E28 520i ignition timing

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UnderNutter
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E28 520i ignition timing

Post by UnderNutter » 09 Jan 2012, 19:38

Lads and lasses,

I want to dynamic time my 520 with an ignition strobe.

Its a late (12/86) car which means, according to the haynes, with the distributor vacum hoses off, I should be looking at 23 degrees BTDC @ 5000 rpm.

Whoa hang on 5000 rpm?? Shouldnt be raised to anything like those kind of speeds at idle, surely??

It also says to plug said vacum hoses: at the throttle body end, the distributor end or both?

TIA

Dave
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1986 BMW 520i lux _____________________________1991 peugeot 205 XL (GTi lookalike)

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RayB
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Re: E28 520i ignition timing

Post by RayB » 09 Jan 2012, 20:27

You can time a car at any RPM not just at idle, you will need a timing light with a digital read out on it though.

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Re: E28 520i ignition timing

Post by UnderNutter » 09 Jan 2012, 22:14

Ray,

I've got my old mans Gunson tachostrobe here, which has a graduated RPM scale (with hi-mid-lo sections) on the side, and a thumbwheel to adjust a pointer on said scales. It has a light sticking out the side that operates inconjunction with the strobe.

Now do I have to set this up somehow, or, is this part of a mechanism for setting precise RPM on a car with no tacho?

Is anyone familiar with the workings of one of these or similar?

Cheers

Dave
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1986 BMW 520i lux _____________________________1991 peugeot 205 XL (GTi lookalike)

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RayB
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Re: E28 520i ignition timing

Post by RayB » 09 Jan 2012, 22:21

That will time it up to about 1200 rpm max, so pretty much idle speed which is obviously still worth doing

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Re: E28 520i ignition timing

Post by RayB » 09 Jan 2012, 22:55

Have you got the instruction manual for it???

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Re: E28 520i ignition timing

Post by M60NJP » 10 Jan 2012, 07:32

Excellent - Real (old school!) timing!

Tip - mark the timing marks with Tipex before doing it - much easiest to see (assuming you mark the right ones!)
5000 rpm does seem high, alll those I've done usually move to the timing point at no more than 2000 and then stay static at higher revs.

I'm not familiar with the thumbwheel, bet you can download the instructions from the web?

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