V6 timing - here we go again!!

[ballymenaman]

Originally Posted by SD1too

Thanks for your reply Andy. My further thoughts:

OK, so with the front tools fitted, we have the inlet camshaft in a particular position and the crankshaft in a particular position. Both these positions constitute correct timing, yes?

Now if I looked at the rear sprockets, I would expect the marks on those to be aligned but you say that they are not. Can you confirm that you're using the appropriate version of the front tools for your engine (colour coded silver I believe)?

That's very clear. So we know that the inlet camshaft is in the correct, timed position because the front tool fits. If the rear marks don't align then has the exhaust camshaft moved?
Is the mark on the inlet camshaft rear sprocket in the position shown in Ennine's photograph (nine o'clock)?

Good! So at what stage are you now, with reference to the above summary?

The point I was trying to make in your last quote is that they're not supposed to be fitted at the same time! Once you've renewed the primary belt, you do not fit the front tool again.

It doesn't time everything. It sets the inlet camshaft in the correct position to allow the primary belt to be fitted. The exhaust camshaft is 'timed' by aligning its mark to that on the inlet camshaft. Do you agree with me here?

Indeed Andy. As Mike recommends, turn it over by hand first. Earlier this year I renewed the single timing belt on our very straightforward 4 cylinder 8 valve OHC daily driver. I made my own paint marks for security and turned everything over by hand several times to check that they still aligned. They did, so I started the engine and watched carefully. The belt seemed too sloppy. I hadn't set the tensioner quite right so I went back to the beginning and laced the whole thing up again and was rewarded with success. Slowly does it, and keep thinking all the time (as Bruce Forsyth used to say a long time ago).

Simon

Simon,

Here is my logic - 1. the front belt links the crankshaft to the cams. 2. The front timing tools set the position of the inlet cams relative to the front belt. 3. The rear inlet cam pulleys can only be fitted in one position as they are keyed. 4. The rear exhaust pulleys are also keyed. 5. the rear belts connect the rear pulleys. Ergo - the front belt times the engine.

The fact that the front and rear tools do not fit simultaneously supports my line of thinking. If I am wrong I have to ask - why would Rover have produced guidance that advocates fitting the front belt with a tool that determines AND FIXES the position of the inlet cam if only the marks on the rear pulleys are used to time the engine?

[COLVERT]

What you say is logical. Fix the front then link the back.

Can't go wrong.----

[SD1too]

Originally Posted by ballymenaman

... the front belt times the engine.
...why would Rover have produced guidance that advocates fitting the front belt with a tool that determines AND FIXES the position of the inlet cam if only the marks on the rear pulleys are used to time the engine?

OK, In think I see your point Andy. You're seeking to dismiss the suggestion that the rear sprocket alignment alone times the engine. You're saying that the rear sprockets are positioned relative to the inlet camshaft's position, therefore it is vital that the inlet camshaft is correct, and the front tools determine that.

I agree with Colvert that your argument is logical. So lock the inlet camshaft, fit the primary belt, then remove the front tools. Now use the rear tools to renew the secondary belts and align the rear sprockets correctly. That is, in fact, what MGR describes.

Andy; I have written a procedure based on the MGR workshop manual description and the U-tube video, and enhanced by Chris75's helpful hints based upon his experience using the tools. I can e-mail it to you if it would help. I don't want to cause further confusion though!

Simon

[ballymenaman]

Something else occurs to me. Why would rover produce 3 different plates for the front tools if the timing is determined only by the rear pulley positions?

[zefrench]

Side note, after I thought I had the timing done, I removed the locking pin and turned the entire engine by hand (socket and wrench) well over 10 complete revolutions of the from crankshaft pulley listening and feeling for metal on metal contact.

This was done prior to starting the engine to make super sure nothing was going to go super wrong.

[Phil-T4]

Originally Posted by ballymenaman

Something else occurs to me. Why would rover produce 3 different plates for the front tools if the timing is determined only by the rear pulley positions?

Officially the rear pulleys only time the exhaust cam to the inlet cam, however in practise the rear alignment marks line up when the inlet is in the correct position.

The front pulley holding tool sets the inlet cam in the correct position for the following to happen.

Inlet valves (2.0 litre engine):
⇒Opens 6° BTDC
⇒Closes 46° ABDC
Inlet valves (2.5 litre engine):
⇒Opens 2° BTDC
⇒Closes 54° ABDC
Inlet valves (2.5 litre engine 190PS):
⇒Opens -2° BTDC
⇒Closes 58° ABDC

[SD1too]

Originally Posted by ballymenaman

Why would rover produce 3 different plates for the front tools if the timing is determined only by the rear pulley positions?

You've hit the nail on the head there I think Andy.

So where are you now? Is the primary belt fitted? Do you still have non-aligned rear sprocket marks?

Simon

[hogweed]

Originally Posted by COLVERT

Can't wait for the various outcomes.---

BANG!!! Pieces of valve and piston everywhere...

Originally Posted by COLVERT

PS. It makes me realise just how lucky I am to have a DIESEL.--

Yes, there's a lot to be said for chains...

[Mike Noc]

Originally Posted by Phil-T4

Officially the rear pulleys only time the exhaust cam to the inlet cam, however in practise the rear alignment marks line up when the inlet is in the correct position.

The front pulley holding tool sets the inlet cam in the correct position for the following to happen.

Inlet valves (2.0 litre engine):
⇒Opens 6° BTDC
⇒Closes 46° ABDC
Inlet valves (2.5 litre engine):
⇒Opens 2° BTDC
⇒Closes 54° ABDC
Inlet valves (2.5 litre engine 190PS):
⇒Opens -2° BTDC
⇒Closes 58° ABDC

I believe the pulleys are handed, but universal for the KV6, and as the camshafts are different for the 3 engine variants, you would expect the marks to line up with the engine correctly timed, so 2 questions Phil;

When you have set them up as per the factory schedule, in your experience, do the pulley alignment marks accurately line up?

Given that the marks are quite near the centre of the pulleys, does it give you an accurate enough picture either way?

I might have a third question, depending on the answers to those two.





.

[Phil-T4]

Originally Posted by Mike Noc

When you have set them up as per the factory schedule, in your experience, do the pulley alignment marks accurately line up?

No, they dont always line up perfectly, this is also evident on vehicles that have never had a belt change, the front (LH Bank) is always inline but the rear (RH Bank) isn't, it can be 1/2 or 1 tooth out of alignment with the timing pin is locked into the flywheel.

Having said that, i was in Yorkshire the end of last month and did 2 belts changes whilst i was there (a 177 2.5 and a 190) and on both of them the rear pulley marks aligned perfectly

Another thing to watch for is the mark on the crankpulley isnt always in the correct place, i have come across 2 or 3 where it is 180 degrees out which confused the hell out me at first!