406oc.co.uk

I haven't posted on here in a long while as I haven't been using the 406 in a while, mainly due to the following problem...

My own engine, the 2.0 8v turbo developed a knocking noise and after checking the head, cam, tensioners, turbo etc. basically all that was easily accessible without screwing too much apart, I found no obvious problems. So due to being a bit of a novice when I comes to working at petrol engines, I decided to take it out for a strip down/rebuild/swap. This way I can work at it more easily and also a rebuild will be helpful for getting a bit more power out of it.

Since then I have found a video on YouTube with the exact same erratic idle. Its not the same 8v engine as mine, but they are both similar engines using the XU10 block.

Just curious if any pug heads have any ideas...

http://www.youtube.com/watch?v=x4KpLBrsrIY

[youtube]http://www.youtube.com/watch?v=x4KpLBrsrIY[/youtube]

Are you asking what the knocking noise is in the Youtube video?

If so then it sounds like a crankshaft problem, big ends probably.
Could be a piston problem, but sounds more like the crank.

I saw the LPG conversion and was reminded of the colossal amount of piston slap I saw on that lpg Astra.

Yes its the knocking noise, mine is doing the exact same, I am sure ill find out if its the bearings as soon as I start taking it apart.

The reason I posted it up is because as said im not too familiar with petrol engines and after taking the engine out I noticed a part in the back of the Haynes that says the knocking could be fuel related. The car was also down in power when the knocking started. Just a pitty I didn't know before I decided to take it out.

Kinda hoping someone has had the same problem before.

First place I'd look is the oil pick-up strainer in the sump as it may be blocked and starving the oil feed. Unfortunately if the big end bearings are knocking then it may well be too late and they'll need re-shelling etc. at this point you might have to think about another engine and making one good one out of the two.

Its great to get useful replies so quick. Glad to see the forum is still busy.

Luckily I have another spare engine that had a turbo failure. So shouldnt be to much bother building a good one from the two.

Hmm. Had a problem a little while back with my V6. Took it to a mechanic and he said it would have to go to Peugeot. So took it there and they said that they would have to replace the block and pistons. Cost me £1500 excluding labour, half what the car is worth to get it up and running again. It turned out to be a piston that was clattering around due to wear on the engine. Its running like new now. Funny enough I bought my second 406 for around the same money it took me to replace the block[emoji28]

Wee update just for anyone following the thread...

Pulled the head off last night and found what looks like marks from the piston hitting the head. Luckily I think it has only grazed it rather than create a noticeable lip on the head or piston. Il will know better once I clean it up. So bottom bearing is totally f*cked. Hopefully it hasn't damaged the crank.

I can't get my head around that, a piston clashing with the head is weird. The conrod would have to be separated from the crank?

Scratch that, just found some info after a quick search, you can see the same marking on the pistons:

The big end and main bearings were badly worn, so much so that the No 4 cylinder piston had been hitting the cylinder head and the crank worn beyond regrinding.

Info found here: http://blog.minisport.com/

Yep spot on.

Bearings and crank are shot. It looks as if the bearing from the cap ended up under the other one. I'm pretty sure the rod is damaged as well becasue the cap was very difficult to release and then it also needs forcing back together again. You can see how the groove on the crank has been worn away.

Nasty

Had to be the crank with that noise