What'S Wrong Here??

2994 Views 53 Replies 15 Participants Last post by PGD, Jan 8, 2011

Road&ster

Discussion Starter · Apr 6, 2010

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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-halli-

· #2 · Apr 6, 2010

Is the engine at TDC in that pic?

Road&ster

Discussion Starter · #3 · Apr 6, 2010

-halli- said:
Is the engine at TDC in that pic?

I don't know, I was just out working on the wiring in the car and thought about the tiing belt.

-halli-

· #4 · Apr 6, 2010

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.

Roo.

· #5 · Apr 6, 2010

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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-halli-

· #6 · Apr 6, 2010

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.

Road&ster

Discussion Starter · #7 · Apr 6, 2010 (Edited by Moderator)

3

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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-halli-

· #8 · Apr 6, 2010

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.

Road&ster

Discussion Starter · #9 · Apr 6, 2010

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?

-halli-

· #10 · Apr 6, 2010

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.

Road&ster

Discussion Starter · #11 · Apr 6, 2010

I'll have another look in the morning.

cheers Halli!

Gixer

· #12 · Apr 6, 2010

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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Paul J

· #13 · Apr 6, 2010

This video may help

Road&ster

Discussion Starter · #14 · Apr 6, 2010

Gixer said:
Any sign of anything being ingested?

none, belt looks fine to me.

damn and buggery! this car is a p.i.t.a

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PGD

· #15 · Apr 7, 2010

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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Road&ster

Discussion Starter · #16 · Apr 7, 2010

4

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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-halli-

· #17 · Apr 7, 2010

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.

Road&ster

Discussion Starter · #18 · Apr 7, 2010 (Edited by Moderator)

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.

Mr Slow

· #19 · Apr 7, 2010 (Edited by Moderator)

2

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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-halli-

· #20 · Apr 7, 2010

Mr Slow said:
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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