Engine Knock

[Cyberbeast]

I have a question which I am sure has been asked many times, but can't find too much about it on ACVWSA. My concern is that my standard 1600DP AC engine has a knock at idle , but it gets softer, and almost disappears as the engine revs increase . While I am standing at a intersection waiting for the green light, I can hear the knock inside the car, but when I drive off, if disappears. I do not have to rev the engine very high to get rid of the knock... so my first question is: I know this is a serious problem, because it is related to the engine bearings that are worn, but if the knock is only audible at idle, can I still drive the car like that for a while? Is the problem extremely serious (does it need immediate attention)? If I drive the car with the knock until the end of the year, will it badly damage any parts, making the engine reconditioning more expensive? I don't want to ruin a good engine. It does not smoke and has good power.

Secondly, if I eventually have some time and cash to spend on the car (end of the year), what will I need to do a complete engine rebuild? This will be the rebuild to get rid of the knock as well. I have a few basic tools like sockets, spanners, pliers, including a socket + cheater bar for the flywheel nut. So what tools will I need? And secondly, in terms of the crankshaft, Pistons, con rods, Camshaft, Heads, Valves, Rings, Pistons, etc... what should be replaced or machined by a shop?

I will also buy or build me an engine stand to put the engine on as I work on it, and get me a Haynes Manual with the Engine Rebuild section...

How much does a rebuild of a standard engine usually cost (more or less)?

---------- I really love my bug -------------

[Tony Z]

1) if it is a bad knock, you will do damage soon.
it is prob just a matter of low oil pressure. increase your idle a little to increase the oil flow, maybe it will help.
Do you change your oil regularly and do you use a god oil?

2) if you are asking those questions then I dont think you should do the job yourself. But you do at least mention the heynes manual. Get that manual a soon as you can and page thru it regularly until you have the guts to do it yourself and then take your time and do it right. Its a really good manual.

[Dirk]

Now I'm no mechanic and definitely not a mechanical engineer.

But after what you told me about you 20w50 oil I'd think it's quite possibly the cause of you trouble. The oil is way to think, which is possibly why you only hear the knock at low RPM's. At high RPM the engine literally forces the oil though. i.e. No knock. At low RPM the pressure is simply not enough to keep the oil moving.

Tony will be able to correct me here.

[IMPI]

When rebuilding the ac engine there is a few things to look for
1 the casing about half the engines I get to rebuild the casing is shot in 50 engines i only had two which did not require a linebore.
2 the heads a crack between the valve seats is not a great concern but any crack towards the plugs is cause for concern.
3 plan on replacing Pistons, valves, all bearings, pushrod tubes, oil pump and gaskets
the following should be remachined: cam followers,crankshaft, flywheel,conrods (small and bigend resized) casing and heads.
4 obviously thigs like rocker shafts and adjusters should be inspected and replaced where neccesary.
I have found Tom Wilsons book How to rebuild your VW engine more valuable than any manual. A good book to get with this is the John Muir book How to keep your VW alive.

Doing it yourself (properly) will probably cost about 6 grand
Armand

[Cyberbeast]

Thanx IMPI. That was the exact answers I needed . Now I know more or less how much money to save up before attempting the engine rebuild, although it will have to wait until December, when I will have the time to do it.

Andre

[Dirk]

You know.

I have lost count of the amount of people that suggested "How to keep your Volkswagen Alive.", after having bought and read it. I know why.

No ACVW owner should be caught without it.