Jump to content

Discovery 3.9 timing mark


Recommended Posts

Once again I need to call upon the massed wisdom of this forum.

My 3.9 N registration Discovery failed its MOT yesterday. One of the failure points was that the emmisions were too high. As the vehicle was LPG I asked them to test it on both fuels and it failed on both.

I have had the vehicle checked over by a professional lpg installer. One of the checks that he wanted to carry out was the timing. Here comes the problem. Haynes book of fairy stories tells us that there is a nice scale on the side of the crankshaft pulley marked with before TDC, TDC and after TDC. Trouble is that mine doesn't have this. There is a single groove cut into the crankshaft pulley. We worked on the assumption that this was the timing mark. Setting up with the strobe we adjusted the distributor so that the groove lined up with the pointer.

This seems to have improved the situation, but I would like to be certain that this is actually the timing mark. And, also, if it isn't, what is?

As an additional note the vehicle has new plugs and leads as the leads were shorting out in a few places.

While I am on here I will pose another question on the MOT. Last year the place that tested it mraked the fact that the tyres foul on the radius arms as an advisory. As I knew this and have not had the time to reset the lockstops I assumed that all would be OK. Not according to the testing station that I took it to this year. They have marked it as a failure point.

So, who is right?

Sorry to waffle on, but I had a long day of it yesterday and an MOT failure was the icing on the cake.

Thanks in advance,


Link to comment
Share on other sites

The single groove in the crank pulley (the one that is square cut a couple of mm deep and a couple of mm wide) is not the timing mark - Sometimes they are difficult to see without cleaning the pulley up, but I have never seen a pulley without them...

It should look something like this:


Link to comment
Share on other sites

From the MOT Inspection manual:

"2. A tyre fouling a part of the vehicle.

Note: This does not apply to vehicles designed to permit tyre contact with the chassis or frame eg. Steering lock stop function."

It's down to discretion, if one tester thinks it is significant they can fail, if another thinks it is insignificant then it is an advisory.

Some items can not be an advisory, and are an immediate fail, such as brakes etc. ALSO, VOSA are continuously updating the manual, adding more advisory points and making more items an automatic fail, so things do change....

Reset the lock stops and take it for a retest, I don't really know why anyone would want to deliberately leave them like that anyways :blink::huh:

I wouldn't argue with them about it :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy