NB8A lacking torque after recon head & new rings

DTH · Postby **DTH** » Mon Mar 05, 2018 11:43 am

Great, thanks for that info!

DTH · Postby **DTH** » Mon Mar 05, 2018 6:45 pm

Update: I removed the cam cover, turned the crank til after the inlet valve of #1 cylinder closed and the yellow mark on the crank pulley aligned with the T on the degree plate & then took some pics. (I tried to remove the spark plug to check TDC with a screwdriver but it was very tight so left it as I didn't want to push my luck.)

IMG20180305120105.jpg

There are several white paint marks & I noticed that the inlet cam sprocket is marked R while the exhaust is marked L.
Even allowing for the angle of the shot these marks on the sprockets in the next pic don't look aligned to me.

IMG20180305121147.jpg

Suggestions most welcome, thanks guys.
Cheers,
david

madjak · Postby **madjak** » Mon Mar 05, 2018 7:41 pm

I'm pretty sure it should be 18 teeth between cams abd I count 19 from the photos.

DTH · Postby **DTH** » Mon Mar 05, 2018 8:16 pm

Thanks madjak, pardon my ignorance - what is "abd" & the 18 teeth please?
Cheers,
david

greenMachine · Postby **greenMachine** » Mon Mar 05, 2018 8:24 pm

David, page 205 of the manual has an illustration (page 1-10-7 ) LHS near the top. That shows the two timing marks for the pulleys (and the crank), which are below the cover at the bottom of your photo of the pulleys - you will need to remove that cover too in order to see them.

I can't remember if/what those marks at the 9 o'clock and 3 o'clock positions are, but the marks at the (approx.) 4 and 8 o'clock are what is shown in the manual, and what I have used. Hence the need to remove that plastic cover. If my recollection is correct, those white marks were probably put there by your mechanic as his preferred way of setting the pulleys and cams. Nothing wrong with that, as long as the factory marks corroborate his.

Note that you need to tension the belt by rotating the crank so that there is minimal slack between the cam pulleys, and between the exhaust pulley and the crank. Rotate the crank clockwise (looking at it) with a spanner, until you are TDC on No1/timing mark. The cam timing marks then should be as shown on 1.10.7.

If they all line up, great. If they don't, well let's not cross our bridges until we get to them.

It is a while since I have done this so I hope Manga (or someone) will chime in here and correct/confirm my recollection.

:mrgreen:

RS2000 · Postby **RS2000** » Mon Mar 05, 2018 8:32 pm

You are not at TDC with the crank in the first picture. That is 10 deg BTDC. Rotate the crank until the second mark is aligned with T.

There is an 'E' and 'I' on the sprockets pointing about 45 deg downwards & towards the centre of the engine that line up with marks on the backing plate. There is a second set of E and I that will now be at 12 o'clock.

DTH · Postby **DTH** » Tue Mar 06, 2018 4:13 am

Thanks RS2000 & Ed, I'm learning, even at my age.

DTH · Postby **DTH** » Thu Mar 08, 2018 7:16 pm

Another update: Cam cover removed again & with the crank in the correct position now

IMG20180308175213.jpg

The cam sprockets look to be juxtaposed i.e. on the wrong sides to me. The one marked E is on the inlet side & the I is on the exhaust side. They are also marked L & R with the L on the one marked E & the R on the one marked I.

IMG20180308175213.jpg

Suggestions appreciated, guys.
Cheers,
david

greenMachine · Postby **greenMachine** » Thu Mar 08, 2018 7:55 pm

DTH wrote:Another update: Cam cover removed again & with the crank in the correct position now IMG20180308175213.jpg
The cam sprockets look to be juxtaposed i.e. on the wrong sides to me. The one marked E is on the inlet side & the I is on the exhaust side. They are also marked L & R with the L on the one marked E & the R on the one marked I. IMG20180308175213.jpg
Suggestions appreciated, guys.
Cheers,
david

FFS!

Enlarge the last photo, it shows the inlet pulley on the exhaust side. Presumably the cams are correct, and he has just put the pulleys on the wrong cams. Maybe.

First up, those images haven't been transposed have they? (As the R looks right way around, probably not)

My initial reaction is to ring up your mechanic, tell him to come and have a look, and to bring the phone number of a tilt tray operator with him.

My more considered reaction is to wonder whether you really want to go back to him?

You have got this far, we can certainly guide you through the steps of swapping pulleys (and checking that the cams haven't been swapped (is this even possible?), but do you want to do this?

Well done!

:mrgreen:

Postby **NitroDann** » Thu Mar 08, 2018 8:03 pm

I can assure you that you are incorrect.

Dann

DTH · Postby **DTH** » Thu Mar 08, 2018 8:14 pm

Interesting comment Dann. Who is incorrect and why, please? I'm trying to understand this.

Postby **NitroDann** » Thu Mar 08, 2018 8:30 pm

The cam gears are on the correct sides.

The inlet cam gear has the 'I' for Inlet at the top, E on the top of the exhaust side.

Dann

greenMachine · Postby **greenMachine** » Thu Mar 08, 2018 8:46 pm

NitroDann wrote:I can assure you that you are incorrect.

Dann

Dann is correct. For reasons that escape me, those two marks shown in that photo (4 o'clock and 8 o'clock) are 'reversed, the 'I' is on the exhaust pulley, and the 'E' on the inlet pulley. My bad.

Sorry David, thanks Dann.

:oops:

DTH · Postby **DTH** » Thu Mar 08, 2018 8:53 pm

The cam gears are on the correct sides.

The inlet cam gear has the 'I' for Inlet at the top, E on the top of the exhaust side.

Dann

Thanks Dann, however I don't understand what you mean as the gear on the inlet side has E cast (& R painted) on it & the gear on the exhaust side has I (& L painted) cast on it.

RS2000 · Postby **RS2000** » Thu Mar 08, 2018 9:28 pm

Ignore the painted R & L!
When in the correct position, the inlet sprocket has E downwards towards the centre, & I at 12 o'clock (probably covered up by the paint)
The exhaust sprocket has I downwards towards the centre & E at 12 o'clock.
The sprockets are correct, but you need to look at them square on to tell if they are timed correctly.