So Confused. Timing Queries for NA8

[Mokesta]

Hey Guys, It's been a while and I am getting old and confused. I have replaced the HLAs on my engine and need to sort out the timing.

I have two timing questions for my NA8 1.8l motor. They relate to the fact that the crank pulley has two notches in it that are 10 degrees apart. I don't know which should point to zero to get TDC. I have sketched two pics which are meant to be the crank pulley with its two notches and the timing marks on the plastic timing cover



Question 1:

When setting the cam timing (putting on a timing belt) I set the cams with the marks facing the marks on the inner cover and I set the crank to Position A or Position B or another place derermined by the pin sticking out of the block?



Question 2:

When setting the spark timing by turning the CAS at the back of the head, I set the jumper in the diagnostics box, set the idle speed to 850 then set the advance to Position A, Position B or another position not shown in the diagrams.
Please help, I'm feeling quite retarded/advanced....

Thanks,

M

[Steampunk]

Pic A = 10deg BTDC
Pic B = 0deg BTDC

So set as per pic A, but if are not installing an aftermarket EMS for future tuning, you might as well set it to 14deg BTDC for that extra oomph.

[manga_blue]

That answers the ignition timing question, Andrew, but I'd really like to know how to set valve timing without removing the front covers.

According to the manual the position for setting the crank is a notch on the timing belt pulley, as per the lower picture. (Cams are set as per the top one.)

Timing Belt Marks.jpg

Does anyone know what this position corresponds to when you leave the front covers on and all you can see is what mokesta has drawn here, i.e. the drive belt pulley notches and the ignition timing scale on the lower front cover.

[NitroDann]

Use the 0 mark as red said for ignition timing.

1.6 engines have a 'T' on that mark. Also you can put a screwdriver down cylinder 1s plugs hole and roate the crank by hand ti find tdc, it wont be perfect, but it will tell you which mark is TDC.

Dann

[Mokesta]

Thanks guys, yep as per Magna_blue's question I have only taken the belt off to get the cams out to get to the hlas. Since the belt didn't need to come right out the crank pulley stayed on and so did the bottom cover. That's why I need to know the timing marks that correspond to the position shown for the pic in the manual.

M

[mxfive95]

Is there any way of identifying where the cams should be in relation to piston 1 at TDC.

Just swapped motors and it won't start. Have a feeling the cams are way out :/ any help is much apreciated

[zossy1]

Is there any way of identifying where the cams should be in relation to piston 1 at TDC.

Just swapped motors and it won't start. Have a feeling the cams are way out :/ any help is much apreciated

So at #1 TDC, both Intake and exhaust valves should be closed.

The cam belt gears are marked and, IIRC, should be in the vertical position at TDC...? The marks are (again IIRC) on the spokes of the gears, not the outside.

If you removed the gears from the cams (say to change cam seals) and mixed them up upon replacement, you will have a problem which will quickly become clear...

Further to this, I always mark my pulleys at TDC before removing anything as is makes it easier when putting everything back together...

[Bauer]

When I did my timing belt recently, iirc the cam lobes on cylinder #1 for TDC Comp stroke were both facing outwards.

[mxfive95]

I eventually got it started

Biggest mistery when it eventually started, it didn't want to rev higher then 150rpm and the timing light showed the timing mark at something like 20 retarded... Roughly 2 on the pulley.

So here's how I did the timing belt. Set piston 1 to TDC using timing marks and also with a screw driver through plug hole. Then Removed rocker cover, water pump pulley and top 2 timing belt covers. Took timing belt off and cam pulleys off. Rotated cams carefully so the locating pins on the cam were at 12. Put cam pulleys on making sure they were the right ones and set it up as manga blue's picture. Put timing belt back on making sure there was no slack between crank and can pulleys on the right hand side as the little wheel on that side is fixed as opposed to the tensioner on the left... Then carefully rotated the engine by hand to ensure none of the valves would hit.
The cycle goes- cylinder 1 at TDC, as soon as its starts going down, the inlet valve starts to open and is closed by the time the piston hit the bottom. Then piston goes up then down, ex valve opens and closes and we are at where we started, TDC.

I can only think the exhaust cam is off an nb8a and the cas location slot is different.

So how did I set the timing? I removed the bolt that limits how far you can adjust the cas and rotated it around untill I had 14 advanced.
It's running like a dream and I'm glad I persisted with some degree of caution:) thanks for the help.

[zossy1]

Then carefully rotated the engine by hand to ensure none of the valves would hit.

Glad to hear it all worked out!

No need to worry about valve strikes though - the B6/BP engines are non-interference