Damn - lost compression in a cylinder :-(

**TenaciousC** · Sunday 27th March 2016, 20:18

After some spirited uphill driving, got a misfire and grey smoke. I pulled the main HT lead and cranked it and it sounded uneven. Also whilst running, noticed some oil smoke coming up from the rear of engine around the centre. I suspect a leak on cylinder 3 as the engine is least affected when that lead is pulled. Given the oil smoke from the back of the engine, I think it may be the head gasket.

At the moment I'm on holiday in Somerset and I need to get back to Warrington on Friday.

I have some questions which people might be able to help with.....

Can I drive this around with the injector disconnected on cylinder 3? Will it cause damage to anything?
This is going to take me a while to fix as I can only spend evenings and weekends on it, and I need a car whilst it's out of action. What do people normally do in this situation ?

Cheers for any advice.

C

**Doingitsideways** · Sunday 27th March 2016, 20:31

Hmm... Somerset to Warrington is a long way to be running while down a cylinder.
Personally, I wouldn't risk it. Do you have any breakdown cover?

If it could possibly help, I could maybe lend you a car until you're sorted?

**TenaciousC** · Sunday 27th March 2016, 20:44

Hi - yes I've got relay, but was hoping to avoid spending the day on the back of a wagon! Thanks for offer of a car... I might very well be in touch with you about that!

C

Originally Posted by Doingitsideways

Hmm... Somerset to Warrington is a long way to be running while down a cylinder.
Personally, I wouldn't risk it. Do you have any breakdown cover?

If it could possibly help, I could maybe lend you a car until you're sorted?

**Doingitsideways** · Sunday 27th March 2016, 20:52

No worries Fella.

I'm on here most days, so give us a shout.

My S70 is pretty much the forum whore anyway

**TenaciousC** · Friday 1st April 2016, 20:27

Got the head off OK. Burnt valve on cylinder 3.

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I noticed when taking the head off that the timing mark on the crank pulley, does not quite coincide with piston 1 being at TDC. Should I go on the mark, or the piston position?

Cheers
C

**Doingitsideways** · Friday 1st April 2016, 21:11

Mark on the flywheel is best.
(Think the 5 pots have one anyway.)

What's caused the burnt valve?
Ran lean?

**TenaciousC** · Friday 1st April 2016, 22:23

Cheers!
Not sure.... could be the injector..... could be leaking stem seals.... also, some oil from turbo/PCV is being burnt. Will know more tomorrow when I strip the head.

C

Originally Posted by Doingitsideways

Mark on the flywheel is best.
(Think the 5 pots have one anyway.)

What's caused the burnt valve?
Ran lean?

**TenaciousC** · Sunday 3rd April 2016, 09:37

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It looks like stem seals to me as there was quite a build up of carbon on the stem. Its partner from same cylinder also pictured.

**Harvey** · Sunday 3rd April 2016, 10:20

Just wondering what grade of fuel / octane you use ?.

**TenaciousC** · Sunday 3rd April 2016, 11:07

Standard 95.

C

Originally Posted by Harvey

Just wondering what grade of fuel / octane you use ?.

**Harvey** · Sunday 3rd April 2016, 11:14

Have a read of this link.

http://www.vpcuk.org/forums/showthre...some-good-news

**TenaciousC** · Sunday 3rd April 2016, 20:05

I'd heard about burnt valves on cylinder 2 being common before. I suffered a burnt valve on a previous normally aspirated 850 (cylinder2).

C

Originally Posted by Harvey

Have a read of this link.

http://www.vpcuk.org/forums/showthre...some-good-news

**TenaciousC** · Sunday 3rd April 2016, 20:08

Note to self: Remember to put on valve stem seals on before assembling valve springs and collets. Happily I only did seven before I noticed !

PS. I hate collets!

**TenaciousC** · Friday 8th April 2016, 21:18

The car is back together and running. However I'm getting a worrying noise coming from the engine. Sounds like a medium pitched whine. Only seems to happen when hot and idling. It's not audible directly after start up, but after a little rev it will start and not go away.

I had hoped it was the PAS pump, but it's not.

Any ideas what it might be?

C

**Orca2** · Friday 8th April 2016, 21:45

If that was a burnt exhaust valve you could have debris from it in your turbo, or damage to a vane as it went through.

**TenaciousC** · Friday 8th April 2016, 21:57

turbo seems balanced and OK (although I haven't inspected it). Noise is not coming from that area.

**Orca2** · Saturday 9th April 2016, 00:09

Get yiurself a mechanics stehoscope they are cheap and v useful for tracking down noises.

**Doingitsideways** · Saturday 9th April 2016, 00:33

Whine could be a belt tensioner/water pump.

When were they last renewed?

**TenaciousC** · Saturday 9th April 2016, 06:39

I thought within 3 years... But on checking they're 5 years old! I was thinking water pump too.

C

Originally Posted by Doingitsideways

Whine could be a belt tensioner/water pump.

When were they last renewed?

**TenaciousC** · Saturday 9th April 2016, 10:29

Here is some footage : https://goo.gl/photos/KRjFU9mPY1aKWAFQA

Noise is more apparent towards the end of he video. I suspect (and hope) it's coming from the belt side of the engine.

C

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