Which TDC Mark To Use
#1
Which TDC Mark To Use
I have the heads off the engine and I thought I would actually see if the crank shaft positioning sensor put #1 at TDC _ well it doesn't.
With everything out of the way, there is an additional timing mark on the front of the timing chain cover.
The green arrow is pointing to it, I had to shine the light behind it to get a decent photo, so you're actually looking at the shadow of the new found timing mark.
The red arrow is pointing to the small protrusion indicating that this is the actual mark for TDC and not the crank shaft position sensor.
I can confirm this easily with the heads off as I can tell that #1 is at TDC.
If I move the harmonic dampener to the CPS position as TDC, I can clearly see that the piston is no longer at TDC, it's about 15 degrees out from TDC.
The question is, which TDC mark to use when timing the cam shaft synchronizer and sensor ?
Everyone is using the CPS as TDC, but as I discovered, it's not actually TDC.
What's the Ford dealership using ?
Here's a better photo, the protrusion on the end of the timing mark can be seen too.
Last edited by Jeff R 1; 10-09-2016 at 11:13 PM.
#2
RF Veteran
iTrader: (1)
The timing mark(s) on the damper/pulley will show TDC using a mark on the timing chain/belt cover.
Depending on the engine there could just be 1 line on the pulley and then 0deg and BTDC/ATDC degs on the cover marker...or 0deg and BTDC/ATDC degs on the pulley and just 1 line on the cover.
But these marks have nothing to do with Crank position(CKP) sensor.
The CKP sensor reads a Tone Wheel, 1 tooth every 10deg, minus 1 tooth for a gap, so 35 teeth.
The gap represents TDC, but because it is an electronic interface the gap doesn't need to be at the CKP sensor when the visual pulley lines match up.
Tone wheel Gap could be at CKP sensor at 10deg ATDC or BTDC doesn't matter as long as it is the same each time.
Ignition system is just programmed for that, its electronic not mechanical like a distributor.
So CKP sensor can be placed where ever it fits, lol, as long as ignition system is programmed for that location.
CPS is the same.
The pulley marks are a visual reference for us, as are cam and crank gear marks
Instructions are available for each engine model, for CPS alignment, that is what Ford dealer would use
Depending on the engine there could just be 1 line on the pulley and then 0deg and BTDC/ATDC degs on the cover marker...or 0deg and BTDC/ATDC degs on the pulley and just 1 line on the cover.
But these marks have nothing to do with Crank position(CKP) sensor.
The CKP sensor reads a Tone Wheel, 1 tooth every 10deg, minus 1 tooth for a gap, so 35 teeth.
The gap represents TDC, but because it is an electronic interface the gap doesn't need to be at the CKP sensor when the visual pulley lines match up.
Tone wheel Gap could be at CKP sensor at 10deg ATDC or BTDC doesn't matter as long as it is the same each time.
Ignition system is just programmed for that, its electronic not mechanical like a distributor.
So CKP sensor can be placed where ever it fits, lol, as long as ignition system is programmed for that location.
CPS is the same.
The pulley marks are a visual reference for us, as are cam and crank gear marks
Instructions are available for each engine model, for CPS alignment, that is what Ford dealer would use
Last edited by RonD; 10-10-2016 at 11:00 AM.
#3
I don't think I understand what you're saying. I'm not so worried about the CKP sensor, but which timing mark to use when positioning the synchronizer in relation to the CKP sensor.
With that said, don't we need a point of reference to initially set things up ?
I'll use the timing mark on the timing chain cover and reset the synchronizer with the tool according to that TDC mark.
The difference is very little on the tooth position of the synchronizer any way between the timing marks.
With that said, don't we need a point of reference to initially set things up ?
I'll use the timing mark on the timing chain cover and reset the synchronizer with the tool according to that TDC mark.
The difference is very little on the tooth position of the synchronizer any way between the timing marks.
#4
I don't think I understand what you're saying. I'm not so worried about the CKP sensor, but which timing mark to use when positioning the synchronizer in relation to the CKP sensor.
With that said, don't we need a point of reference to initially set things up ?
I'll use the timing mark on the timing chain cover and reset the synchronizer with the tool according to that TDC mark.
The difference is very little on the tooth position of the synchronizer any way between the timing marks.
With that said, don't we need a point of reference to initially set things up ?
I'll use the timing mark on the timing chain cover and reset the synchronizer with the tool according to that TDC mark.
The difference is very little on the tooth position of the synchronizer any way between the timing marks.
Jeff, would be nice for update in your situation, running/not running/sold/scrapped.
I currently have a sort-of similar situation but reading your post as collateral info.
As for the timing marks info by RonD, ya it was a bit difficult to grasp and had to re-read 3 times but it is informative. Pix would help.
The Harmonic Balancer has 2 parts, inner and outer with hard rubber between, I read this rubber can slip as it ages throwing the tooth ring off.
So my question is, how do we check tooth ring to HB marks?
#5
NOT drumming up old thread, just looking for thread completions info.
Jeff, would be nice for update in your situation, running/not running/sold/scrapped.
I currently have a sort-of similar situation but reading your post as collateral info.
As for the timing marks info by RonD, ya it was a bit difficult to grasp and had to re-read 3 times but it is informative. Pix would help.
The Harmonic Balancer has 2 parts, inner and outer with hard rubber between, I read this rubber can slip as it ages throwing the tooth ring off.
So my question is, how do we check tooth ring to HB marks?
Jeff, would be nice for update in your situation, running/not running/sold/scrapped.
I currently have a sort-of similar situation but reading your post as collateral info.
As for the timing marks info by RonD, ya it was a bit difficult to grasp and had to re-read 3 times but it is informative. Pix would help.
The Harmonic Balancer has 2 parts, inner and outer with hard rubber between, I read this rubber can slip as it ages throwing the tooth ring off.
So my question is, how do we check tooth ring to HB marks?
Truck has a new rebuilt engine in it.
I think if the rubber was deteriorated enough that the tone wheel was out of "sync" with the timing marks, the whole thing would fly to pieces.
I suppose the tone wheel itself could move in the end because it is just pressed on, but I don't think it could move because the rubber was deteriorated.
In the end if the cam synchronizer was out a few degrees one way or the other, I don't think it would make any difference, or throw up any codes.
When I got the truck the cam synchro was out more then 45 degrees and it ran and idled fine, no codes either, but it was really gutless and was easily stalled. (manual)
The last guy put in in wrong.
The truck still has a slightly annoying problem, it hesitates slightly on take off, I have to pause slightly after a press the accelerator before giving it some clutch, if I don't, I can stall it.
It's almost OK when it's hot, but on first start up, it's kind of annoying.
It's almost like the throttle position sensor is faulty or it's not been set right, it's been replaced though with a Ford one.
Pretty much ruled out vacuum leaks, the only thing that is left is the MAF sensor, but before I blow money on a new one, I will take it to a garage, I have someone that I trust, and I know he would be able to figure out what's wrong.
#6
I was JUST going out the door when my phone CHIRPED for your post.
I have pix now to verify the marks and positions.
You say it FLY APART, couple other forums said theirs slipped several degrees. No one mentioned it moved away from the crankshaft. My HB 2 part faces are flush but the rubber that's poking out looks old and chippy/crusty.
ANYWAYS...
I've been saying for a several decades now these newer vehicle designers needs their heads examined for some of the rather stupid stuff they're designing, but CEO's are partly to blame for being CHEAP! (more $ in their pockets)
One would figure after all these decades the possible tried & failed stuff would be... well history.
THANKS for the reply!!!+!
I have pix now to verify the marks and positions.
You say it FLY APART, couple other forums said theirs slipped several degrees. No one mentioned it moved away from the crankshaft. My HB 2 part faces are flush but the rubber that's poking out looks old and chippy/crusty.
ANYWAYS...
I've been saying for a several decades now these newer vehicle designers needs their heads examined for some of the rather stupid stuff they're designing, but CEO's are partly to blame for being CHEAP! (more $ in their pockets)
One would figure after all these decades the possible tried & failed stuff would be... well history.
THANKS for the reply!!!+!
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