GLT Cylinder head probs

Last year my 240GLT estate burnt out the exhaust valve on #4 cylinder. I replaced this, and #3 which was looking dodgy, but kept 1 & 2 which seemed fine. 3K miles later I've lost compression on #1 cylinder. I've not lifted the head yet but suspect another valve problem. Could this be localised 'hot spots' caused by the unleaded?

I'm running on unleaded, with timing adjusted, and when OK the engine runs sweet as a nut. I've tried running with two head gaskets to lower compression but that made no difference so I've gone back to one.

The engine never runs hot, starts first time, every time (even with three cylinders!) and is otherwise very reliable.

Any thoughts?

Also (just in case) does anyone have a spare B23 head for sale or know of a reliable breakers in the Scottish borders? I'm betwixt Edinburgh and Newcastle.

Cheers,

John Schofield

[vjck_uk]

Hi John,
Not a good idea to just change the dodgy valves as you have found out to your cost.
You should'nt have any trouble with unleaded as your valve seats are stellite inserts.
You may find that the camshaft to valve clearance is to close.
You can get shims from volvo to adjust them and it's not to bad a job.
If you do them with head off then leave them a few thou wider than reccomended as it's better to be that way than to close.
You will probably find you can use some existing ones in other locations and just need to but a few extra.
Just take the measurements obtained with a micromter,to the agents and they will get them no trouble.
I made a tool to remove them in situ but if the heads off it's a doddle.
I've been running my b230 on unleaded since it came out and it's been no bother.
Regards.
Vaughan

[migrator]

John,

I too am betwixt Edinburgh and Newcastle - Cockburnspath actually. I know that this is not in the Borders but I use Ricky's (known as Volvo City) at Gorebridge in Edinburgh. I have found them helpful and they usually supply good parts. I have found them willing to swap if not OK.

There is also a big breakers in Gala but I forget the name (I remember the location though).

Thanks for the replies, and apologies for the tardiness but the weather up here has stopped me investigating the engine further until this weekend.

The problem was indeed #1 exhaust valve. I could therefore just change the valve(s) again, but somehow this doesn't feel quite right as that's a bit like tackling the symptom rather than the problem. Why are the exhaust valves burning out? They may of course have been replaced at some stage with 'inferior' items that have now reached the end of their lives. In which case, just fit new 'good' valves and carry on. Or am I missing something?

I have been offered a complete 240GLT with 117K miles on the clock for 400GBP. This has loads of service history (back to 57,000 miles) and a good running engine that I could transplant but that seems like cheating if it's only an exhaust valve.

I'll try Ricky's tommorow for a head price just in case the existing one is damaged in some way - haven't been able to check for non-visible cracks etc.

All further thoughts gratefully received.

John

maybe it needs to readjust the timing. seems to me, ignition must be set more early (bigger advance, i mean).the unleaded you have using may have lower octane ratio.

I'd have thought that the whole problem of burnt exhaust valves has arisen because they've got too hot. This could be attributed to using unleaded fuel or localised hot-spots in the combustion chamber due to incorrect ign timing.
I think if I were you, I'd either go back to fitting two head gaskets, as recommended by VCC or use a lead additive to protect the valves.

Yes, I totally agree that it's probably localised hot spots - and low octane unleaded is probably the largest part of the problem. Though I keep getting a niggle that I'm missing something (if you'll forgive the pun).

I think the next step may well be check the timing and retard if needed to run on low fat unleaded OR fit two head gaskets and use an additive as I do on older engines in other cars. And change the valves of course!

I'll let you know how I get on.

Cheers,

John.