The Manhattan Project

[AndrewSlater]

A new battery was ordered and we visited Luftgekuhlt.
I bought some beer but was told I couldn't drink it until the engine ran.


Whilst waiting for the battery I tinkered with setting the hand throttle lever correctly as it is one of the things that can prevent starting on the CIS troubleshooting guide.
Another cause is 'operator error' but I am putting that out of my mind for the moment!

A new symptom was that the car had also stopped cranking which I put down to the inadequate and flat battery.

So the battery arrived, I fully charged it and fitted it.


The starter still no longer cranked although I thought I could hear the solenoid clicking

Now the '74 911 has a starter lock-out system. If you sit in either seat and don't fasten your seatbelt the starter becomes disabled.
In desperation I enabled / disabled all of the seat switches only to find that I could get the fasten seat belt light flashing and now I could no longer hear the solenoid click.
In further desperation I removed the logic relay and shorted out the starter bypass - still the solenoid clicks but the starter fails to start.

I've stopped for today but am guessing that either my new starter motor has died prematurely or there is another problem.
Considering it was cranking reliably I am at a loss.

Time for more reflection - I'm guessing that beer will have to keep a little while longer.
If anyone has any suggestions then please let me know.

[AndrewSlater]

Still no beer celebration.

Tonight I bypassed the ignition key and the starter still failed to crank.
I decided it was likely that my 'new' starter had prematurely died after a handful of cranks so I decided to remove the starter.

A little while later and ….
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I gave it a quick test and it seems faulty.
I will test it again tomorrow with a view to getting another one.

This one is a 0.8kW one as per the original '74 spec. However my starter cable seems to be a 35mm2 rather than a 25mm2 one so possibly I could get a 1.7kW starter instead ( or maybe I should go for a high torque one ).


Any suggestions as to which makes of starter are good and pros and cons of 0.8kW or 1.7kW?

[911hillclimber]

Ask Andy Lightweight for details.
He has used as I have, the same design starter for several years and there has never been a problem. Mine churns my big 3.2 for 3 seconds and then the engine fires, maybe to do with the ECU, but instant action on turning the ignition switch. This is ion my 73T.

Andy can remember everything, I'm the opposite, so he will have the right manufacturers name.

[jjeffries]

Have you verified that the braided engine ground strap is securely fastened, to clean metal? John

[Lightweight_911]

/\ /\ /\

Definitely worth checking the earth strap.

If it turns out that you need a new starter, I would go for a 'high torque' one.

As Graham said, I've fitted one to every 911 I've owned (plus the 904 & my 356C) - bought from Auto Electrical Supplies:

https://www.autoelectricsupplies.co.uk/product_list/213

[AndrewSlater]

Given that the starter had gone from working to not working within a few minutes a didn't think it was the earth braiding - but to prevent any doubt I took the strap off and confirmed it was connected to all nice and shiny metal. I ran the Dremel over it again just for good luck.

Suspecting the starter motor had simply died I ordered a Wosp LMS027 as per Graham and Andy's recommendations.

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After checking it ran, it was time to fit it.

The first problem was that the face plate was in the wrong orientation as the body fouled with the heat exchangers.
Once I had re-orientated the face plate it became clear that the fixing holes in the face plate were both too tight on the bell housing mounting studs and the spacing wasn't quite right. I ended up having to run a 10mm drill through them both to open them up and then open one up to 11mm to get the plate to fit on the bell housing.

Once this was done the starter fitted.
The terminals end up in a slightly different position to the original starters so the cabling is a bit tight.

After a few hours of struggling, modifying and tweaking we were ready to test if the engine cranked.

However when we did test the new strater it cranked fast first time -- and at what a speed compared to the old one!
Great result hopefully tomorrow I can reconnect the fuel pump and try to get this engine eventually started.

[911hillclimber]

Sorry to read about the mounting plate.
Mine simply bolted on and all the wires reached easily! That was 5 or so years ago.

Good luck with the first start.

[Lightweight_911]

.
Never had to make any modifications to any of my installations - bolted right up & worked 'straight out of the box' …

.

[AndrewSlater]

The starter fitting was only a small hiccup.
When I removed the mounting flange I found that neither of the holes would fit either of the studs, so I opened them up a smidge to allow them to fit the studs. However although they would fit the studs one at a time when I tried the flange on both there was clearly a tolerance error - which is why I then had to open one up to 11mm to get it fit.

I still appreciate the recommendation - the hiccup aside it appears to be a really quality piece of kit.

I had read on ImpactBumpers that someone else had the same fitting problem - but that was a good while ago so hoped it had been rectified by now. I will drop Wosp an email out of courtesy to let them know.

[AndrewSlater]

I spent Saturday afternoon trying to get the engine to start with the new functional starter but with no joy (or beer). I came to the conclusion that there was definately something amiss.

There were a lot of positives now:-
The starter worked well
The CDI box was providing a good spark
Fuel was getting to the injectors when the air plate was lifted ( and also a little during cranking )

Just no sign of it firing.

It was Goodwood Sunday Breakfast this morning and we took the 912 (luckily it started first time).
After an enjoyable morning it was time to return and check out some basics.

I had had an awful thought that maybe I had timed the second bank 180 degrees out, but that wasn't worth thinking about too much.

I used the fuel pipe technique to confirm that with cylinder #1 at compression, cylinder #4 was on the exhaust stroke. Just to check I wasn't going mad I then turned the crank another revolution to TDC again and confirmed cylinder #1 was now on the exhaust stroke and cylinder #4 was on compression - all good.

Starting to doubt my sanity I popped the distributor cap off again, when I spotted it was pointing at cylinder #1 (although the engine had cylinder #4 on compression).
Eureka having the distributor 180 degrees out might not be helping things.

The engine was reset to TDC on cylinder #1 and the distributor removed and re-set.

After a little while longer double checking everything we had combustion.


… and then time for a well received beer



The timing and idle were re-adjusted and then the engine was given a break-in run to get it up to temperature.

The engine will still a lot of further tweaking and tuning but the good news is that it now runs tolerably well to start with and with no leaks. A good starting point to build upon!

[jb]

What a journey.
Congratulations
I am so pleased that you finally got it running ok

[sladey]

Wow! Full marks on your perseverance and great to get it running

[Gary71]

Great news! 1st started on a new build is a nerve wracking time.

[Lightweight_911]

Great news Andrew !

Was the beer any good ?

[AndrewSlater]

Thanks for all the comments guys - the beer did indeed taste good once the engine ran.
Mind you with the euphoria of the engine running a pint of oil would probably have gone down well too!

I had contacted Wosp with regard to the starter and they replied very quickly saying that it had been brought to their attention a year or so ago that the holes in the flange were a little too tight on tolerance so they had changed to 10.5mm holes. It would appear they had somehow used some of the old style mounting flange on the unit I got.

Tonight the plan was to check a few extra parameters and try to tune the car a little better. The car was suffering from backfire particularly at start-up so I assumed it was running a little lean.

I had already set the timing to 5 degrees ATDC at 900 rpm, but had not checked the dwell.
Tonight I measured the dwell to be approx 36.2 degrees so within the 38 degrees +/- 3 degrees spec.

The next job was to set the mixture a little better - so out with my Gunson Gastester.
The spec is for a CO reading of 1.5 to 2.5 at idle, so we aimed for 2.0.
At the start of the night the car was running a little lean at around 1.2 or 1.3.
After multiple tweaks of mixture and corresponding tweaks to the idle we finally got a reading of 2.02 on the tester which is as close as I will get with the tools at my disposal.

The engine runs a lot smoother and better now with no signs of a backfire - all in all I'm pretty impressed with the results.
It starts almost instantly using the hand throttle.
I'm thinking CIS is the way to go!

I have a few jobs left to do in terms of checking the engine but touch wood it is all looking good.