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5326

Omega General Help / Re: MV6 Cambelt

« on: 04 August 2009, 08:47:56 »

I have a pair of cam locks http://www.lasertools.co.uk/item.aspx?cat=313&item=1705 (left) and http://www.lasertools.co.uk/item.aspx?cat=313&item=1704 (right).

Work fine for me.

Two questions I have are
1. If the international colour for port (left) is red and starboard (right) is green why are these tools coloured green for left and red for right 
2. What are all the other bits in the full kit for?

5327

Omega General Help / Re: Off with its heads!

« on: 18 August 2009, 22:40:46 »

While it easy to access I would recommend undoing the 4 bolts that hold the breather in place so you can clean it out properly.

5328

Omega General Help / Re: Reading the Oil Dip-Stick, and, Oil Level Warning

« on: 16 August 2009, 22:17:37 »

Until yesterday I had a 1994 2.5 V6 with a nice simple flat metal dip stick with MAX/MIN/ADD OIL. I used to try not to let it drop below half way between the max and min because in hilly areas (like Cornwall ) the CHECK OIL or worse OIL LACK would be triggered going up the steeper hills.

Yesterday I picked up a 2003 2.6 V6 with a wire dipstick and the knobbly lump on the end. The CHECK OIL message came up after climbing from Exeter up onto Dartmoor. When I checked the level it was just on the low step.

See page 200 in the users manual for a diagram.

5329

Omega General Help / Re: Cambelt removal

« on: 16 August 2009, 16:51:20 »

if you dont use a locking kit they will move due to the pressure of the valve springs on the cams,
if you havent used a locking kit be very careful getting them lined up right and turn the engion by hand to see if there is any blockeges or if it rund free.

Didn't use a locking kit because according to the How to for changing the head gaskets the crank has to be at 60 degrees before TDC (which it is) to avoid the pistons and valves talking to each other. :-/

Turning the engine back 60 degrees from TDC was the correct thing to do. Now it is there do not turn it until you have reassembled everything and the cams are locked in position ready for the belt to go back on.

If the cams don't have to come off the head you could have saved yourself a fight to realign the cams by locking them at TDC, removing the belt and then turning the crank back 60 degrees (to avoid accidents).

5330

Omega General Help / Re: Urgent: Oil in bores

« on: 13 August 2009, 14:41:16 »

1 teaspoon = cloud of smoke on startup
1 cupful = bent conrod

If you left a cupful of oil in a cylinder overnight it would probably seep past the piston rings but might not.

Best to mop up the last of the oil with kitchen roll before you take the plugs out or else spin the engine on the starter motor before you put the plugs back in.

5331

Omega General Help / Re: Head gasket or not???

« on: 14 August 2009, 14:37:25 »

I dont use an angle gauge as they are a bit cumbersome around the head bolts, I simply use a reference or a bit of card.

Put 8 bits of towel in the bolt holes before each stage and remove them as you tighten the bolts so you dont get lost!

I bought an angle gauge & used it for the first stage but it was a hinderance rather than a help. I didn't use it for the second stage as I was concerned it might shear off.
A longer bar gives better control because you don't have to work so hard. The breaker bar and 1/2" extension I used were surprisingly springy which made the later stages a series of surprisingly loud creaking and cracking noises For the final stage I switched to a 3/4" drive T bar and extension which was more comfortable.

5332

Omega General Help / Re: Head gasket or not???

« on: 12 August 2009, 13:44:58 »

Sounds as though you have caught it at its earliest stage, hopefully you won't have any damage to the mating faces of the cylinder heads or block.

When you have the heads off  I would suggested having the heads crack tested. A failing head gasket would usually make the car undrivable, a minute crack caused by a casting flaw could give similar symptoms to yours.

5333

Omega General Help / Re: Heater Matrix Pipes.

« on: 11 August 2009, 23:50:53 »

I haven't got the digital climate controls, just the early manual controls linked to a mass of vacuum hoses. It is noticeable that when you turn either of the temperature control knobs a short way the hot coolant starts flowing and the heater matrix gets hot (& smells hot if I haven't used it all summer)

I think that in GM's quest to cram everything into the Omega they left out effective insulation on the heater box. The flow through the hoses at the rear of the engine has to be maintained otherwise it would mess up the cooling flow through oil cooler and cylinder heads so they couldn't fit an on/off valve & had to fit a 3 port bypass valve instead.

With 3 equal size pipes it might be possible for someone to fit the HBV incorrectly & mess up the flow through the rear of the engine which might cause overheating or misleading temperature readings. The important thing is that the flow through the engine is continuous.

When I had my engine out a few years ago I was careful not to disconnect the HBV completely because I wasn't sure I could remember how to put it back otherwise. I assume there should be some markings on the valve but being black plastic they probably don't show up in photos.

5334

Omega General Help / Re: Heater Matrix Pipes.

« on: 11 August 2009, 23:07:01 »

I am a little confused, how else do think it might behave?

My expectation is that when you want heat the heater bypass valve (HBV) lets hot coolant flow through the heater matrix and when you don't the HBV bypasses the heater matrix & avoids cooking the centre console.

5335

Omega General Help / Re: Misfire, clouds of white smoke and nasty smell?

« on: 06 August 2009, 17:09:21 »

You don't really want sparks either, I don't know how true it is but I have read that the DIS pack can fail if it the HT leads and plugs aren't fitted & working. The spark has to go somewhere and if it can't discharge via the spark plugs it finds another route.

You can use a remote switch on a lead with a couple of crocodile clips to crank the engine. One clip to the battery 12v terminal on the starter motor, the other clip to the solenoid terminal on the side of starter motor. You can hold the switch in one hand and the gauge in the other. The ignition key stays in your pocket.

5336

Omega General Help / Re: Misfire, clouds of white smoke and nasty smell?

« on: 06 August 2009, 12:17:54 »

I think Kevin has given you the correct numbers (12-14 bar). The figures I came up with would be more appropriate for a worn out, Land Rover with cart springs.

Not sure about the spark plug thread, you will be taking them out anyway so I would take one with me to the shop to be sure.

5337

Omega General Help / Re: Misfire, clouds of white smoke and nasty smell?

« on: 06 August 2009, 11:48:10 »

Oops, it is more complicated than I thought. Air gets hot when it is compressed which raises the pressure.

These people http://www.pumaracing.co.uk/comp.htm give a better explanation.

5338

Omega General Help / Re: Misfire, clouds of white smoke and nasty smell?

« on: 06 August 2009, 10:58:07 »

Caveat: I used 10:1 as an example. The last engine I used my compression tester on was my old Land Rover which may have started out at 8.5 to 1 but was very well worn.

5339

Omega General Help / Re: Misfire, clouds of white smoke and nasty smell?

« on: 06 August 2009, 10:54:22 »

You can work out a theoretical compression pressure (for a perfect engine) by multiplying atmospheric pressure by the compression ratio.

If your engine has a 10 to 1 compression ratio the theoretical pressure would be 10 * 14.7 psi = 147 psi. This is an absolute pressure (the difference between it and a vacuum). For gauge pressure you have to subtract atmospheric pressure ie 147 - 14.7  = 132.3 psi.

If you use a gauge with Bar on it the maths is simpler because 1 Bar is very close to atmospheric pressure ie 10 * 1 Bar = 10 Bar absolute or 9 Bar gauge.

Because the gauge has a rubber hose you lose some of the compression ratio due to the volume of air in the pipe so you will never see the theoretical pressure.

The key is the difference in pressures between individual cylinders. I think rule of thumb is that anything over 10% variation is bad news. With the symptoms you have described I would expect most of the cylinders to be around 120psi/8Bar and one below 75psi/5Bar.

5340

Omega General Help / Re: changing crank sensor

« on: 05 August 2009, 22:44:00 »

No. The sensor is at the same height as the crankshaft. The oil is several inches lower in the sump.



The sensor is retained by a single torx headed bolt. The cable has some aluminium sleeving on it to try and protect it from the heat from the exhaust manifold. The worst part of the job is trying to route the cable up behind the engine.

I do wonder whether the heat isn't a factor in the sensor failures. I tried very hard to keep the cable away from the manifold.