Bottom end failure - opinions

[N2AE86]

Just want to begin this post by saying I m 90% certain the bottom end is in the process of failing on my Golf – ADZ engine.

Ran on 2/3 cyls one morning – and was fixed with a new dizzy cap.  Problem is since then there is what I suspect to be light rod knock.  Engine sounds rougher on idle, doesn’t sound very happy at around 3k and there is a distinct rattle on the idle down.  It’s not full on spanners being chucked down a lift shaft noisy, but there is a nock/rattle going on.

Oil levels were low so it’s burnt a fair amount of oil over the past month, which won’t help.  More oil hasn’t done anything.

Now before I yank the engine and chuck a replacement in there, can anyone tell me if there are any potential quirks to the ADZ which might give off the same knock / rattle?  A busted motor mount, a dead tensioner etc?  It’s proving very difficult to pinpoint the noise which is why I have a bit of doubt about my diagnosis, plus I don’t know the engine well.

Whilst I am fairly certain it’s the start of rod knock, just wondered if anyone with more specific knowledge of the engine can chime in with some advice incase I am missing something.

Thanks

[tweed]

Take the sump out and have a look!
I don't know anything about that engine.


But sounds like you might of cracked a piston or something like that, big end shells maybe.

[Rmachines]

Its not piston slap is it?  Its not so common on the tall block engines but it can happen, its when the piston/bore becomes slightly oval and knocks slightly from side to side on the up and down stroke,  worse when cold, better/gone when warm, also worse under load.   If it doesnt fit that discription, its not piston slap but its very rare for these engines to suffer from anything like that to be honnest, cracked pistons often make a tick/click/knock, where as bottom end is a heavier knock, strange though,  I know running on 2/3 cyls will put a lot more strain on the crank, which could have spun a shell but unlikely unless there was an under lying issue previous to that.   

How long has this gone on?   As bottom end failure usually gives you 100 miles from when it manifests its self to when it eventually blows a hole through the block,  if its done a fair few miles and only getting slightly worse/not changed i wouldnt be to worried about the crank side of things.

[N2AE86]

Thanks for the suggestions guys, much appreciated.

Piston slap / oval bores – it hadn’t entered my mind but yeah, on consideration it might be.  However I have run the engine to temp however and it’s not reduced the knocking as expected.  With more oil in the engine it has reduced the knocking noise by a small amount – but nothing huge. 
 
Stuck a compression tester on the car and its showing healthy on all 4 (and running properly now) so that’s off the cards – it’s not smoking out of the exhaust either.

Think it’s safe just to assume the engine is going to fail one way or another, or is now as loose as a $5 dollar whore.  Just found out a replacement lump is £150 delivered, for the price I may as just swap it, as I don’t want it to blow up on the wife.   

I can then turn the old lump into some furniture! 

Cheers

James

[harlemex]

Its your big end shells mate. New block needed, unless you can do the shells. If you can do them, better be soon before total wipeout 

[tweed]

You can do them with the engine still in.

[twotwofour]

I've no idea where you are but I've seen engines for £50 available in north yorkshire

[N2AE86]

Hey guys,


New lump is on its way from Stevens VW Breakers - will chuck that in just to get the car running again.  £150 for the lump and delivery is acceptable - its got a warranty as well.

Will probably break the old engine apart and check out the damage - if one of the bearings is screwed as long as the crank / rod havent taken damage I will probably rebuild that block with new parts and reinstall - then try and get another 150,000 miles out of the car!  

Cheers

James

[thai-wronghorse]

That's quite reasonable considering its the delivered price. Fingers crossed you get it up and running soon.