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Randomer
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Discussion Starter · #1 ·
Take a look at this pic of the timing belt & cam pulleys on my car...



What (if anything) is wrong with that picture?

My car has what I believe to be a timing issue, it won't start but will turn over, has spark & fuel, so timing is the suspect at the moment.
I've been looking at pics on the interweb but it seems that usually the "I" and "E" are aligned, whereas in my pic the "I" and "I" are (almost) aligned.

confused....
 

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remove the spark plug closest to the front of the engine and insert a long thin screwdriver into the hole. Turn the crank with a ratchet (car out of gear) until the screwdriver is at the top of its travel (TDC). Then take a photo and the two lines cut into the face of the cogs should match up with the marks behind the thermostat housing.
 

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I could well be barking up the wrong tree, but it doesn't look like the "E" and "I" will line up with the marks on the block when it's at TDC. If the "E" is lined up then the "I" would be about 60[sup]o[/sup] out?
IIRC It should look like this:

 

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put your fingers on the timing marks on the original pic and rotate your fingers clockwise at the same speed for one and a bit rotations. It looks like it will line up to me.
 

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Randomer
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3 photo's for you.

1. At TDC according to my highly trusted guage (a screwdriver)


2. At TDC again (I take it it's at TDC twice per revolution, ie 180 degrees apart?)


3. Marks lined up, I got the I and E mixed up, but even so it didn't look spot on to me. (NOTE: this was with the engine NOT at TDC)
 

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Hmmm, looks totally wrong to me.

The I should be on the Exhaust side of the engine and the E should be on the Intake side of the engine when at TDC. (see Roo's pic above)

You need that belt off and the cams put right sharpish.
 

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Discussion Starter · #9 ·
lets suppose for a minute that it is wrong, how on earth does it get that way?? the car was driving fine until I slowed for some traffic lights, then it just cut out/stalled and wouldn't restart again.

info: car had oil pump replaced approx 300miles before the above problem ^^^, anything I should be worried about? or just coincidence?
 

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Turn it again until the E mark on the Intake cam (driver's side) is lined up with the timing mark and see where the I mark is on the other cam. Turn the crank so the intake cam goes around one revolution and check the other cam again - keep on turning one revolution at a time until the two marks are as close to being together as possible - then note where the screwdriver is.
 

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Difficult to say 101% from the pics Jim as the angle looks a bit funny, but i gotta agree with Halli, it looks out to me from the pics, sorry mate.

As for the reason, well that's why we advised you not to cut the cam cover.

Anything can get in there, all you need is a very small stone and once it's in it's virtually impossible for it not to jump the belt.

Any sign of anything being ingested?

Cheers
Mark
 

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Isn't it 4 engine revolutions before the marks align back up again? As shown in Roo's picture

Maybe the pully was never sat home right after the belt change, or not tight enough.. then just happend to settle there
Either way it needs changing to line up
 

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Discussion Starter · #16 ·
I had another look at it this morning....

So, with the timing mark on the crank pulley at TDC (and my screwdriver guage confirmed this)...


And this is the situation with the cam pulleys...


So I tried lining up the "E" on the intake cam with the marking behind the thermostat (it is lined up correctly, just the angle of the pic I think).
Now see where the "I" on the exhaust cam is?


And with the cam pulleys as in the pic above, this is where the tiing mark was positioned.


I turned the crank over several times with a large ring-end spanner, not once could I get the cam pulleys to line up correctly.

It seems that the TDC position of the crank pulley is correct, as my screwdriver guage showed me, but the position of the cam pulleys seems wrong to me.

I've not had much dealings with the subject of cams and timing etc so would like some confirmation that the above pics do indeed show a problem with the timing, also how something like that could happen, and how to go about putting it right.

cheers,

Jim.
 

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I wonder if the exhaust cam has been put on incorrectly. They have two positions (they are the same pulley but can be put on in two positions)

It could be that the exhaust cam is lined up correctly, but the timing marks on it are wrong due to it being incorrectly positioned on the pegs.

Shame you're not closer, I'd have a look at it and line it up for you.
 

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I would hope the cam pullies have been put on correctly, the last work done on the car was by a reputable garage who work on a lot of mx5's, that's even if they were in fact removed (car had engine out, oil pump replaced, new timing belt).
Also, the car was running beautifully for 300+ miles after the works had been done, then suddenly stopped working and wouldn't re-start.
The recovery guy (a local garage called out by the RAC) said he thought it was the timing, he seemed to know his stuff (as you'd expect) as he said he prepped rally cars (they like their rallying over here in Northern Ireland).

The problem looks like the engine timing. How did it get like that? and how do I fix it?

edit: maybe I'd better see about doing a compression test too, just in case.
 

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Fixing is easy, pull the timing belt, line everything up then re-fit. it'll be easy as you don't have any of the covers to remove, I could do it in 30 mins if you were a bit closer.

I'm with Gixer on the cause though, stone in the workings causing everything to jump. Exposed camgears are FTL IMO


EDIT cops of your EDIT
A Comp test will tell you feck all, your valves won't be closed/open at the right time. The timing/misaligned cams are definately the cause.
 

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Fixing is easy, pull the timing belt, line everything up then re-fit. it'll be easy as you don't have any of the covers to remove, I could do it in 30 mins if you were a bit closer.

I'm with Gixer on the cause though, stone in the workings causing everything to jump. Exposed camgears are FTL IMO


EDIT cops of your EDIT
A Comp test will tell you feck all, your valves won't be closed/open at the right time. The timing/misaligned cams are definately the cause.
+1 to all of that, especially the cause - it wouldn't take a large stone to make the belt jump. Would just need to drop down to the crank pulley and the power of the engine would drag it through and teeth would be jumped. Nothing stopping it from being dragged through again and again. Look for scratches on the crank pulley.
 
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