Which cars got a chain cam?

Lum

rev_henry wrote: »

Do chains not give ample warning by rattling for quite a while before going, whereas belts just snap at any point?

Only if you buy cheap nasty ones and then never look at them again for the next 60,000 miles.

I have to confess to doing exactly that on my old Volvo 940s...

...non-interference engine

oldagetraveller

Lum wrote: »

and without a cambelt/chain

So, what drives the camshaft? Pray tell.:)

Lum

oldagetraveller wrote: »

So, what drives the camshaft? Pray tell.:)

Last pushrod engine I had the camshaft had a small cog on the end that was driven by a larger cog on the end of the crankshaft.

grizzly1911

Lum wrote: »

...non-interference engine

Seen that mentioned a few times in this thread.

What is it?

rev_henry

grizzly1911 wrote: »

Seen that mentioned a few times in this thread.

What is it?

Basically means the engine won't destroy itself if the cambelt snaps, so if your being stingy you can just wait until it snaps before replacing.

Lum

Basically what rev_henry said.

The long version is that you have the valves at the top of each cylinder that let fuel/air in and exhaust gasses out. These open up by being pushed into the engine.

You also have the pistons that go up and down.

In an interference engine, the piston is pushed so high up the cylinder that if the valves are not closed, it will hit the valves.

In a non interference engine the piston doesn't go up so high and this can't happen.

When a cambelt/chain breaks, the valves are no longer being driven so they stay where they last where, however the pistons are still moving and in an interference engine chances are at least one valve is going to get mashed by the piston. In a non-interference engine no damage will be done, you'll just lose all power until you replace the belt/chain.

So on my old Volvos I never bothered changing the cambelt, just had breakdown cover and drove until they snapped,

They never did, but if they did the replacement cost would be the same as if I'd got it done at the 60,000 mile service.

mcfisco

So, what drives the camshaft? Pray tell.

Maybe they want a desmodromic valved engine?

A Ducati 989RR engined car would indeed be nice - as long as it was light enough

split_second

pitkin2020 wrote: »

You will be able to limp home if you walk!! With a snapped belt the car won't be going anywhere. If you take your car to a stealership be prepared [STRIKE]to drop your pants and get yourself bent over the service counter[/STRIKE] for a hefty bill because that bill is going to hurt the wallet!! lol

i won't pay dealer prices
car has had anti roll bar and suspension work in last 12 months, fiat have supplied nothing more than an owners manual since purchase (from an independent dealer) in 2004, car is an ex fiat demo.

i'm getting it looked into, typically i buy my own parts from motor factor/ebay and have an ex mechanic for a dad and his mate is still a mechanic, they sort the car out between them and there is a very trusted mot garage for the annual paperwork. looked on ebay and a proper kit can be obtained for under 3 figures, is this reasonable?

zappahey

Lum wrote: »

To me cam chains are a high risk/reward gamble. Sure if you take the gamble and win (camchain doesn't break while you own the car) then you will be better off overall. If you lose the gamble you're looking at a very expensive new engine or, if you are very lucky it gets detected on time and you are looking at an expensive camchain replacement, much more expensive than replacing a belt.

That seems to be an odd perspective.

The only rationale I can see for belts is cheapness (for the manufacturer, not for the mugs that have to pay for the replacement) and noise reduction.

Unless you're at the banger end of the market, I would suggest a chain break is extremely unlikely.

Lum

I did state that I was talking about purchasing older cars, and that if you are buying a new car then a chain wins every time.

The OP stated 8 years, which means a 2003 car. If we're assuming a generic family hatchback many of these will be nearing the end of their life as modern cars really don't seem to last as long these days.