Timing belt tension adjustment

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Maksym Moyseyenko - 09 Jun 2004 06:37 GMT

I just changed the timing belt in my Maxima GXE 94, and thanks God it
looks like I didn't screw up valve timing.

I'd like to share my concerns about timing belt tension adjustment.
I did everything as per FSM and ended up with hex hole in 11-11:30
position. Which contradicts to the information I read on the Internet
stating that for VG30 engines normal tensioner hex hole position would
be 5-5:30.

Now here are my thoughts:
a) It's said in the FSM to start adjustment from fully outward
position. Which is in my understanding 8:00. Then turn 75-80 degrees
clockwise. So it goes to 10:30. Then use feeler gauge etc. So as I
said I ended up in 11-11:30 position.

b) 11:30 and 5:30 positions would make the same tension to the belt
because the virtual line from 5:30 to 11:30 is parallel to the timing
belt. So still nothing too wrong with 11:30 position.

c) What is the purpose of the spring in the tensioner? After the
tensioner is secured by the bolt there is no way how the spring could
affect the tension. So the only purpose I found could be to keep the
belt on proper tension until the bolt is secured. But for this the
tensioner should be at 5:30 not 11:30.

So is there a mistake in FSM or my argumentation has a flaw?

Car still runs decent after the t/b change but it looks like it
doesn't have all the power after heating up. Gonna check CTS...

Ah, and another question. Why do we need to set TDC on the comression
stroke before doing the job? What is wrong with exhaust stroke?

Thanks in advance,
Max

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Steve T - 09 Jun 2004 08:09 GMT

> I just changed the timing belt in my Maxima GXE 94, and thanks God it
> looks like I didn't screw up valve timing.

If you use a nissan belt it's impossible to screw it up as it has marks on
it.

> c) What is the purpose of the spring in the tensioner?

To tension the belt before you lock it down. If you just wind up the spring
to get the tensioner back and snug the nut, install the belt, unsnug the
nut and let the spring do it's job then tighten the nut back up it's a done
deal. If you had to work against the spring to adjust the belt, you were
doing it wrong.

> After the
> tensioner is secured by the bolt there is no way how the spring could
> affect the tension. So the only purpose I found could be to keep the
> belt on proper tension until the bolt is secured. But for this the
> tensioner should be at 5:30 not 11:30.

Exactly..

> Car still runs decent after the t/b change but it looks like it
> doesn't have all the power after heating up.

If you used an aftermarket belt with no marks, $20 says you have the rear
cam advanced a tooth, you do realize the marks on the covers aren't quite
right and the marks on the belt are? Seen this done dozens of times and
kills the power the car is supposed to have. To fix it you get to take it
all back apart!

Signature

Steve

http://www.atlantaracing.com

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Maksym Moyseyenko - 09 Jun 2004 16:36 GMT

Thanks for the reply Steve.
See my comments below.

> > I just changed the timing belt in my Maxima GXE 94, and thanks God it
> > looks like I didn't screw up valve timing.
>
> If you use a nissan belt it's impossible to screw it up as it has marks on
> it.

Yes I used a Nissan OEM belt.

> > c) What is the purpose of the spring in the tensioner?
>
[quoted text clipped - 11 lines]
>
> Exactly..

So it looks like Nissan FSM has a mistake?! As I pointed in a) I ended
up in 11:30 position according to FSM. That means that spring would
unwinds _from_ the belt no to the belt. Which just doesn't make sense.

> > Car still runs decent after the t/b change but it looks like it
> > doesn't have all the power after heating up.
[quoted text clipped - 4 lines]
> kills the power the car is supposed to have. To fix it you get to take it
> all back apart!

I used Nissan OEM belt. I agree that by symptoms it looks like one of
the cams is advanced a tooth. But when I installed the belt I didn't
use marks at the rear upper cover - I simply don't have them. I just
matched all the three marks on the belt with dots on the
crank/camshaft sprockets while in TDC1. It should be enough.
May be I have to check it... I hate to undo the whole thing!!!

Btw do you know why do we have to set TDC1 on the compression stroke?
Why not on exhaust stroke? In both cases all the marks line up...

Reply to this Message

Steve T - 10 Jun 2004 00:20 GMT

> I used Nissan OEM belt. I agree that by symptoms it looks like one of
> the cams is advanced a tooth. But when I installed the belt I didn't
> use marks at the rear upper cover - I simply don't have them. I just
> matched all the three marks on the belt with dots on the
> crank/camshaft sprockets while in TDC1.

If you're sure all the marks lined up with the marks on the pulleys, you're
fine. Maybe the EFI engine temp sensor is wacky? You were in that area and
if it is corroded, when you disturbed the wires to it you could affect how
it works. Not fun to get to without a special tool. Also replace the
subharness and the sensor if you do this.

> Btw do you know why do we have to set TDC1 on the compression stroke?
> Why not on exhaust stroke? In both cases all the marks line up...

The cam pulleys wouldn't, they'd be 180 deg out i.e. the dots pointing down.

And yes it sounds like a FSM is wrong if it instructs you to have the
tensioner where the spring pulls the tensioner away from the belt.

Signature

Steve

http://www.atlantaracing.com

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Maksym Moyseyenko - 11 Jun 2004 05:54 GMT

> > I used Nissan OEM belt. I agree that by symptoms it looks like one of
> > the cams is advanced a tooth. But when I installed the belt I didn't
[quoted text clipped - 7 lines]
> it works. Not fun to get to without a special tool. Also replace the
> subharness and the sensor if you do this.

I think you mean coolant temperature sensor. I don't think 90+ Maximas
have EFI temp sensor.

> > Btw do you know why do we have to set TDC1 on the compression stroke?
> > Why not on exhaust stroke? In both cases all the marks line up...
>
> The cam pulleys wouldn't, they'd be 180 deg out i.e. the dots pointing down.

Yes, looks like you are right. Thanks.

Reply to this Message

Bill G - 11 Jun 2004 09:08 GMT

> > If you're sure all the marks lined up with the marks on the pulleys, you're
> > fine. Maybe the EFI engine temp sensor is wacky? You were in that area and
[quoted text clipped - 4 lines]
> I think you mean coolant temperature sensor. I don't think 90+ Maximas
> have EFI temp sensor.

The coolant temp sensor is up on top. All it does is send the info to your
dash guages. Whether you have it plugged in or not will not affect the
engine performance. Kinda like the oil pressure sending unit. It just
measures something for the human eye to look at but doesn't affect/control
anything.

Bill G
'91 SE Auto
166K miles

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Maksym Moyseyenko - 12 Jun 2004 05:13 GMT

> The coolant temp sensor is up on top. All it does is send the info to your
> dash guages. Whether you have it plugged in or not will not affect the
> engine performance. Kinda like the oil pressure sending unit. It just
> measures something for the human eye to look at but doesn't affect/control
> anything.

Just checked in FSM. There are two sensors actually. Engine coolant
temperature sensor (ECTS) sends signal to ECU in order to adjust
engine working mode. Thermal sensor sends signal directly to the
temperature gauge. The two sensors are completely independent.

Reply to this Message

Steve T - 12 Jun 2004 07:36 GMT

>> The coolant temp sensor is up on top. All it does is send the info to
>> your
[quoted text clipped - 7 lines]
> engine working mode. Thermal sensor sends signal directly to the
> temperature gauge. The two sensors are completely independent.

Exactly. You call it ECU, I call it EFI, next year they'll call it ECI. It's
like air flow meters, I get corrected and told it's a MAS. Whatever....

Tell you what, call the dealer and tell them you need an ECTS and I bet they
won't have any idea what you're talking about! Tell them you need the temp
senosr for the EFI and they'll go get you one.

Signature

Steve

http://www.atlantaracing.com

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Steve T - 12 Jun 2004 07:32 GMT

>> > I used Nissan OEM belt. I agree that by symptoms it looks like one of
>> > the cams is advanced a tooth. But when I installed the belt I didn't
[quoted text clipped - 10 lines]
> I think you mean coolant temperature sensor. I don't think 90+ Maximas
> have EFI temp sensor.

Whatever you want to call the sensor that the engine computer measures the
engine temp. They change what they call this stuff from year to year, the
parts guy will know what you're talking about. If you call it a "coolant
temperature sensor" they'll sell you the one for the gauge on the dash,
that's why I call it the EFI temp sensor.

Signature

Steve

http://www.atlantaracing.com

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