adjusting out. But if it makes YOU feel better, fly at it. The engine won't care that's for sure.

[monarch]

As far as I know, adjusting the valves on the early 1UZ-FE requires removing the camshafts.  That's a big job.  Time consuming.  As the acceptable RANGE is .004 in, having a valve out of spec, larger, by .002 is not so bad.  Any mechanic who would insist on spending five or six hundred dollars to adjust a few valves that are so close to the limit, borders on unethical behaviour. 

I have been rebuilding engines for over thirty years.  Maserati to VW, Volvo to Ford, Lotus to Mazda - and even a Toyota or two....and two thousandths is nothing to worry about - or spend huge dollars adjusting out.  But if it makes YOU feel better, fly at it.  The engine won't care that's for sure.

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Camshaft removal is not required to adjust the valve clearance on any pre-1998 (non variable valve timing) Lexus engine. Just a valve shim removal toolkit is needed ($28 on ebay). Valve clearance check is listed in the factory repair manual as part of the tune up procedure of pre-1998 Lexus engines. Driving with a valve clearance out of spec is like driving with spark plug gaps and ignition timing out of spec - it degrades engine power and fuel economy and increases emissions which in turn has a domino degrading effect on the reliability / durability of other engine componets as well as the engine itself.

Have you ever had the opportunity to view / measure the amount of wear on various reciprocating componets of a perfectly maintained high mileage Toyota / Lexus engine? If not, then you may not be aware of the durability potential of these engines. When the valve clearance of a Toyota engine is always kept within specs, valvetrain wear is so low that even after 450,000 miles the engine still has very low emissions, like new compression and near new levels of power and fuel economy:

http://www.saber.net/~monarch/454.jpg

http://www.saber.net/~monarch/smog92.jpg

[VMF]

how much is the procedure and can it be done on your own?

[SRK]

Camshaft removal is not required to adjust the valve clearance on any pre-1998 (non variable valve timing) Lexus engine. Just a valve shim removal toolkit is needed ($28 on ebay).

I stand corrected.

[monarch]

how much is the procedure and can it be done on your own?

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Toyota dealers charge about $230 for 4 cylinder engines and about $375 for V6 engines so I would imagine Lexus dealers charge around $500 or more for the 1990-1997 V8.

Yes, V8 valve clearance adjusting is a do-it-yourself job for any owner who has the skill level to change the timing belt (which you obviously do). Most of the work is just the usual routine and rather tedious work of removing various engine covers and cable brackets in order to get the valve covers off http://www.saber.net/~monarch/valveshim.JPG On the passenger side of the engine the throttle body needs to come off (good opportunity to clean it at the same time).

There is considerable information about 1990-1997 V8 valve clearance adjusting on these websites:

http://planetsoarer.com/camshafts/camshaft2.html

http://www.lextreme.com/forums/archive/index.php/t-1.html

The best valve adjusting toolkit is Toyota Part # 09248-55020, but it's currently on backorder at OTC tools and sells for a hefty $99. A near equivalent toolkit is the standard Toyota valve adjusting toolkit Part Number 09248-55010 which is always available on ebay for $27. The valve lifter depressing tool of the cheaper kit doesn't work very well on the Lexus V8, however. An effective work around is to depress the valve lifter using a large screwdriver that has been covered with 5 layers of tape to prevent any chance of nicking or gouging of the metal of the valve lifter. A strong plastic rod might also work well.

The factory manual says to remove the valve adjusting shim by blowing compressed air into a hole built into the shim. I found a cheap ordinary aerosol can of compressed air from an office supply store works well for this purpose. Once the shim has been loosened in this manner from the valve lifter it can be pulled up and away from the valve lifter using a magnet. If the measured valve clearance was larger than factory specs. a thicker valve adjusting shim needs to be installed. Conversely, if the measured valve clearance was smaller than factory specs. a thinner valve adjusting shim needs to be installed.

[VMF]

thank you for the info, i ve been meaning to do the for quite some time now but just dont have enuff time to do so, hopefully will do that next month.

[Lexls]

I hope to create a tutorial for this task and give it to Lexls for him to post on his outstanding website (if Lexls wants it).

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Yes, I would love to get a tutorial on this! Just email me when you're ready and we can go from there.

[VMF]

what is the part number for the tool for the v8 engine?

i'm gonna do mine and i'm gonna write a howto article

[monarch]

The toolkit specifically for the 1990 -97 V8 is Toyota Part # 09248-55020, but it's currently on backorder at OTC tools and sells for a hefty $99. A near equivalent toolkit is the standard Toyota valve adjusting toolkit Part Number 09248-55010 which is this one on ebay http://cgi.ebay.com/ebaymotors/ws/eBayISAP...sspagename=WD1V

The valve lifter depressing tool of the cheaper kit doesn't work very well on the Lexus V8 - it doesn't depress the valve lifter enough, but an effective work around is to depress the valve lifter using a large screwdriver that has been covered with 5 layers of tape to prevent any chance of nicking or gouging of the metal of the valve lifter. A strong plastic rod might also work well.

Both tool sets include a tool that keeps the valve lifter depressed while you remove and install the shim. It works well.

[VMF]

A near equivalent toolkit is the standard Toyota valve adjusting toolkit Part Number 09248-55010 which is this one on ebay http://cgi.ebay.com/ebaymotors/ws/eBayISAP...sspagename=WD1V 

at the bottom of the auction it states that: Does not work with Land Cruiser 1993-1997

or Lexus LX400 1994-1997

[monarch]

It should say "does not work with '90-'97 LS400", but like I said, only the valve lifter depressor tool does not work. The other tool which holds the lifter down after the lifter has been depressed DOES work because it's identical to the lifter hold down tool that's found in the expensive $99 kit.

In fact, in one of the tutorials I previously posted a link to, the author substituted a butter knife in place of the lifter hold down tool.

It's OK to substitute tools as long as you don't do anything to nick or dent the valve lifter. Either a strong plastic rod or strong rod shaped piece of wood might make an ideal lifter depressor tool. A large screwdriver covered with several layers of tape works good for me.

[VMF]

so you are saying its ok to get this tool to work on 1uzfe?

[monarch]

Yes, but it may depend on your personal preference / philosophy. If your preference is to use the best tools for the job in order to eliminate any chance of anything going wrong them maybe you should order the $99 toolset 09248-55020 from OTC tools http://www.otctools.com/. You have to call them to order it because they don't display it in their online catalog

[VMF]

thank you man:)

i will keep you updated on the progress:)

[mickg]

How do you buy the shims?

Do you measure the individual clearances, note the existing shim thickness, add the required differential measurement, and then purchase just the shims required?

Or does Toyota supply a "variety shim pack"?

Mick

[jzz30]

you need to measure the shim thats in there with a micrometer and add the clearance that you need to it and order that specific size from the dealer.

[monarch]

How do you buy the shims? Do you measure the individual clearances, note the existing shim thickness, add the required differential measurement, and then purchase just the shims required?

Mick

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Yes, you purchase just the individual shims required.

Examples:

If a measured valve clearance is too narrow then it will need a new shim that’s at least one size thinner in order to loosen up the clearance to the desired range.

If a measured valve clearance is too wide then it will need a new shim that’s at least one size thicker in order to tighten the valve clearance to the desired range.

Shims are available in a range of sizes in increments of .05 mm ( .002") Each individual shim has its own individual part number.