How to time the 4ze1 2.6 4 cylinder engine.

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How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Thu Feb 23, 2012 1:09 pm

Please sticky this thread.

I've been promising this for a good while now. So here ya' go!

This is how you time a 2.6 4ze1! :D

1st bare crank end with new seal.
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Next install this washer.
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Set the lower timing (crank) pulley in place on the key and crank. The bolt was installed so the crank can be rotated. This is what it looks like when the lower timing marks are lined up. (not perfect line up in these pics yet).
Image
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When the crank pulley is on the mark the pistons will be in this position. Both #1 + #4 are in the top dead center position. At this point the engine doesn't care which is which.
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If the crank were rotated 180 degrees(not 360) the #2 + #3 cylinders would be up like this.
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Anyway next step is to install the cam pulley and rotate untill the mark on the pulley matches the mark on the plate. At this point the cam shaft is set so that the #4 cylinder is at TDC. So when both the lower and upper pulleys are on the mark we are timed for #4 TDC. This is Isuzu spec. The cam now decides the firing order from now on. Just a note. The white mark in this pic will soon be changed to red. that way all important base marks are red in my pics. I also counted teeth so that I could paint another mark on the opposite side of this pulley for setting the valves.
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Once both pulleys are on the marks you want to fit the timing belt from lower pulley, over the oil pump pulley, onto the cam pulley so it is tight on the left side. It will now be hooked behhind the tensioner. The proper way to get slack in the tensioner is like this.
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Now rotate the crank a few turns clockwise and reset to #4 TDC at the crank pulley.
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The cam pulley should also line up. Since I have a NEW head mine lined up perfectly! :D
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At this point you can now tighten up both bolts on the belt tensioner.

The next step is to adjust the valves. but I'll skip that step to finish the timing and come back to valve adjustment.

Leave the engine at #4 TDC. Find the dist cap and look inside for the terminal marked #4. Make a mark on the edge of the cap that lines up with this terminal.
Note this is a screw down cap as opposed to a clip hold down. the pick ups got a slightly different dist.
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Now put the cap on the dist and mark the dist body to match. Notice my paint ran a bit so I made a precise mark with a sharpie.
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Next I put a put a new O-ring on my dist and lubed it with silicone spray. I also installed the timing plate to the head. (Note-this part is different between the clip on and screw on dists) Lube the shaft and gears with assemby lube or motor oil.
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Now install the distributor while pushing and turning as it engages the cam gear. It may take a couple of tries. When all is said and done the rotor should just be starting to point at the mark you made on the dist body. (dist turns clockwise). This is with the mark on the dist adjustment base and the timing plate centered.
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Congratulations your engine is now timed very close to right on for start up.

But there is more. Next install the lower timing cover. You did see fit to high light the timing marks correct?
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I'm now going to not only stress to "never install a timing belt by the harmonic balancer/damper marks" but I'm going to show you 2 good reasons why.
1st is my old damper. The engine is set at #4 TDC. The big white mark in the lower left is what should be on the TDC mark now. The outer ring of this damper has slipped badly.
Image

2nd reason. This is a brand new OEM Isuzu damper. It's not quite on the mark either. So I marked it in the correct place. Never had a new damper that was off before. The smaller mark on left is factory. The larger mark on right is mine.
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What it should look like when all is right.

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These links have write-ups and pics of most anything you ever will do on a 2.6 Isuzu. Engine, brakes, suspension, interior, you name it! Enjoy!
Original '88 Trooper frame off build.
viewtopic.php?t=12172
The continuing Trooper project.
viewtopic.php?f=15&t=43909
My '88 Spacecab build. In progress.
viewtopic.php?f=15&t=56442

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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby shooter » Thu Feb 23, 2012 1:52 pm

Very vice. My new damper was off by 3 degrees in the same direction as yours. Question. Looking at the dizzy hold down bolt, didn't you miss your alignment a bit? Dizzy appears to be rotated counter clockwise to me. If all marks, etc were aligned, shouldn't the bolt be dead center of the adjustment window? Regardless, excellent tutorial.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Thu Feb 23, 2012 1:58 pm

shooter wrote:Very vice. My new damper was off by 3 degrees in the same direction as yours. Question. Looking at the dizzy hold down bolt, didn't you miss your alignment a bit? Dizzy appears to be rotated counter clockwise to me. If all marks, etc were aligned, shouldn't the bolt be dead center of the adjustment window? Regardless, excellent tutorial.

I think that has to do with the bolt down dist. it is slightly different shaped in the hold down bolt area. I used the timing plate from a clamp down style(it was cleaner) and it didn't line up. So i had to use plate That came with the dist. Yeah it has a little more adjustment in 1 direction than the other. The marks are centered on each other though. Once the ignition is timed with a light I suspect It'll be adjusted a bit more.
These links have write-ups and pics of most anything you ever will do on a 2.6 Isuzu. Engine, brakes, suspension, interior, you name it! Enjoy!
Original '88 Trooper frame off build.
viewtopic.php?t=12172
The continuing Trooper project.
viewtopic.php?f=15&t=43909
My '88 Spacecab build. In progress.
viewtopic.php?f=15&t=56442
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby T89 » Tue Mar 20, 2012 5:02 pm

Can the 2.6 be installed into the engine bay with the distributor and oil pan already installed? Or is it easier to put the distributor and pan on after the motor is installed?
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Tue Mar 20, 2012 10:22 pm

[quote="T89"]Can the 2.6 be installed into the engine bay with the distributor and oil pan already installed? Or is it easier to put the distributor and pan on after the motor is installed?[/quote]
I install mine as complete as possible. easier to add or remove parts once it's out of the engine bay. Short answer to your question is YES you can. Installing engine into my 1st gen Trooper.
[IMG]http://i172.photobucket.com/albums/w3/squatchout/PTB%205-4-08%20update/P3290006Small.jpg[/IMG]

[IMG]http://i172.photobucket.com/albums/w3/squatchout/PTB%205-4-08%20update/P3290008Small.jpg[/IMG]

I do install the exhaust manifold/header after the engine is in. I use the rear manifold bolt to attach the chain to along with the front lifting hook.

I had already removed the head from the block when I realized I need to pull it from my pickup recently.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby HuntingRat » Mon Apr 09, 2012 11:45 pm

So the catch is to set the rotor to the #4 cylinder instead of the #1?

Also searched for the valve adjustment tutorial...no luck. Was there ever one made? I'm pretty confident on how to do it, but tutorials like this are always nice.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby johnny5ive » Sun May 06, 2012 8:19 pm

The only thing I would say that I do differently is before I tighten the bolt on the belt tensioner I turn the crankshaft counter-clockwise just a little which takes all the slack and puts it on the tensioner side. By turning it only clockwise you run the risk of having the timing belt too loose.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Tue May 15, 2012 10:25 pm

[quote="HuntingRat"]So the catch is to set the rotor to the #4 cylinder instead of the #1?

Also searched for the valve adjustment tutorial...no luck. Was there ever one made? I'm pretty confident on how to do it, but tutorials like this are always nice.[/quote]

No I haven't yet I need to do that.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Tue May 22, 2012 12:40 am

OK, someone clear this up for me:

With the 4Z motors, if #4 is at TDC, does that not also mean that #1 is at TDC? I'm still having trouble getting my Impulse to start, and after reading your tutorial here again, I am wondering if the machine shop timed the motor to #1 and not #4 and all this time I was thinking that this doesn't matter because 1 and 4 fire together and 2 and 3 fire together or am I completely off in my thinking and my timing is off and that is why the motor will not start?

I have removed the plug from the #4 hole, and using a probe I stop turning the motor over by hand when the probe sticks out the most. At that time, all my marks line up also so I think I am at TDC with #4. At the same time, I can probe the #1 hole at it appears to be at TDC also. Is this correct?

Thanks- Bart
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby Selahdoor » Tue May 22, 2012 12:50 am

nfpgasmask wrote:OK, someone clear this up for me:

With the 4Z motors, if #4 is at TDC, does that not also mean that #1 is at TDC? I'm still having trouble getting my Impulse to start, and after reading your tutorial here again, I am wondering if the machine shop timed the motor to #1 and not #4 and all this time I was thinking that this doesn't matter because 1 and 4 fire together and 2 and 3 fire together or am I completely off in my thinking and my timing is off and that is why the motor will not start?

I have removed the plug from the #4 hole, and using a probe I stop turning the motor over by hand when the probe sticks out the most. At that time, all my marks line up also so I think I am at TDC with #4. At the same time, I can probe the #1 hole at it appears to be at TDC also. Is this correct?

Thanks- Bart


When the #1 cylinder is at the top of it's travel, so is the #4 cylinder.

But only one of them is ready to fire.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Tue May 22, 2012 11:33 am

[quote="Selador"]When the #1 cylinder is at the top of it's travel, so is the #4 cylinder.

But only one of them is ready to fire.[/quote]
OK, right. So, how do you tell which one is ready to fire? Or does it not matter, so long as they are both at the top of their travel when you insert the dizzy with the rotor pointing at #4? I'm just trying to make absolutely sure my timing is set right because the symptoms I am having with the Impulse tell me that it isn't. But it could still be something else.

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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Tue May 22, 2012 12:03 pm

The dist is what decides when it will fire. If it's pointed at 4 then 4 will fire. The crank position sensor for the computer is part of the dist. It's inside and synced with the rotor position. Crank position sensors do occasioanlly fail. easiest is to just replace the dizzy.

The 4ze1 is a batch fire fuel injection. All 4 cylinders fire (fuel injectors) at once. No big deal because the charge only sits in the port for a fraction of a second before it's drawn into each cylinder.

Bart put a timing light on your truck hooked up to the #4 plug and crank it over. Is it flashing? Is it flashing on the pulley timing mark? Actually you can do either 1 or 4 and should get the same results at the crank pulley. This is because both fire at the same rotation spot. just 360 degrees off from each other. You can also remove the upper timing cover and shine the light on that timing mark on the cam pulley. it should only fire on #4 when the marks line up if the cam is timed to #4.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Tue May 22, 2012 12:12 pm

Thanks, guys.

Yeah, what I am talking about here is the timing for the 4ZC1 in my Impulse. At this point, I am still dealing with a problem. I can get the car to crank but not start, so I am trying to figure out why. I have spark, and while I have not checked fuel pressure or checked my injectors yet, I know I am getting fuel to the rail. So, I just wanted to make ABSOLUTELY SURE I am timing things right, because the timing being off would be a main reason why it will not start. I do have the upper timing cover off, and both the mark there, and the mark on the lower timing cover line up when #4 is at TDC. The only thing that seems a little off in my case, is lining up the rotor to point at #4 in the cap once the dizzy is inserted, it just seems very close but not perfect, but again, I think it is close enough to were it should at least freakin start.

I am temped to buy a new distributor and see if that fixes the problem. If it is not related to ignition though, I must be dealing with a weird fuel problem or something else I cannot sort out.

Bart
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby Selahdoor » Tue May 22, 2012 1:46 pm

nfpgasmask wrote:The only thing that seems a little off in my case, is lining up the rotor to point at #4 in the cap once the dizzy is inserted, it just seems very close but not perfect, but again, I think it is close enough to were it should at least freakin start.
Bart


If the cam gear is off by a tooth on the timing belt, the distributor would seem almost on, but not quite.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Tue May 22, 2012 2:07 pm

So, is there a way to tell if the cam gearis off by a tooth? I don't think that is the case with my car, but just so I know.

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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby Selahdoor » Tue May 22, 2012 2:27 pm

nfpgasmask wrote:So, is there a way to tell if the cam gearis off by a tooth? I don't think that is the case with my car, but just so I know.

Bart


You'll have to take the entire timing cover and balancer off. Don't count on the balancer mark being accurate.

Check the mark on the crank gear first. If it is spot on, check the mark on the cam gear.

This is more tricky than it sounds. You have to get a really good, square-on look at them. And the marks that you line the gears up to, can be decieving. For instance, the mark for the crank gear is not the long mark that goes pretty much straight up the middle. It is a mark that is off to the right of that.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Tue May 22, 2012 2:54 pm

Bart, I don't know that engine but I'm "assuming" the same family so similar enough.The rotor should be just a little early if everything is lined up on the marks. As in the leading edge of the rotor should just be getting to #4. I believe the rotor spins clockwise.

I would spray some starting fluid in the throttle body and try starting it that way if you are sure the cam is right. if it runs on starting fluid it's not an ignition problem but likely fuel.

If the cam belt is off a tooth it is obvious at the timing marks on the block. The dist can also be off a tooth or so in either direction. It should still start and run but poorly.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Tue May 22, 2012 3:04 pm

[quote="squatch"]Bart, I don't know that engine but I'm "assuming" the same family so similar enough.The rotor should be just a little early if everything is lined up on the marks. As in the leading edge of the rotor should just be getting to #4. I believe the rotor spins clockwise.

I would spray some starting fluid in the throttle body and try starting it that way if you are sure the cam is right. if it runs on starting fluid it's not an ignition problem but likely fuel.

If the cam belt is off a tooth it is obvious at the timing marks on the block. The dist can also be off a tooth or so in either direction. It should still start and run but poorly.[/quote]

Right, when I get the rotor in, it is a little early, so I think I have it all right and timed right. Usually what happens is the very first time I try to start it, it seems like it wants to start or might catch just a little but then it dies. Then any subsequent attempts seem to produce the same results, cranking but no start. The plugs are getting flooded I think. I tried starter fluid and it did nothing. I suppose I could have a large vacuum leak but I don't know where that could be, doesn't make sense since everything is nice and tight. I have not pulled off the EGR yet to see if it is stuck open.

What about the MAF, could a bad MAF cause a failure to start? I woudln't think so, but...

Bart
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby chadzu » Thu Jun 28, 2012 12:08 am

the distributor gear also has a mark on it, offset from the roll pin several degrees. This mark should line up with the ridge in the head casting where the dist. Shaft rides in the head. If you have the crank mark lined up, the cam gear lined up, and the dist. Gear lined up your 4z motor is timmed properly. Line up the dist. Body mark with the clamp mark and the motor will likely be within a degree or two of proper advance.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby bradzuzu » Fri Jul 06, 2012 1:47 am

Theoretically you could set tdc of #1 compression stroke and mark #1 on the cap to and drop your didtrubutor in the same way only with the rotor facing down.. 180 from #4 same same...
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby T89 » Fri Jul 13, 2012 2:07 am

I just spent the whole evening trying to do this. I did it initially when the engine was out. I took the timing belt off to prime the oil pump after I installed the engine in the trooper.

I got the timing belt back on after lining up my marks and I went to turn the crank pully clockwise but as I turned it the tensioner would wind up and it caused the timing belt to skip a tooth. I didn't realize it was doing that until I felt the motor stop turning over because the valves were out of time.

So I got #4 at top dead center, and lined up my cam marks again. Put the belt on. Except this time, I tightened the bolt on the tensioner. Then I turned the crank clockwise and viola. It turns over smoothly.

But I couldn't get the timing marks lined up perfectly. It is difficult to see the lower timing mark with the engine installed. It's about a half a tooth off. I don't think it is a case of it being a tooth off because even if I moved the cam gear one tooth over on the belt it still wouldn't be pointing at the mark. With the marks perfectly lined up I can get the belt on. But once I release the tensioner, it pulls slightly on the cam gear pulling it a half tooth off. I tried moving the cam gear a half tooth off in the other direction before releasing the tensioner but then it didnt pull the cam gear a half tooth over.

I didn't have any of these problems when the engine was on the stand.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby T89 » Fri Jul 13, 2012 2:16 am

[quote="John"]The only thing I would say that I do differently is before I tighten the bolt on the belt tensioner I turn the crankshaft counter-clockwise just a little which takes all the slack and puts it on the tensioner side. By turning it only clockwise you run the risk of having the timing belt too loose.[/quote]

I am going to try this tomorrow and see if it helps get the marks where they need to be. I remember setting the timing belt on the engine stand and my marks were spot on.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby IsuzuGeek » Fri Jul 13, 2012 11:27 am

Yeah, see, this is where I got a little confused with my Impulse, people telling me timing is off like a broken record, but in my case, all marks line up every time 1 and 4 are at TDC. They all line up spot on. So I just cannot see how I could have my timing off. My problem is elsewhere.

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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Fri Jul 13, 2012 11:22 pm

Yeppers john makes great point on this.
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Re: How to time the 4ze1 2.6 4 cylinder engine.

Postby squatch » Fri Jul 13, 2012 11:27 pm

The lower mark is hard to see. That's why I hit them with some touch up paint.

One of the best tools I own is a little mirror about 1.5"x2.5" on an extendable stick like a radio antenna. I use it all the time with a small flashlight to see stuff I couldn't other wise. I have a magnet on the same kind of stick too.
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