Timing Belt/water Pump Replacement

[JPI]

Let's go back to the basic again guys. Here are a couple things you have to remember. VVT-i = valve bender. Non VVT-I = No bender. Lexus raise the compression ratio to 10.4 in 95 but it doens't mean a thing. The shape of the piston is modified to reduce weight and create a low-friction piston. The valves cut are about the same. We are an Independent Lexus repair in the dallas area, We work at least 10-15 Ls400-SC400 week. I personally rebuilt, install, modify these engines. Countless T-belt and water job on the 1UZ, I could do it with my eyes close! I don't see how and why people have these myth about the valve bender. You bend the valves because there is something else wrong(water in the engine, blow headgasket etc ......).

JPI

[wandawoods]

Let's go back to the basic again guys. Here are a couple things you have to remember. VVT-i = valve bender. Non VVT-I = No bender. Lexus raise the compression ratio to 10.4 in 95 but it doens't mean a thing. The shape of the piston is modified to reduce weight and create a low-friction piston. The valves cut are about the same. We are an Independent Lexus repair in the dallas area, We work at least 10-15 Ls400-SC400 week. I personally rebuilt, install, modify these engines. Countless T-belt and water job on the 1UZ, I could do it with my eyes close! I don't see how and why people have these myth about the valve bender. You bend the valves because there is something else wrong(water in the engine, blow headgasket etc ......).

JPI

excellent! finally hear from JP1 who actually works on 1UZFE engines for living, and nails the answer down for all of us! :D

[wandawoods]

Threadcutter said the following about his '95 LS400 engine: "I have a couple of bent intake valves from # 1 Cylinder to prove [the '95 engine is interference]." And mehullica, the highly experienced Lexus dealer tech who has performed hundreds of timing belt replacement jobs and owns his own LS400 told us "1995 on up is interference".

in fact, I heard from couple of service managers at local lex dealer stated both my 97 LS4 and 96 SC4 (the same gen-II 1UZFE) are NI engines. so different dealers can have totally different story which only flames the confusion.

I will trust JP1 a lot more because he actullay cranks open the engine and do works on them. timing belt job only involves engine "exterior", so the Lex tech may not know engine interior details at all no matter how many times he has done it. just my $0.02

[Threadcutter]

Threadcutter said the following about his '95 LS400 engine: "I have a couple of bent intake valves from # 1 Cylinder to prove [the '95 engine is interference]." And mehullica, the highly experienced Lexus dealer tech who has performed hundreds of timing belt replacement jobs and owns his own LS400 told us "1995 on up is interference".

in fact, I heard from couple of service managers at local lex dealer stated both my 97 LS4 and 96 SC4 (the same gen-II 1UZFE) are NI engines. so different dealers can have totally different story which only flames the confusion.

I will trust JP1 a lot more because he actullay cranks open the engine and do works on them. timing belt job only involves engine "exterior", so the Lex tech may not know engine interior details at all no matter how many times he has done it. just my $0.02

To all:

Moments ago, I just awoke from a sound sleep and viola! it had come to me!...........

For those of you who are in the "95 - 97 Non- Interference" camp, I have a challenge to you;

Whether you are a private individual or a professional from a Stealer or "Indie" and are going to be replacing the timing belt on a 95 - 97 1 UZFE motor, you should have no problem trying a very simple experiment. That is, if you have the strength of your convictions about this particular motor being non interference. You're going to "be there" anyway, so why not?

The experiment is to simply remove the timing belt by whatever means necessary and attempt to start the motor. I'll guess that the best way is to do this is to only tear down the motor the minimal amount necessary to gain access to the belt, cut it and remove it.

Now, we all know the engine won't start. BUT, I maintain that there WILL be at the minimum, damage to at least one set of valves in the engine. When I say "set", I mean either intake or exhaust in at least one cylinder.

If you, in the "95 - 97 Non- Interference" camp are correct, there will be no valve damage and I will acquiesce and admit that it is a Non Interference engine. I will admit in advance that yes, it is a bit of a sophomoric challenge, but I also can't think of a better way for you to be able to prove your point once and for all.

You see, my motivation for making such a "scurrilous and outrageous" statement about the motor being "Interference" in the firstplace was merely to try and save someone else from the "PITA" & expense that I recently expereinced. It was mostly self induced (ie; my fault), but it was based on BAD INFORMATION, eg; Statement that motor is "Non Interference" when in actuality, it is. If all of you want to just "whistle past the graveyard" and run your motors until the timing belt breaks, please feel free to do so. I was just attempting to spare you a headache.

Do I have any Takers?

BTW;

JPI; You couldn't be more wrong. There was no "water in the cylinder", no "Blown head gasket", no "foreign debris in the cylinder", etc., ad nauseum.......

[JPI]

What happen to your car? Details? Don't challenge me... I work on Lexus for a living!

JPI

[sha4000]

just get a book that shows you how to do a timing belt job for all cars and you will see it states that the 98ls was the first to become an interference engine

[ArmyofOne]

just get a book that shows you how to do a timing belt job for all cars and you will see it states that the 98ls was the first to become an interference engine

I have personally seen the pistons from both a 1995 and a 1998 (at jasons shop matter of fact)...the pistons are cupped at the top on the 1995, on the 1998, they arent. the reason they are cupped, is because the indentation allows for enough clearance between the pistons and the valves, should the belt break.

[wandawoods]

...the reason they are cupped, is because the indentation allows for enough clearance between the pistons and the valves, should the belt break.

here we have it, that's a definate definition of non-interference (free running) engine.

one question though, any chance a broken timing belt itself hits the valves and make them bent?

wait a minute, just realize it's a stupid question. the TB is outside the engine block, no chance it will hit any valve inside the engine.

[alsalih]

Ok guys this needs to end. Real simple, does anyone out there have the Lexus factory service manual for either the 95, 96, or 97 model. Please look in the engine mechanical section where it has the procedure for replacing the timing belt and see if it notes (as mine does for the 98) to turn the crankshaft pulley 50 deg clockwise before removing the belt and in addition underneath it will be a NOTICE which mentions that if this is not done the piston head and valve head can make contact! This is best way to resolve this once and for all. Can someone please look this up and let us know.

[JPI]

We got a hold of some 95 pistons today, So here are the results. Lexus redesigned the water jacket and raised the piston dome. We slowly crank it over 3/4 of a turn, Valves slight touch the pistons. For the year 95-97, it will go case by case. I had a 96 t-belt broke and have no problem what so ever. But I do want to let everyone know don't take any chances and change out your t-belt at 90k.

JPI

[monarch]

You see, my motivation for making such a "scurrilous and outrageous" statement about the motor being "Interference" in the firstplace was merely to try and save someone else from the "PITA" & expense that I recently expereinced. It was mostly self induced (ie; my fault), but it was based on BAD INFORMATION, eg; Statement that motor is "Non Interference" when in actuality, it is.

Congrats Threadcutter, for sticking to your guns on this issue. You were right, as was mehullica, the Lexus dealer tech http://i5.photobucket.com/albums/y189/mastertech/tb.jpg

[JPI]

You see, my motivation for making such a "scurrilous and outrageous" statement about the motor being "Interference" in the firstplace was merely to try and save someone else from the "PITA" & expense that I recently expereinced. It was mostly self induced (ie; my fault), but it was based on BAD INFORMATION, eg; Statement that motor is "Non Interference" when in actuality, it is.

Congrats Threadcutter, for sticking to your guns on this issue. You were right, as was mehullica, the Lexus dealer tech http://i5.photobucket.com/albums/y189/mastertech/tb.jpg

Please read the post above that I made and the findings. Thank you.

JPI

[ArmyofOne]

We got a hold of some 95 pistons today, So here are the results. Lexus redesigned the water jacket and raised the piston dome. We slowly crank it over 3/4 of a turn, Valves slight touch the pistons. For the year 95-97, it will go case by case. I had a 96 t-belt broke and have no problem what so ever. But I do want to let everyone know don't take any chances and change out your t-belt at 90k.

JPI

this may have to do with a mid 95 switch to NI...its very possible.

[Threadcutter]

We got a hold of some 95 pistons today, So here are the results. Lexus redesigned the water jacket and raised the piston dome. We slowly crank it over 3/4 of a turn, Valves slight touch the pistons. For the year 95-97, it will go case by case. I had a 96 t-belt broke and have no problem what so ever. But I do want to let everyone know don't take any chances and change out your t-belt at 90k.

JPI

JPI:

We got a hold of some 95 pistons today.

I assume that you mean you were able to locate a running engine, perhaps in a complete/running vehicle.

We slowly crank it over 3/4 of a turn, Valves slight touch the pistons.

Then, in your opinion, is this a "Non - Interference" or an "Interference" engine ?

Is it safe to assume that you cranked it over slowly by hand?

[monarch]

We still have not resolved the issue of whether or not the '95-'97 Lexus V8 is a "Non - Interference" or an "Interference" engine ? I'm hoping for more professional input about whether or not the pistons and valves will collide and be damaged if the timing belt breaks on the '95-'97 Lexus V8.

[wandawoods]

monarch,

member alsalih made a good point to look it up in the service manual:

"Ok guys this needs to end. Real simple, does anyone out there have the Lexus factory service manual for either the 95, 96, or 97 model. Please look in the engine mechanical section where it has the procedure for replacing the timing belt and see if it notes (as mine does for the 98) to turn the crankshaft pulley 50 deg clockwise before removing the belt and in addition underneath it will be a NOTICE which mentions that if this is not done the piston head and valve head can make contact!"

and, I did look thru the service manual for my 97, and sure enough it does have the exact warning "piston head and valve head can make contact" if crank pulley is not turned before removing timing belt. also, JPI indicated the pistons can "slightly" contact the valves by his latest observation for a 95.

I would rather tell everyone to play it safe than be sorry later. no matter how slight it can be, as long as pistons can contact valves, it still can cause great damages, so it seems that we must assume it's an interferenced engine, and definately replace timing belt every 90K as recommended by service schedule.

[Threadcutter]

monarch,

member alsalih made a good point to look it up in the service manual:

"Ok guys this needs to end. Real simple, does anyone out there have the Lexus factory service manual for either the 95, 96, or 97 model. Please look in the engine mechanical section where it has the procedure for replacing the timing belt and see if it notes (as mine does for the 98) to turn the crankshaft pulley 50 deg clockwise before removing the belt and in addition underneath it will be a NOTICE which mentions that if this is not done the piston head and valve head can make contact!"

and, I did look thru the service manual for my 97, and sure enough it does have the exact warning "piston head and valve head can make contact" if crank pulley is not turned before removing timing belt. also, JPI indicated the pistons can "slightly" contact the valves by his latest observation for a 95.

I would rather tell everyone to play it safe than be sorry later. no matter how slight it can be, as long as pistons can contact valves, it still can cause great damages, so it seems that we must assume it's an interferenced engine, and definately replace timing belt every 90K as recommended by service schedule.

I would rather tell everyone to play it safe than be sorry later. no matter how slight it can be, as long as pistons can contact valves, it still can cause great damages, so it seems that we must assume it's an interferenced engine, and definately replace timing belt every 90K as recommended by service schedule.

Good Lord!..........IT IS AN INTERFERENCE ENGINE, PURE AND SIMPLE!

I'll once again apologize in advance, because I'm really trying hard not to sound snotty, but what more proof do you need? I have the bent valves to show for it.

Good grief, is it really that difficult to admit a mistake? It isn't for me, I make them all the time.

Please think about the repurcussions of what you are doing............Some poor "schlep" (like me three months ago) is not going to understand the nuances of what you mean when you say "I would rather tell everyone to play it safe than be sorry later. no matter how slight it can be"..................Just say "1995 through 1997 1UZFE is an Interference Engine" You'll be doing a lot af people a big favor if you do.

Out of curiousity, have you ever had your head in the front of a '95 - '97 1UZFE to change the timing belt?. If it hadn't been for the LOUSY information that I read "somewhere", my last venture would have been a Stark Raving success.

For anyone that is considering changing the timing belt/water pump/idlers on a 1995 through 1997 1UZFE;

It is do-able. Do yourself a big favor & don't listen to anyone that says it isn't an Interference engine because it is!!!!! Buy a set of two "Cam Sprocket Locks". Strip everything off the front of the engine to gain access to the cam sprockets, then align the sprocket marks to the marks on the heads & the timing mark on the crank to the mark on the timing cover. Then install the Cam Sprocket Locks on both Cam Sprockets, Then and only then remove the timing belt tensioner, remove the old timing belt and replace it with the new belt. Re-install the tensioner. Then and only then remove the sprocket locks. You should get the picture by now. Bottom line is that you don't want either cam or the crank to move at all while the timing belt is off.

Why is this so !Removed! difficult to understand?...............................and admit to?............

[wandawoods]

calm down, threadcutter! as I stated, I'm sold that it's an interferenced enigne, especially the service manul has spelled that out.

anyway, changing you TB every 90k can never be wrong.

[Threadcutter]

calm down, threadcutter! as I stated, I'm sold that it's an interferenced enigne, especially the service manul has spelled that out.

anyway, changing you TB every 90k can never be wrong.

C.W.:

anyway, changing you TB every 90k can never be wrong.

Yes, absolutely! We're in full agreement..........

Thank You Very Much...........

[oohryry]

I have 115000 miles. I'd better change mine soon. How much does it usually run. I know it has to be a lot of work.

[wandawoods]

I have 115000 miles. I'd better change mine soon. How much does it usually run. I know it has to be a lot of work.

lex dealers usually charge around $1200 for parts+labor for the basic TB/water pump replacement. if you purchase parts yourself and find a competent mech to do it, you should be able to get it done $600~$700.

other than timing belt/water pump, remember to include these things beyond basic TB job:

timing belt idler and pulley

2x CAM seals + 1x CRANK seal

complete coolant flush

drive belt tensioner

sorta like killing a few birds with one stone regardless who will do the job for you.

[Threadcutter]

I have 115000 miles. I'd better change mine soon. How much does it usually run. I know it has to be a lot of work.

lex dealers usually charge around $1200 for parts+labor for the basic TB/water pump replacement. if you purchase parts yourself and find a competent mech to do it, you should be able to get it done $600~$700.

other than timing belt/water pump, remember to include these things beyond basic TB job:

timing belt idler and pulley

2x CAM seals + 1x CRANK seal

complete coolant flush

drive belt tensioner

sorta like killing a few birds with one stone regardless who will do the job for you.

oohryry:

I fully agree with the above. I'd add new caps/rotors (you've got to remove them anyway) & then it only makes sense to do the plugs and wires as well.