When is a seized engine not a siezed engine

05-05-2007, 08:01 PM

I have just spent hours removing and stripping my daughters beetle 1200 engine. The saga started when I was at big bang last week when I got a call to say that the beetle had died on the M6. The symptoms were a strange metalic tinny noise coming from the engine. The daughter pulled over and stopped the engine then calls me for advice. believing that the noise and loss of power was caused by a dropped valve, I ask my daugther to start engine so I can hear the new noise. The engine wouldn't turn over and I thought the engine had seized. Recovery man arrives and thinks the same and brings them home. Next day daughter goes out and tries to turn the engine over by hand and she is able to do this, but it wouldn't start. Still thinking a dropped valve is the cause I buy a set of valves and all the other bits i think I may need.
Having drained the oil there were large pieces of shiney brass/ copper coloured debris caught in the oil filter and old oil. So far I have removed the heads and am not sure if I should start removing the pistons with a view to splitting the main block as this is as far as I have ever stripped an engine that far.
On examination of the valves some of them seem a bit rusty on the faces.
Why would an engine seem to be seized one moment then not the next day?
Where could the debris be from?
Anyone got any ideas? Any help would be a bargin.
Thanks

Dougie · 05-05-2007, 09:15 PM

At the risk of being shot down in flames I would guess the large lumps of brass in the oil are the distributer dive shaft disintegrating, with a bit lodged in the wrong place it would appear the engine is seized, only to turn again when it fell out. That would also account for it turning over and not starting.

Does the rotor arm turn when the engine is turned over by hand?

If I'm right, I would say that amount of debris will leave the engine needing a complete rebuild and would start looking for a decent second hand replacement...

05-05-2007, 09:18 PM

if it seized from over heating as it cools it will then turn over but the camage will have been done. chances are the main bearings may have turned in the case and a piston possibly number 3 may have stuck in the bore.
you need a full strip to access the damage and clean out the debris

the rotor arm is connected by a shaft and gears to the crankshaft phospher bronze/brass gear.

Dougie · 05-05-2007, 09:28 PM

Quote:

Originally Posted by kkkango

if it seized from over heating as it cools it will then turn over but the camage will have been done. chances are the main bearings may have turned in the case and a piston possibly number 3 may have stuck in the bore.
you need a full strip to access the damage and clean out the debris

the rotor arm is connected by a shaft and gears to the crankshaft phospher bronze/brass gear.

Dizzy drive is the only thing I can think of that is in there and that colour...

05-05-2007, 10:12 PM

Thanks to you both for your suggestions. The rotor arm does turn as normal when the engine is turned over, and the pistons seem to act normally. Someone else had suggested the heat sieze but i had never heard of it. I would like to fix the engine but if you both think its time to look for a new one then so be it.
Thank you both for taking the time to answer my thread. I will let you know what happens. Best Regards

Neil E · 08-05-2007, 07:22 PM

For the cost of just time, I would consider removing the cylinders check for play at the big end end bearings.
Hold the conrod and check for play in the big end.
The tappetty noise and the bronze color filings in the oil are typical of bearing failure,
Maybe a drop in oil pressure or a blockage in one of the oil galleries may have caused the problem and caused overheating? whicj would cause the starter motor not to turn as quickly due to engine being tight.
Just an idea

18-05-2007, 07:30 PM

Hi Neil, Thanks for your suggestion. I have managed to get the engine into a workshop and strip it as far as I can. In doing so I have removed the piston barrels and am awaiting some help to split the crankcase. While removing the barrel a piece of piston dropped out so that could be the result of something else going wrong with the bearings. Anyway I hope to get the crank case split new week as it wasn't having any of it with a light tap on the alli case as suggested in the maint manual. I have managed to get hold of a 1600 engine that was taken out of a camper and on the first look there are a few things that are not familiar to me. Dissi etc. Me thinks tomorrow will be spent trying to get it fitted to the beetle.

**Roadrunna** · 18-05-2007, 07:56 PM

Yep. Heat siezed

I had that happen on my bug through lack of oil. Filled it up with oil & left it to cool down.

It got me the rest of the way to newquay, back home & then running around for 2 weeks before it finally finished itself off

I'd say the bits you found in the strainer were bearings as well.

**Roadrunna** · 18-05-2007, 07:59 PM

If you're putting the 1600 in place of the 1200 then you might need to check bits like the clutch release bearing. Think they might be different.

Also, you'll need the exhaust from the 1600 as well as they're different to the 1200.

Can't think of any other bits off the top of my head.

02-06-2007, 05:40 PM

Thought I would let you all know What I found when I got the crankcase split as you were good enough to supply me with the info.

The No.3 piston big end bearing had decided that it had had enough and decided to weld itself to the crankshaft. The bearing fail allowed for play to occur and resulted in piston slap of the No 4 piston. This piston was damaged and resulted in a large bit of piston falling out of the barrel as I removed it.

I haven't repair the damage yet but am in the process of using the bits of the 1200 engine on the long engine I have aquired. Along with the bits that Roadrunner suggested were different there are other bits too. These include the inlet mainfold as the 1600cc means the angle the manifold attaches to the head is different. Also I am told that as a result of changing the manifold this may cause a problem with the clearance between the carb and the alternator/dynamo stand that may result in a bit of a rework. In addition the tin wear on a 1200 is different to that on a 1600 and may also need reworking or replacing.