I have an engine carcass sitting in my garage. When I get home tonight I'll take a look at it and see if I can make some sense of what you're asking.

I think that picture you show is the balance shaft assembly. Maybe someone else can confirm. What exactly is the "alignment" you are needing? Are the gears not meshing, or are they not stacked up with one another, or something else?

 

The motor makes more violent and different noise after reassembly than just the rod knock that initiated the bearing change project. Seeing these same photos, a mechanic suggested that the gears shown in each photo control the timing so must be properly aligned with the correct crankshaft position upon reassembly. I was not aware of this and so suspect that this might be the cause of the new, loud, violent noise. If true, then the supposed fix would be to drop the oil pan again, drop this item again, inspect the gear teeth on each to assure no damage, properly position the crankshaft, reassemble all. If all true, how is the proper crankshaft position found? Thanks as always.

 

Nah, those aren't timing gears. The Mazda 3 engine that I have in the garage is a 2.0L which does not come with a balance shaft assembly. The 2.3L and 2.5L engines do. The gear that is on the crank shaft is not on my junk engine.

Timing a Mazda3 has to be done carefully otherwise the engine will either run very poorly, or worse not start, or very worst will be destroyed because it is an interference engine and the valves will be smashed by the pistons.

For timing the engine do a YouTube search for baxrok2.

There are 4 parts to his timing videos and they are very informative. You need three things to be correctly positioned for the timing to be correct on the Gen1 version ('05-'09). A timing "pin" is inserted into the side of the engine and the crank is turned until it hits the pin. Crank is now set. The camshafts are turned until the grooves at the end of the cams are horizontal. Insert a flat timing bar into the grooves and the cams are now set. Then the crank pulley has to be aligned (fifth tooth or something like that) to the CKP (crank position sensor). Now the crank pulley can be bolted in place without anything else moving. The timing will all be set correctly.

The Balance Shaft assembly must have been installed incorrectly. It can be removed if you install a very small and inexpensive BSD kit.

 

I guess I should have thought of a simpler reply for you. It sounds like all work was done by taking off the oil pan and NOT removing the timing cover. If the large crank pulley was not taken off then the timing on the car was not disturbed. If the crank pulley was removed, like for taking off the timing cover to replace the timing chain, then the entire timing sequence needs to be followed. It's a fairly easy sequence to follow BTW.

For the Gen1 cars ('05-'09) there are free downloads of the Factory Shop Manual (or Factory Service Manual). These are super helpful for doing any maintenance on these cars. Google and you can find them using the two names I provided along with Gen1 Mazda 3.

 

Great info, thanks! I appreciate the reply, the detail of the information you are sharing and pointing me in the right direction to further fix the issue(s). Gracias. Danke. Obrigado. Merci.

So, to follow up, the timing cover was not removed nor was the large crank pulley removed. Only the small A/C unit pulley came off while moving the crank to expose the connecting rod registers and replacing the bearings.

Mazdaswag.org parts distributor confirmed this piece as the balance shaft assembly (BSA) , which you first pointed out. I don't understand how that was reassembles incorrectly: four bolts came off, then four bolts went on with the unit sitting flush. If either the gears failed to align or another obstruction occurred the unit would not have sat flush, supposedly. That said, if it is not the timing (as dismissed above following your analysis) then my guess is the BSA.

Or, perhaps one of the connecting arms registers came undone/loose due to the one-time use torx bolts that I simply reinstalled rather than replacing. Also, while a torque wrench set to 15 ft lbs was used (aiming for that plus 90 degrees), those bolts tightened hard without reaching the point of indication of that torque so I stopped pushing hard in order to avoid stripping the heads.

Or perhaps I tightened too much and the bearings jammed then broke? That happened in the Tom Clancy book on a Russian nuclear sub, much like the O ring on the space shuttle: some small piece causing catastrophic failure.

So, the four options seem to be: timing (discarded), bearings broke (unlikely), connecting rod register bolt broke (maybe?) BSA incorrectly reassembled (most likely).

Is a BSD you mentioned below the same as the BSA (typo maybe?)? If different and inexpensive and serves the same purpose and allows to remove the currently-installed BSA that likely is the cause of the violence in the motor, that seems to be a good path.

I have a m4a (iPhone) recording of the engine noise (started it a third time for the sole purpose of recording the sound to then take to the mechanic). Would hearing that confirm/negate any hypotheses? If so, how could I share that - this file format not accepted here.

Thanks again.

 

Interesting stuff. I don't think the connecting rod clamp end can be overtightened to the crank such that the bearing would bind. I'm pretty sure the bolt could suffer, but the bearing should still have clearance. Just my thought.

My conn rod bolts have an e-torx head (maybe your's are the same?), and man those things grab really nicely with an e-torx socket. The FSM does not show the breakdown of the short block so I can't find anything on the torque spec. I am familiar with the "torque to X and then go another 90 degrees" in the case of the crank bolt. Man, I don't think that can be done without a impact wrench! Super easy with one, but you have to paint marks on the bolt head and also on the surface next to the bolt head so you know when you've gone 90 degrees. I did not know those conn rod bolts are one time use. If so, I would replace them when you drop the pan again. And never ignore the proper torque for something internal to your engine. That's begging for lighting to strike.

BSA = Balance Shaft Assembly. BSD = Balance Shaft Delete (kit). You can get rid of the whole balance shaft assembly if you don't want a repeat of your weird noise situation. I cannot fathom how the BSA could be installed incorrectly. Like you said, just four bolts. The attach pic is the BSD from Massive. Massive makes a good timing tool kit if you ever need one.

 

Thanks for the link to baxrok2. Very informative videos.

Clarifications:
* The one-time bolt comment was from one customer and the admin guy at my mechanic. The customer builds / rebuilds engines and the admin guy, while not the chief mechanic, has done some engine work. While they sounded confident in their comment that these were one-time use, stretch bolts, the customer said that he reuses the ones in his engines at least a second time.
* The torque target of 15 ft lbs plus 90 came from here:

.
* found this source recommending to keep the BSA: https://www.jackstransmissions.com/blogs/pages/keep-your-balance-shafts. Why replace the BSA? Just curious if there is a reason. As it seems likely that it was reassembled correctly (put it back on as it came off), I'm partial to leaving it as is unless necessary to use BSD.

So, follow on questions:
* If the timing was not disturbed due to the work being done without having removed the timing plate, could the timing be removed as the cause of the violent noise?
* If the BSA was replaced correctly as it seems could that be removed as the cause of the violent noise?
* If these two are eliminated, what else could it be?
* If the timing is adjusted/confirmed with the engine in the car using the instructions by baxrok2 would the cam shaft timing plate/bar fall out due to gravity as the engine would be upside down vs the video? Or does it stay in place some how?
* Must the passenger axle be removed to access the belt side of the engine block to adjust the timing?
* Struggling to find free FSM. Is there a source you prefer and trust?

Thanks

 

This in the notes of a used 2006 Mazda 5 2.3L engine on eBay: " Incorrect removal and replacement of the harmonic balancer on a 2.3L engine will result in movement of the timing chain causing bent valves. Watch our video tutorial. Very simple but extremely important."

https://www.ebay.com/itm/MAZDA-5-2-...005&rk=3&rkt=12&sd=112720160684&itm=113725591603&_trksid=p2047675.c100005.m1851

 

The Harmonic Balancer is the crank pulley. You can google Mazda 3 harmonic balancer and verify. The balance shaft assembly was added to the 2.3L (Mazda L and Ford duratec) and 2.5L (Ford duratec) engines to smooth out any vibration effects from an unbalanced crankshaft. It has nothing to do with timing the engine. Timing is strictly a camshaft (i.e. valves) and piston and spark harmony-and-love thing. You can verify the actual timing with a diagnostic tool. I think it is something like 9 degrees BTDC at idle.

I'll respond to your other post later.

 

Here are a number of Mazda3 downloads. If I google Mazda3 gen1 factory shop manual I see a whole bunch of options, so I'm not sure what you need exactly.
https://www.mazda3forums.com/95-maintenance-care/273242-service-manuals-download.html

Answers to your questions:
* Timing is not your issue
* If the BSA was installed correctly, then that is not your issue
* What else? I don't know. Something broke inside your engine that got overlooked when you replaced parts? I've never rebuilt an engine before, and I've only torn down one short block completely but didn't have to put it together.
* When setting the timing, the engine is not upside down. Remove the valve cover and you can see the ends of the camshaft and the slots where the timing flat bar goes. The bar lays flat on the head and slides into the slots.
* If you watch the timing videos from baxrok2 I don't think it shows him removing the axle - probably just the wheel, but I haven't watched those in a year.

I'm surprised no one else is chiming in. Sorry, but this is all the help I can provide you for now.

 

Thank you for input and replies. Very much appreciated. Learning day by day as a DIYer.

 

FWIW - I have the 2007 Mazda 3/Mazda Speed 3 FSM uploaded to my Google Drive. Drop me a PM and I can shoot you a link so you can download the manual for yourself.

 

Turns out that the BSA was loose. I presume that the gears failed to align on first reassembly as the bolts were loose when checked. So, with all tightened up, the engine runs smoothly. No need for a timing adjustment. Baxrok2 answered my questions on YouTube - very cool. Thanks all for the help, especially Datsun1600 - you went above and beyond. Much appreciated.

 

Hi Gary_L,

Thanks for the offer for the 2007 Mazda3 FSM. Since I have only 13 posts I can only PM admin.

Can this be sent within the Forum, or to email, or send me a link to a cloud storage folder (e.g. OneDrive, Google Drive, Dropbox, etc.)

Thanks!

 

tbbalfe,

I appreciate the kind words, and super appreciate that you actually followed up here. It seems to be a rare thing for some reason. People start a good thread, others get involved, and then the OP disappears and we never know what happened. Your "fix" will help someone down the line.

Glad that your car is running normally again.

 

So yay it's my turn I spent a rod bearing and am now in the process of the same tear down. I am so very glad I found this thread and am thankful for all of your responses and allowing us the end result. Is there anything I need to be aware of in this process? As this is my first import car and the very first I've ever been into. I have built many 350s and ls engines so I'm not a total noob. But I do want to treat my mazda3 right.

 

Also what are the torque specs on the balancer?

 

So I had to use a .075 oversized bearing on the number 4 cylinder but all worked out now I am noticing a tick in the head, I am having to pull the head and I am curious can I put a different more powerful or efficient head? If anyone knows or is reading this please reply soon. As I will be purchasing the head soon thanks

 

Here is some important info that should be shared in this thread.
The BSA (Balance Shaft Assembly) DOES need to be "timed" to the engine. Its purpose is to "B"alance the engine by providing an unbalanced weight to counteract the unbalance of the engine. With Cylinder 1 at TDC, the holes on the face of the pucks that face the front of the engine should be at 6 o clock (pointing DOWN on an installed engine). If the BSA is not properly timed/synchronized, the engine will run MORE unbalanced than if a BSD is used.

 

Here is a drawing of the BSA as installed and timed at 6:00 (note engine is being "worked on" out of car and upside down)

 

The BSA tuns twice for every rotation of the crank, so it will be at 6:00 with cylinder #1 at TDC for either the compression stroke or the exhaust stroke.

 

Here is a great video that explains the operation of balancing shafts: