Revving low after timing belt change

[Raptorark]

Hello guys,

I've replaced the old timing belt with a new one (also replaced water pump and tensioning pulley; service belt also replaced), I've also placed crankshaft and camshaft at the "right places". I've used the original BMW's references to put pulleys at the right phase.
The problem is that, now, the engine starts up but it stalls at very low rpm. It doesn't rev up even if I push the throttle body.

I am blaming myself cause I didn't mark with a marker the camshaft pulley at the original position and, now, I am thinking the camshaft pulley wasn't placed at the right spot even before.

How do I check if the camshaft is in the right position?

[Brdjo]

which engine?

[Raptorark]

Oh sorry, M20 125cv
The car is from 1986 so it's a early type

[Brianmoooore]

Where's the distributor?

[Raptorark]

I think it's not in front of the camshaft pulley like in the newest series.







Today I've gave a try moving the camshaft phase by 1 tooth in anti-clockwise orientation. Nothing to do: the engine starts and can hold idle revs but it doesn't rev up if I push throttle.
I've then put back it at the right phase but nothing to do... same as yesterday.

I hope I didn't crack valves

[Brianmoooore]

Did you align the distributor marks as well as the crank and cam pulleys before you fitted the cambelt?

[Raptorark]

Nou, where do I have to watch? I didn't know about that, the guide on E30 wiki didn't mention that

[Brianmoooore]

Wiki guide probably refers to all 325is and later M20B20s only, where the pulley half way up the block that the belt runs on drives the oil pump only, so timing this pulley doesn't matter.
It certainly does matter on early 320is.
I should probably state that it's over a quarter of a century since I timed up ANY engine with adjustable ignition timing, and I've never timed up the ignition on a six cylinder BMW engine.
There is, apparently, a notch on the distributor body, that can be seen with the cap off, that should line up with the notch in the centre of the rotor arm when the flywheel is set to TDC.
Your engine runs, so you can't be far out, so slacken off the distributor clamp bolt and rotate the distributor. To do the job accurately, you need a timing light, and to set the timing to 19 degrees BTDC at 5000 RPM for 95 octane petrol, according to Autodata, (or 23 degrees, if you believe Haynes.)

[Raptorark]

Wiki guide probably refers to all 325is and later M20B20s only, where the pulley half way up the block that the belt runs on drives the oil pump only, so timing this pulley doesn't matter.
It certainly does matter on early 320is.
I should probably state that it's over a quarter of a century since I timed up ANY engine with adjustable ignition timing, and I've never timed up the ignition on a six cylinder BMW engine.
There is, apparently, a notch on the distributor body, that can be seen with the cap off, that should line up with the notch in the centre of the rotor arm when the flywheel is set to TDC.
Your engine runs, so you can't be far out, so slacken off the distributor clamp bolt and rotate the distributor. To do the job accurately, you need a timing light, and to set the timing to 19 degrees BTDC at 5000 RPM for 95 octane petrol, according to Autodata, (or 23 degrees, if you believe Haynes.)

OK Really thanks about this. So now it's time to flashlight it out. I will update this topic once I will get the thing

[Raptorark]

So, this is the situation.

Crankshaft:



Distributor:



What do I have to do? Where is the notch?

[Brianmoooore]

So Where is the notch?

If it exists, AFAIK, it should be on the surface that the cap sits on.
Are you sure that the rotor is pointing at cylinder 1? Don't forget that the rotor turns at half crank speed, so only points at cylinder 1 every other turn of the crank.
As I said earlier, since the engine runs you can't be far out, so you don't really need the notch - just slacken the distributor clamp bolt and rotate the body slightly to advance the spark (probably) until the engine runs properly, fine tuning with a timing light.

[Raptorark]

I will check if it points at the cap plug n.1

By the way, maybe this is the notch (marked in this pic)

[BenHar]

Is that the actual engine?

If so I would recommend that you get a new rotor arm and probably a distributor cap too.

Ben

[Raptorark]

Yes, it's the actual engine! Ok, I will restore the distributor.

So, I've found the notch. It was hidden from behind Ed even the cylinder spark order is drawn on the distributor cap. I must rotate it but I can't pull it off at the moment... I have to check how to do it cause it's my first time and I don't want to destroy the rotor's cog

[Brianmoooore]

Don't remove the distributor. Just slacken the clamp bolt underneath enough so that the distributor body can be rotated, but will stay put when you let go.

[Raptorark]

So that's why there's an half-cog shape under the distributor

[Raptorark]

OK, I've rotated it to reach as much as possible the rotor arm on TDC position.

Now the engine starts and it revs better while idling... but still it is unstable. If i push the throttle now, it revs up but really slow.



This challenge is really hard

[Raptorark]

Ok, I think I got it.

As you know, there are 4 pulleys on the timing side of the engine: crankshaft, camshaft, tensioner and the intermediate one.
The "intermediate" is a shaft driving the oil pump and the rotor arm; that's why the rotor is so far placed from distributor's notch...

I have to rotate it (have to remove timing belt another time arrrr )

[fixedwheelnut]

Pretty sure there is a dot on the edge of the wheel that lines up with a dot on the other pulley adjacent to it, while crank and cam are at TDC, been thirty years since I have changed one with an adjustable dizzy though

[Brianmoooore]

Pretty sure there is a dot on the edge of the wheel that lines up with a dot on the other pulley adjacent to it, while crank and cam are at TDC, been thirty years since I have changed one with an adjustable dizzy though

Can't find any mention of any marks on the pulley in any of the three manuals I have that might be relevant, although they do suggest you make your own before removing the old belt. As far as I can tell, pointing the rotor arm at plug one post in the cap, lined up with a mark on the distributor body, is whwt you should do.
Of course, it doesn't matter if you can rotate the distributor enough to compensate, but if enough movement can't be made without part of the distributor fouling the block, then the belt will have to come off again.

[BenHar]

Can't you remove the distributor with its drive and turn it a tooth or two?

Ben

[Brianmoooore]

Can't you remove the distributor with its drive and turn it a tooth or two?

Ben

Possibly, if it comes out from the top, and can be refitted after turning.
My main experience with distributors in on BMC 'A' series engines, where the it is driven by an offset slot, so can only be fitted one way.
IIRC, though, if you removed another bolt and sleeve, the drive could be extracted and the helical gear refitted a tooth different.

[fixedwheelnut]

Can't you remove the distributor with its drive and turn it a tooth or two?

Ben

Possibly, if it comes out from the top, and can be refitted after turning.
My main experience with distributors in on BMC 'A' series engines, where the it is driven by an offset slot, so can only be fitted one way.
IIRC, though, if you removed another bolt and sleeve, the drive could be extracted and the helical gear refitted a tooth different.

You have to be careful as the oil pump is driven by a hex drive inside the shaft of the distributor and can pull out and fall in the sump sometimes, rare but know of two people it happened to,

[Raptorark]

I will make the rotor to move by driving manually the oil shaft pulley. I will get timing belt another time under tools

[Raptorark]

Ok it's all done! Finally I had enough time this morning.

I've removed the timing belt, have rotated oil-shaft pulley at the right marked place (there was a notch) and set distributor at the right place.

I've bleeded the coolant system and set the engine on fire It's perfect, the car has finally restarted make pollution over this corrupted world.
Last thing I have to do is to buy timing light and make a fine adjustment.

Thank you all!

[Brianmoooore]