LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Question about changing cam seals on 98 with VVT-i

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Old 09-10-15 | 02:19 PM
  #76  
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Originally Posted by ChampGS3
First I want to say Thanks to Sha4000 for undertaking such an adventurous and complex repair and for asking the critical questions!

I also have a 98 VVTi in my GS and will be tackling this same Cam Seal replacement very soon I too have the FSM from Toyota / Lexus and I agree that the head removal portion, that explains the cam removal process, leaves much to be desired in some of the key details that were brought up in this thread. I have read this portion of the FSM a number of times and had wondered if both cams were in proper servicable alignment when the 50deg past TDC. Now that I know this ahead of time I won't be caught when I attempt to complete this project over a weekend as this is my DD.

I still am a little fuzzy about the drivers cam and the process of turning it CW or CCW to get the arrows aligned to place the service bolt? I would really love to speak with you over the phone about your experience.

Please text me at your earliest opportunity at 6787709017 or leave your number here and I will reach out.
Best, David
I sent you a text. This is a very long and tedious job but very doable in a weekend as long as you have the correct told and parts. I'm guessing that you will be doing the timing belt as well as the valve covers too since everything will be off anyway. Just make sure you spray ALL the bolts down the night before and take your time getting them off.
Old 04-05-17 | 11:20 AM
  #77  
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this thread is golden! should be a sticky
Old 04-05-17 | 01:55 PM
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Originally Posted by Scraape
this thread is golden! should be a sticky
Hey Scraape ask your questions in this thread and I'll try to help you out as much as possible. I just got back in the house because I was outside trying to work on some issues with the 430 I just bought. Don't remove that front bearing cap until you have the service bolt in the Cam and then remove it in the sequence with the other bearing caps. Read the pdf that I posted in the first post VERY carefully and don't rush.
Old 04-05-17 | 02:24 PM
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Originally Posted by sha4000
Hey Scraape ask your questions in this thread and I'll try to help you out as much as possible. I just got back in the house because I was outside trying to work on some issues with the 430 I just bought. Don't remove that front bearing cap until you have the service bolt in the Cam and then remove it in the sequence with the other bearing caps. Read the pdf that I posted in the first post VERY carefully and don't rush.
viewing the PDF now, thanks. Is this the front bearing cap you are referring to? Or is this the timing belt rear plate that the manual is referring to?
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Last edited by Scraape; 12-21-17 at 10:49 AM.
Old 04-05-17 | 02:40 PM
  #80  
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Your pic is not showing up. No need to remove the intake.
Old 10-02-17 | 03:04 PM
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Default Correct "sst" special service tool

Originally Posted by sha4000
Ok let me explain. I never aligned the cams once I took the valve covers off.

1. I did the timing belt job and replaced the water pump and both Idler pulleys.
2. I did not put the new timing belt on since I knew I had to change the cam seals.
3. At this point both cam pulleys and the crank pulley are set to 50 degrees past TDC
4. I unbolt the bolts on the cam pulley using my cam pulley holder tool which worked great. Here's the link.
Amazon.com: OTC 6613 Variable Pin Spanner Wrench: Automotive
5. I removed the cam pulleys.
6. I removed both Valve covers.
7. Everything is still set at 50 degrees past TDC.
8. I check the right side cam ( passenger side ) and see that it is already lined up with the markings and service bolt hole so I place the bolt in the hole. I never moved the exhaust cam because it was already lined up.
9. I check the left side cam ( drivers side ) and see that the markings and the hole are not lined up so I'm going to have to do it myself. This is where I stopped initially and contacted you by email.
10. While waiting for you I built a little courage lol and start to turn the left side exhaust cam little by little with a 24mm hex wrench which is the correct size for the hex shaped part of the camshafts. I felt some resistance before I could get the cams lined up so I stopped.
10. I went to a PTA ( Parent Teacher Association ) meeting at my sons school and now I'm back trying to get some clarification on what you did and what I need to do next.

Sorry for the long details because I hear my phone email notifying me that you have probably replied to my post while I'm writing this post. I'm a slow 2 finger typist and I want to be absolutely clear about what I've done and what I need to do. You have already done the job so I would appreciate clear and precise instructions on how you did it if you would be so kind. Remember this write up will probably get stickied since no one else has done a write up and I'm taking lots of pictures to help out all future ppl that dive into this job. This scares more ppl than a timimg belt job that's why I'm being so cautious.
The "spanner tool" link for exhaust cam scissor gear alignment, and cam phaser adjustment is flimsy and is prone to slip.

If the tool slips you risk damage to valvetrain or cam phasers (VVTI)

AST TOOL is a US. manufacturer of a more durable tool...#7200

Can also be used for holding AC clutch, power steering pulley during disassembly and reassembly

Old 10-04-17 | 01:41 PM
  #82  
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The tool did it's job but I did have to set it just right on the cam pulley to make sure it did not slip. To be honest that AST tool would have had the same problem because of the way the notches are positioned on the pulley if I remember correctly. I have not used the tool since doing all that work.
Old 10-30-17 | 08:55 PM
  #83  
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Default Indexing scissor gear - special service tool

Originally Posted by sha4000
The tool did it's job but I did have to set it just right on the cam pulley to make sure it did not slip. To be honest that AST tool would have had the same problem because of the way the notches are positioned on the pulley if I remember correctly. I have not used the tool since doing all that work.
Removed camshahfts on 1998 LS400 to replace the VVTi cam phaser but had to reset one of the scissors gears due to backlash noise (service bolt not employed on 2nd disassembly so clackety clack noise.

The exhaust cam on 1UZ-FE used a scissor gear, subgear which reduces the gear backlash to zero, thereby considerably reducing gear noise..

Some images of AST TOOL #7200 in use...worked beautifully for resetting the subgear so service bolt could be installed for reassembly..the tool pins fit like a glove in the subgear
This image depict Exhaust Scissor Gear with AST Tool pins in place before they are threaded into the arms of tool Same pins installed threaded into service tool
Profile depicting the heft of the pivot mechanism of the tool... Zero slop. Machine tool quality.
Tool turning subgear assembly
Another angle
Due to spring tension on subgear, found it nessary to hold cam in vertical position with tool at bottom and wrench on flats of camshaft to install service bolt into service hole to preload scissor gear subgear before reinstalling exhaust camshaft assembly.
Diagrams depicting how scissor gear subgear design reduces backlash to zero.

Pretty impressive engineering...and very effective at reducing noise.

Last edited by YODAONE; 10-30-17 at 09:04 PM.
Old 10-30-17 | 09:27 PM
  #84  
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Nice work but that's not what I used the tool for in my application. I used it to hold the camshaft pulleys so I could loosen and then tighten the bolts when removing and then reinstalling them. Installing the service bolt was pretty simple using a size 24 wrench once I got over my angst. Once the cams were removed everything else was pretty simple. This job gave me lots of stress at the time.
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