Valves or head gasket

[johnm]

Maggie suddenly started really loud "pinking" type noise under load and lost power. On reaching home compression test showed 150 on numbers 1 and 2 and nothing worth noting on numbers 3 and 4.

I'm assuming therefore either major head gasket failure (no evidence to see) or simultaneous valve failure on two cylinders.

By coincidence she passed 200K miles last night at 80mph on the M4.

[bmcecosse]

Head gasket gone I'm afraid. But either way (gasket or valves) it's head off job.

[johnm]

Yep that's what I figured and I've no time to do it and it's our only car just now

[bmcecosse]

Just need to work through the night then ! I have had to do headgasket at the side of the road (far from home) - with hardly any tools - including a mile walk into town to get a gasket and back again it took me 3 hours all told. I always carry a gasket with me now.

[johnm]

Well the head's off and apart from a beige deposit on all of them (light on the exhaust and dark on the inlet) the valves look complete and there' s an eighth inch gap in the gasket between 3 and 4, so I think that's pretty clear!

Having removed the old gasket from the head there's a load of remnants on the surface what do you recommend for cleaning the two surfaces block and head???

I'll now order a gasket from ESM and I think I'll replace the heater tap while I'm at it too

[bmcecosse]

Just scrape away carefully WITHOUT damaging the surfaces - paint scraper (type with stanley blade is good) . Can you not just get a gasket from local autoparts place - 998 Mini is the one to ask for - get two, one for spare! Meantime - may as well grind in those valves.

[johnm]

Many thanks bmcecosse. I'm away now until Tuesday so ESM should have the bits on my doorstep by then.

It's an unleaded head fitted 15 years ago and I hadn't considered trying to grind hardened valve seats.

[bmcecosse]

Oh they still need some grinding - especially as some of these 'hardened' seats aren't as hard as they should be !

[eastona]

What a coincidence. My car's called Maggie, and I had a head gasket failure in exactly the same place 2 weeks ago. And my first name's John....



Hope you're sorted now.

Andrew

[johnm]

What a coincidence. My car's called Maggie, and I had a head gasket failure in exactly the same place 2 weeks ago. And my first name's John....

It's even weirder, we're in Glos too

[johnm]

OK, so the new gasket is fitted and Maggie will reverse up the hill out of the garage with no problems!

The book says torque the head bolts to 40 ft/lbs which I've done with my bendy torque wrench (not ideal I know) it didn't seem over tight is there any advice on whether they should be tighter?

I will re-torque them in a couple of weeks. Then recheck the tappets and other bits and bobs.

All further advice welcome. I realised I haven't done this since I fitted the unleaded head 15 years and 100K miles ago

[bmcecosse]

Well done - nothing wrong with 'bendy' wrench! As long as it sits at zero when not in use.

[johnm]

Thanks! It just needs the exhaust clamp redoing now, the threads failed when I put it back.

I'll let it run gently for a day or two and then torque it down again. Bendy seems pretty close to zero at rest and I hadn't thought of that!

[bmcecosse]

So - if it sits at say +5 when at rest, then add that 5 to the figure you want. So - if aiming for 40, go to 45. In fact - I would torque that head to 44 ft lbs on standard studs. Later studs and nuts can go to 50, but stick to 44 max on these ones.

[johnm]

Many thanks for all your advice bmcecosse. Torqued them all to 44 last night and they all went by slightly varying amounts, probably should have put new studs and nuts in really and will do if there's a next time!

I'll let it run for a couple of weeks and then recheck and hopefully that'll be it for another 15 years and 100K miles

[bmcecosse]

Fingers crossed! Hope you also re-adjusted the valve gap settings.

[johnm]

bmcecosse wrote

Hope you also re-adjusted the valve gap settings.

Sure did