Sparks visible from exhaust manifold on number 1

[Cruz]

After the longest time I've ever had without a problem the van engine has been noisier for the last 3 days and running rough. When warm there is a lack of power through all the gears but at high revs in each gear the power returns until I change gear and then the same happens again.

Anyway I put some petrol in to see if it was the same and it was, not as bad as on gas but the same none the less.

I parked up this evening and gave the engine some short sharp single burst of revs and I could hear a popping noise as the revs returned to normal.

So I took the engine cover off, started the van up and gave it some revs from the engine bay and I noticed the exhaust manifold on cylinder 1 (rear right manifold as you look into the engine bay) was popping and sparks could be seen around part of the exhaust gasket area (the dark helped).

So I assume I am seeing the electrical activity inside the engine as that gasket is shot and that's why I am getting rough running because of the air being drawn in and the van is noisier because the manifold is blowing??

Would I be right to think that? And will it cause any damage running it until I can get it fixed? (scared of touching the bolts myself in case they snap)

[BOXY]

I assume I am seeing the electrical activity inside the engine

The only electrical activity inside the engine is the tiny spark at the tip of the plug. After that its all petrol and air burning at about 16 metres per second. Where exactly are you seeing sparks?

[Cruz]

I'm looking at where the exhaust manifold is bolted to the head. There appears to be blue sparks between the exhaust and the head as I rev it hard

[BOXY]

If you're looking at the exhaust manifold from under the engine and you're seeing blue flames not sparks, it sounds like and exhaust valve isn't sealing.

[itchyfeet]

^^ i tend to agree the symptoms sound like a burnt valve and a gasket that has deteriorated
get yourself a compression tester and do a compression test first they are cheap enough on ebay

if it is a valve driving it wont make it much worse short term.

i suppose perhaps ignition timing out or vac advance broken could cause pre detination and the reason you are only seeing it on one cylinder is becuase thats the only faulty gasket

[Cruz]

Just been out. I can get the studs off that manifold. Thankfully. The gasket is toast as a good portion of it is missing.

I am seeing yellow flames between the gasket and the exhaust joint (as the joint isn't seating fully with only half a gasket). I assume what I am seeing is the combustion in that cylinder?

The exhaust is a JP exhaust that has exhaust clamps at several joints in the system. I've no feelings in my arms now from messing with it so I'll take it to the local garage to get a new gasket fitted. It's a simple job when it's on a ramp...........

Using a stock image from the net the black line points to where I can see a bit of the internal combustion

[itchyfeet]

If you had no other symptoms then id say change the gasket and dont worry but you say its down on power
its possible a gasket fault could cause problems with back pressure i have read it before but i have doubts that its only a gasket
change it and see what happens
Id invest in a compression tester as said

[Cruz]

Cheers Itchy.

it's been fine until wednesday when it sounded more like the exhaust had started to blow and it's got worse, as has the performance, as I assume more of the gasket has disintegrated. The compression was checked about 1 year ago and was fine but I assume anything can happen between then and now.

I really need the van tomorrow afternoon. I've got a gasket so I'll try to see if a local place can fit me in as it's just a case of unbolting, breaking the connection on the other end of that part of the exhaust (the joint where one pipe pushes inside another and clamped) and fitting the new gasket. Anyone with a ramp could do it in 10 minutes as it's stainless so it shouldnt be on solid

[California Dreamin]

Has yours got bolts or studs...if it's bolts you could just whip them out and push a new gasket in the gap....if studs then use two nuts to lock onto each other to remove the studs then do the same with a new gasket.

Martin

[Cruz]

Did just that this morning Martin . Van sounds better and runs slightly better but the timing needs sorting.

Thanks all