Technical Rule of 9?

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Technical Rule of 9?

glenn2602

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Cinquecento 899cc with an overhead valve engine.. and those spring-loaded tappets that fill with oil ..

Does the old rule of 9 when adjusting valve clearances apply? i.e... valve No1 fully open ..adjust valve No8?

Many thanks to those who helped re injector - which wasn't the fault. The car still won't start. It cranks, has spark and fuel .. I'm now thinking that the valve clearances might be at fault. If it isn't the valve clearances, I'm stumped (and I'm certain that it isn't a sensor of any sort at fault).

I've got a workshop manual for the car but the photos and info mainly relate to an overhead cam engine...

The nearest info I can find was an online article which says bring the engine to tdc and adjust the relevant valves, then bring the engine to tdc again and adjust the next valves... repeat..

Surely it's tdc at the top of the compression stroke?
 
With hydraulic tappets, there is no manual adjustment. The rule of 9 would still apply, but measuring clearances may not tell you anything.
With the engine running, oil pressure should keep the clearances at their correct setting, whatever has been designed into the tappet. It might be possible to check the clearances with the engine running, some engines in the past were set this way. You have to get a feeler blade in there with it running, and keep increasing the size until it won't go in any more, then you have the running clearance. OK as a comparison across the eight, but without the figure being published, not otherwise of use.
Once stopped, the tappets should hold their setting, but if any leak the clearance will increase. This is not itself an issue as they should pump up almost immediately as it turns over and starts.
As you've started a new thread, we have no details of the issue or diagnosis so far. Expecting us to remember is pushing your luck a bit. Few if any will search either.
If you are certain about fuel and spark, have you done a compression check? Whilst you have the lid off, any stuck or sticking valves might be apparent, but really they'd only affect individual cylinders, so shouldn't prevent starting, only give poor running.
Any diagnostic test done?
 
With hydraulic tappets, there is no manual adjustment.
There is with the 899 Cinqs.
They had rockers with manual adjustment on the pushrod side and hydraulic tappets on the valve side.
The hydraulic bit was a bit rubbish... (If it worked, it wouldn't need the adjuster!!).

Very late 899 Cinqs and 899 Sei had different rockers with no adjustment and better hydraulic tappets.


Personally I retrofitted the old solid setup from a Panda.
 
I have a Haynes for the Cinq, nearest I could get when I had the Sei 1100, so had not really looked closely at the 900 engine section.
Interestingly, early in the Cinq history I heard tales of cam follower failure, necessitating engine removal to fix. I'd assumed the hydraulic tappets were in the block, like many OHV engines, but apparently not.

Haynes describes the tappet preload adjustment quite well, and does suggest that this should be done at TDC for each cylinder. Using the rule of 9 may give incorrect results, so best to follow manufacturer's advice.
If the OP does not have a Haynes, might be a good idea to get one before going any further. Although, I still doubt this will affect whether it starts or not. Issues with tappet preload are more likely to result in poor starting and running, not failure to do so.
 
Hello rallycinq and jackwhoo.

Yes, there's a spark .. the car eventually started this morning after I fitted a second hand fuel pressure regulator. It started immediately .. and of course, there appears to be nothing wrong with the original regulator..

I'm going to have to have a look at the tappet preload. There's a bit of blue smoke and the car seems underpowered and 'rough' with a bit of tappet noise, though it covered 5 miles on a test run no bother.

I don't think there's trouble further down in the bores/rings. I'm quite hopeful that the 'fumey' smell and sluggishness can be rectified by a bit of tappet work ..
 
Wow well done getting it started .
Don't worry about fume smell at moment . You have done a lot to motor , wouldn't be surprised if smell is from oil that escaped during head off work burning off hot bits.
Set valve pre load as planned then give it a good thrashing .
You will both feel a lot better afterwards.

Well done again finding dodgy pressure regulator.
 
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