UK 1989 740 Estate Auto B200E

Your reasoning is plausible. The head gasket of red-block engines does seem to get a lot of mentions on this NG, mine included.

What may be happening is, when you turn the engine off, a little water is squeezed into the combustion chamber by the pressure within the cooling system. This may be soaking the plug and stopping it working when you first start up. When the engine is running, the higher pressure of combustion is forcing it way into the cooling system and pushing water out.

In bad cases you can get what is known as hydraulic lock, when there is enough water in the cylinder to stop the starter motor being able to turn the engine.

Just before you next stop the engine, undo the coolant cap (be careful

- do it slowly) and leave it loose until you next start the car. This should stop the pressure pushing the water into the combustion chamber. If this solves the mis-fire, it suggests the head gasket has failed, but also check the plug for wetness, and see if the plug smells of antifreeze (if you can get your nose near he plug hole, have a sniff here, also). Check your oil filler cap for mayonnaise-type emulsion.

If the gasket shows signs of failure like this, I would attend to it soon. I have seen ally heads from engines where this is a problem, where the tiny flow of water under pressure has started to etch a miniature version of the Grand Canyon in the head. If this has happened, it can often be filled with a blob of weld, prior to the head being machined flat

I'm going to hijack this thread, sorry Andy!

How easy is the B200E's head gasket to change for an amateur mechanic such as myself? I've done old fashioned pushrod engine head gaskets before (Triumph Heralds), but the overhead camshaft in the B200E scares me.

Will I need any special tools, patience, luck etc? How long should I allow for a such a task the first time round (assume the head is actually ok and doesn't need re-machining)?

Thanks,

David

No more difficult than the Herald. The only special tool needed is a good torque wrench, but while you are at it, change the timing belt too (unless it is nearly new).

You need to take care and be diligent at every stage, to make sure that it is right before proceeding further, but a head job is really just nuts and bolts. You will be diconnecting the radiator hoses, taking off the valve cover, both manifolds, the distributor, and the timing belt. Make sure you have the right tools, take your time over it, but don't be scared.

There are two difficult(-ish) parts to the job. One is loosening the crankshaft pulley bolt, the other is retrieving the nuts that you keep dropping when you try and refit the inlet manifold (IME swearing seems to help here).

Make sure you know the relevant torques, and the order that the head bolts should be tightened in.

Be sure that you get all the relevant timing marks lined up correctly when refitting the timing belt.

You need to be accurate when checking the head for flatness - I usually take it to the nearest machine shop to get them to check it with a dial test indicator, or similar.

I think your greatest concern is to make sure the camshaft timing is not altered.

Whether you remove the manifolds or leave them on is your choice. Which is more difficult? Getting that one last stuck exhaust nut, or hoisting all that extra weight and getting the head gasket in place undamaged, and meanwhile not damaging the intake and exhaust plumbing? In some ways the Volvo OHC head is easier, since there are no pushrods or rocker arms to deal with (you can leave the cam in place).

Just throwing out some food for thought, I myself haven't owned or looked at one of the OHC red engines in almost ten years.

Before any removal, look at the spark plugs - one spotlessly clean indicated the leaking cylinder.

I find it easier to leave most things still connected to the intake manifold and leave it (intake manifold) in the car about 2" from it's normal position.

You'll also have to take the exhaust manifold off to get the head machined. I always take the head off with the exhaust manifold attached, then remove it, putting it back on after the head is in place. Heat each exhaust nut cherry red before putting a socket to them and you won't break any studs.

And you need a decent 10 mm allen key socket for the head bolts - I had a cheap one the first time and it broke on the 3rd bolt!

A bungee cord from manifold to front wheel holds it out of the way.

It's about as difficult as changing the Herald head _plus_ changing the Volvo timing belt _plus_ re-adjusting the tappets on an old Fiat twincam.

You need to change timing belts att intervals anyway. The tappets need some annoying tooling (which most people forge from old screwdrivers) and a supply of shims to set them. But none of it's really _hard_, there's just a bit more of it.

The black Haynes manual (not the blue one) tells all.