E30 Zone

I was at Castle Combe Rally day (like a track day) yesterday with my E30 325i ..... after 2 laps it dropped onto 5 cylinders ..... turned out to be broken rockers ..... there were 3 broken though I wonder whether just one broke and the bits and pieces may have taken out the other 2 ??

The engine is high mileage though not too tappety (until yesterday LOL) and I've not had either the sump or tappet cover off previously. Its a standard engine with an ANT Chip, ITG panel air filter and BTB 6 branch.

My question is ...... is this a known problem/weak area of the M20 engine and if so, are there either genuine or aftermarket improved quality rockers to eliminate this issue ......

OR: if its not a recognised problem .... any ideas on why it happened ?

I was told it could be because I buzzed the engine ...... this certainly wasn't the case yesterday as it was on my first two exploratory laps of a track I've not been to before. And I regularly get told I should rev it harder ..... it seems torquey enough (with a 4.4:1 diff) that changing earlyish is quickest.
One helpful sort queried whether it could have jumped a tooth (or more) on the cam belt (of unknown age/mileage) with the resulting piston to valve clash causing the calamity. Am not sure whether this can even happen, but presumably it would have broken all the rockers if this was the case ?? The engine still runs .... enough to drive it onto the trailer.

CHEERS for your thoughts
MARK

They've been known to break, I've seen it on a couple of cars ( both 325 ). The belt jumping is not unknown but it would have to be slack and like you say more rockers would be damaged are the broken ones all inlet or exhaust or a mixture and are they all next to each other?

john

This is not unknown with a high milage engine,I seem to remember Simon13(I think) reporting a similar problem at 250000miles...and a lad in Bristol as well,'cos I felt sorry for him and posted him a spare rocker!Sounds like a top end rebuild is called for,and fit a new belt whilst you are there!!GSF list rebuilt heads BTW,they seem expensive untill you get the bill from the engine rebuilder for the bits you cannot do your self...

Yeah, one exhaust and two inlet .... all next to one another around number 3 cylinder. There were some quite big pieces spread around a bit so one broken one may have taken the other two out ?

I only had a quick look before covering it up in disgust/disappointment ........ I presume that to replace rockers with the engine in place that the rocker shafts have to be removed by taking the radiator and maybe the grille out to slide them forward out of their cradle ?

CHEERS
MARK
I posted my last post at 2 or 3ish Sunday afternoon (sad, I know) but it says 12.14 Monday morning (tomorrow) ..... what's that all about ?