Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Tick Tock on 19 March 2011, 20:45:06

Title: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 19 March 2011, 20:45:06
A couple of weeks ago I noticed the exhaust was throwing out a lot of vapour when the engine had warmed up, and after a 10 minute stop I tried to start the engine, but it was hydraulically siezed..... a cylinder full of water methinks!! 120k on the clock, and only changed the cam belt last year!

After a couple of attempts, engine started okay, and was still running as sweet as a nut, although a couple of miles later the 'low coolant level' warning came on. Good job it was just a local journey, so managed to get home and the poor thing hasn't left the driveway since.

In my former years, I carried out full engine overhauls on 'straight 6' BMC 2912cc engines (technology from 40 years ago). I couldn't stomach a garage repair bill of £***** and the car isn't worth it, so have decided to set myself a spring/summer top-end project. I've got quite attached to the old girl, so no rush, no hassle, just take it a step at a time. Here's how far I've got in 2 days.

(http://emgauge70s.co.uk/omegapic02.jpg)

I've never come across so many pipes, cables, hoses and connectors before, but have to admit I'm still feeling enthusiastic about the project. I've taken plenty of pics, drawn lots of diagrams, and labelled plenty of bits.... most of which I can identify so far  :)

Still not even half way there yet, but next job will be removing the camshafts. Any pointers or advice welcome (or even words of encouragment). A big thank you for the PDF doc by iggy21uk on OOF, outlining the main process of taking the V6 lump apart.... and plenty of pics to help me along the way.

I've since found that the timing cover and backplate come off much easier when the front belt tensioner is removed first!
Title: Re: Head gasket - work in progress v6 2.5
Post by: 0795omega on 21 March 2011, 12:36:23
braver man than me! but big pat on the back for taking it on,just go at it like you say steadily as and when you feel like it,satisfaction of doing it all yourself when finished will be great/not to mention huge saving in garage bill!! good luck.
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 21 March 2011, 13:02:55
Thank you 0795omega....

Have been advised to put this thread in general chat, so over and out from this page.
Title: Re: Head gasket - work in progress v6 2.5
Post by: Jimbob on 21 March 2011, 13:42:54
[movedhere] Test Zone [move by] Jimbob.
Title: Re: Head gasket - work in progress v6 2.5
Post by: Varche on 21 March 2011, 14:01:22
Good luck with the job.

Is it a 98 car by any chance? My Red Omega loses water and I suspect it is from the rear of the passenger side bank rear cylinder. It will be interesting to see where your problem is? maybe you would only need to do the passenger side if you see the problem on head removal? Unless you are planning some form of overhaul at the same time.

Keep us posted as the job progresses. :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: sotmh on 21 March 2011, 14:03:32
yep.  as 0795omega says; take it slowly and step by step as and when.

You've taken right pre steps: photos diags etc.  This will be great when come to reassembly.

I'm sure there will be lots of help on here if you get stuck.  Also see V6CDexr? on his project.  He is says he is a novice.  If that is the case I have not even been  formed yet in these stakes and I'm attempting mine, all be it 2.0l.

Whatever happens, don't get disillusioned just persevere. :y

Title: Re: Head gasket - work in progress v6 2.5
Post by: Marks DTM Calib on 21 March 2011, 14:10:31
Here's Mick Dundees under the knife (2.6 but very similar)

http://www.omegaowners.com/forum/YaBB.pl?num=1236287115/0
Title: Re: Head gasket - work in progress v6 2.5
Post by: andyc on 21 March 2011, 17:30:52
Been there, mine had a leak on the NS head at the back.
Just remember that when torquing the head down don't take a phone call and forget where you were....

and remember to fit the coolant pipe to the back of the block before you start building up the coolant bridge, to be far i was 2:30am .

keep at it as its isn't as bad as it looks and the slam panel makes a nice place to sit while your working on the engine

All the best with the job

Andy
Title: Re: Head gasket - work in progress v6 2.5
Post by: Elite Pete on 21 March 2011, 18:14:45
What you need while your there is a nice set of 3.0 cams for a bit more umph and I know just where there might be some ::) ;)
Title: Re: Head gasket - work in progress v6 2.5
Post by: Darth Loo-knee on 21 March 2011, 20:24:13
Well Done :y :y :y :y
It is Brilliant to see Owners having a Go themselves and Posting what they're doing  :y :y :y :y :y

I think you are doing it right by marking up the parts so you know where they go.

Before removing your Cams make sure the Crank is turned anti clockwise 60 degrees BTDC, this ensures all the pistons are down the bores  :y

Same thing when you remove the cams put them in the order you take them out or how you see them from the front of the car... e.g Number 1 to the left (drivers side) then 2> 3> 4 (passenger side).
Make sure each Cams Caps are in the right order too even make a note of the numbers on the side so you don't mix them up that is really important :)

Go luck with it and keep us posted :y

Daz
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 21 March 2011, 22:40:26
Thanks for the feedback and hints / tips. I've spent a couple of hours looking at MD's 2.6 job as per link above (all 17 pages of it), and although it's a slightly different lump, there's lots of interesting info there. I did wonder why the crank should be 60 dgreees BTDC, but it's all become clear now.

It's a 2001 mini facelift, and no idea which pot is giving trouble yet, but I'll be taking both heads off.... not much point going this far and only doing half a job!

How much difference do the 3.0 cam followers make to the performance, and what physical differences are there?
Title: Re: Head gasket - work in progress v6 2.5
Post by: millwall on 21 March 2011, 22:44:23
well done that man  i wouldnt have the balls to have a go at such a big job :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: Darth Loo-knee on 21 March 2011, 22:55:12
3.0 cams will increase by about 15-25 bhp. Wont notice it off the mark but from 70 ish  :y

Title: Re: Head gasket - work in progress v6 2.5
Post by: henryd on 21 March 2011, 23:32:07
Quote
3.0 cams will increase by about 15-25 bhp. Wont notice it off the mark but from 70 ish  :y


just finished doing mine,above about 3500 rpm is when the action starts :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: russ0205 on 21 March 2011, 23:50:50
Braver man than me good luck mate, :y :y :y :y :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 23 March 2011, 20:22:21
The weather has been cracking these last couple of days, so have managed to spend another 2 or 3 hours on the project. Camshafts are off the heads, and on the bench in order (along with top bearing halves), and this afternoon I managed to remove PS pump and get N/S head off.

All in all, it's looking good so far, so I suspect the original problem is on the O/S bank of cylinders. I wont be able to get that head off until I've removed the oil cooler pipes, and the rigid coolant pipe that enters the block at the rear of the engine.

I'll take some more pics when the sun's out, and post on here for those interested. I must admit I was beginning to feel a bit disheartened with all the bits and pieces I've had to remove, but now the engine block is starting to look like a pea on a drum in that vast space under the bonnet, and the job is going well so far..... definately not for the fainthearted!!!!

It may be a few days before I get everything cleaned up and start looking at the parts I'm going to need to put it all back together.... the 3.0 cam followers look like an atractive possibility, so on the look-out for some.  :D
Title: Re: Head gasket - work in progress v6 2.5
Post by: The Red Baron on 23 March 2011, 21:04:47
have a word with elite pete, im pretty sure he has a set of 3.0l cams knocking around. :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: henryd on 23 March 2011, 23:08:09
Quote
The weather has been cracking these last couple of days, so have managed to spend another 2 or 3 hours on the project. Camshafts are off the heads, and on the bench in order (along with top bearing halves), and this afternoon I managed to remove PS pump and get N/S head off.

All in all, it's looking good so far, so I suspect the original problem is on the O/S bank of cylinders. I wont be able to get that head off until I've removed the oil cooler pipes, and the rigid coolant pipe that enters the block at the rear of the engine.

I'll take some more pics when the sun's out, and post on here for those interested. I must admit I was beginning to feel a bit disheartened with all the bits and pieces I've had to remove, but now the engine block is starting to look like a pea on a drum in that vast space under the bonnet, and the job is going well so far..... definately not for the fainthearted!!!!

It may be a few days before I get everything cleaned up and start looking at the parts I'm going to need to put it all back together.... the 3.0 cam followers look like an atractive possibility, so on the look-out for some.  :D

it isn't the followers you want,its the 3.0 camshafts :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: mrgreen on 23 March 2011, 23:26:54
well done to you, it's the kind of project i love for us mere mortals it's a matter of marking everything as it comes off i always do this with tape and a number system! what comes off must go back on even though you have no idea what it does(well in my case anyway!) looking forward to more pics as you go along
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 24 March 2011, 00:27:31
Quote
Quote
The weather has been cracking these last couple of days, so have managed to spend another 2 or 3 hours on the project. Camshafts are off the heads, and on the bench in order (along with top bearing halves), and this afternoon I managed to remove PS pump and get N/S head off.

All in all, it's looking good so far, so I suspect the original problem is on the O/S bank of cylinders. I wont be able to get that head off until I've removed the oil cooler pipes, and the rigid coolant pipe that enters the block at the rear of the engine.

I'll take some more pics when the sun's out, and post on here for those interested. I must admit I was beginning to feel a bit disheartened with all the bits and pieces I've had to remove, but now the engine block is starting to look like a pea on a drum in that vast space under the bonnet, and the job is going well so far..... definately not for the fainthearted!!!!

It may be a few days before I get everything cleaned up and start looking at the parts I'm going to need to put it all back together.... the 3.0 cam followers look like an atractive possibility, so on the look-out for some.  :D

it isn't the followers you want,its the 3.0 camshafts :y

Well that makes more sense regarding extra BHP..... I did wonder why just the followers would / wouldn't make any difference. So the next question is - tolerances regarding camshafts in a different head.

I've read so many times that it's critical to make sure the camshaft bearings retain their original positions on re-assembly, which makes sense from an engineering / matching point of view. Surely by fitting different camshafts would knock this theory out of the window?
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 24 March 2011, 00:31:28
Having the N/S head on the bench and looking carefully at it, is there any reference (on here or in print) that shows the oil flow and lubrication of the camshaft bearings (and more importantly), the flow of oil back into the sump?
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 24 March 2011, 00:53:29
Another pic - this time of the underside of the head & gasket, showing a good seal between the cylinders and the coolant chambers, with typical corrosion taking place in the 'less than critical' areas.

(http://emgauge70s.co.uk/omegapic03.jpg)

The inlet valves on pot 6 look to be a lot cleaner than on 2 & 4, anyone got any suggestions as to why?

It will be interesting to see what the other head reveals.
Title: Re: Head gasket - work in progress v6 2.5
Post by: Jimbob on 24 March 2011, 07:39:42
I dont, but whenever I see pics like these I realise how clean my old heads were!

http://www.omegaowners.com/forum/YaBB.pl?num=1258052938

reminder to self....put some decent fuel in  :-[
Title: Re: Head gasket - work in progress v6 2.5
Post by: henryd on 24 March 2011, 09:09:14
Quote
Quote
Quote
The weather has been cracking these last couple of days, so have managed to spend another 2 or 3 hours on the project. Camshafts are off the heads, and on the bench in order (along with top bearing halves), and this afternoon I managed to remove PS pump and get N/S head off.

All in all, it's looking good so far, so I suspect the original problem is on the O/S bank of cylinders. I wont be able to get that head off until I've removed the oil cooler pipes, and the rigid coolant pipe that enters the block at the rear of the engine.

I'll take some more pics when the sun's out, and post on here for those interested. I must admit I was beginning to feel a bit disheartened with all the bits and pieces I've had to remove, but now the engine block is starting to look like a pea on a drum in that vast space under the bonnet, and the job is going well so far..... definately not for the fainthearted!!!!

It may be a few days before I get everything cleaned up and start looking at the parts I'm going to need to put it all back together.... the 3.0 cam followers look like an atractive possibility, so on the look-out for some.  :D

it isn't the followers you want,its the 3.0 camshafts :y

Well that makes more sense regarding extra BHP..... I did wonder why just the followers would / wouldn't make any difference. So the next question is - tolerances regarding camshafts in a different head.

I've read so many times that it's critical to make sure the camshaft bearings retain their original positions on re-assembly, which makes sense from an engineering / matching point of view. Surely by fitting different camshafts would knock this theory out of the window?

the 3.0 camshafts have the same size bearing journals,just fit the four 3.0 cams but use your existing bearing caps in there original positions,both engines are timed the same so a straight forward rebuild :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 24 March 2011, 10:14:22
Thanks for the info on camshafts, all makes sense now  :)

There's quite a noticable difference between the condition of the heads using injector cleaner and better quality fuel, and no doubt better performance to boot.
Title: Re: Head gasket - work in progress v6 2.5
Post by: BlueBridge on 01 April 2011, 02:12:36
How is the rebuild going?
Title: Re: Head gasket - work in progress v6 2.5
Post by: Tick Tock on 01 April 2011, 11:42:00
Things are progressing slowly at the moment, as the weather has turned a bit colder outside and it's been raining on and off the last few days..... Thanks for asking  :y

(http://emgauge70s.co.uk/omegapic05.jpg)
Here's a pic of the heads and cams etc, all awaiting cleaning and refurbishing - that should keep me busy in the workshop for a while!

(http://emgauge70s.co.uk/omegapic07.jpg)
Another pic showing the N/S cam cover. It looks like oil has been seeping out of a crack - presumed damaged a while ago, and no doubt contributing to the plumes of smoke that would appear from under the bonnet after being worked hard. I'll be on the lookout for a replacement, and the mating face looks a bit too wavy for my liking, so anyone dismantling a V6 2.5 engine please let me know.

(http://emgauge70s.co.uk/omegapic06.jpg)
An interesting picture showing the difference between the O/S and N/S exhaust manifolds and sheilds. Despite the oil stained and burnt N/S, the car wasn't using much oil - maybe an egg cup full every 500 miles. Hardly any smoke when stopped, if car was being driven with economy in mind. I knew the cam cover gaskets needed to be done, so good job the head problem came along before I'd done the job.

Title: Re: Head gasket - work in progress v6 2.5
Post by: sotmh on 02 April 2011, 12:28:30
Well done on persevering.  You will definitely feel a great deal of self satisfaction once its completed. 8-) :y
Title: Re: Head gasket - work in progress v6 2.5
Post by: Miggylover on 04 April 2011, 16:54:48
nice little write up this, look forward to seeing the end result