Head gasket replaced. Now wont start any ideas?

[pringle1988]

Hi all
Recently I bought an e36 BMW 328 sport and have had major problems with it, long story short it needed head work doing. Got the head back and onto the car, connected everything up and the car wont fire at all it just cranks over.
I lifted the injectors out when turning it over and they are spraying fuel, not a lot however but im no expert on how much would usually come out.
There is definatly a spark as I shocked myself accidently when testing it (Im not sure if I have earthed the leads correctly and I have a feeling this is the problem). If somebody could supply any information on this it would be a great help.
Any other ideas would also greatly help.
I can upload a picture in the morning of how I have earthed them if this would be of any use?

Thanks
James

[dan19evans]

Why did it need 'head work'? Did the car overheat? If so, did you have the head skimmed?

[pringle1988]

Yeah I bought the car and to be honest never looked at it in enough detail. It must have overheated on the previous owner as the water pump and head gasket were both new. After pulling up one day and noticing water bubbling in the expansion tank (temp gauge was fine) It seemed as if it was overheating again.
Went to change the head gasket etc and when undoing the head 2 bolts were stripped in the block. (This is now repaired) Got a new gasket and the head professionally skimmed.

[Amused2death]

Have you got the timing right?

Could possibly be 180 degrees out.

[dan19evans]

Does it sound like it has compression? Have you compression tested it?

[pringle1988]

Im almost certain the timing is correct but how can I check to make sure? Its gone back together the way it came off.

The cylinders do have compression yeah.

[MGJohn]

Compression check would be my first thought too. After checking/double checking all those timing indexes are where they should be as the two previous posters have also advised.

Your skimmed head will not be the first one to have been cocked up. I bought a very tidy non-starter recently which had no compression after a pro-head skim. Previous very frustrated owner decided to simply get rid. He was one of the many who have no idea what goes on under their car's bonnet. Very poor compression so removed head suspecting bent valves by whoever worked on car before. Valves as straight as can be ~ I discovered the pro-skim in previous ownership was cocked up and was nowhere near flat ~ 25 thou out in the centre of the bow across the length of the cylinder head face ~ also checked the block for truth with a good straight edge ~ I use a top quality engineer's rule. These things should always be double checked before reassembly. Even the best run pro-workshops have occasional cock ups.

Here's that pro-skimmed head at the centre. Note the relatively large gap under the rule...



Close up of the gap under the straight edge:~



I fitted a known good spare cylinder head I had and the engine started as soon as I turned the key.
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[attym3]

Have you got the leads going to the right plugs? F.O, 1 5 3 6 2 4, I belive. Also is the dizzy cap on the right way up?

[Pigeon]

First check the ignition timing as said. Also, have you got the cam timing correct? Easy to get it one or two teeth out without noticing, which makes it look as if everything's OK but will make it difficult or impossible to start.

[Marf]

Dizzy 180 out or an earth missing somewhere would be my guess.

[Baby Huey]

I had a Renault 11 Turbo which needed regular head gaskets. One time I got the engine back together and it just would not go. After much head scratching I called a friend who was an RAC patrol man.

He simply sprayed plenty of Easy-Start into the carb and it roared into life and ran perfectly.

[neiljohnson]

Well it wont be leads or the dizzy as it runs indivdual coils on this engine.
It is possible the timings out as getting the vanos correct on these engines can be awkward!!

Engines are simple in the grand scheme of things so what you need check is.

You say you have fuel & spark so check the compressions if these are ok then its going to be the timing

[TooLateForAName]

Could be cam or crank position sensor fault? Wires OK to them?

[*Al*]

TooLateForAName said:

Could be cam or crank position sensor fault? Wires OK to them?

Quite possibly this, these engine suffer with faulty crank and cam position sensors.

Original fault with the HG was probably the original water pump blades breaking due to brittleness of the plastic? These are normally changed for newer metal type impellers/ pump.

[pringle1988]

Thanks everybody for your replies, I now have the car running and it was to do with the cam sensor.
The problem now is I have quite a loud tapping sound. Its the same sort of sound you sometimes hear for a couple of seconds on startup but it continues and has no sign of going away.
Is there something I should have done before putting it back together? It sounds like its near the camshafts so im thinking followers? Ive heard somebody talking about idling the car at about 3000 rpm for a bit to get the oil circulated. Im not sure if this is a good idea or not as metal on metal cant be good.
Also does anybody know what the gap is supposed to be between the cam lobe and the top of the follower when the piston is at TDC on the compression stroke?

Thanks again.

[pringle1988]

Anybody?

[The Wookie]

pringle1988 said:

Anybody?

Yeah, I think the M52 has hydraulic lifters. Ideally you should have primed them before refitting, but if you didn't remove them then they've probably just partially drained.

Don't worry, revving it up to get rid of the air wont hurt it

MGJohn said:

..

Can I just add that that is unbelievably rubbish

[MGJohn]

The Wookie said:

pringle1988 said:

Anybody?

Yeah, I think the M52 has hydraulic lifters. Ideally you should have primed them before refitting, but if you didn't remove them then they've probably just partially drained.

Don't worry, revving it up to get rid of the air wont hurt it

MGJohn said:

..

Can I just add that that is unbelievably rubbish

Yes, if it has hydraulic cam followers they can sound like and old rattly Diesel after rebuild start up until they are up to hydraulic pressure. All 16 or 24 of them....

When I have a cylinder head skimmed, I disassemble each hydraulic 'tappet', clean out the old oil and ensure the tappet spring allows the tappet to fully compress. If it cannot fully compress because it has hydraulically 'jacked up' with the oil still in it, that valve may never seat properly.

In a higher mileage used car I sometimes buy, despite what the previous owner tells me about servicing and maintenance, I always drop the old oil and even with petrol turbo engines, install DIESEL GRADE engine oil along with a new oil filter. The slow acting detergents in Diesel engine oil can help cleanse away the varnish that can build up on engine internals like those haydraulic lifters. I keep it in say 1-2000 miles then drain hot and refill with regular recommended engine oil.

This treatment can often give the engine a new lease of life.... transform it remarkably even. With better throttle response, acceleration, getting up to speed quicker and smoother running. Plus, that noisy tappet(s) can 'magically' suddenly run near silent with a much more acceptable near silent rustle instead of the annoying clacking sounds...

With cars I've had from new, I change the engine oil around half the manuufacturer recommended intervals. No doubt in my mind this is long term beneficial ~ I tend to keep my new cars a long time ~ and because I've always done this, their maintenance is a known quantity so never ever any need for the 'Diesel' oil treatment.

EDIT TO ADD @ 10:10

I believe there is no clearance between the camshaft and follower with the lobe of the Camshaft NOT acting on the tappets ... from my observations on those engines I've worked on with hydraulic lifters. That's the point of hydraulic 'tappets' I believe...but, I will like to have confirmation from those with better knowledge of these things... Other engines with 'buckets' that are not hydraulically operated need shims to allow for that clearance.
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Edited by MGJohn on Thursday 29th July 10:10