So I bought this 2005 Mariner with the Mazda l4 2.3 DOHC, with noise in the timing chain. The owner told me that one day it just wouldn't start, and they took it in, and the timing chain had broke, so they had the timing components and valves replaced. The thing ran afterwards (even the 60 miles to my house) but it had some bad noise coming from the timing side of the engine.

I tore her down and found that the upper bolt on the Guide arm of the timing system was stripped out and slapping around, which allowed the chain to stretch out. I retapped the bolt for the guide arm and got a new bolt to fit snugly in there with some lock tite on it for safe measure, threw a new chain on it, and used the Chilton service manual to retime the engine.

Somewhere in the middle of this process, I managed to totally lose power to the entire vehicle. I chalked it up as a dead battery and kept working. Once I went to fire it up when it was all back together, I jumped the battery with my truck, but it wouldn't seem to charge. I had the battery tested and it tested as a good battery. after cleaning up the terminals and connections I found that the power line to the fuse box was finger loose, so I tightened that back up. (but before I found that, I would turn the key forward, and as soon as I got to the "on" position, the power would die, and would have to unplug the battery a few times just to get power to the dome lights again. After having found the fuse bolt loose, and tightening it, I haven't had an issue where I lost power again.

Now, when I go to start this thing, the crank and everything spins around (at 270rpm according to my OBD2) but it doesn't sound like I think a car should sound like when you go to start it. there is no chattering whatsoever, it just sounds like an electric motor whirring, steadily. absolutely no repetitive noises at all. It only makes this noise, and while you're holding the key forward. After a while, it sometimes backfires, but it sounds like its through the Air box, like all the gas is building up.

Ive checked, and checked and checked the timing, over and over. even tore it back down all the way again, and reset everything, following the manual to the T so theres no way my cams and crank are out of time. (even if they were off like a tooth, wouldn't it still start and run, but like ***?)

The only thing I'm thinking of here, is the CKP sensor. It says I have to replace it whenever its taken off, because of the alignment tool, but the new one I ordered that came today for my second attempt at setting the timing, didn't come with the tool. So, I got real **** with it and tried to center it the best I could with the tooth on the wheel that was pointing at it.

What's bothering me is I've checked for spark, and I have it. I definitely have fuel. But what I don't think I have, is compression.

I rented a tested from oreillys and the thing said I had absolutely ZERO compression on all four cylinders.....

This thing ran before I took the loose timing chain off. Could I really have bent all 16 valves, by hand.... while taking the pulley off?

It definitely seems easier to turn the crankshaft by hand now than it did before, and I remember before I finally availed at taking it off for the first time, that it was a real bitch. It was difficult at first just to get past the compression point but then it started to get harder and harder, like possibly the chain was slipping off due to the slack maybe idk.

I still don't see me bending every valve by hand like that.

Every time I take the valve cover off and check for TDC on the cams with the shim on the end, they line up perfect. So the cams are definitely in time with each other.

Whats going on here? is my best bet to tear the head off and just inspect the valves?

Even if the crank was off time with the cams, you'd think there would be some compression....

Help...

 

The cams maybe in time with each other, but are they in time with the compression stroke of number 1 ?
Maybe the crank is 180 degrees out ?

Turn the crank until #1 is top dead centre on he compression stroke, both the exhaust and intake should be closed.
I'm not familiar with this engine, but most have ignition timing marks on the harmonic dampener.
#1 is on compression when the "0" mark is at TDC.

 

the way this motor is designed there are slots at the end of the cams that when in top dead center, and a 5mm piece of steel is slid into them, align with the top of the head. They are offset so they only allow the shim to be placed when at tdc. These motors have no timing marks and they shim for the cams and a pin for the crank are what set them at TDC. There is also a bolt for the crank pulley that goes through it and into the timing cover.

if my timing is off, like... at all. It's going to literally be like 1 degree or so. Which I find unlikely even. The cam lobes for cylinder 1, with everything set at tdc were pointing at 1 and 11 oclock. Which if I'm right means the valves should have been closed.

Tomorrow im going to go through a checklist looking for spark, fuel, and compression again. When I cleaned this car out for the first time I found a can of starter fluid in the back so I'm suspect of the fuel pressure. If I find that I'm getting good spark and good fuel pressure I'm going to do a leakdown test and see where the air is going. I read something recently about IAC valves causing no/low compression?

Idk... pretty sure I'll be pulling this head off this week...

honestly when I was looking st the little things the cam lobes push against, I wanted to say the intake valves looked as tho they weren't sticking out as much as the exhaust ones for cylinder 1. Could. Really have bent 8/16 valves, or more, just by turning the motor by hand? Seems highly unlikely to me but idk

 

WAIT!

i may have just had a lightbulb!

the only thing I have NOT done, every time I go and reset the timing? Is rotate the crankshaft 360 degrees, with the camshafts remaining locked at TDC. Would this do anything for me? Does the stroke really matter when you're setting the timing ? I guess I just thought that "piston going up, means compression." I think this really might be it, because when I was monkeying forever trying to figure out why the timing chain had so much slack in it, I might have turned the crank in such a way that when I went to set the timing, I set it at TDC for the wrong stroke, (i.e. Not the compression stroke.)

 

The valve train turns half the speed of the crank, but at any rate, the lobes are correct at 1 and 11 o-clock for # 1, and the position of the lobes determines the compression stroke.
And yes the piston going up is compression stroke, but you also have to know that he valve train determines the actual compression stroke.
The piston travels up for exhaust too, but then the lobes would not be and 1 and 11 anymore.
Most all four cylinder engines firing order is 1342.
Go through each pistons firing order and watch the valves open and close, the next piston should be #3 and both valves should be closed _ the rest will follow in sequence of course until you get back to # 1.

As far as the IAC valve causing a no compression issue, I don't see how that can happen.
With the air throttle valve wide open for a compression test, you by-pass the IAC valve, so it wouldn't effect the compression test.

If you turned the engine by hand and the valve timing was out, you would have felt the valve coming in contact with the top of the piston.

I don't know if this engine is a non-interference engine, but if it has a chain rather then a belt, it probably is an interference engine _ which means that the valves can be bent if the timing chain is off.

Are there any hydraulic lifters on this engine _ underneath the lifters ?
How are the valve clearances adjusted ?

EDIT:
Something else too, can the cam shafts be interchanged.
I'm sure you've checked this, but it should be mentioned.

Another EDIT:
Assuming that I was watching the right videos, what can happen with these are the bolts that hold the cam shaft sprockets can loosen up and cause timing issues.
The sprocket have no pins in them, so if the bolts come lose, the sprockets are free to turn on their own.
There's a special washer that has to be replaced on both cams if the bolts are disturbed.

One guy had the intake bolt come lose and the cam had moved, just to the point where it wouldn't start _ it hardly shifted.

I would check and make sure those bolts are tight, I think 55 foot pounds is what they should be.
If the sprockets did move, then valve damage probably occurred.
The bottom sprocket at the end of the crank also has no key, it relies on this special thin washer and the proper torque of the harmonic dampener bolt to keep it from moving.

At any rate, if there is something else to add, Ron will post.
He's sort of the go to guy around here.

 

I have not attempted to swap the cams but something I have been thinking about is what you just mentioned. The fact that the alignment of the sprocket on the cam could be off or something, from either being setup wrong before or loose or whatever. I haven't touched the bolts on either one myself, but I've had to put a crescent wrench on the intake cam, in order to align it properly so that the cam locking tool would slide into place. And it almost looks like the one side is pressed in a little more/less than the other. (I'm gonna get crazy and inspect the lobe movement tomorrow with the cover off. And there does seem to be hydraulic tappets, or whatever I'm referring to as "the things the lobes press on)

Would it do me any good to order an endoscope that I can plug into my phone/laptop and visually inspect the valves? Or could something as small as a leak you can't see cause 0 compression across the board?

I am not certain how the valve clearances are adjusted, I haven't tore into anything farther than the timing cover and chain essentially. Haven't removed the crank sprocket or any of the cam sprockets.

When I tore the cover off I noticed right away that the top bolt to the guide arm was stripped out and flopping around, which allowed the chain to stretch out. I never heard any sort of noise that would indicate I struck the valves with the pistons but I do remember how it used to be much harder to rotate the crank by hand due to compression and how before I was actually able to release the ungodly tight pulley bolt, how it started to get reallllllll hard to complete a clockwise rotation past TDC.

I'm thinking tomorrow I'm
Going to skip the leakdown test and just hook up some shop air to the cylinders and check to see where the air is coming out of each cylinder.

The only thing I'm thinking I could have done wrong here is the compression test... you mentioned having the air throttle wide open... I didn't do that... could that be why I wasn't getting any readings?


EDIT: What is concerning me right now (idk if I mentioned this before) is if I crank the key forward with the throttle held down (trying to shut off gas thinking that the cylinders are flooded and causing the rings not to seal) and let it spin for idk 10 seconds, I get a loud pop in the air box, which I'm assuming is built up gasses detonating....

 

Watch this video, skip ahead when he gets to where he "times" the valve train.


Because there are no alignment pins on the cam sprockets or the one on the crank, the timing has to be checked like in the video.

If the valves were bent, I don't think you would see that with a scope.

Hooking up some air to the cylinders is a good plan, you will be able to hear if the valves are leaking.

Even with the throttle closed you would have some compression, but you have zero.
And the fact that you can turn the engine over by hand and you feel no resistance indicates that there is no compression. (I'm assuming that the spark plugs were in place)

Holding the throttle wide open shuts the injectors off.
It's a flooded engine protocol.
If for what ever reason it does become flooded, that's what you would do.

And about the cams being wrong, the intake has variable valve timing, so it would be highly unlikely that they have been switched.

 

My motor does not have the VVT so it just looks like two of the sprockets on the left.

You can kind of see them in this photo. http://imgur.com/132Nuos

I'll watch that video and see if the timing of the cams pertains to my situation.


edit: what's bothering me right now is the crank tdc pin. Orginally I used a 40mm bolt, which serves do exactly what I've seen in all these videos, where the crank weight buts up against the side of it coming flush with the pan. Now, the chillton book says to use a bolt exactly 63.4 mm long, which would make the crank weight stop underneath it, instead of bumping up against the end on it, on its side flat. I thought this was my problem so I made a 64.3 mm bolt and redid the whole thing but still the same result. I think next time I'm going to go back to the 40mm bolt, but focus more on the cams and loosing their bolts and spinning them in order to get the chain tension right

im gonna take some more photos, if not a video to see if that will help figure out what's going on wrong here

 

Do your air leak test with the compressor.
This will tell you for sure if any of the valves are bent.
With out knowing this, it will be impossible to determine if there is anything else wrong.

The length of the bolt that's used to lock the crank at TDC, I would think is quite critical, make sure the length is right according the manual.
If all is right, then the bolt that's used to lock the harmonic dampener to the timing cover will line up.

The engine is designed to have the cams and crank locked into place first with the cam bolts lose and with out the dampener in place.

The chain, hydraulic tensioner and guides are then tensioned in their running position.
Finally the cam shaft bolts are torqued down and the timing cover is put in place.
After that, the dampener is locked to the timing cover and that bolt is torqued.

The whole thing seems quite critical, any deviation from this procedure may have bent the valves.

Who knows who has been messing around in there, maybe the special lock washers on the cams are missing.
I think someone got in there and tried to fix it and didn't do it right.
They got in running, but because it wasn't done right the chain broke.

As for the shop, they obviously didn't do it right, they didn't fix the stripped out tensioner bolt.
They probably caused it.

 

Oh, that shop DEFINITELY didn't know what they were doing. I know for a fact they actually did something, because the head gasket looks brand freaking new. And they definitely stripped out that bolt.

That leads into this news. I just got done washing up from tearing the entire head off of the motor. Every single intake valve is bent so badly that you can see daylight through them. And theres some substantial denting to the piston heads, but none of them have any holes or anything like that.

I noticed when taking the cam gears off that not only is one different than the other (even though when compared tooth to tooth, they are the same). I think the intake one was on backwards though because the backside of the exhaust on had recess on it that matched the end of the cam, an so does the other, but only on one side, and it was facing the Bolt side, not the cam. In my mind, you'd think that should be up against the end of the cam. you can see what I'm talking about in the photo album I'm uploading to imugr right now.

all of my exhaust valves are royally jacked. It had to have been on the way out during the 60 mile drive from the shop that the previous owner had it being worked on at, to my house. I find it hard to believe that I made dents that deep just from turning the crank by hand lol.

What do you think is my most cost effective route here? They want like 350$ for a whole new head at advanced auto but it looks to me like my exhaust valves are totally useable. Wont I need some special tools just to get those damn things out? someone said something about having to lash the news ones and crap and idk if its cost effective for all the ticking around ill have to do? It doesn't look like I need new gaskets or anything, and I know the head bolts are supposed to be one time use only but this car has 208k on it and idk how important it is to me right now to spend an extra 50$ just to have new bolts. plus, they technically have only been in the head for like a week. idk how much stretching they've done during that short amount of time.


Pics of the b*tch
http://imgur.com/a/lnW7L

 

The big notches in the pistons are factory (with out checking) _ probably the intake side to allow more fuel in.
You can see the smaller indents on the opposite side, those are definitely not supposed to be there, but it won't hurt the engine.

That's always the question, should I rebuild the old head or replace it with a refurbished one.
If you have a trusted machine shop, then I would take the head there and have them rebuild it.
Pressure test, check for cracks, maybe new guides and certainly new intake valves _ surface check etc.
I don't like to cut corners, it just comes back and bites in the *** down the road.

350.00 bucks doesn't sound too bad for a complete head, I'm assuming that comes with valves and ready to go.
Most come with out the cam shafts.

You will need new head bolts if they are TTY _ again trying to save 50 bucks will just show up later as more problems _ head warpage and leaky head gasket.

Either or can be a F-U-C-K up.
Bad machine shops that don't to things right, or new/refurbished heads that come from China _ crappy metal and bad castings.

About getting the valves out _ the machine shop will do that and if they do it right, the valves will be in the head ready to go.

Pretty sure the hydraulic lifters are underneath the buckets that the cam lobes come in contact with, so I don't know what that other person means about having to lash the new valves in.
Maybe he meant "lap" the valves in, but you don't want to do that, that's an old school practice that shouldn't be done anymore.

When it's time to put it back together, take great care and follow the valve timing procedure exactly.
Just from looking at the way the pistons are designed and the finicky valve timing procedure, there is very little room for error here.
If it's out just a couple of degrees either way, I'm betting the valves will be bent again.
Imagine the piston on it's way up and the valve moving out of the way with only a few mm clearance before it makes contact with the piston.
I think they were trying to eek out as much horse power as possible here, so the longer the intake valve stays open, the more fuel/air mixture can flow into the engine.
They didn't want to loose any compression either, so tolerances are very tight.

For what ever reason if you do want to take it apart your self, this is the valve spring compression tool you need. or something similar to that.
The clamp needs to be big enough to clear the head itself.

https://www.princessauto.com/en/deta...or/A-p8003725e

 

i haven't looked into he price to do everything myself but to be quite honest, it really sounds like buying a whole head is the easiest and most cost effective way to go. Oreillys wanted 360$ out the door for just the valves and a gasket kit. But I lucked out and all my gasgkests are good. I think I saw a set of bolts for like 20$ on eBay or something. A semi local salvage yard wants 125$ for a used head but they won't guarantee any of the moving parts just the head. Considering I only paid 600$ for this beast I thing I did okay. Might do myself a service to buy the actual timing pin/shim kit while I'm at it so I can take the guessing out. I honestly think the chilton manual is wrong and I need the 303-507 tool. Just wouldn't make sense that the cam weight should butt up against the side of the pin and not the end of it on it's flat. I made a home made pin as per the directions of the manual and I followed it to a T. Exactly 63.4 mm long. But all the videos I see show the pin stopping the flat on the weight where it's flush. I'll try and find the video I watched that showed it. https://youtu.be/IL5P7wEIymM just like that. There's no way that pin is 2.5 inches long. The 40mm bolt I used originally provided the same results in that video.

 

You can always talk to the Mazda/Ford dealer to verify the actual length of that "stop" bolt.
Wouldn't be the first time a manual was wrong, I find the newer the vehicle, the more inaccurate the manuals become.
Looks like you have the project under control.

 

yeah good idea, ill call the Ford dealer and see what they say I need for the pin. If it's the 303-507 or whatever. If I'm honest I've never take on a task this daunting lol, but the motor looked so small I wasn't as intimidated as I have been by v8's that are tucked up against the firewall. I do have to say that I'm just the slightest bit worried about whether it will be harder to install the head with the air intake already attached like I took it out or without. I'll either have to hold the whole thing while attaching hoses under the air intake or deal with trying to thread in all the hidden bolts with little clearance behind the radiator.

 

You'll do fine, don't rush things. Take it a step at a time.
After watching all these videos the best advise I can give is when torqueing down the cam sprockets is this.
Don't rely solely on the locking plates on the end of the cams when torqueing down the bolts to keep them from turning, it's been said that if you do it this way, you'll brake the cams.
There's an area on the cams where you can get a wrench on, use that to take the load.

 

yeah ah I definitely have utilized them lol. There's only one bolt in the center of the air intake that I have very little clearance, and zero line of sight on. I wasn't able to actually remove it before removing the whole head so I don't really see myself installing it with the head already installed. I'll probably just set a couple rags on the top of the block while setting everything in so I can hook everything up without scratching anything or the head gasket or something.

 

http://imgur.com/8xSRviX
well shes all tranplanted in, just ran into a snag with the vacuuk hoses and where they go exactly. There's just this one I can't figure out where goes, haven't searched super hard yet because I ran out of daylight before I could look around. Maybe you'll know? I'll post a pic. I'm pretty sure the rest is right, guess I'll know eventually. I'm really paranoid about figuring her up seeing as I've had it apart 3 times now but, with all that practice she's gotta be right now.



http://imgur.com/8xSRviX

 

Can't help you with that vacuum line at all, I'm just not familiar enough with it to figure it out.
It sure didn't take you long to get the head sorted though, I'm impressed !

And about starting for the first time _ you know the drill _ gently rotate the engine by hand.
I carry that step a bit further too, I put #1 plug back in, you should feel compression resistance.

 

Well, just as I feared originally, I missed. vacuum hose up under the intake manifold. Got her on best I could but theres no way that is humanly possible to put that clamp on there without removing the manifold, I guess unless I had some super long pliers.

She's running now, but it... well. aint right. Idk if its fuel/trim orientated, or just transmission damage, but she's vastly under powered on acceleration and when you get on it, she doesn't want to shift, and herks and jerks. I wonder if the cat is bad/clogged up because when I got it running again it was throwing rich system codes and bad 02 sensor codes for sensor 2, so I replaced that, and haven't had a single code since then.

At first I only noticed it in third gear, she's just wind up all the way to 5000rpm and wouldn't shift until I let off the gas, and would jerk/hesitate while going up hills. i even did the fuel/trim relearn process, but I did drive It a little bit right after hooking the battery up to put some gas in it, but the next time I started it I did the whole "put it in park and yada yada."

Now when I try to put some stank on it when taking off, even If first gear, she'll wind way up into the top end and not want to shift, and do It so poorly, like theres no *** at all. and the last time I did it, I noticed the exhaust smelled real rank.

I did change the plugs, wondering if I wash having some misfire nonsense, and two out of the 4 plugs were pretty damn wet. When I drive it real gingerly like a grandpa it does "okay".

I got a trans filter coming tomorrow, the oil looked pretty damn black, and some valvoline max ATF (the Dacron V whatever the crap it says it needs, turns out I accidentally got the right sh*t.) and a bottle of some Lucas trans fix. I'm not super hopeful about it fixing whatevers going wrong but it should help some. Im leaning more towards vacuum or fuel issues or perhaps the clogged cat. I'm gonna yank the 02 sensors out and see if theres any kind of difference.

You know I wonder if it would do my any good to upgrade my scan tool. All I have is a cheap little obd2 scanner that just reads codes and has some live data like voltages and rpm and stuff. Theres an 80$ one on amazon with some pretty decent reviews, I wonder if I can see any more information than I could with what I got with that. my fear is that its just a glorified code reader with more information about each code. But currently I'm not pulling any codes with the shat conditions I'm currently suffering.