Just had a thought (and it's only Monday!). On the 33, when it gets hot it sometimes makes a sort or rattly/tappety noise and there is a lack of power. This usually happens in traffic, and as soon as you get going again it is fine. As it is currently running on synthetic oil I thought maybe the oil was getting too thin at high temperature. Now I'm wondering if maybe this is pinking because the block is getting too hot. This is more worrying thought. Anyone have any pinking knowledge, so to speak
BW, Honkeytonk once got some super thin Mobil 1 oil put into his 155 (misunderstanding with the garage). It rattled like a bucket full of nails when hot at idle, was OK when the engine was revved and the oil pressure increased. One way to tell, when the engine is hot and you come to a standstill, does the noise gradually come in after a few seconds ???? If so, I'd say it is the oil is too thin.
The info on Honkeytonks car was from his brother...Jason77, so that is my disclaimer for any wrong info in the reply !!!!!
BW, one of my 33 16v I had a few years ago had the same problem of pinking especially in the summer. I had new plugs fitted. The £20 each ones that alfa sell oops and along with using super ul the problem went.
Cheers guys. I might get some new plugs fitted then, it's at WAD's in Wolverhampton right now getting a bit of tlc, so I'll give them a call. It'll come back filled with fresh 10w/40 anyways so if that's the problem it's covered now anyway
Pinking is a unique sound, well it is to me anyway. It's unlikely to happen except if your running a lot of ignition advance. Retard the timing and see if that solves it.
How often is the car run? I've heard high octance fuel looses it effect if it's sitting for a long time. This may be rubbish though, as I've only ever heard people debating it. The Octane rating also drops if the petrol become oil contaminated.
I would have said it's likely to be poor lubed tappet's. Don't know what the 33 should use, but I would never run anything but 10W40 or 10W60 in the TS engines.
I drove the car before the timing belts were changed and it seemed no different when it had been done, so hopefully the timing isn't out. The car is used 3 or 4 times a week, probably does about 150 miles/week so the fuel is always fresh and (almost always) high octane, 97 or 98 ron.
You'll have to excuse my ignorance here but what is most likely to cause pinking (if that is the problem) - plug electrodes getting too hot, or the valves maybe?
I'll run it up to high temperature when it comes back from WAD with fresh oil and new plugs...and see what happens
Ehm, guys, isn't 0W/40 supposed to be equally thin as 10W/40 when the oil is hot? The main difference being the viscosity when cold (the W stands for Winter, right?). What's more, an oil with a wider viscosity range (0W/40) should maintain viscosity over a wider range of temperatures. That's why we have multigrades...
Absolutely right, the first bit refers to the viscocity of the oil at minus 20C, the second bit refers to the viscocity at 100C. 10W-40 means a 10 weight (hence the "W") oil which has the properties of a 40 weight oil at high temp. It might be worth trying a 10W-60 or 20W-60 (although they are harder to come by).