disaster strikes -- stuck cam bucket

It does not appear to be an oil feed issue.  Both the camshaft and the cam block bearing surfaces look perfect - so oil has been flowing to that point at least.  The passageway from the oil spray hole to the interior of the cam block is clear of any debris.

The bucket is completely seized.  An application of heat to the surrounding head area did not allow it to be freed by spring pressure.  Maybe the spring is broken, but the springs were brand new German-made.

The base circle of the tappet is untouched - so this is not an issue of too little clearance.  I checked the clearances three times before first start.

Next step, engine removal.
 
If the valve is seized or bent it won't allow the spring to push it or the bucket back up.
Engine out, head off, and go from there.

Always a bummer to have to go back in after bolting something back together, but I doubt there is any major damage other than to that valve/guide and the obvious bucket/cam damage (and maybe some minor piston crown interaction).
I would definitely re-measure all the valves and guides to ensure there is correct clearance though.  In fact, generally re-check the entire head work since it sounds to have been done by someone not necessarily familiar with Laverdas. No matter how competent they are, a generic head shop will quite often bollox up Laverda heads.
 
... further to that...

You mentioned you re-used your original valves and had new guides fitted (by a non-Laverda-specialist). Most automotive engines use a valve guide of nominal size 7.00 and the stem has the clearance so is ~6.98 (for example).  Laverda use stems of 7.00 and the clearance is in the guide, so guide is ~7.02.  Thus, it's not uncommon for a head shop unfamiliar with the marque to install guides and ream to their typical 7.00.  The result of the above highly likely scenario is that you have less than normal clearance, leading to the valves nipping up in the guide when hot.  Bucket damage is secondary to that when clearance increased due to a lazily closing valve. Eventually the valve has either galled in the guide and seized fully, or else has clipped the piston and bent slightly, thus won't close.

The above scenario has been repeated many times over.
 
Just wrote a reply about the same thing happening to me but lost the lot when Microsoft decided to do an automatic update without any warning,FUCKERS.Anyway it happened to me years ago work done by Eadie's at the time,they reckoned I overreved it bending the valves.Bite me another $400 to fix it a week after getting it back on top of the $1500 first charged to do the head rebuild,big money to me  20 years ago.
 
Hi Chris

maybe it will make you feel a tiny bit better, I am having to haul the freshly rebuilt Triumph Spitfire car engine back up off its mounts tomorrow to be able to get the oil pan off and out to replace a BRAND NEW but defective oil pump. You can't trust brand new parts or machining work from anyone these days...

pissed me right off, primed the oil pump, spun it up with a drill, then fitted the distributor drive and the fancy new distributor, fitted the carbs, hooked everything up, fired the engine, no oil pressure within 20 seconds, shut the bloody thing off and started troubleshooting, distributor and drive back out, hook a pressure gauge right to the outlet of the new oil pump, spun it up with the drill, getting about 2 psi if that...... bloody hell! Should be about 65 psi. Thank goodness I slathered everything in high quality assembly lube when I put it together. The old oil pump got knackered when the previous engine put a rod through the block, so I can't even re use the old oil pump.

and I wanted to take the car for a drive tonight after so long apart for the second bloody time....

Paul LeClair

ps you may wind up having to drill a hole in the deformed bucket and thread it for attachment to a slide impact hammer or similar to yank the deformed bucket out
 
Paul - quite often there's a pressure relief valve on the oil pump outlet on those old shell bearing pommy car engines. Usually just a ball/spring affair. Make sure that's working OK before throwing the oil pump across the workshop in disgust. If the ball isn't seated it won't make any pressure.
 
I (almost) agree with everything written above, and very sorry to have to say it, but your motor is coming out and the head coming off, but before you do that, you will have to remove the exhaust system and carbs, when you have done that, drain the oil through the plug and wait for it to stop, then (very carefully) and so as not to disturb anything, remove the sump plate (triangular) and lower the (so called) sump strainer, I think you will find it covered in fluff, caused by changing the oil and the fresh stuff not being compatible with the old stuff, some oil will get sucked through, but even the slightest lack of lubricant will cause exactly what you are witnessing, the tappets are lubricated by oil draining by gravity, when an engine is open, you can see the stains running down the front inside of the cases where this happens, the stains are caused by some of the oil drying before it reaches the sump again, so there is never a lot of it, your cams and cam  bearings may well have been getting enough lube to keep then at least running, but that does not mean there is enough to "coat" the tappet as well.
CLEM
 
Paul
You get that playing with old British cars that is why they used to use wing nuts on the engine mounts.
I feel your pain both of you.
 
Paul LeClair said:
Hi Chris

maybe it will make you feel a tiny bit better, I am having to haul the freshly rebuilt Triumph Spitfire car engine back up off its mounts tomorrow to be able to get the oil pan off and out to replace a BRAND NEW but defective oil pump. You can't trust brand new parts or machining work from anyone these days...

pissed me right off, primed the oil pump, spun it up with a drill, then fitted the distributor drive and the fancy new distributor, fitted the carbs, hooked everything up, fired the engine, no oil pressure within 20 seconds, shut the bloody thing off and started troubleshooting, distributor and drive back out, hook a pressure gauge right to the outlet of the new oil pump, spun it up with the drill, getting about 2 psi if that...... bloody hell! Should be about 65 psi. Thank goodness I slathered everything in high quality assembly lube when I put it together. The old oil pump got knackered when the previous engine put a rod through the block, so I can't even re use the old oil pump.

and I wanted to take the car for a drive tonight after so long apart for the second bloody time....
Click to expand...

Damn, sorry to hear that.  Just when you think you're done, it all goes pear-shaped...

Paul LeClair said:
ps you may wind up having to drill a hole in the deformed bucket and thread it for attachment to a slide impact hammer or similar to yank the deformed bucket out
Click to expand...

Yes, that is exactly what I was pondering last night.
 
CLEMTOG said:
I (almost) agree with everything written above, and very sorry to have to say it, but your motor is coming out and the head coming off, but before you do that, you will have to remove the exhaust system and carbs, when you have done that, drain the oil through the plug and wait for it to stop, then (very carefully) and so as not to disturb anything, remove the sump plate (triangular) and lower the (so called) sump strainer, I think you will find it covered in fluff, caused by changing the oil and the fresh stuff not being compatible with the old stuff, some oil will get sucked through, but even the slightest lack of lubricant will cause exactly what you are witnessing, the tappets are lubricated by oil draining by gravity, when an engine is open, you can see the stains running down the front inside of the cases where this happens, the stains are caused by some of the oil drying before it reaches the sump again, so there is never a lot of it, your cams and cam  bearings may well have been getting enough lube to keep then at least running, but that does not mean there is enough to "coat" the tappet as well.
CLEM
Click to expand...

Clem, not sure what you mean regarding oil compatibility.  The motor was completely dismantled and cleaned inside and out, and all oil ways blown out with compressed air.  Oil delivery to the head was confirmed before first start.  There was no "old" oil anywhere.  What exactly do you mean by "fluff"?  As you suggest, I'll pay close attention to the strainer, but I'm confused by your comments.
 
beauchemin said:
Clem, not sure what you mean regarding oil compatibility.  The motor was completely dismantled and cleaned inside and out, and all oil ways blown out with compressed air.  Oil delivery to the head was confirmed before first start.  There was no "old" oil anywhere.  What exactly do you mean by "fluff"?  As you suggest, I'll pay close attention to the strainer, but I'm confused by your comments.
Click to expand...

I'd put my money on the valve nipping up over fluff on the strainer being the cause :D :D

Chris, I'd be interested to know if the shim is seated correctly on the valve stem?
 
motoddrob said:
I'd put my money on the valve nipping up over fluff on the strainer being the cause :D :D

Chris, I'd be interested to know if the shim is seated correctly on the valve stem?
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I will post photos of all the bits when I get the head apart.  Any suggestion on how to remove the bucket (apart from smacking the valve head!)
 
it s not fluff caused by old oil, its caused by using a different oil when you change it, maybe you did 100 miles or so, then retorqued everything (good plan) and changed the oil, the big but is if you changed brands, then some are not compatible with each other, as far as I know, it is quite rare, it does happen, and there is no known list of what is not good after what, the fluff could even be caused by contamination of the sludge traps, which usually only get cleaned out if a crank strip is being done, and yes it has been proven in this household (and that of  an acquaintance) that crank repairers do not always clean out those sludge traps, on one crank I had to have redone, there was a hole in the tin where the repairer had punched it through with a blade of some sort and then TIG welded it up and polished it out, that segment of crank was perfectly clean for about 60 degrees, the rest had solid, but now loosened crap in it, there was also a lump missing of one of the crank webs where it had been walloped (which is normal) but had broken a bit off (not normal), this also was ground out.

THE CRANK REPAIRER I AM TALKING ABOUT IS NOT KEITH NAIRN OR TODDY
both these gents have given me great service and great prices for many years, in the case of Toddy about 36 years!
 
CLEMTOG said:
it s not fluff caused by old oil, its caused by using a different oil when you change it, maybe you did 100 miles or so, then retorqued everything (good plan) and changed the oil, the big but is if you changed brands, then some are not compatible with each other, as far as I know, it is quite rare, it odes happen, and there is no known list of what is not good after what, the fluff could even be caused by contamination of the sludge traps, which usually only get cleaned out if a crank strip is being done <snip>
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At 300kms and six heat cycles, this was the very first service (except for an early primary chain adustment.)  In additon to new pistons and valve train, there was a complete crank strip & rebuild (yes, including clean sludge traps.)  I used 20/50 mineral oil.
 
beauchemin said:
Any suggestion on how to remove the bucket (apart from smacking the valve head!)
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If it doesn't come out from the top, you have no choice.  Maybe David Copperfield can help... :D

piet
 
sfcpiet said:
If it doesn't come out from the top, you have no choice.  Maybe David Copperfield can help... :D

piet
Click to expand...

The bucket's a write off anyway - weld a bolt to the top face and use a slide hammer or home made equivalent
 
motoddrob said:
I'd put my money on the valve nipping up over fluff on the strainer being the cause :D :D

Chris, I'd be interested to know if the shim is seated correctly on the valve stem?
Click to expand...

I dunno Rob. The mechanic could well have been concentrating on the fluff on his calendar rather than the engine he was working on.
 
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