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Broken Down On Wroxham Island


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but it depends on the examiner seeing that it’s BSS compliant. An all metal affair is best for passing but that might be an hangover from my canal days. 

I would suggest the BSS examiner has to follow the rules like the rest of us and not make them up to suit himself.  I kept the paperwork for ours just in case though but we had no problems

The good news is that if you have to go down the recon route and you are replacing like for like at least they are easily sourced, suggest you give Toby a ring in Stalham and see what he has got sat in his stores

Griff

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5 hours ago, Cheesey69 said:


The fitters who came out to me yesterday,noticed 5mm valve clearances on two cylinders and the others was not far behind, only cylinder four seemed right. 
Tentative guess is that the camshaft may have eaten the bearings but if it has he has never seen it before in an engine so young. 

I'm not familiar with those engines but that much valve clearance suggests to me that the pistons have clobbered the valves and bent them. They don't seat properley hence the pop. 

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12 minutes ago, floydraser said:

I'm not familiar with those engines but that much valve clearance suggests to me that the pistons have clobbered the valves and bent them. They don't seat properley hence the pop. 

Back home at Stalham and Richardson’s fitter agrees but as to how? Timing chain could have jumped but why?

the inquest continues 

 

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i didnt think the bmc was an inteferance engine, so that shouldnt be possible, maybe if the seats have hardened inserts, they can wedge a valve open, or simply the rocker shaft has come loose and opened the gap, the fact it was working the day before implies somethings loosened and moved.

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yes its a possibility that if the rocker adjustors had not been properly tightened they could work loose under the engine vibration, I had an old v4 transit that one valve would loosen up on its own (even with the locknut) but could adjust it with a quick pull over to the side and about 2 minutes work, with the engine still running.

looking at the manual - http://www.calcuttboats.com/pdfs/Workshop Manual 1.8.pdf i see it does indeed have inserts in the head for the valve seats.

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40 minutes ago, Smoggy said:

If camchain has jumped and clearances are as big as you say I would think valves are bent for sure.

Chain probably held on by tension only till it stopped then dropped loose.

And  I think you have hit the nail and the head  it makes sense!

you sir win the internet today!

 

 

 

 

 

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19 minutes ago, JanetAnne said:

Seeings as the valve heads are in line with the pistons rather than angled, I would have thought any possible contact would bend the push rods rather than anything else.  

 

Very good point, and probably a much cheaper fix.

I'm too used to dealing with angled valves.

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If woodruf key has sheered this will only cause the valve timming to move it WILL not afect the valve clarance, valve clearance can be caused by wear on camshaft or followers or if valve seats have dropped the pistons will not touch the valves on these engines the valve are verticl/in line with the pistons are the adjusting screw nuts loose or tight, are all rocker leval/inline?  timeing chain cannot slip or jump on sprockits if adjuster worn they rattle did engine only have top end ie decoke which dosnt affect any thing else except head gaskit and valves,seats .or  if full overhaul then yes crank grinde or just shells, rebore or just rings new chain and tensiner if valve timming is out then cam nut or crank nut or woodruf keys sheared. John

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I think the interesting part is that even if the camshaft/ chain/ tensioner/ drive wheel or whatever has failed, where does the 5mm gap at the tappets come from?  

The engine is valve safe and the pushrods are straight. I am assuming that the valve springs are all complete and that the valves stems are all the same height (give or take a few thou)? So, even with the valve train becoming completely disconnected from the crank, the clearances ought to still be as set....

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10 hours ago, JanetAnne said:

I think the interesting part is that even if the camshaft/ chain/ tensioner/ drive wheel or whatever has failed, where does the 5mm gap at the tappets come from?  

The engine is valve safe and the pushrods are straight. I am assuming that the valve springs are all complete and that the valves stems are all the same height (give or take a few thou)? So, even with the valve train becoming completely disconnected from the crank, the clearances ought to still be as set....

An idea by a fellow boater. 
The camshaft has eaten its bearings. 
Need to get together with Ricko’s for help. 
going to stick in the 1.5 bmc as have been told it’s a better lump. 

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If I remember correctly the 1.5 is a 5 bearing crank and the 1.8 is only a 3 bearing crank so the 1.5 will be the sturdier engine, not that they are highly stressed in a broads cruiser, I doubt the extra 300cc has much benefit on the rivers.

Surely it didn't eat the bearings overnight, that would only happen while actually running but you said it was running fine when you turned it off, would be noisy too.

One of the common problems on the stuff I work on is cam failure on low hour engines due to condensation causing corrosion on the lobes but it's normally only a couple of lobes not all at once and a solid tappet engine would get very noisy first.

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13 hours ago, Cheesey69 said:

All adjusters tight. 
rockers only move on starter not when crankshaft turned by hand. 
That’s the clue. 
Turning by hand gives the chain time to slip, by starter enough friction to turn camshaft 

but this is best guess

Another complete guess: if the starter turns the crank via the flywheel end and hand cranking is via t'other end, broken crank?

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32 minutes ago, floydraser said:

Another complete guess: if the starter turns the crank via the flywheel end and hand cranking is via t'other end, broken crank?

Isn't the timing chain at the front on a bmc (happy to be corrected as not worked on one for years)? Be hard to not notice the complete lack of resistance turning the pulley if broken that far forward and the starter still wouldn't turn it as it's at the back.

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