cam sync - rover v8

[Seight-v8]

hello all,

So for one of my winter upgrades i would like to get cam sync running...

I've got a new cam spocket (GEMS) type and i'm gonna modify it to work with my vems.

I know i need one pulse, from the sprocket to make work it...but where in the firing cycle would be best to place it to pulse.

I still dont really understand how the cam sync work in vems.....so any help appreciated.

cheers

scott

[mattias]

In general, place it so the signal comes when cylinder #1 is in TDC.

[rob@vems.co.uk]

Surely before cyl1 is at TDC?  When the sync pulse comes then the sequence restarts, most people will want the index to initialise on Cyl 1.
I makes no real difference if you start the squence on the second cylinder in the sequence, but seeing that describing engine indexing is a pain in the arse at the best of times, it would be better to keep the h[] order in firing order.
So if you can move the trigger so that it syncs when Cyl1 is 180 to 90deg BTDC surely that would be better?

[mattias]

Look at how other systems recommend the cam sync placement and you'll see what I mean.

In setting up the reference tooth table and ignition output table this is the least of the paradigms to overcome.
To put it simply, it's just a matter of rotating the ignition output table until cyl #1 fires at the correct spot, something that needs to be done either way.

In this case, you can put it wherever you want as long as it's possible to configure where it is - either way it will require you to fully understand how to set up the trigger and related tables.

[dnb]

The pulse should come at least 45 crank degrees before TDC cyl #1.  But it should also be well after TDC cyl #7.
This is my winter mod too...

[gunni]

I though the general consensus was to have it before the missing teeth , i.e say about 120deg BTDC on the compression stroke.

[mattias]

Look at Autronic and others, they want it at cyl 1 TDC.

The important thing if your primary trigger is of the missing tooth type is that the cam sync pulse should not race with the missing teeth. If it's before or after doesn't really matter, that's all relative.