Sensor wheel mounting

rmaddock · Post by **rmaddock** » Tue Feb 28, 2006 5:04 pm

Okay, I know this question has been asked a million times before but here it comes again.

I'm about to bite the bullet and get my crank machined to mount the timing wheel. I've read all the previous posts and believe that I understand where it should be BUT here's a picture of how I understand it:

<img src="http://mysite.wanadoo-members.co.uk/bog ... cture3.gif?">

Rotation is clockwise (big red arrow). Assuming that the engine is at TDC and I have 4 cylinders (which I have), then the gap nees to be where it's shown.

Can somebody confirm this please?

Also, is it the exact centre of the gap which should be lined up?

Thanks.

Ivan · Post by **Ivan** » Tue Feb 28, 2006 5:12 pm

Where ever you place the gap when the engine is at TDC you need to place the sencor 90Â° before the gap.
It is possible when you aling the gap whit the TDC piont it is difficult to install the sensor.

MartinM · Post by **MartinM** » Tue Feb 28, 2006 5:33 pm

EDIT : deleted - but it's not like my installation. Post back when it all works!

rmaddock · Post by **rmaddock** » Tue Feb 28, 2006 6:18 pm

Now I am confused.

I think the gap is BEFORE TDC. The gap is not aligned to TDC in my picture. TDC could be anywhere. I simply state that the engine is assumed to be at TDC. So, if you rewind the engine (i.e. turn it anti-clockwise) by 90 degrees, the sensor and the gap will be aligned.

Then, turn the engine the correct way again and 90degrees later your are at TDC. Surely that makes the sensor, as shown, 90 degrees BEFORE TDC?

Is this a problem of semantics? When you say 90 before TDC, do you actually mean 90 degrees in the direction shown on the pulley as "before"...which would be clockwise OR do you mean that the sensor is triggered 90 degrees before the engine reaches TDC, which would be anti-clockwise.

My brain hurts.

For your information, my sensor has been mounted in a convenient place...there just happened to be a couple of unused threaded mounts on the timing cover. I've turned the engine to TDC according to the pointer on the crank pulley. I've then marked the pulley in line with the sensor and this mark will provide my reference for positioning the gap.

<img src="http://mysite.wanadoo-members.co.uk/bog ... cture1.gif?">

MartinM · Post by **MartinM** » Tue Feb 28, 2006 7:19 pm

I never, ever, ever, ever, ever, ever, ever, ever, ever said the sensor is/should be 90 degrees before TDC.

Let's try another way....when the engine is at TDC, the gap still has 90 degrees to go before it aligns with the sensor. i.e the sensor is 'before' the gap.

When the sensor is n o'clock the gap is at n-3 o'clock when the engine is at TDC

Follow THE EASIEST WAY TO DO IT (tm). You'll be OK then!

(...mind you, it wouldn't be a bad thing for someone else to confirm this, but I'm confident!)

EDIT: So in your second photo, the gap should be at just after 6 o'clock

neilthewheel · Post by **neilthewheel** » Tue Feb 28, 2006 7:23 pm

Yes. You are correct. With crank alligned at TDC, Position of sensor is 9 teeth to the left of missing tooth on a clockwise rorating engine.

rmaddock · Post by **rmaddock** » Tue Feb 28, 2006 7:38 pm

Martin, I don't mean to doubt you, but I've seen this question asked a lot recently and now have two different answers.

Also, can I quote the "Technical Info" page:

"If this was a typical clockwise rotating engine, the sensor would be positioned 90 degrees to the left side of the crank sensor (9 o'clock position), when viewed facing the crank."

I think that agress with what I said first.

Is Brent out there to confirm this please?

MartinM · Post by **MartinM** » Tue Feb 28, 2006 7:47 pm

EDIT : deleted

MartinM · Post by **MartinM** » Tue Feb 28, 2006 8:09 pm

IGNORE THE ABOVE....for some reason the forum won't let me edit it

MrSandman · Post by **MrSandman** » Tue Feb 28, 2006 11:34 pm

Your initial picture looks coorrect to me.

The EDIS needs a signal at 90 degrees before TDC. This is what you have achieved. If you engine is wound backwards until the gap and sensor are aligned, it will be at 90 deg btdc.

This topic seems to cause lots of concern but seems fairly straightforward to me. Unless I am missing something.

rmaddock · Post by **rmaddock** » Wed Mar 01, 2006 10:26 am

Thanks. This was my understanding of it. Maybe the confusion comes from the fact that if you were talking about setting the static timing to x BTDC then you would be wanting the timing pointer to point further to the right on the crank when using a strobe.

I'm going to do it the way my picture shows...the worst that can happen is that I'll have to drive backwards.....tee hee.

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