"Let me ask this.
Has the timing belt been changed? I’m just wondering if a camshaft is off a tooth or two (maybe too advanced) and this is the cause of the abnormally high readings.’’
Yes, the timing belt was replaced in 2008 by a mechanic.
The top of the belt and camshaft sprockets will be exposed when I check the valve clearance. Will this be enough to tell if the belt is off a tooth? If it will be enough, what should I look for?
Rotate the engine to TDC and check the timing marks on the camshafts. If the timing is correct, the marks will line up as they should. If one is off by a tooth, the mark will be off. If both are off, both marks will be out of line. You can find they way they should line up in most repair manuals, like Haynes or Chiltons. Even www.Autozone.com 's free repair guides should have it.
“Even with the low interest rates, the compound interest will make for a nice nest egg”
Sadly, no. Precisely because the low interest rates one can get for $200-300 a month are below the rate of inflation.
I’d follow BustedKnuckle’s advice about checking the belt timing.
There could be 2 issues; one is the existing problem with the low compression on Cyl. 3 and the second is raised compression which now exists.
That’s the reason I asked about a timing belt change; to determine if something was possibly amiss between the 2006 compression test and the current one due to a timing belt installation problem.
If you go with new spark plugs you might try gapping them a little wider than the specification that is called for.
Add about .007- .010 to the gaps. That will increase the intensity of the spark and make them less prone to fouling, especially on Cyl. 3.
Well, it looks like the EGR sensor issue is solved (knock on wood). What I did was run a guitar string (pipe cleaner probably would have been ideal) through the nipple on the back of the intake ( fire wall side) that the EGR solenoid vacuum hose connects to and cleared out the black junk, then turned off the CEL and have been through two run cycles and so far no P1195 code.
… Now for the valve clearance and timing mark inspection
Okay, the valve clearances are all pretty much within spec except for the intake valves @ cylinder #3. The valve clearance on the left of this cylinder is .006 in. and the one on the right is so tight that I couldn’t even get the thinnest gauge, which is 0015 in. in between the lobe and the valve. So my question is, is it worth it to pay to have the clearances adjusted or should I just go all the way with it and do a valve job? I’m assuming that the valves on #3 must be damaged because this cylinder has been misfiring for many years meaning that the valves have been tight for quite a while, at least since 2003. If I do decide to do a valve job I would do all that I could at home and then take the head to a machine shop for them to do the rest to keep the cost down. Or would I not save much $ by doing it that way?
What do you guys think?
Oh, I forgot to mention. The shop manual has .010 in. – .012 in. as acceptable valve clearance on both intake and exhaust valves.
I would go for the adjustment. It may not work, but compared to the cost of doing the head, and the fact that at the age and miles of this engine, a good valve job will probably unseat the rings and make this a major oil burner, the cost will be a bargain.
If it doesn’t work, I think you should look for a reman engine or another car.
I would adjust only that tight valve on No. 3, run a compression test on that cylinder, drive it for a while, and see what happens. The fact that there is a problem with an intake instead of an exhaust could mean there’s some hope.
With an exhaust valve there would be damage, no doubt about it. With an intake it’s possible the valve face and seat could be gunked up but not burnt. With the valve properly adjusted it’s possible that any deposits that may exist might disappear with some driving and you may go many miles like this.
If you decide to do a valve job then yes you can save a ton of money by doing the cylinder head removal and installation at home along with sending the head out to an auto machine shop for the actual valve work.
Around here anyway, they charge about 5 dollars a hole on a valve job; meaning 5 bucks for the grinding of each valve, the seat, and the setup on that particular valve. (Cylinder head with 8 valves X 5 = 40 dollars, etc.) Any vatting or head surfacing would be extra.
I still have the valve cover off and would love to be able to adjust it myself. Can either of you guys tell me how to do it with common tools ?
A tool that compresses the valve spring is required I believe. Shop around for an experienced mechanic who works at a reasonable scale and has a realistic approach to the situation.
It’s possible to make those pictures smaller. Just sayin’.
LoL. They are pretty big.
I’ll see what I can do…
This design for opening the valves eliminates a lot of weight so that the valve train is more responsive, it is the hardest to adjust. One way is to remove the cam, but you may have to do that a couple of times, and that means messing with the timing belt/chain.
I haven’t done one of these, but I think that there is a way to depress the bucket under the cam, with a special tool, so that you can fish out the shim and replace it with a thinner one. So you will need the tool and a selection of shims.
Since you have the valve cover off, look at the tappet (aka bucket) under the cam lobe and see if the shims are visible or accessible.
Ok4450, why do you say to only have the valve clearance adjusted on the tightest cylinder? To keep the cost down? Or is it possible that something harmful could happen if all of them were adjusted. If it’s just to keep the cost down I don’t mind spending the extra money to have it done right. I know I said that they are all pretty much in spec except No. 3 - but they’re not all completely within spec - just close; five of the exhaust valves are @ .013 in. and some of the other intake valves are off a little.
So if I take it in I would just tell them to check and adjust all of them-to be on the safe side- unless it’s potentially harmful to the engine or ridiculously expensive.
There is a tolerance on the adjustment. If they are in tolerance, there is no need to adjust them. I have seen a quote for making the adjustments that was ridiculously expensive.
keith, I do have the official Mazda work shop manual and It shows the special tools needed to do the job without removing the camshaft. I just haven’t been able to find them online and also kind of shyed away thinking that they would be terribly expensive.
The tools it has listed are: 49 T012 003
49 T012 002
49 T012 004
49 T012 001A
If you could find these and get a price that would be great.
Your workshop manual should have pictures or drawings of these tools. Take it to an autoparts store and look at the special tools area. The larger the store, the better.
You might get away with this trick, since its the #3 cylinder. Slightly loosen the front cam bearing cap, then remove the rest of them. You may be able to tip the cam up enough to get to the shims without special tools and without upsetting the timing chain. You have the engine to look at so you will have to judge if this is feasible.
Slightly loosen the front cam bearing cap on #3 intake camshaft, right? What makes it a “front” there doesn’t seem to be any others unless your referring to the intake camshaft as front and the exhaust camshaft as being the back. I don’t mean to be nit picky, I’m just a little nervous and don’t want to mess anything up. Also, I don’t have a torque wrench so would it be okay if I just snugged the cap bolts when/if I put it back together?
The front, as I meant, is the end of the engine where the #1 cylinder is and where the timing chain is. The back of the engine is connected to the transmission.
Do not do this if you don’t have a torque wrench. Snug is not OK, I mean it might be if you got lucky, but I would not count on that. Also, you are the one looking at the engine so you will need to determine if this is even feasible. I don’t know where the shims are located in relation to the bucket. On a Nissan, you have to remove the cams because the shims are inside the bucket.
And does it matter if the piston is at top dead center or should I just turn the engine until It gives the most space between the lobe and the shim?