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[BazaJT]

I'm following this with real interest-and I own neither a diesel or a BMW!Things like this just fascinate me,I really must get out more

[Kevin Wood]

Only one outcome there then...

Yes, swap it for a proper car with spark plugs. 

[JamesV6CDX]

So my "as new" head arrived. I had no doubts as to it's condition as it was from a breaker with lots of 100% feedback and glowing reviews. It arrived next day, well packaged, and upon a quick look, looked fine. I had utter confidence. Today was "fitment" day, and I had someone over to help lift it on.

So gave the head a good clean, and once I started looking properly at the mating faces, I was faced with this:



Upon examination a swirl flap screw on the Donor car, has dropped into ports 5 and 6, and also on one of the others, and has been banging around causing damage to the face of the combustion area in the head. It's confined to within the fire rings.

Here are the two most damaged combustion areas:



You can tell it's a swirl flap screw, look at this one - you can see the shape !!



And this one:



I turned the cams and inspected the valve seats with a light with the valves open. The LOOKED ok but but this didn't convince me.

I poured petrol into the inlet ports, and, on pots 5 and 6, (with cams out, so valves closed) and it immediately emptied the contents straight out of the valves. Bugger. Can't fit that in a million years.

Contacted seller. Full refund given, no questions asked, once I gave them the pictures.

I then decided to remove all the valves in the head, so I could closely inspect the seats and see if it can be salvaged



A couple of the inlet valves were ever so slightly bent which confirms the foreign object theory.

The seats LOOK ok.

The plan is to TRY and make one good head from the two. Nothing to lose given that it's free. So I'm going to really thoroughly grind in the valves from the old head, which are known good, into the new one. And then do the paraffin test again, to see if they are making a good seal.

Watch this space

Interestingly the new HG has arrived. It's huge!!



And..... here's some valves!



I should say the valve guides feel ok, no slop etc.

[X30XE]

Niiiiccceeee. Breakers. So called because if it isn't already broken, they'll kindly oblige for an exorbitant fee. 

Just finished re-seating the valves on the LR V8. Bloody boring job.

[henryd]

So long as the valves seat correctly I wouldn't worry about the surface pitting

[Nick W]

Niiiiccceeee. Breakers. So called because if it isn't already broken, they'll kindly oblige for an exorbitant fee. 

Just finished re-seating the valves on the LR V8. Bloody boring job.

You needed some tools:





That's an oscillating lapping tool between a pair of cylinder head stands.


You put the head in the stands with the valves facing up, drop all of them into the correct holes with a healthy smear of coarse paste on the seats, and give each valve 30 seconds with the lapping tool in a small cordless drill. Pull the valves, and if you have a nice even seat on each one repeat the process with fine paste. Takes less than 10 minutes per head including flushing the remains of the paste with your favourite solvent.

[JamesV6CDX]

I'm going to have to walk away from this for a bit.

I just realised I didn't really enjoy any of what I did today. It felt like a chore.

Not that anyone enjoys removing 48 valves 

[106pete]

Why oh why do BMW still have this swerl flap problem, I love the way the pistons carried on with the screw in the bore, I wonder how many miles it's been like that?

[X30XE]

Niiiiccceeee. Breakers. So called because if it isn't already broken, they'll kindly oblige for an exorbitant fee. 

Just finished re-seating the valves on the LR V8. Bloody boring job.

You needed some tools:


That's an oscillating lapping tool between a pair of cylinder head stands.


You put the head in the stands with the valves facing up, drop all of them into the correct holes with a healthy smear of coarse paste on the seats, and give each valve 30 seconds with the lapping tool in a small cordless drill. Pull the valves, and if you have a nice even seat on each one repeat the process with fine paste. Takes less than 10 minutes per head including flushing the remains of the paste with your favourite solvent.

Yeah. I tried using neodynium magnets to ease the tedium of the suction cup coming loose, along with a cordless drill. If I had to do it again or regularly I'd invest in the proper toolage.  Didn't help that some of them were miles from seated. Factory build quality or careless rebuild previously or some other variable... I'm not sure.

Love the freezer / workbench hybrid with customised handle btw

[Nick W]

Yeah. I tried using neodymium magnets to ease the tedium of the suction cup coming loose, along with a cordless drill. If I had to do it again or regularly I'd invest in the proper toolage.  Didn't help that some of them were miles from seated. Factory build quality or careless rebuild previously or some other variable... I'm not sure.

Love the freezer / workbench hybrid with customised handle btw

I scrape the valve clean in the lathe, and polish the heads with coarse scotchbrite. That makes the sucker a lot more effective.


The freezer is about 35 years old, and the plastic handle was broken for years. That handle is the second thing I made when I got my first lathe. I wish I had rounded the ends off the posts

[X30XE]

Yes that would be a better methodology.  I was messing about cleaning the valve sealing faces with a brass filament wire brush and cleaning the face with sandpaper.  Had I cleaned the shit off the valve seats rather than grinding it off it would have been easier.

That freezer is going to make an excellent horror film prop one day 

[JasonH]

Those screw imprints are awesome.

On the head gasket I've got a feeling they need to be matched to the head. There's something about a number of holes in the gasket and on the head.

[JamesV6CDX]

Those screw imprints are awesome.

On the head gasket I've got a feeling they need to be matched to the head. There's something about a number of holes in the gasket and on the head.

Yep, got that covered, thanks mate

[JamesV6CDX]

Been away a few days, and today went to help a member with a cambelt issue, so not much recent progress.

I have, however, now lapped in all of the 24 valves, from the old head, to the new one. I have closely inspected all of the guides. The stems run well in them, with no slop or sticking.

Having lapped in the valves, the seats and valve faces all look fine, too.

Next step is to fit them all. I can't decide whether to buy a special tool to make light work of fitting the collets, or, whether to use a small magnetic screwdriver and a dab of grease 

Usually wouldn't hesitate, but not much access to the top of the valve stem once the spring compressor is in situ.....

[78bex]

Been away a few days, and today went to help a member with a cambelt issue, so not much recent progress.

I have, however, now lapped in all of the 24 valves, from the old head, to the new one. I have closely inspected all of the guides. The stems run well in them, with no slop or sticking.

Having lapped in the valves, the seats and valve faces all look fine, too.

Next step is to fit them all. I can't decide whether to buy a special tool to make light work of fitting the collets, or, whether to use a small magnetic screwdriver and a dab of grease 

Usually wouldn't hesitate, but not much access to the top of the valve stem once the spring compressor is in situ.....

https://youtu.be/-zvH7xiU0KQ