2.5 petrol running on 2 cylinders

[hairyone]

Help,

My 2.5 petrol 90 recently started sounding like a tractor, is down on power and seems to have a very noisy tappet. When I pull the spark leads to cylinders 2 and 3 nothing happens (i.e. the revs don't drop like they do on 1 and 4). The spark on 2 and 3 are as good as 1 and 4, I've also swapped plugs and leads and it has made no difference.

I'm going to pull the rocker cover off later and adjust the tappets, unless I see anything obvious like broken valve springs I'm not sure what to do next.

I did recently swap the dizzy a lucas 45d4 with one from an MGB (the bushes were worn in mine). Yesterday, I got around to swapping the cam and vacuum advance over. I was hoping the bad running was down to the worn dizzy - no such luck.

I'm guessing that I'm going to have to get the head off and inspect, any tips, advice and special tools I ought to have before starting?

Cheers

Aaron

[hairyone]

It's not looking good, I went out and bought a compression tester and the readings were 160-170 psi (dry) for cylinders 1 and 4, and no reading for 2 and three. Whilst doing the tests, there was a wooshing sound from 2 when the tester was in 3 and vice versa, but not when it was in 1 and 4.

There's no pressurisation of the sump (at least nothing coming up the dipstick tube) and the coolant water level is constant with no bubbles.

So I'm guessing the head gasket has gone between 2 and 3.

So the next question is how easy is this job: I'm thinking new head gasket, exhaust and inlet manifold gasker. Torque wrench for the head bolts and feeler gauges for the tappets. Have I missed anything?

Should i leave the manifold attached and undo the 2 bolts on the down pipe or take the manifold off?

[LR90]

FWIW I had a 2.5 Petrol, quite liked it.

I've changed a manifold coz I bust a downpipe stud only to discover it was cracked anywat. If you can leave it all intact its less work and less chance of busting something else. Plenty of room round a 2.5 so certainaly worth trying.

Beyond that, well its just a coolant drain and head off. IIRC you don't need to mess with the timing case so its pretty straightfwd. As you say if its down on 2 and 3 chances are its just a head gasket. Good luck.

[hairyone]

Thanks for all the advice

Last week over the course of a number of evenings I changed the head gasket and on Saturday I was finally able to refill the coolant and start her up -- job done.

For the benefit of others who like me might be doing this for the first time:

In retrospect it was obvious that the gasket had been getting worse over a period of months. When I first got the vehicle it would start on the button and when cold the choke could soon be pushed in. Lately it wanted loads of choke and I could never put it all the way in without risking a stall at junctions.

I mostly followed the instructions in the LR workshop guides, though you could probably get away with not disconnecting the heater cables.

As suggested I left the manifolds on (along with the carb). I toyed with the idea of hiring an engine crane but then decided to have a go anyway. So I put a nice thick blanket on the wingtop and climbed inside the engine bay. With my backside on the radiator and a foot on each engine mount (watch the brake pipes!) I leant forward and took hold of the rear lifting bracket and the front of the manifold. I was then able to lift it onto my lap after wiggling the exhaust manifold stude from the downpipe bracket(watch the oil pipe at the rear of the head, I only disconnected it at the top) and sit back onto the radiator. After a short breather I put the whole thing onto the blanket on the wing and climbe out.

Cleaned up the head an block removing all gasket traces and inspected it, no cracks or burnt valves, but the exhaust valves seemed quite pitted..

I had intended to use to chopped head bolts to guide the head back on, unfortunately I had only ordered

one spare. Being impatient I simply wired the head gasket to the block using some fine garden wire through the two end bolt holes next to the spark plugs.

Lifted the head back into place (reverse of removal) and got a bolt or two threaded and ten whipped out the garden wire, before it could damage/groove the gasket.

The rest was straightforward.

Torqued the bolts, and the took it for a drive to get it heated and then let it cool and torqued again.

Based on the LR workshop guide and advice from the various forums the job looked straightforward, the only thing that worried me was being able to lift the head off with the manifolds and carb on.