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Zetec Rattle


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Well, sort of - the higher the revs, the faster the rattle but at some revs, it disappears altogether.


Just to make things worse, i can't get the engine to start at all now!! It was fine on Sunday and then, this evening, i removed the oil pressure sensor to connect up the oil pressure gauge and it wouldn't start! Cranked ok but that was it. I put the oil presdure sensor back in and just about got it to start but it would only run for a few seconds and it would die immediately if i touched the throttle.


Too *bleep* off to look into it more now :-(

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Ok as I have had all of the above as problems with my current engine, I will say it's still big end bearings! A wiggle by hand is not how you check them they will move on the crank as they are designed to. Take off the caps and physically take a bearing out to look for scratches or bits missing.


When going turbo me and Chris noticed I had 2 bent valves and my car ran fine it would pop and bang on over run and at high revs it would feel like it had a misfire but other than that ran great.

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Watch this short YT vid:



When I did that with mine, they didn't move a mm. Also, my rattle isn't there consistently - between idle (when it did idle :( ) and about 2.5k RPM, the rattle stopped. If it was a bearing, surely it would rattle all the time?


I've also just remembered that, on Sunday, I ticked a setting in the Emerald ECU app while the engine was running - something about injector grouping (according to a blog, Emerald had recommended doing that). It seemed to make no difference at the time but maybe it is preventing the engine starting?


Will untick it tonight and pray that gets me back to only a semi-crap car :unsure:

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That video would be a very extreme case which would more than likely need a new crank and pistons not just bearings. mine did not move at all other than sliding on the crank which there suppose to do but the shells were complete scrap






Mine would only make a noise on slight throttle then disappear with abit more throttle sounded perfectly fine on tick over but when under load it was much worse.

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Ah, ok - and that does sound more like my noise. Is it possible to replace those bearings without taking the engine out, from underneath?


(Engine running now, i had done something stupid in the ECU setup)

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OK, well I think it's confirmed...


My font of much knowledge (YouTube) finally found a video of someone suggesting a simple test (which is probably common knowledge among more experienced builders but not me :blush: - apologies if someone had already suggested this and I missed it) - just remove HT leads to one cylinder at a time. If the rattle stops, then that cylinder has the problem and it's a bottom end issue.


I've just done this - removed lead from cylinder 1 and, ta-da, rattle gone, no matter how much I rev. Still rattles when I repeat this on the other 3 cylinders...


I still don't really get why it doesn't rattle - the crankshaft is still going round and the same bearings are still moving? :unsure: Anyway...


The issue of why my bearings should be worn after just 3.5k miles is concerning but maybe I had poor oil pressure from my crappy oil pickup pipe, as cb750 suggested? I've just done an oil pressure test and I'm getting 5 bar (70psi) at idle, 6 (85psi) when revving - seems a bit high but it is still a new-ish engine.


Does this all seem reasonable/sensible? I don't want to take my sump off again for nothing...

Edited by nelmo
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I hate to say it but I said about the bearings when you first posted about the problem, when doing this amount of work it is best to check things properly it will save you alot of time in the future trust me I know, been there and done that.


Because the explosion that happens in the cylinder forces the piston back down with more pressure than it just being pulled down. You are taking such small tolerances which is why you can't feel it when moving by hand.


If one has failed they all will have. You can buy a set for around £30-40 make sure you use engine assembly grease when fitting new ones.


Loads of things can cause this issue, dirt in the oil, oil starvation possibly caused by your pickup being to close to the sump. Wrong oil. Also when you get a new engine you are suppose to run it in with special oil if not done correctly damaged could have been caused

Edited by Matt brown
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  • 1 month later...

Well, finally got round to getting the sump off (again!) and my big end bearings are shot (at least on cylinder 1 so far - not checked the others yet).


More worrying, i have a scratch on the crankshaft but i don't know how serious it is. Can anyone tell from this picture - does it need something doing to it?




The actual scratch that breaks the surface is only a fine line, it is not that whole mark in the pic...


Opinions? Desperately hoping i don't have to take the crankshaft out....

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That looks like a crank regrind to me. Not the answer you probably wanted to hear but if you put new shells on that, you'll be doing it later anyway.


Looking at the bearing will probably tell you more. If it's worn through the white metal and the copper, it's usually damaged the crank.

Edited by richyb66
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Looks like the bearing shell has smeared itself onto the crank surface probably due to low oil pressure. If it is then I've seen cranks polished to remove this but you need to check the crank for further damage and ovality. If it was me I would be looking at a regrind and new shells for peace of mind. You need to look at the main bearings as well as just the bid end ones.

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Neal for piece of mind I would go down the road of taking the engine out and have the crank reground and have new bearings fitted.


This has been a long ongoing saga for you so better to have it checked out and make sure your oil pickup is not to close to the sump and start with something that you know will not let you down.


Regards Martin

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