piston slap?

[vrookie]

I have a 1987 760 turbo with a noisy engine, kind of loud when cold not as loud after running awhile a guy told me to try a product called Blue Devil in the engine.
Has anyone had any experience with the product.

thanks

[billofdurham]

I haven't used Blue Devil nor even heard of it. Possibly it hasn't crossed the pond yet.

I have Googled it and all I can find are various leak stoppers under that brand name. In the past I have always used Molyslip to quieten noisy engines. Any additive with molybdenum disulphide will help to quieten most noises but they should be looked on as a temporary solution at best.

So, how long is temporary, you may ask. A friend of mine started using Molyslip 5 years ago in a noisy engine. He usually covers 10 - 12,000 miles per year, changes the oil every 10,000, throws in a dose of Molyslip at each oil change and the engine is still running sweetly. Now that's what I call real temporary.

Bill.

[jimmy57]

That will not make $1 difference so if it costs more than that don't do it.
B230's are great engines but they do have that one character flaw.
The big end of the connecting rods has a big side clearance to crank throw sides. The piston is supposed to control the rod side motion. The problem is the pistons do not effectively do that. This was an idea for reduced friction. The norm is for the rods to have a small clearance to rod throw sides and for the rods to locate themselves on the journals.
If you bored the cylinders and then honed for the lowest acceptable piston to wall clearance and re-bushed the rod small ends you might get a quiet engine for 25 K. I have done those things and that was the result back when the engines were relatively new and people would complain and get warranty paid repairs. Those repairs soon stopped because the fix was expensive and temporary and the noise was not causing a problem.
The 93-95 with piston cooler jets do better with this but a lot of that is the extra oil flow to cylinder walls that deadens the noise.
The noise is just a noise. It is harmless other than making noise.

[vrookie]

Thanks very much for an intelligent and thought out response,I'm thinking about changing from 10w30 to10w40 higher mileage oil will this help a little.
Thanks again