Apologies:Very limited interest topic, but just in case…
DOHC 2L Ford Sapphire with its upper timing chain guide slider thingy broken away from its mounting bolt and grinding against the chain.
The guide seems to be made of something like Bakelite (!) but even Ford wouldn’t do that, would they?
I’m thinking I might try and make one from HDPE (High Density Poly Ethylene), perhaps from one of those kitchen chopping boards. Nylon would probably be better but I’m not sure if I can get a big enough piece of it. Steel might also be a possibility.
I’ll have a better idea once I’ve got the original fragments out, which looks like it’ll require pretty extensive dismantling.
I’d be interested in any comments/opinions, especially informed ones. I’m thinking any particles of soft plastic that get loose shouldn’t be very abrasive, but I suppose they could still seriously block oilways.
[quote=“Ducked”]Apologies:Very limited interest topic, but just in case…
DOHC 2L Ford Sapphire with its upper timing chain guide slider thingy broken away from its mounting bolt and grinding against the chain.
The guide seems to be made of something like Bakelite (!) but even Ford wouldn’t do that, would they?
I’m thinking I might try and make one from HDPE (High Density Poly Ethylene), perhaps from one of those kitchen chopping boards. Nylon would probably be better but I’m not sure if I can get a big enough piece of it. Steel might also be a possibility.
I’ll have a better idea once I’ve got the original fragments out, which looks like it’ll require pretty extensive dismantling.
I’d be interested in any comments/opinions, especially informed ones. I’m thinking any particles of soft plastic that get loose shouldn’t be very abrasive, but I suppose they could still seriously block oilways.[/quote]
I guess if all else fails you could buy one from Ford? I like the idea of making it though. You’d think it would be nylon, but HDPE should do the job. Ford spares? No?
Good luck and keep fishing for bits. Oil change could be a good idea while you’re at it.
Eh, you mean Sierra right? 1998cc DOHC unit with single-row chain-driven cams, made between about '90 and '95?
Is this the widget that we’re talking about?
I’m sure you can get the parts from Ford Lio Ho. They’re pretty good at keeping stock of common service parts, even on older models. They used the same tensioners and guides in the 2.0 Scorpios so the engine itself is pretty common.
[quote=“redwagon”]Eh, you mean Sierra right? 1998cc DOHC unit with single-row chain-driven cams, made between about '90 and '95?
quote]
That’s the gadget. Impressive you’ve got a pic at your fingertips, and potentially useful to me since the Haynes line drawing doesn’t show it very clearly. Truly it has been said “you da man”
Things cracked at the top bolt hole and waggling about making grinding noises. Am I unreasonable to think that putting large pieces of “Bakelite” (?) inside an engine is unimpressive engineering?
Having said that I suppose it does make more sense just to buy one if I can. Not sure if the melting temperature of the available thermoplastics would be high enough anyway, gets pretty hot in there.
Main concern at the moment is will I have to bugger up the aircon to get clearance. Suspect so.
BTW I think (in the UK market anyway) the booted (saloon/sedan) version I’ve got was called a Sapphire, the Sierra’s the hatchback. Same engines of course.
Well you got lucky in that I had worked on one of these before and still had this page bookmarked. You’ll find full instructions in there on how to change the camchain, but another article said the engine will be worn out before the chain, so don’t bother. IIWY I’d just swap the worn out guides and also the tensioner while you’re in there. In that case you don’t need to remove the oil pump chain, or the crank pulley or the lower cover either. It doesn’t look too daunting except for the usual Ford creativity in using 5.5-sided nuts in places only the severely disabled can get to. No disrespect to disabled folk intended, but sometimes you have to wonder what Ford engineers are thinking…
Bakelite is of course very stable in temperatures than would kill most plastics in the same price range, so…
I’m thinking that even Ford Bakelite Engine Bits shouldn’t break unless there’s some load on them. I dont think it could be designed so the chain rubs it continuously (since it wouldn’t last long enough to avoid claims?) so there seem to be two main possibilities:-
(a) The guide thing is routinely but intermittantly and briefly loaded in normal operation, perhaps at startup until any slack is taken up by the tensioner cylinder becoming oil-pressurised (but it’ll have a non-return valve?) or sump oil drag. This intermittant loading has eventually caused it to fail from Bakelite Fatigue.
(b) Irrespective of whether the guide thing is routinely loaded in normal operation, this isn’t what caused the failure. Load on it has increased recently (and/or/IOW its been clouted harder than usual) because the slack on the chain has increased due to chain wear and/or the chain tensioner reaching its limit, so it can’t take up any more slack. Guide thing failure is then a symptom of a larger problem.
(a) Means I only have to fix the guide thing. (b) Means I also have to replace the tensioner and perhaps also the chain, otherwise my replacement guide thing will go the same way.
I bet its (b). I’ll have a look in the manual and see if it looks possible to asses tensioner extension and/or chain wear without further dismantling (you can’t re-fit the tensioner according to Ford)
Those things do just get old from heat cycling and die of old age. It happens. The bakelite guides are NOT the tensioner, they just help keep the chain on the sprockets. The consensus on the Scorpio site is that the chain will last the life of the engine, and I believe them. It’s adequately sized, the valve springs are not very stiff, the cam profile is mild, the lubrication is great and it’s not a high revving engine. I don’t see why the chain wouldn’t last 300,000km.
Just replace the guides and tensioner and go on your merry way.
