Hi all,
I have removed a M42 CPS holder from its timing case, trying to locate CPS holder onto a M44 case so I can weld it on using a jig to hold it in the correct place.
Yes it will be square to the pick-up wheel
yes it will have the correct air gap
BUT if it is 2mm +/- up or down from where it should be will this affect the timing?
M42/44 CRANK SENSOR LOCATION
Moderator: martauto
-
Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Wheel is 170mm diameter, so a bit of simple arithmetic says that 1.5mm positioning error will change the timing by approximately 1 degree
Cheers for info:
Yes I'm not asking how to work it out (simpler way would be to use another timing case that iv got and a degree wheel to measure where it needs tobe)
I already have the doner M44 engine so its cheaper todo this instead of buying another £250 engine..
It's not like theres a lot of weight in the CPS so once the correct location is found and its tig welded on then can't see any unforeseen problems.
The question is does it need tobe in exactly the right place? There dosnt seem tobe any relation between TDC and the flat on the trigger wheel...
Yes I'm not asking how to work it out (simpler way would be to use another timing case that iv got and a degree wheel to measure where it needs tobe)
I already have the doner M44 engine so its cheaper todo this instead of buying another £250 engine..
It's not like theres a lot of weight in the CPS so once the correct location is found and its tig welded on then can't see any unforeseen problems.
The question is does it need tobe in exactly the right place? There dosnt seem tobe any relation between TDC and the flat on the trigger wheel...
-
Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
The flat on the trigger wheel 'resets' the ECU, which then counts the pulses from the teeth, so that it knows exactly where the crank is. If the flat is picked up by the TPS too early or too late, then of course the timing will be out - by one degree per 1.5mm error.
Im learning!
I expected there to be more of a obvious relation between TDC, trigger wheel and CPS..
Is the ECU programmed to know that after X amount of teeth has been counted from reset point, #1 piston is at TDC?
What does the Cam sensor do?
Im nearly sure that the mount is very close to correct position..
I mounted the m42 timing case onto block with crank and the m44 timing case onto another block with crank then lined up the TDC mark on the oil pump housing with the TDC mark on the trigger wheel from there marked the centre of the m42 case cps holder on the trigger wheel, transferred the trigger wheel to the block with the m44 casing, then I lined up the cps holder that I cut from another casing with the bust idler mount.. With only cutting away enough of the CPS holder I could more or less line it up by the casting shape..
Trigger wheel = complete m42 crank pulley.
The above sound like its will be accurate enough?
When Im done how can I check that its correct? stroboscope?
If its not 100% correct can the CPS position be adjusted electronically?
Wud post some photos up but can work out how to attach!
Cheers for help...
I expected there to be more of a obvious relation between TDC, trigger wheel and CPS..
Is the ECU programmed to know that after X amount of teeth has been counted from reset point, #1 piston is at TDC?
What does the Cam sensor do?
Im nearly sure that the mount is very close to correct position..
I mounted the m42 timing case onto block with crank and the m44 timing case onto another block with crank then lined up the TDC mark on the oil pump housing with the TDC mark on the trigger wheel from there marked the centre of the m42 case cps holder on the trigger wheel, transferred the trigger wheel to the block with the m44 casing, then I lined up the cps holder that I cut from another casing with the bust idler mount.. With only cutting away enough of the CPS holder I could more or less line it up by the casting shape..
Trigger wheel = complete m42 crank pulley.
The above sound like its will be accurate enough?
When Im done how can I check that its correct? stroboscope?
If its not 100% correct can the CPS position be adjusted electronically?
Wud post some photos up but can work out how to attach!
Cheers for help...
yeah thats pretty much it "Is the ECU programmed to know that after X amount of teeth has been counted from reset point, #1 piston is at TDC?" normally the cam sensor gives 1 signal per engine cycle 2 rev of the crank, this tells the ecu that tdc compression it cumming up, from the crank wheel it knows the piston is at tdc but needs to know if it is tdc compression or exhaust. thats the way most aftermarket management work.