Welcome to the North American Subaru Impreza Owners Club Thursday March 21, 2019
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC Technical > Service & Maintenance

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Old 10-15-2018, 05:47 PM   #1
Scooby Newbie
Member#: 488200
Join Date: Jul 2018
Location: Brookline, NH
2006 WRX TR
World Rally Blue

Default Re-Align Driver's Side Cam Gears - 2006 WRX - SOLVED

Post #745 in "Meaty's Timing Belt" thread in this sub-forum has pictures of the cams in the timing belt install/removal position and a good explanation to go with them. Basically, I think that the cams *should* self rotate opposite the recommended direction of rotation when the belt is removed and the recommended direction is for realignment only (I can confirm that when I removed my timing belt, both cams self-rotated opposite their recommended directions of rotation). The bottom cam may not rotate, as it is only slightly lifting the exhaust valves in the alignment position, this is also why it should be positioned first.

After the cams have rotated opposite the recommended direction, you have to go clockwise on the top, driver's side cam because going the other way would result in the intake valve fully opening and beginning to shut again before reaching the timing mark, which doesn't appear to position the cam at the tip of the lobe. Same with the exhaust/lower cam.

This doesn't seem to mean that you are safe if you rotate past the marks, but the cams should want to snap back, not forwards, as the lobes are in the lift phase/on the lobe's ramp when the marks line up (tip: use a breaker bar instead of a ratchet just in case!). Furthermore, as long as at least one cam on a bank is unloaded, all valves controlled by that cam are closed, removing the risk of valves hitting valves on that bank, and, since all pistons are at mid-stroke when the crank timing mark is properly aligned, assuming the crank hasn't shifted, there is no risk of valves hitting pistons either; you should be able to rotate the other cam freely in either direction through a complete rotation.

If I'm wrong, someone please correct me, as I don't want to spread misinformation. Also, review post #745 of Meaty's thread, watch some videos, and decide for yourself whether this information is correct, as I am no expert and take no responsibility for bent valves!

Here is a picture of the driver's side cams in the aligned position to help you visualize the situation (this was taken from post #745 of Meaty's thread, if the OP has an issue with me reproducing it here, please let me know and I'll remove it):

Lastly, "Company 23" makes a cam holding tool that is really helpful for this job. If you're just trying to replace the belt, you can lock both driver's side cams into the proper position before removing the belt. If you're removing the cams, the tool allows you to slowly rotate them into the service position (no valves open) and then slowly rotate them back into the aligned position before locking them. It can be found here: http://www.company23.com/506*
*I am not affiliated with Company 23 in any way and purchased this tool with my own money. This is not an advertisement!

Other tips:
-Cam seals and crank seal seat flush with cases, not bottomed out!
-If you're resealing the oil pump, anaerobic gasket maker (not flange sealant, which is apparently corrosive to aluminum castings, per Permatex customer service) removes the risk of clogged oil passageways associated with overdoing it with RTV sealant (it is miscible with the oil and the excess that gets inside the motor won't harden).
-If resealing the oil pump, red loctite on the screws that hold the cover on is recommended (two of my five screws were not nearly as tight as the rest). Using red loctite probably means you're not going to get the pump apart ever again, but they're not that expensive and could probably stand replacement at a second or third timing belt change anyways. If you want the pump to remain serviceable, any medium strength threadlocker should work well too.
-Don't use loctite on the timing belt cover bolts! If you do, it is likely that some of the nuts molded into the inner timing belt covers will break free from the somewhat brittle cover and spin freely upon attempted removal, making the next timing belt job considerably more difficult (you need to remove the cam gears to get the inner timing belt covers off - the covers are ~$26 per side)
-If you are replacing cam seals, you may want to consider removing the screen/filter in the driver's side head banjo bolt fitting. Like the one commonly removed from the turbo oil feed banjo, this can clog and limit oil flow. Anecdotally, my filter/screen was split on one side and had a decent amount of debris in it. The other side of that hardline (it's short, ~5'', only goes to the top of the head) also has a screen, but that can be easily accessed with everything assembled, so not as critical to do at the same time as this job.

Hope this makes sense/helps someone else. Thanks poster #745 (BaronOBeefdip)!

Original Post:
I am planning on doing the timing belt on my 2006 WRX and replacing cam seals while I'm there. I've watched Mike the Meatball's Youtube video series on the topic:

I've also read the service manual and a few other threads and am comfortable with almost the entire procedure, but can't seem to find any straightforward information about re-aligning the driver's side cams, although it does appear that they need to be spun in specific directions for realignment.

I know that the driver's side intake/exhaust cams are under valve spring pressure when aligned and that they easily slip from this position. I am also aware that the "service position" of these cams is slightly off from the aligned position and that there is no valve spring pressure on them in this position. This is the position I anticipate being in after removing the cams for replacement of cam seals, whether because the cams slip to this position or because I move them to this position before removing the cam sprockets.

My question then is: Can/Should I rotate the topmost cam a full 360 degrees clockwise and the bottom cam a full 360 degrees counter-clockwise, if necessary to re-align the marks from an unloaded position? I know that the factory service manual says to only rotate the top driver's side cam clockwise and the bottom driver's side cam counterclockwise, but, if I unload the cams in the recommended direction intentionally to service the seals, this means that I will have to go a full 360 degrees to realign them, assuming that they don't slip the other way when I remove the timing belt, and I can't get my head around how rotating these cams in these directions avoids the problem of intake and exhaust valves colliding, unless Subaru expects them to slip in the opposite direction, although I have watched videos of people doing these belts where they slip in the recommended direction of rotation and the mechanic rotates the sprockets opposite the recommended direction of rotation. Here is one example:

I am aware that when the crank is aligned with its alignment mark that all pistons are mid-stroke, so at least I don't have to worry about that!

Also, the factory service manual shows the upper cam having slipped counterclockwise and the bottom cam having slipped clockwise, so is it OK to let them slip in that direction (or indeed is that the direction they WILL slip in upon timing belt removal)?

Factory Service Manual page can be seen here:

More information: In "Meaty's Timing Belt" thread in this sub-forum, posts disagree with each other on this precise topic. For example, one poster (post #634) says to rotate cams in the "correct" direction all the way around if you go too far. Post #732 however tries to clarify the procedure by explaining that you should release tension on the cams opposite the correct direction then bring them back into alignment by going in the correct direction, which makes more sense to me, as I can't see how the direction of rotation makes a difference, as I believe that cams will still contact each other regardless of the direction of rotation if they are both in certain positions and rotating a cam through a full 360 degrees means that if the other is in a bad spot (i.e. a valve is fully open or almost so) that rotating the other cam through a full rotation would ensure a collision, rather than prevent one. Of course, if the other cam is unloaded, there shouldn't be an issue, but then why the focus on direction of rotation?

Thanks for reading!
* Registered users of the site do not see these ads.

Last edited by currancchs; 02-06-2019 at 03:35 PM. Reason: More information
currancchs is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 02-06-2019, 03:27 PM   #2
Scooby Newbie
Member#: 497363
Join Date: Feb 2019

Thank you for this very helpful information to my specific questions/problem!
JEThree is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 08:09 PM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2019 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.