Dwell Plate

[Stu125]

Hi all
Quick question....When you are replacing the timing belt is it possible that the Dwell plate (behind crank timing gear) move?
My car seems to have developed some pinging on 91 fuel since the timing belt was replaced.
The car runs well and I have checked the marks all line up a couple of times and thats the only thing I can think of.
Does not ping on 98 fuel but costs heaps

Any advise would be appreciated

Stu

Sorry 2004 3.8L Exceed

[psproule]

Cant answer re the dwell plate as I have not seen a 3.8 apart, but you didn't happen to disconnect the knock sensor by accident?

Pat

[m1s3ry]

It shouldn't as its held together with the crank sprocket and spacer with 2 dowel pins.

However, i have seen these pins broken, particularly if the sprocket has been off a few times as people tend to lever it off via the plate.

[Stu125]

Thanks for the reply's
Didn't have the sensors disconnected

For the sake of half a day I might strip the front off again and make sure the dowel pins are not damaged

Stu

[Stu125]

Well pulled the timing belt off again and found the issue
Yes the dwell plate behind the crank gear was in the incorrect spot
On the back on the crank gear it has 2 small dowels which obviously locate the dwell plate. The plate has obviously dropped off these dowels and shifted around by about 5mm. This upsets the your engine timing which would be the reason why it has been pinging.
I fixed it all back up put it all back together and it seems to be running like a dream

I also noticed when I pulled it apart that the belt was very loose in between the 2 cam gears. I fixed that up so I think I am fairly lucky that I pulled it apart for another look

I have attached a photos of the dwell plate

Cheers

Stu

[erad]

It is difficult for the plate to slip round because the keyway should also locate it. Are you sure you have the plate the right way round? It looks as if it has been mounted back to front. Check that the blades of the plate are not bent as well - if they are, you will wipe out your crank angle sensor (trust me - I did it!) Learn by the mistakes of others, because you will never live liong enough to make them all yourself.

Also, If the plate was mounted back to front, the sprocket for the timing belt will be too far forward. ANd the lugs will be out of place rotationally. This would have caused your timing to be out of whack and thus cause pinging you noted.

Turn the plate around and all should be well, but check the clearance between the blades and the sensor. When I bent my plate, it was weekend and I decied to hammer it straight. I set it up on a flat surface and used a dial gauge to verify that the blades were running true and alo they were all in the same plane.

[NMPajboy]

It is difficult for the plate to slip round because the keyway should also locate it. Are you sure you have the plate the right way round? It looks as if it has been mounted back to front. Check that the blades of the plate are not bent as well - if they are, you will wipe out your crank angle sensor (trust me - I did it!) Learn by the mistakes of others, because you will never live liong enough to make them all yourself.

Also, If the plate was mounted back to front, the sprocket for the timing belt will be too far forward. ANd the lugs will be out of place rotationally. This would have caused your timing to be out of whack and thus cause pinging you noted.

Turn the plate around and all should be well, but check the clearance between the blades and the sensor. When I bent my plate, it was weekend and I decied to hammer it straight. I set it up on a flat surface and used a dial gauge to verify that the blades were running true and alo they were all in the same plane.

The key way dosnt actually locate it as the key dosnt go that far back. It has the keyway cut out to allow it to slide over the key with the cam belt sprocket. Dont know how you could mount it backwards as its got a 6mm deep step in the centre to recess it into the back of the crank sprocket.
This one almost looks like it's been purposely redrilled to advance ignition. It's a common mod on bike engines. But I could see how the small roll pins could punch new holes while tightening the crank nut.

[chrisall]

The key way dosnt actually locate it as the key dosnt go that far back. It has the keyway cut out to allow it to slide over the key with the cam belt sprocket. Dont know how you could mount it backwards as its got a 6mm deep step in the centre to recess it into the back of the crank sprocket.
This one almost looks like it's been purposely redrilled to advance ignition. It's a common mod on bike engines. But I could see how the small roll pins could punch new holes while tightening the crank nut.

I just took mine off today and can't see how you would put it on backwards as plate is sandwiched between the spacer and the sprocket. The spacer sits in the recess.

Form the OP's pic it looks like it rotated once it was over the key, and the roll pins punched new holes when the pulley bolt was torqued up to 185NM. Here is a pic from the manual of how it's supposed to look:



Cheers,

[Stu125]

Hi guys

As per the above posts the plate cannot go on backwards otherwise it will not go in the crank sensor gap.
The key way does not locate it as the gear sits about 5mm over the end of the keyway.
What locates it is the small pins on the rear of the crank gear. On mine it had dislodged and bent the plate and just sat about 5mm out. There are no new holes only the 2 original and marks an indents where the pins have sat.
When I changed the belt I didnt have the crank pulley off so it must have dislodged slightly


Stu

[Fastman]

I've got my crank cog off at the moment and the keyway slot on the dwell plate doesn't line up with the keyway slot in the cog. I don't know how to add a picture but the left side of the slot on the plate lined up with the right side of slot on the cog

[chrisall]

I've got my crank cog off at the moment and the keyway slot on the dwell plate doesn't line up with the keyway slot in the cog. I don't know how to add a picture but the left side of the slot on the plate lined up with the right side of slot on the cog

That doesn't sound right, if the sprocket, plate and spacer didn't all align then you wouldn't be able to reinstall the 3 parts over the key as the plate would be in the way.

I also have mine off at the moment whilst doing the timing belt and all 3 slots are perfectly in line. Are you sure that your plate hasn't moved as per the OP?

Cheers,

[Fastman]

Well it looks like it's ment to be that way but like you said it can't be fitted as one piece like that. The picture that was posted of the plate looks the same as mine with 2 holes either side but my pins aren't in the holes his are mine are in the other 2 hence the keyway slot doesn't line up. Should I just line the slot up and put the pins in the other holes?
Mine is a 2002 NM Pajero exceed if that makes any difference

[chrisall]

Well it looks like it's ment to be that way but like you said it can't be fitted as one piece like that. The picture that was posted of the plate looks the same as mine with 2 holes either side but my pins aren't in the holes his are mine are in the other 2 hence the keyway slot doesn't line up. Should I just line the slot up and put the pins in the other holes?
Mine is a 2002 NM Pajero exceed if that makes any difference

This is how my sprocket, plate and spacer looks:



As far as I know there should only be one pair of holes to locate the plate and spacer correctly on the 2 roll pins in the sprocket.

Cheers,

[Fastman]

Oh the pins are meant to be in the sprocket 😢 I think I might see what I can buy today. I have one pin out with the end burred over and one near all the way in the sprocket with the edge burred over.
Thanks this has been a big help

[Fastman]

Well all sorted. I got lucky with Facebook I posted looking for the part and one fella contacted me saying he had a 3.5v6 in a pajero out the back and if I came and took it off I could have it. So a 250km round trip to the back of nowhere to strip a engine. Lol after working all day too it was a long night we made it home at 1am. Fitted the part put it back together and away she goes. Thanks for all the help it saved me big time