Anyone felt the need to replace the M30 rocker eccentrics?

Post Mon Apr 27, 2009 2:38 pm

So the M30'd cabby project I bought 6 months ago is a bit noisy/tappety. Engine has done 120k I believe. No problem, did a full InspII including resetting all the clearances to 0.30mm cold. Got it all back together, and it is not noticably quieter.

1,000 miles later, I figure I'll go check the clearances again - just in case. Odd thing is that they are out again, some as far as 0.34mm.

Now it is very possible I made a pigs ear of it first time, but I triple checked the clearances (turned the engine several times) before putting it back together.

Chatting to Fritz's a while back, they mentioned that they had seen this before and that they thought flat spots worn into the eccentrics were to blame.

I am thinking of buying 12 new eccentrics, subject to how pricy they are. Anyone got any experience, or thoughts?

Martin.

Post Mon Apr 27, 2009 2:46 pm

No but i will let you know how i get on with mine on saturday as mine is a little tappety too.

Post Mon Apr 27, 2009 2:56 pm

Try using a Gunsons Clikadjuster:

http://www.gunson.co.uk/item.aspx?cat=668&item=1824

Post Mon Apr 27, 2009 3:01 pm

The eccentrics are only pennies and very easy to fit.

Post Mon Apr 27, 2009 3:24 pm

DRIFTBOY wrote:The eccentrics are only pennies and very easy to fit.

Perfect, thank you.

@Speedtouch, any idea if that Gunson's adjuster works on the M30 engine. I would have thought it needed a screwthread adjuster, rather than the bent wire eccentric on the M30s. I like the idea of something a little more accurate than feeler gauges and trying to keep a small allen key still.

Martin.

Post Mon Apr 27, 2009 3:37 pm

I also need to do my clearances at the weekend, so I think I'll order some eccentrics in advance if they're cheap 'n easy!

Post Mon Apr 27, 2009 3:44 pm

Well worth it in my opinion.

I'ven even seen worn ones (although the top of the valve stem was probably worn as well) that have run out of adjustment and simply will not close the clearance up enough!

Only one small nut and bolt holds the eccentric in.

While you are there you might as well renew the spray bar banjo bolts and washers and thread lock them.
Just as a precaution, and again, not expensive or difficult.

Post Mon Apr 27, 2009 3:51 pm

DRIFTBOY wrote:
While you are there you might as well renew the spray bar banjo bolts and washers and thread lock them.
Just as a precaution, and again, not expensive or difficult.

Had exactly the same thought - see my post in the genuine parts section :lol:

Post Mon Apr 27, 2009 3:55 pm

MJJ_ZX6RR wrote: @Speedtouch, any idea if that Gunson's adjuster works on the M30 engine. I would have thought it needed a screwthread adjuster, rather than the bent wire eccentric on the M30s. I like the idea of something a little more accurate than feeler gauges and trying to keep a small allen key still.

Martin.

Tbh, never tried one on a BMW engine; you're probably correct in doubting its suitability for adjusting eccentric type rockers.

[gets coat...]

Post Mon Apr 27, 2009 4:00 pm

if you order the spray bar bolts from bmw they come with threadlock on them. (this I know as I was rebuilding my head yesterday and was pleasently surprised when I looked at them!)

Eccentrics I'd definately do, replaced all of mine when I renenwed a rocker arm a few months ago and made adjustment a lot easier as many of mine were worn

Post Mon Apr 27, 2009 5:18 pm

Do the spraybar mod while your there too!

http://www.cscoupe.org/tech/spray_bar_fix/70590.html

Post Wed Apr 29, 2009 5:33 pm

Bolts - 11421738621 x2 £6.86 for the 2
Washers - 11421252343 x4 £0.55 for 4
Eccentrics - 11331744354 x12 £31.92 for the 12

Don't really know why I'm spending more on this engine - I'll almost certainly end up swapping it out (for the one in the E34 on my drive with a rebuilt head on it!) sooner or later anyway!