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Discussion Starter · #1 ·
so i spent the half day sat taking the timing belt off.

spent today fixing the coolant leak around the goose neck and installing thermostat and waterpump with respective gaskets.


also intstalled new timing belt and tensioner.

now the question is this. i followed the FSM and the haynes manual for belt installation.

placed all marks correctly in their respective positions. counted 40 teeth between marks on camshafts and 43 teeth from driverside cam to crankshaft.
the next step is to set the tensioner which kinda sets itself. then rotate the crankshaft atleast twice to see if everything lines up. well the marks on the belt didnt although the marks on the pulleys did. i continued turning the crankshaft until the belt resembled the initial setting and all white marks are off one tooth.

is this wrong or should be expected? i assumed when i set the white belt marks exactly to the pulley and camshaft marks the upon rotation they should all line back up not be one tooth off.
granted it takes quite a few rotations to get the belt and all its markings to move all the way around the cam and crankshaft sprockets.(my arms hurt)

have it back together for the most part but still could easily take off covers and check or set again. i did it twice and got same results. once i did it with tensioner adjusted fully and then i did it again with tensioner adjust on its own spring force. both times after rotating the belt around the markings were all one tooth forward. i did nothing and rotated it again and they were two teeth off(forward).

lets here the thoughts and opinions. i will post some pics of the job as well. not much of a write up tho.

thanks
 

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Discussion Starter · #2 · (Edited)
really???

no thoughts or input?


ok i be patient, here are some pics of the 2004 S/C LB timing belt job.

first two pics are of the belt wear.

next two are the alignment notch on crankshaft and last is overall shot of everything
 

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Discussion Starter · #3 · (Edited)
more pics....

a few more

first one i point out the leak/seepage i had at hose clamp area.

picture 2 shows LH camshaft align mark and notch.

third pic is of under the thermostat housing. there is a long tube connected to the back side of the housing preventing me from removing it totally. had to work on it as installed. i just removed the gooseneck and lifted the thermo housing up to find space to clean old gasket and install new RTV
i have another pic of this one as well.

the last pic if of old waterpump and thermo housing before work.
 

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Discussion Starter · #4 · (Edited)
last ones....

if anyone has questions please feel free

first pic the timing covers are off and the second pic they are on.
third pic is RH camshaft align mark and notch.

fourth pic is of back timing cover and wear marks from a very loose and sloppy belt(115k)

the last pic is of the thermo housing and i point out the long tube that is connected and is difficult to remove. i did not remove it just wroked on it best i could while it was in.
 

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Discussion Starter · #5 ·
so really...?

well all back together and trying to figure out why the timing marks on crankshaft are now situated at 8oclock instead of 12 oclock.

truck runs good atleast better than before and a lot quieter.


any ideas?
 

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Dunno, I had mine done at Nissan Dealer. Before, the tensioner was worn and the belt was sloppy. Truck runs so much stronger after the job.
 

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Discussion Starter · #8 ·
thanks

Dunno, I had mine done at Nissan Dealer. Before, the tensioner was worn and the belt was sloppy. Truck runs so much stronger after the job.
thanks for the reply.
mine was extremely sloppy as well and cant believe it ran as it did. tensioner didnt look too bad but it had little effect on such a loose belt.

if your under warranty, i can see having them do it. but if your mechanically inclined its a pretty easy job no matter which model engine. just making sure the settings are correct is the hardest part.

anyhow, since i been talking to myself and I, me has determined i set the timing on my truck on the exhaust stroke of piston 1 and not the compression stoke. i think this caused the timing indicators on the crankshaft pulley to rotate CC to sit between 7-9 o'clock instead of 12 where the indicator arrow is.

going to take it out again and verify correct positioning. funny how the service manual never mentioned this or the haynes. the only down side i see right now is the amount of gas i am using. seems like i am really using it. other than that, the truck does run significantly better than before.

glad i did it.
 

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When I did the belt on my '01sc I couldn't find an alignment mark on the oil pump for the crankshaft pully. Had to do a little calculating to figure the mark for that pully. If you're suspecting you used the exhaust stroke on #1 to set it then I'd check it before tearing it apart. You probably already know this, but I'll run it past you anyway.
Bring #1 to tdc and check that the mark on the crankshaft pully is at 0 degrees and the rotor is pointing at #1 terminal on the dist. cap. If those 3 things line up then I think you've got it. If you set it on the exhaust stroke I don't think it would run very good.
 

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ok, what was your question again?
Sorry, I haven't been paying attention to this thread
What I done on the xterra yesterday was line up all three timing marks with the marks on the belt. your numbers are right, 40 between the cam, 43 on the left (drivers) side.
Another verification, put the pulley on and your timing marks should be at the top. The Crank turns twice as many revolutions as the cams. compression and exhaust strokes are the same for the crank.
 

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Discussion Starter · #11 ·
ok, what was your question again?
Sorry, I haven't been paying attention to this thread
What I done on the xterra yesterday was line up all three timing marks with the marks on the belt. your numbers are right, 40 between the cam, 43 on the left (drivers) side.
Another verification, put the pulley on and your timing marks should be at the top. The Crank turns twice as many revolutions as the cams. compression and exhaust strokes are the same for the crank.
thanks
well let me ask it this way,

how did i move the alignment marks on the crankshaft from 12 o'clock to 9 o'clock?

just looking on how that is possible? like i said it runs good and strong but when i shine a timing light down to the crankshaft pulley while standing in the middle front of truck, the marks are no longer there at the arrow indicator for me to adjust the distributer from 0degrees to 20 degrees.
 

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not sure why the timing would change that dramatically. If the belt marks are all off the same number, then the cams and crank are timed.
The distributor is gear driven off the left cam, so that shouldn't have moved (unless you pulled your distributor).
 

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Discussion Starter · #13 ·
not sure why the timing would change that dramatically. If the belt marks are all off the same number, then the cams and crank are timed.
The distributor is gear driven off the left cam, so that shouldn't have moved (unless you pulled your distributor).
nope never touched the distributer.

i got one more guy i can ask about that before i get back into it on friday and take it back apart.
 

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Have you brought #1 to tdc and checked the rotor and crankshaft positions? Wouldn't tear it apart until I did that.
 

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Discussion Starter · #15 ·
to the best of my memory...

i pulled the truck into my garage and shut it off. spent the next hour or so cooling it down and removing the radiator. took everything down to the crankshaft pulley and outer timing covers.

rotated crank with ratchet until 0 degrees mark was lined up with arrow indicator.

pulled timing covers and found camshaft marks 180 from they were supposed to be.

rotated crankshaft around until camshafts lined up and 0 degrees mark on crankshaft lined up with arrow indicator.

pretty much thats how i left it.

FSM doesnt really say to do much more than that.

i broke #5 spark plug wire and i am getting the new set tomorrow. since i have to remove the supercharger feeder tube to replace it i am just gonna tear it down and use a probe in cylinder #1 to verify TDC and then set the timing again.

wish i knew the exact reason for this shift as it would certainly make fixing it alot easier.

i did rotate the passenger side camshaft CCW off the mark until it clicked, BUT i returned it (CW)to the timing mark right away. just thought i would throw that out. i am positive it didnt rotate around or any further than one click. i think the timing mark is located in the middle of the cam stroke.


thanks for the mental power and the suggestions.
 

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What did you use for a timing mark on the crankshaft timing gear? When you set the timing mark on 0, after finding it 180 out, did you check the location of the rotor? If the passenger's side cam gear timing mark lines up w/the mark on the back plate, and the crankshaft is pointing to 0 then you're at tdc. Rotor s/b pointing to #1 terminal.
I see what you're saying about the timing mark located at the middle of the stroke. That would put it off 90 degrees or so.
Just throwing stuff out there.
 

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What did you use for a timing mark on the crankshaft timing gear? When you set the timing mark on 0, after finding it 180 out, did you check the location of the rotor? If the passenger's side cam gear timing mark lines up w/the mark on the back plate, and the crankshaft is pointing to 0 then you're at tdc. Rotor s/b pointing to #1 terminal.
I see what you're saying about the timing mark located at the middle of the stroke. That would put it off 90 degrees or so.
Just throwing stuff out there.
the crank shaft timing gear has a dimple in it.
if all the marks on the belt line up with dimples or marks on the cam gears, then your in time. I dont see any way it could be out of time.
(I know you know, but I gotta ask) you realize when the manual says left, that means the left side of the engine and your looking at it backwards (left is drivers side)I second guessed myself a couple times on my daughters X
 

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The dimples, belt marks, AND backplate marks (for the cam gears) have to line up. The DSM also shows an alignment mark on the oil pump, for the crank gear dimple, but I never found one. When everything is lined up the crank gear is still 1/2 tooth off. I think you have to turn the crank 1/2 tooth off tdc (forget which way) to get the belt on.
After it's installed and rotated a couple of times I think the only marks that matter are the dimples and backplate marks. I don't think the belt marks come around true. Might be wrong about the belt marks, but not the dimples and backplate marks.
 

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Discussion Starter · #19 ·
The dimples, belt marks, AND backplate marks (for the cam gears) have to line up. The DSM also shows an alignment mark on the oil pump, for the crank gear dimple, but I never found one. When everything is lined up the crank gear is still 1/2 tooth off. I think you have to turn the crank 1/2 tooth off tdc (forget which way) to get the belt on.
After it's installed and rotated a couple of times I think the only marks that matter are the dimples and backplate marks. I don't think the belt marks come around true. Might be wrong about the belt marks, but not the dimples and backplate marks.


yes the belt marks dont matter after everything else lines up. and they cant. why? it physics. the belt is longer on the tensioner side so it will throw the belt marks off on each rotation. as long as the crank and camshaft marks line up with the punch marks its good. the belt marks should line back up eventually but thats a lot of revolutions.

anyhow, PERSONALLY i was half a tooth off on the crankshaft which caused the indicators to be off. i reset it and got them back. also knocked off a hose to the intake. caused me some trouble. finally found it and truck ran good. then got leak on water pump and had to install a second one. no leak now. Followed FSM for timing check and found timing off and set to around 6 degrees BTDC. MPG was approximately 13.8 at this setting. in process now of checking MPG with timing set to aproximately 12 degrees BTDC. 1/2 tanks to go or so.


truck dogged at 6 degrees but has good power now at 12. but i dont think its all accurate, so i trying and testing and adjusting. may advance it alittle more as i dont really think 0 = 0

driverside cam shaft seemed to be loose. more so than passenger side. trying not to think about that. so far i am guessing i have had to dump around 3 grand so far this year in getting it back to almost new running condition.

Heres a question,,,, IF i loosen the nut and rotate the distributer as far as i can towards the firewall, should that be considered 0 degrees BTDC? and my timing arrow should ine up with the first mark on the crankshaft?
 

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I don't know if rotating the dist. all the way to the firewall will be 0. If you bring #1 to absolute tdc (use a probe) and set the crank on 0, the rotor should be pointing to #1 terminal on the dist. cap. The position of the rotor will give you an estimation of how far you're off.
My knock sensor quit working years ago, so I've been able to time by ear. Just advance the dist. 'till you hear spark knock, under load, and back it off a little. S/b just about perfect. Another way is to fill the tank w/regular gas, advance 'till you hear spark knock, and fill it up w/high test. Sometimes takes 3 or 4 tries. To hear spark knock, just put the engine under load (climbing a hill in too high a gear will usually do it). Or just goose the throttle in too high a gear.
 
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