Safe Speed Forums

No cam? What makes the pushrods push?

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Yes Botach, I was I think I’m right in saying the age of the ‘sealed for life’ engine has arrived which, although useful, is sad in other ways I think.


I’m sure you’re right Mole, although it’s getting pretty tight with bikes too. Mine was withdrawn from manufacture a year or two ago because of the Euro 3 emissions.

A quick search reveals they are up to Euro 5 now They won’t be happy until everything runs on fresh air with the engine managed by an Intel Hexacore© centrally controlled by the DfT IT crew working in cohorts with SCPs..

It could happen!

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Motorcycle engines have lower emissions anyway, even without cats.
Better design and they warm-up faster.
The CX 500 revved to 10K because it had very SHORT pushrods, driven from a chain-driven camshaft.
As someone said, of the CX500 engine: "it was designed as a joke to show how you could combine loads of stupid ideas into a single package, but the designers went to lunch and didn't tell the production team"
The astra engine is an interference engine, which means that if the timing belt breaks/slips the valves will contact the pistons, which valves then become history, as valves, and are replaced by scrap.
Either way, the head has to come off.
Belts were a waste of time, but their replacement gave workshops loads of work...and if the owner didn't believe that they HAD to be replaced at 40k/6-year intervals then the bill for a head workover and a new belt/water-pump soon convinces them.
That said, the Ford TDDI engine had change intervals as 100K/6-years (70K in the real world).
The Ford TDCI engine has chain drive (most models) with no replacement time given.
However, they are a bit intolerant of oil change intervals being ignored, and low oil levels.

I don't know why this has carried-on. The original poster obviously had a no-maintenance attitude to vehicle operation and as such was a risk to others. Maybe a wind-up.

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The world runs on oil, period. No other substance can compete when it comes to energy density, flexibility, ease of handling, ease of transportation. If oil didn’t exist we would have to invent it.”

56 years after it was decided it was needed, the Bedford Bypass is nearing completion. The last single carriageway length of it.We have the most photogenic mayor though, always being photographed doing nothing

I'd be pretty amazed if ANY bike engine could meet the type approval emissions requirements (as opposed to the MOT emissions requirements) for a car! Yes they warm up quickly and they're not very big so they don't produce a great deal of pollutants in absolute terms, but in percentage terms, they're pretty filthy. I think it's maybe a bit cynical to suggest that belt driven cams were only put there to create work for manufacturers. My own car has a V engine with only one cam per bank, but later versions had two cams per bank. That's a hell of a long chain run! I'm pretty certain a chain driven camshaft is more expensive to produce - which will get passed on to the punter. The thing is that if it doesn't need a cam belt for 3-4 years, most of the punters who bought the car new (i.e. the ones that provide the bulk of the manufacturer's income) won't ever have to pay for one, so they won't care. True, the next owner will get stung for one, but they're normally happy to because they've not taken the (much larger) hit in depreciation that the first punter has taken. The difference in residual value between 2 cars - one with a belt and one with a chain at the point where it goes to the second owner will be trivial (basicaly, it can't be more than the cost of a cam belt)! It's only when you get to 10 year old, 100,000 mile sheds on their 5th owner that the lack of a cam belt becomes a positive selling feature! These people tend not to go to franchised main stealers and rarely buy genuine spares, so the manufacturer isn't likely to make any money out of them and therefore doesn't care what they think!

I'm afraid they're past that point already! Even getting on for 10 years ago, the Yank emissions requirements were so tough in California that the air coming out of the tailpipe was cleaner than that which was going into the air intake as you drove through a typical LA day!

But then the cam chain tensioners fell apart at 30,000 - 35,000 miles ... done a fair few of them in my time! Still have a soft spot for the old CX500 though

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You only need two tools - WD40 and duct tape. If it doesn't move and it should, use WD40. If it moves and it shouldn't, use duct tape. :0)

Nice bike to ride.
As long as they ran they were great.
Woe betide the owner who didn't use antifreeze, since the water pump seal did not last long on water only....and the water pump was on the end of the.........camshaft, as in directly.
Did a few hundred thousand on a cx 500, then had a blinding bit of inspiration and bought BMW. My first lasted 369 thousand before deciding that being drowned in salt every winter was enough.....my current K has done 43 thousand so far, and doesn't do winters any more (neither do I, not on a bike anyway.....). The current K has a cat....and full abs2.......clean as a whistle on an MOT emission tester....mind you, the engine prefers 99 octane....German bitch.
And those who replace a cambelt with a turkish-toilet maker are destined to spend more than they would using a workshop.
I only use Gates Powerline or OEM.
And NEVER believe the previous owner....ALWAYS change the cambelt and water pump (if needed) immediately.
I couldn't care if the car paperwork contains a sworn statement, written in the mechanics blood, that the stuff has been changed 10 thousand ago....

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The world runs on oil, period. No other substance can compete when it comes to energy density, flexibility, ease of handling, ease of transportation. If oil didn’t exist we would have to invent it.”

56 years after it was decided it was needed, the Bedford Bypass is nearing completion. The last single carriageway length of it.We have the most photogenic mayor though, always being photographed doing nothing