Advice on timing cam gear up on a 2.1DJ

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josephcarey1
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Advice on timing cam gear up on a 2.1DJ

Post by josephcarey1 »

Hi guys,
I wanted to double check this before I seal my engine case back together.

I have installed my new cam shaft and have done exactly what both Haynes and Bentley books have said.
Line the dot up on the cam gear in between the two dots on the crank gear.
Trouble is that it looks like I could be 180 degrees out.

My example,
Put the cam in and line the marks up.
Rotate the crank 360 degrees and the crank dots come back to the same position but the dot on the cam gear is somewhere else.
Rotate the crank another 360 degrees and they both line up.
To me this tells me that it is possible to put the cam in the wrong position.
Am I being stupid or does it not matter?
Obviously I want to get this right first time, so can someone tell me if there is anything else to do.

Many thanks!

JC

davidoft1
Posts: 1474
Joined: 27 May 2009, 18:56
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Location: hayling island

Re: Advice on timing cam gear up on a 2.1DJ

Post by davidoft1 »

josephcarey1 wrote: 07 Feb 2021, 14:34 Hi guys,
I wanted to double check this before I seal my engine case back together.

I have installed my new cam shaft and have done exactly what both Haynes and Bentley books have said.
Line the dot up on the cam gear in between the two dots on the crank gear.
Trouble is that it looks like I could be 180 degrees out.

My example,
Put the cam in and line the marks up.
Rotate the crank 360 degrees and the crank dots come back to the same position but the dot on the cam gear is somewhere else.
Rotate the crank another 360 degrees and they both line up.
To me this tells me that it is possible to put the cam in the wrong position.
Am I being stupid or does it not matter?
Obviously I want to get this right first time, so can someone tell me if there is anything else to do.

Many thanks!

JC


The crank runs twice cam speed , so will be lined up correctly every other turn, it’s correct

josephcarey1
Posts: 32
Joined: 27 Oct 2020, 09:36
80-90 Mem No: 0

Re: Advice on timing cam gear up on a 2.1DJ

Post by josephcarey1 »

davidoft1 wrote: 07 Feb 2021, 14:48
josephcarey1 wrote: 07 Feb 2021, 14:34 Hi guys,
I wanted to double check this before I seal my engine case back together.

I have installed my new cam shaft and have done exactly what both Haynes and Bentley books have said.
Line the dot up on the cam gear in between the two dots on the crank gear.
Trouble is that it looks like I could be 180 degrees out.

My example,
Put the cam in and line the marks up.
Rotate the crank 360 degrees and the crank dots come back to the same position but the dot on the cam gear is somewhere else.
Rotate the crank another 360 degrees and they both line up.
To me this tells me that it is possible to put the cam in the wrong position.
Am I being stupid or does it not matter?
Obviously I want to get this right first time, so can someone tell me if there is anything else to do.

Many thanks!

JC


The crank runs twice cam speed , so will be lined up correctly every other turn, it’s correct

Hello mate! Thanks for the quick response.

So regardless of where the crank is, as long as the dot comes back in between the two dots should mean that it is in the right position?

That’s good then. I can continue with my work.

davidoft1
Posts: 1474
Joined: 27 May 2009, 18:56
80-90 Mem No: 16628
Location: hayling island

Re: Advice on timing cam gear up on a 2.1DJ

Post by davidoft1 »

josephcarey1 wrote: 07 Feb 2021, 14:51
davidoft1 wrote: 07 Feb 2021, 14:48
josephcarey1 wrote: 07 Feb 2021, 14:34 Hi guys,
I wanted to double check this before I seal my engine case back together.

I have installed my new cam shaft and have done exactly what both Haynes and Bentley books have said.
Line the dot up on the cam gear in between the two dots on the crank gear.
Trouble is that it looks like I could be 180 degrees out.

My example,
Put the cam in and line the marks up.
Rotate the crank 360 degrees and the crank dots come back to the same position but the dot on the cam gear is somewhere else.
Rotate the crank another 360 degrees and they both line up.
To me this tells me that it is possible to put the cam in the wrong position.
Am I being stupid or does it not matter?
Obviously I want to get this right first time, so can someone tell me if there is anything else to do.

Many thanks!

JC


The crank runs twice cam speed , so will be lined up correctly every other turn, it’s correct

Hello mate! Thanks for the quick response.

So regardless of where the crank is, as long as the dot comes back in between the two dots should mean that it is in the right position?

That’s good then. I can continue with my work.


Yes

Basically put it together with them lined up and it can’t be wrong, turn the cam once and you will see the crank turn twice.

The piston runs 2 cycles for every one of the cam , induction, compression, power, exhaust

Induction and power have the piston in the same place in the crank cycle with the cam cycle controlling the air flow

Same on compression and exhaust

4 stroke cycle

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