I rebuild engine but it doesn't start, help !!!

930cab89 · 03-21-2011, 07:34 AM

I've dismantled and changed the piston rings along with the valves and the guides + all the gaskets on my 930 from 1989. I've now put the engine back into the car, connected everything but it doesn't start. The distributor is set as it should (contact on rotor towards the little groove on the distributor when engine in TDC for cylinder 1) and the spark cables are connected in the right firing order (checked with Wayne's book and the technical data from the car).

There is a spark at the plug and gas comes out of the injection lines but the car does not start, it does not even cough.

The only thing I've left over to suspect is the timing. The guy who set it for me said that for this engine, the intake valve stroke in TDC overlap with 0.1mm tappet clearance should be at 1mm and so he set it at that value. But now that the engine does not start, I've checked the needed value for this engine and Porsche indicates between 0.65 and 0.8mm.

Could this be the reason that the engine does not start? If not, what else could I look at?

Thanks in advance.

930cab89 · 03-21-2011, 07:59 AM

Just want to add that the distributor cap, rotor and spark plug lines are new.

T77911S · 03-21-2011, 08:14 AM

no.

you can still be 180 out with the timing. usually if you are, you get bad backfiring though.

here is how to check,
remove the left intake valve cover. turn the engine over by hand. (wrench). when the intake for #1 closes, stop turning when Z1(TDC) lines up to the seam inthe case. then recheck the dist rotor and timing mark.

Superman · 03-21-2011, 08:18 AM

Sounds like you put the crankshaft in upside down.

moneymanager · 03-21-2011, 08:23 AM

I'd bet on the distributor... everything backwards, or, more likely, 180° out of phase. I agree you'd likely hear some kind of a cough, but it's sure the usual suspect. Lots of posts here on that problem.

kodioneill · kodioneill's Garage

The 930 distributor rotation is counter clockwise. Check that and also check the 930 forum. There's a sticky that has a lot of information on no start conditions.

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/547032-sticky-common-answers-why-my-car-doesnt-start.html

930cab89 · 03-21-2011, 10:18 AM

Ok I'll check again. By the way, how do I turn the engine over now it's in the car? I can't get a wrench on the pulley nut with all the parts installed in front of it. Is there another trick?

kodioneill · kodioneill's Garage

What's in front of the fan? How about some photos?

930cab89 · 03-21-2011, 11:42 AM

Well, all the usual stuff so it's nearly impossible to get a wrench on that nut:

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by kodioneill

What's in front of the fan? How about some photos?

930 engine sits a little further back towards the rear bumper than the 911. I bet the wrench cant slip down in there. I don't know what to suggest besides a big open end wrench or a crows foot.

Edit - Just jog the engine with the key. You don't have to be exactly on TDC to see if your dist is out 180.

930cab89 · 03-21-2011, 12:14 PM

I did it with the key, after a 100 tries, I got somewhere near the Z1 mark but I didn't check if it was when the the intake for #1 closes.

brads911sc · brads911sc's Garage

I know this may go against conventional wisdom, but mark the distributor and move it 180 degrees... from wherever its at... if that is the problem, it will start, if not move it back. My distributor was one tooth off. So I moved it in one direction 1 tooth.... it fixed my issue. As a note, mine was off 1 tooth and it still ran well enough to do the 20 minute breakin. i only realized it when I went to set the timing and I couldnt get close to Z1.

jstobo · 03-21-2011, 12:58 PM

To Turn engine: put wrench on fan bolt, push in belt to take up all slack, turn fan cw while pushing in on belt. The engine will turn over. To make it easier-pull the plugs. Good luck.

kodioneill · kodioneill's Garage

Quote:

Originally Posted by jstobo

To Turn engine: put wrench on fan bolt, push in belt to take up all slack, turn fan cw while pushing in on belt. The engine will turn over. To make it easier-pull the plugs. Good luck.

Like he said. Check your rotation you may have to take off the intercooler to get the cap off.

T77911S · 03-22-2011, 04:24 AM

Quote:

Originally Posted by brads911sc

I know this may go against conventional wisdom, but mark the distributor and move it 180 degrees... from wherever its at... if that is the problem, it will start, if not move it back. My distributor was one tooth off. So I moved it in one direction 1 tooth.... it fixed my issue. As a note, mine was off 1 tooth and it still ran well enough to do the 20 minute breakin. i only realized it when I went to set the timing and I couldnt get close to Z1.

it depends on which direction you are off one tooth. i have to pull my dizzy out and move it one tooth if want to go further in a certain direction because i am at the end of my adjustment. it jsut depends on if i want to go more retarded or more advanced and what tooth i am on.

i would not just pull it out and turn it. if you are not 180 out and you put it 180 out, you can cause a serious backfire.

930cab89 · 03-22-2011, 06:28 AM

I'll do it like it should be done this evening. I'll pull the plugs and remove the left intake valve cover and put the engine on the Z1 mark when the the intake for #1 closes.
Then I'll align my distributor and give it a try.
I'll keep you posted.

T77911S · 03-22-2011, 08:45 AM

you will have to keep turning after #1 closes to get to Z1.

check dist rotation too, as posted.

verify firing order.

930cab89 · 03-24-2011, 06:25 AM

Ok, so now I've set the distributor as told: I aligned Z1 after intake valve of #1 closes and aligned the contact on the rotor towards the little groove on the distributor and installed the spark plug cables according to the firing order specified on the little picture in the engine bay but the engine does nothing. There is a spark so I now have to turn to the gas. I don't understand why there could be a problem, I didn't touch any electrical devices on the car nor the pump or anything. I'll verify this evening if gas comes out of the injectors (I have not checked that yet). I can smell some gas odours in the engine bay.
Any other suggestions? This becomes boring, I want to drive my car!

moneymanager · 03-24-2011, 07:01 AM

You've got the wires in the distributor cap correctly for its counterclockwise direction, right? And the business end of the rotor is right on the wire for cylinder #1? And you have spark at the spark plug connectors?
I'd forget about a problem with the gas if you didn't mess with anything associated with it and you can smell it. There's enough to at least cough; fact you have no response suggests electrical stuff.

brads911sc · brads911sc's Garage

+1

Remember this turns counterclockwise. So the wires will be set up in the firing order in a counterclockwise way.
Also, the rotor position is critical. The leading edge of the rotor will be on the notch in the distributor housing which will also correspond to the #1 plug wire, but again it is on a counterclockwise rotation so you could be one tooth off and still look close.

Quote:

Originally Posted by moneymanager

You've got the wires in the distributor cap correctly for its counterclockwise direction, right? And the business end of the rotor is right on the wire for cylinder #1? And you have spark at the spark plug connectors?
I'd forget about a problem with the gas if you didn't mess with anything associated with it and you can smell it. There's enough to at least cough; fact you have no response suggests electrical stuff.