NC30 engine problems

[gammakeith]

Hi guys, I could do with some advice please. My (well actually my daughters) recently purchased NC30 has turned out to have a head gasket failure on the front bank which is a bit of a blow. Still, at least I know why there is low compression on the front left cylinder and why its been blowing out antifreeze which it has clearly been doing for a while due to the state of the engine cases.

To complicate matters the front right engine bolt was badly seized and the whole mount broke away from the head while I was working the bolt out (more corrosion due to the water leak) so I that has probably scrapped the head. Its slightly warped anyway (at least by more than the 0.1mm tolerance) so would have needed a skim which is clearly not going to be straightforward on a gear driven engine. I am guessing that the head has warped from it over-heating at some point which probably means I ought to look at the rear cylinder head as well even though the compressions seem OK? The other point of concern is that 15 out of 16 valves are way out of spec (inlets are 0.229/0.178/0.229/0.229/0.254/0.254/0.254/0.254 and exhausts are 0.406/0.406/0.356/0.508/0.330/0.406/0.356/0.356). Given the aforementioned issues am I better looking for a good replacement engine? Alternatively, there is a front head on ebay at the moment with good mounts but that obviously may turn out to be warped as well. Bores, cams, rockers etc all look good so its not all bad news. I'm comfortable working on engines but not sure about parts availability etc so would welcome any advice Thanks! Keith

[vfrman]

If that ebay head is good, I would think the only parts you need are gaskets...

Your question is pretty hard to answer without being right there looking at that engine you have. I hate wasting things, so I'd probably fix the motor, but that's just me.

[hunter]

Going by your description i would say you have a pretty good motor there,
If you were to get a replacement motor there's no saying it wouldn't need all or most of the shims doing,
I would get a head.

[gammakeith]

OK, I will go for the head on Ebay and cross my fingers its OK!

I'm still baffled why I have so many valves out of spec. I have worked on quite a few engines that use shims for the valves and never seen one with so many valves that need doing. Even my Ducatis have usually only needed 2 or 3 (out of 16 tweaking). Also, its more usual for clearances to get tighter with time. Do so many loose valves indicate anything to worry about on these engines? The combustion chambers are reasonably clean so it doesn't seem to be due to carbon build up.

Thanks!

Keith

[manicguitarist]

Maybe someone has adjusted them before and done a cack job?

[gammakeith]

I wondered about that too. However, there is little evidence of any "ham-fisted" maintenance. The only bolts that showed signs of attack were those for the carb rubbers. I think it is more likely that the valves have never been done from new ?

Keith

[manicguitarist]

Many of us have never done this level of maintenance - ok, at least I haven't anyways.

I'd be interested in a thread, if you could make one, showing the current work with pictures of the inside of the engine and such.

[gammakeith]

OK, will try and oblige with a summary and photos at some point. Daughter is back from Uni this weekend so will probably be quite horrified at all the bits her nice "new" bike is in

Keith

[richyrd5]

hhmm,so it was you who outbid me on that ebay head!!! .i was just going to get it as a spare to go with my rear and rvf cams but seeing your predicament i will bid no more and hope you get it for the £30 its at now.good luck .also 16 valves on a ducati!!!,surely you mean 8?unles of course you have a desmosedici??

[vfrman]

Which translated, means 16 valves. LOL.

But he said 16 because each valve has two shims to measure...one for the opening, and one for the closing action.