Mounting crank trigger wheel-what position?

Need to mount my crank trigger wheel but arnt certain of its exact position in relation to crank


Dave walker claims crank sensor must be at the first tooth after the gap when crank is 90deg before TDC (ie qtr of revolution)

He is using 36-1 wheel, so would this mean when engine is at TDC the sensor will be at tooth 9? (4x9=36)

I'm using 60-2 wheel, and Louis(Mk1.) from here sent me a diagram stating that sensor should be pointing to to tooth 20 with engine at TDC

Could anyone confirm this is how it should be?

Not doubting louis but if above is correct i think sensor should be pointing to tooth 15! (4x15=60)

I am sure someone will correct me if i am wrong

 

It is critical to get this right as it means the figures seen on the laptop during mapping will match the real world timing figures

 

I know its critical to get it right, thats why i'm asking for advice

Any more info anyone?

 

C'mon you clever boffins, i know you'r out there

Info pleeeeze

 

erm i think you should read into this in more depth.
the toothed wheel obviously has to be positioned so that the missing tooth is x degrees before tdc. when the crank is x degrees before tdc your sensor should be lined up to the first tooth after the gap.

x can be anything from 60 - 180 degrees if i remember right.


you are not concerned about the position of the wheel when the crank is at tdc or any other point in the cycle.

 

presuming you are using emerald.. its should be settable as any figure.
DTA advise leaving 10+ degrees over and above any prospective dialed in ign advance as a guide.

360 degrees, 60-2 wheel, 6 degree per tooth, 90 degrees is 15 teeth

36-1 wheel I use on DTA is easy as 36 teeth, 10 degree's per tooth..
set motor at TDC#1 (physical) and clock the trigger wheel relative to the crank trigger (trailing edge of 1st tooth after missing one in the case of DTA), count the teeth as they pass, nail it on, jobs done.

hope this helps

 

Cheers bill, i'm using pug ecu to run the bodies with

Will ask wayne from chipwizards tomorow about this

 

Where you set it is entirely dependent on what ECU it is (they vary), so yeah I imagine Wayne will be the best help for you

 

yep as per the diagram need to get my finger out and make a trip upto rochdale aswell

 

Cheers louis, so if engine is timed up to TDC#1 the gap is passed the crank timing mark on plastic cover by 5 teeth and sensor is pointing to back edge of 20th tooth?

I was at waynes last week, he put on a mapp on my ecu for me

When i called round he was mapping a very nice porche 944 turbo kicking out 400 bhp!

 

@ martyn16v..... oh i see, i thought that would be the case

Jut just want to make sure i will mount this pulley right first time as it is going to be welded to power steering pulley

 

depends on were you mount the crank sensor,so if its mounted on the power steering bracket as mine is just position the trigger wheel as per pic

 

Thats what i ment, cheers bud

 

what have you used to mount your crank sender ?

 

use the power steering mounting lugs and a cut down bracket modded to take the sensor

 

that lookes exactly the same as i had on my valver in my mk1

That is untill i smashed it and engine got pushed against front shassis leg and it bent my pick up wheel[:^(]

Got another wheel from scrapy but it's different so i'm getting it machined to fit onto the pas pulley

I'v made a bracket out of spare pas pump bracket,strong enough to lift the engine with!

But now that i'm running pas in a mk2 i will have to modify it to fit new set up