Isuzu SUV Forum banner

How to time the 4ze1 2.6 4 cylinder engine.

73K views 64 replies 17 participants last post by  RickP 
#1 ·
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.


Next install this washer.


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).



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.


If the crank were rotated 180 degrees(not 360) the #2 + #3 cylinders would be up like this.


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.


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.


Now rotate the crank a few turns clockwise and reset to #4 TDC at the crank pulley.


The cam pulley should also line up. Since I have a NEW head mine lined up perfectly! :D


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.


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.


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.


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.




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?


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.


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.


What it should look like when all is right.

 
See less See more
19
#27 ·
I tried setting the timing belt and taking the slack out of the right side by turning the motor over counter clockwise. However, when taking the slack out, I end up with my cam marks lined up and then the crank sprocket off 1 tooth.

Tomorrow I shall try setting the cam mark, then setting the crank mark off one tooth. Hopefully, when I draw the slack out everything will line up.
 
#28 ·
It's kind of a Pain keeping the belt tight when installing it so you get the timing right for sure, sometimes you have to move the cam sprocket ever so slightly to get the right tooth combo then turn it back, then take out the slack and set the tensioner tension.. I like to (rock )turn the motor back and forth a few times then come up to the marks to make sure all is well..
 
#29 ·
I tried it again today. The mark is still off. I took the slack out of the left side and but when it's all said and done the crank marks line up but the cam mark is about half a tooth off.

I think when I set the timing on the stand, the tensioner bolt wasn't released. So I was able to line up the lower mark and then move the upper mark with a wrench on the cam gear to move it counter clockwise a half tooth, lining up the cam mark. But this was moving some slack off the tensioner side and moving it to the left side. Once the tensioner is unsprung though, it pulls the cam gear slightly, taking the slack out of the left side and moving the cam mark half a tooth off.

I know if isn't a matter of it being off a whole tooth. If I was, it would still be off half a tooth but in the other direction.

I am thinking there is plenty of adjustment in the distributor to be able to set the appropriate ignition timing.
 
#30 ·
Thanks Squatch, this is the best I've seen on the topic. My next step is to remove the cam (I dont want to bend any valves), then remove the lower timing cover and follow your footsteps....Harry
 
#31 ·
Side note..
When you get the head or block surfaced it brings the pullys closer together.. I've seen in several occasions where the cam will be off by half the tooth.. It's nothing to worry about and generally the belt will stretch a bit and retard the cam timing anyway.. Chain drivin cams do the same thing as well.. If you try to jump the tooth advanced it pulls to far.. Other side note a slightly retarded cam will give more bottom end, it works out to about 2-3 deg ,which can be adjust with the distributor timing ...
 
#32 ·
some questions :
next saturday will work with my engine again , 1000 miles rebuilder for me ,new cylinder head , piston rings , crankshaft bearings , oil and water pump . this is the time for adjust cyilnder head bolts and valves
. the engine knock ( pistons ) with 93 octane gas , when use 98 octane is much better , but I see 1 point delayed in camshaft gear , verify urgent !! temperature is Ok without problem
the engine start in 1/ 2 second is very good !! but I need work in timming belt and distributor . ( nippondenso )

stupid question !!! , because in my country all engines have a cylinder 1 near to radiator and cyilinder 4 Gear box side ( ford - chevy . etc etc old series ) in 4zd1 is the same ???
fuel consumption in city 1 liter each 10 km . last trip with my caravan behind 20 liter each 100 km - bad bad bad ! is a 4zd1 no is a HEMI 7 LITER !!!
lisen to answers
excuseme for my bad english .
regards from argentinas pampa
 
#33 ·
It sounds like your engine is pinging really bad, that can ruin the pistons very quickly !! # 1 is up front like usual.. What is your ignition timing set at ?? The cam timing may or may not be off but if it is you need to correct that first and foremost ...
Did you ever verify dots on the crank itself to the cam dot ?? The pullys / balancer likes to slip/turn and it will throw off your initial engine crank/cam timing ... Squatch has plenty of pictures showing all of this so take your time and look through so you will have a good understanding of what you need to Look for...
 
#34 ·
bradzuzu said:
It sounds like your engine is pinging really bad, that can ruin the pistons very quickly !! # 1 is up front like usual.. What is your ignition timing set at ?? The cam timing may or may not be off but if it is you need to correct that first and foremost ...
Did you ever verify dots on the crank itself to the cam dot ?? The pullys / balancer likes to slip/turn and it will throw off your initial engine crank/cam timing ... Squatch has plenty of pictures showing all of this so take your time and look through so you will have a good understanding of what you need to Look for...
ok thanks for your help
ignition timming 6 degrees to 800 RPM . next friday night ( the summer this year is very hot here ) will work in all itmes . and will send pictures with my work -
the distributor is the target , also timming belt too , i think to buy spare parts in Us , ( especially ignition parts ) are difficult to buy in my country now

best regards
 
#35 ·
well , in this moment I verify vacuum advance , 800 RPM 6 degrees ok , when the engine go to 1200 rpm , the same 6 degrees wihout changes , when the engine go 1455 RPM advance 12 degrees , when the engine go to 1600 RPM THE ADVANCE GO TO OUT OF SCALE 12 degrees more !! is WRONG -
Maybe my engine a new vacuum advance but in my country is not avilable , colud you pls to help , where buy this part in USA -
this is my treasure , attach picture my first trip
 

Attachments

#37 ·
this is a 95 . carburated ( nikki ) , without air pump system , type federal US , in this moment attach pictures with timming belt . 1/2 point delayed to signal timing belt camshaft . the cranckshat pulley is compact in 1 piece ,I remember when put the white mark in line with the mark of oil seal support . could you pls help me , 1/2 point is really bad ??
 

Attachments

#38 ·
bragado said:
this is a 95 . carburated ( nikki ) , without air pump system , type federal US , in this moment attach pictures with timming belt . 1/2 point delayed to signal timing belt camshaft . the cranckshat pulley is compact in 1 piece ,I remember when put the white mark in line with the mark of oil seal support . could you pls help me , 1/2 point is really bad ??
 

Attachments

#39 ·
You should probly move this to a post in drivetrain problems dude, you'll get more input.. You should probly remove the lower cover and match up all the timing points, I'm guessing the ballencer has slipped ...
 
#40 ·
bradzuzu said:
You should probly move this to a post in drivetrain problems dude, you'll get more input.. You should probly remove the lower cover and match up all the timing points, I'm guessing the ballencer has slipped ...
ok in this moment the cranckshaft bolt was fix with loctite , I need to a pNeumatic tool . I m in problems ... will work in that
thanks you !!
 
#41 ·
well , disasembled , all parts and aseembled again , all ok , when I see the pictures of squach , your matchmark plate side cammshaft is in the same place of my gear is .
is possible , the jappanese man was drunk when assemble my engine -
thans a lot , and now I m going to fininsh my truck .
 
#43 ·
IsuzuGeek said:
Selador said:
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.
Bart
Both are at TDC, but one's at the top of its compression stroke, and the other's at the top of its exhaust stroke.

Piston #4 is at TDC at the top of its compression stroke, and at the top of its exhaust stroke, but how do you know which is which, when it comes to timing? YOU don't, but the camshaft does: when the timing marks are lined up, THAT'S TDC of #4's compression stroke (which also happens to be TDC of piston #1's exhaust stroke). That's just the way Isuzu designed it. Why they did it that way when most other vehicles use cylinder #1 as a reference, who knows: maybe it facilitated assembly line speed. You COULD take it upon yourself to modify the markings such that they correspond to the position of the piston in cylinder #1, but why bother, now that you know the 4ZE1 bases them on cylinder #4?
 
#44 ·
Regarding TDC: yes: pistons #1 and #4 are simultaneously at TDC when the crank and cam timing marks are lined up: the difference is that #4 is at TDC of the compression stroke, whereas #1 is at TDC of the exhaust stroke. Rotate the crank 360 degrees, and the opposite becomes true.

A point of confusion that's hard to get past is that Isuzu, for no compelling reason I've yet read, decided to base the ignition timing of the 4ZE1 engine on cylinder #4 (despite the fact that most every other engine ever built bases ignition timing on cylinder #1). In other words, when the crankshaft and camshaft are simultaneously lined up with their respective timing marks, it's the #4 spark plug that's firing. Consequently, you attach the inductor of your timing light to cylinder #4's spark plug wire when fine-tuning the ignition timing.
 
#48 ·
PhilD said:
Squatch: thanks for the great post! Is there a particular alignment the mark on the harmonic balancer is supposed to have relative to the keyway, or something like that?
I'm sure there is but I have no idea what the measurement is. Just line the timing pulleys up and put the cover on. If it doesn't line up with the TDC on the cover it's off some.
 
#51 ·
I do believe I have managed to get the timing right BUT the engine begins to stall after a minute or so at 2000 rpms and loses power under load. Replaced injs., m.a.f. and several other parts. Map sensor was not in place when I got the truck three years ago with the old engine in place and it ran just fine. I would replace it if I knew it would help and if knew the wiring for said sensor. I can't find any, open or otherwise, plug that would fit the m.a.p. that goes with this truck. Any advise would be appreciated. It has been quite an experience trying to learn these 4ze1's. I hope I can get it right!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top