Those don't even look like Volvo pistons - they never usually have offset dishes like that.

Detonation certainly can happen on one pot only - a favourite being if one fuel injector is partially blocked, resulting in that pot going lean. However that's impossible with a single carb. I can't see how a damaged spark plug would cause this....or even how it would get that badly mangled in the first place.

The other factor is that rough edges in the CC can act as hot-spots, causing pre-ignition...that may have worsened the situation.

Andy and Chris...did this sound like a mechanical knocking, or more 'hollow' than that?

cheers

James

how about a inlet manifold leak allowing one cylinder to run lean and eventually causing detonation?

I wouldn't know a Volvo piston if it hit me in the head Fogs, but Andy was convinced it wasn't a Volvo head gasket, maybe another dubious entry into Kar's dubious past.

However that's impossible with a single carb

nope, thats possible, due to a vacuum leak at the manifold gasket....
been there, seen it... (half molten piston+head)

I see shimon had noted that as well

heya wouter... random question for you...

dya know if all volvo 66 used the same ie ducellier ignition? or like the 340 some years with AC Delco and some with Ducellier etc?

I thought the breaker points for a 1.1 or 1.3 or 1.4 were the same if they have a ducellier ignition? according to the post "service nightmare" the replacement ones arent the same...

look forward to hearing from you

shimon

AFAIK it was volvo that started to screw around with the ignition suppliers.

daf 4 cyl = ducellier ALL THE WAY ..

The engine is only the n/a B172

I ahd an interesting one with our old 360. It had sucked in some tinfoil and that melted bent the plug over and knocked the shim out! the amazing thing was no bent valve.

thanks mate!!

but 340s have a mixture of ducellier, bosch, ac delco, SEV... thats annoying so many types!!

check this out for info..........

http://www2.qha.com/catalogues/ZC1-01.pdf

thanks

shimon

Thats very definately had something go through the engine, proberbly a bolt /screw/ jet or similar from the carb or air box. ouch
detonation causes more localized damage, and although it looks similar, the individual marks are much smaller. the noise would be caused by the object being pounded into the head by the piston. the noise from somthing rattling around inside the cylinder is very severe.

Detonation is the combustion of the mixture becoming un controled, more of an explosion than combustion, and sounds a lot like somthing in the cylinder. un checked it causes massive damage to pistons, valves, headgaskets etc in a very short space of time.

Pinking is ignition of the mixture too early, instead of the mixture being ignited in time for the flame front to push the piston back down the cylinder as it just starts to travel downwards, it is ignited so the flame front collides with the piston as the piston is traveling back up the cylinder, usualy causing a metalic rattle as the piston is rocked violently in the bore. this can continue for cosiderable time before damage is caused, but can cause hot spots / heat build up that can quickly lead to detonation.

Naturaly aspirated engines can tolerate pinking quite well, forced induction engines will develop detonation and eat themselves very very rapidly, If you hear your car pinking, get off the throttle!

lesson over!

Sorry to see your destroyed engine mate, time for the turbo!

I did find one of the airfilter bolts in one carb nozzle Iain, I did wonder if a washer had gone through, but found no trace. Noise originally was quite, just an odd tapping at certain revs. When I changed the plug, it sounded as though a pack of horses with tin cans strapped to their tails were going past. After Andy and me took it apart, got all the lil metal lumps out (which I guess if you were good at jigsaws would have made the head smooth again ) it makes the original tapping noise, but constantly, not sometimes in a certain rev band.

And yeah, you are right, I'm looking for a B18FT, and time, and somewhere to do it, and all those other things that I'll need, like money, and bribery to knowledgable people I nearly bought a 480T today, but it went just over price that I can afford atm, I'll probably run my 1.7 until a reasonable one comes up (i.e with less MOT and hopeless looking body I guess) Hope to see you at Ludlow

My guess from that, is that a washer got stuck in the plug originaly, and came out of the plug and into the engine as the plug was removed.
I think adam had a few 400 turbo engines floating about, if you could get one I have all the stock management bits, and a suitable clutch, cant help with space though! If need be, I still have my original b14, if you can come and get it you can have it

Oooo, Might take you up on the stock goodies and clutch for the turbo block, then all I'd need is the engine and manifold modded right? Would it hurt to run on the B14 exhaust for a while, or is the downpipe fitment flange different, as I don't feel like modding the manifold twice

What do you want for the goodies?

If the bits help mate, call it a drink at the next meet, there in the way anyhow, b14 exhaust would work, sort of, but would be a big restriction, you dont need to mod the manifold to fit the exhaust, you have to mod it to clear the brake servo, what ever you do you will need to make the front pipe to suit the turbo. my web page has most of the mods you need to do to fit the engine, although its one of the more straight forward engine conversions, dont underestimate whats involved, If need be i can do a step by step run down of whats needed If that will help

err, just had a look at my web pages and there seems to be the most important 2 pages missing.... oops