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Today I ... (bollocks!).


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1 hour ago, Nick Jones said:

Because SRAM” according to the house cyclist……

Yep. A company that makes products designed by marketeers not engineers. Chains (except for the stupid 12 speed one) are OK, pretty much everything else is barely adequate to sh1te. Including the ridiculous gear ratios.

Have you got the end stops set and the angle right? And take it the cables and housings are good. 

18 minutes ago, JohnD said:

Now, doctor, would the symptoms be a clue? Changing up from lowest to middle is fine, from middle to highest (biggest) is variable, but holding the lever until it does engage helps.    The other way is a disaster, the chain always falls between the chain wheels.

To me, that 'box' that holds the chain and guides it over the chain wheels, looks too big, it's twice as wide as the chain.  Is there a version which could guide it more accurately?

The 'box' (chainguide) needs to be wide to account for the angle of the chain changing depending on which sprocket is engaged at the back. However it is worth checking that both sides of the chainguide are straight, parallel and not bent or bowed. This can occasionally happen if the gears have had to be forced because the rest of the setup isn't right.

And check that it is are aligned as specified by the manufacturer in relation to the chainrings - angle and height off the largest ring.

Also some are meant to have a plastic buffer on the inner face of the inner rail. If this is missing/worn there will be shifting issues similar to what you describe. 

Similarly if the end stops are incorrectly set. Again will give symptoms you describe. End stops should be set before adjusting the cable.

And if the chainrings or chain are badly worn then similar shifting and engagement issues. A worn chain wears out the rings and gives shifting issues. Trying to use a new chain on worn rings will give differenct engagement problems.

Look up Sheldon Brown on t'internet.

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Don't be so quick to blame SRAM. If you have a lot of miles on the chainring, or if it is a poor quality, the teeth wear down ever so slightly and it will fall off towards the pedal side. I don't skimp on quality when it comes to bicycle drivetrain parts.

Then this happens after tens of thousands of miles on a bike a chain snaps for the first time. I stood up to climb a steep rocky hill and wait..... Nothing but neutral. The worst part was getting back to the car 4 miles away.

Wait that's a SRAM chain. Hmmm

IDGS6545.JPG

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Thank you, Colin.   The guy at the bike shop used a chain gauge and said it was not worn or stretched.     I'll have a look at the other factors you mention.

Would that bike gear were as easy to correct as Citroen door mirrors!

John

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5 hours ago, Escadrille Ecosse said:

Have you got the end stops set and the angle right? And take it the cables and housings are good. 

Pretty sure. The irritating thing is that it works ok about 95% of the time and then just falls off for no obvious reason. If I wind the stop in any more I don’t get the gear.

5 hours ago, SpitfireBGT said:

I stood up to climb a steep rocky hill and wait..... Nothing but neutral

Many, many years ago in student days I did something similar trying to beat the cars away from Hampton Court roundabout. A very delicate area made very firm contact with saddle/crossbar - irrelevant which really, it spoiled my morning and had me walking carefully for a couple of days.  That was the result of pulling a few teeth off the second smallest sprocket on the cassette. Yes, I was in totally the wrong gear for the job and yes both sprocket and chain were very worn. The bike shop guy was impressed though. Unusual failure he reckoned…..

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3 hours ago, Nick Jones said:

A very delicate area made very firm contact with saddle/crossbar

This makes me wince at the memory of enduring the same when my chain snapped, sprinting away from traffic lights up hill in rush hour London traffic. Hugely painful and caused a sudden swerve and deceleration with a herd of impatient taxi drivers right behind me. I'm sure I saw one of them laughing gleefully as I limped to the pavement.

Edited by PeteStupps
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Searching for something to watch on TV this eve, found Sky Arts showing Cirque du Soleil's "Alegria".  Wow!   Circus, like I've never seen before!    Fantastic acts, expanded by fantasy costumes, an MC more sinister than in Cabaret, clowns that are mimes, but funny as well as pathetic.    If they ever come to the UK, I must see them! This show is on YouTube - see if you agree!

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Today I.... oh crap.

I took the Scimitar the other week when I went up north for a few days. Performed faultlessly, including out dragging the Range Rover Sport at a set of lights near home. Then left him to it at the next set. Childish yes, but the two young lads in the converible Merc that rolled up next to me thought it was good value. They knew what it was and appreciated the noise the car makes when the vacuum secondaries open up.

Anyway laugh is on me as I have had the car out a couple of times since and it had started to run a little rough at low speed.

Some investigation yesterday afternoon as Rover V8s have a number of potential failure modes.

Water levels good and ignition all seemd OK so pulled the plugs to have a look. Not the easiest job in iteslf especially for the rearmost plug on each bank. It's a bit tight back there.

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All on the bench. No1 on the left with left bank nearest.

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Can you tell what it is yet?

So did a compression test, although not able to get the gauge onto 7 and 8.

1-155psi, 2-155psi, 3-152psi, 4-20psi, 5-155psi, 6-65psi

Oil down the bores made no real difference to the low readings.

Now the RV8 is renowned for munching cams, exploding hydraulic tappets and broken rockers so I was 'hoping' it might be one of these as that is relatively easy to sort with the engine in the car. Don't even need to take the heads off usually.

However took the rocker cover off and all looks well. Turning the engine over the valves all operated although I didn't check lifts.

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So what do we think, head gasket? burnt valves? broken rings? burnt piston?

Head off this afternoon for a gander. Bollocks....

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Right bank 2 isn’t playing…..

Probably a burnt valve, probably exhaust. Stick some compressed air in the plug hole and listen to where it goes?

You mentioned that all vales seem to be opening ok - which sure is a consideration on these engines- but are they all closing properly? This can be another hydraulic lifter failure mode though fairly uncommon.

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20 minutes ago, Nick Jones said:

Probably a burnt valve, probably exhaust. Stick some compressed air in the plug hole and listen to where it goes?

You mentioned that all vales seem to be opening ok - which sure is a consideration on these engines- but are they all closing properly? This can be another hydraulic lifter failure mode though fairly uncommon.

Hmm. Good point. Worth trying the blowdown test.

 

 

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Quote, Colin, "Oil down the bores made no real difference to the low readings"

Says valve problem to me, Colin. But if the oil made no difference in the other cylinders, then not enough oil?  The oil should improve the ring seal temporarily, so that even bores with good rings should up their compressions.

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Too busy looking at plugs and not paying enough attention to the compressions….. are the two low ones adjacent? If so I’m switching my bet to HGF between cylinders…..

Composite gaskets or those bloody horrible shim things?

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Thank you gentlemen.

John. Good point, I hadn't checked the other cylinders with oil.

So I just did one. Which brought to light that I was using the replacement compression tested which is in bar not psi.

So the big 15 is 15 bar and not 150psi. Doh! :teehee:

What that means is that the compressions on the 'good' cylinders are actually around 210psi. The engine has 'worked' high compression heads and a relatively short overlap cam.

The bad ones are still bad. And they are adjacent cylinders.

I tried the blowdown test on number 4 and the air is coming out of the exhaust . So I definitely have a burnt/not closing valve there.

I didn't bother doing a blowdown on number 6 as the head needs to come off anyway so either same or the gasket as well. It's the inlets that are adjacent on the centre two cylinders so hopefully not a cracked head.

They are composite gaskets and not the metal shim. It does have the problematic outboard bolts but they are basically fitted just tight enough not to come loose.

So. Right hand head needs to come off and probably new cam/followers too. But hopefully engine can stay in.

Bollocks. Off to drain everything down.

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If it's any comfort, I started the Vitesse engine  today, after refitting the rebuilt gearbox.   After a period of near heart failure, with NO OIL PRESSURE AT ALL I finally saw oil dripping from the rocker shaft and the gauge registered!   Phew!

It was just filling the cooler and the rest of the system, about 1 litre and half's worth.    I did  not run it for any length of time.    Next stage is back to 3 Sisters for a test session, and then a race, if I can enter in  time.

So, Bollocks, then Not Bollocks!!

John

Edited by JohnD
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My passport expires next year, at the end of August, and knowing that France demands at least six months of 'life' for entry, that I shall be going to CLM next year and hearing the constant grief of people whose passports just disappear into  the maw of the  bureaucracy and return far too late, I applied for a new one online, yesterday.    Easy-peasey!  You even provide your own passport photo, which the website checks for validity (too dark, too light, smiling etc!)  Nip down to the Post Office to send it off, ask for registered delivery and how I may check that.     "You can't  through us, but go online to the Passport Office tomorrow and see that it has been delivered."  OK!

So today, after receiving an email, sent this morning, telling me to send the passport, I get onto the Gov.co.uk "Track your passport application" webpage!   Not reassuring, and nor was the message online telling me  not to try to track it until at least three weeks have gone by!!!!!  And all that I get when I enter my details and application code is another bloody message telling me to send in  my passport!  I might as well walk to Hemel Hempstead !

Oh, Schengen!  oh, Bollocks!

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The Mills of God, and the Passport Office grind exceedingly slow.     I received an email at 0644 (!) this morning, entitled "Old passport received" and begging me, "Please don't contact us about progress!"

I just hope that 10 months is long enough!

John

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