Crankshaft End Float

[NURBY]

Can someone please explain the causes, cures and symptoms of crankshaft end float

Specifically, I'm after the causes in relation to manufacturing defects although I'm sure there are many

I've also heard that poorly aligned throwout bearings can have an effect

Also, what symptoms would a car suffering the early stages have

Thanks in advance

[vxah]

Thats a question and a half is that! Excessive crank endfloat is not a common failing in my world these days (vauxhall workshops)however we did have a few cases back in the day... I would say that the cause will not normally be easy to identify if its manufacturing defect as there would be so much wear and damage done. The thrust bearings are not really pressure fed like the mains etc so i guess a little oil starvation of them might be a big starvation to the thrust? Also the thrust surface area is quite small so loads from the clutch release could be high,more so with heavy clutch pedals etc? So if there is a sustained load on the crank end for example from a faulty clutch or a miss aligned con rod etc this may cause extra wear?
You should use a dial gauge on the end of the crank and lever it back then forward to get a reading,i think about 10 thou is a maximum?

Repair is not always easy as failure can chew up the crankshaft and the cylinder block sometimes!
As said not an easy answer but i hope it helps.....

[Red 4]

Yep, big question and lots of variables I know

Thanks for your advice and suggestions, much appreciated

ps. change of user name for me

[davepoth]

On old triumph engines this was usually the fault of worn thrust bearings. In the Triumph 1300 it could lead to a difficult gearchange because the release bearing on the clutch pushed the crank rather than the clutch plate...

[drosser]

I realise that this post is very old - however, I am surprised that it has not raised it's head again. I generally drive Vauxhalls as I find them to be best suited to my requirements. I am 71 years old and have been driving since I was 17 (actually 8 for tractors and 16 for motor bikes). I have only ever had one job carried out in a garage (on wife's car due to time pressure). I am not a mechanic but reckon there are not many tasks that I have not completed. I have been quite impressed by the Vauxhall 'whisper' diesels from a size, comfort and driver enjoyment (boy racer day have gone!). I started to look at various forums and have been shocked by the apparent number of weaknesses that it suffers from. It would also appear that engine removal is the easiest way to replace / rectify the problems - timing chain at the rear of the engine / DMF & clutch change / oil pickup seal replacement etc. all appear to be more difficult than necessary.
My main concern, however, is the regular occurrence of extremely increased crankshaft end float, even on low mileage engines (often sub 20,000 miles). This is, obviously, due to normal thrust washer wear - also, repair does not appear to be an option. The lucky owners who still have warranty have the engine replaced - others are advised to buy replacement / reconditioned engines (with all of the inherent risks). I have not yet found anyone describing the actual cause and effect - the closest I have come is a comment from a reply on another forum where he noted "Just as with every other one of these with this issue I have encountered,the crank thrust washer gouges a trough in the thrust face on the 4th main bearing web leaving the crank unservicable and leaving the rear flange of the sump and the rear face of the flywheel to act as the new thrust faces". I should note that the reason for the stripdown was an apparent failed DMF.
Does anyone on this forum have any experience of this phenonenon? Does the vibration from the failed DMF impact on the situation (unlikely, I would have thought) - or is there an issue with the 4th main bearing web (why always the 4th one)?
Any previous issues that I have come across with endplay has been down to high milers - resolved by carefully replacing the thrust washers. Any useful related experiences or knowledge would be gratefully received.

[GreenV8S]

drosser said:

(why always the 4th one)?

I'm not familiar with that engine, but if that's the one getting worn then I would assume that's the one which has the thrust bearing.

As to why it's affecting this engine, perhaps this engine has a particularly heavy clutch or tends to be driven in environments which encourage drivers to ride the clutch or has a thrust bearing which is slightly under specced, or doesn't allow much wear before contact occurs elsewhere..

[stevieturbo]

drosser said:

is the regular occurrence of extremely increased crankshaft end float, even on low mileage engines (often sub 20,000 miles). This is, obviously, due to normal thrust washer wear - also, repair does not appear to be an option.

It's common ?

Can't say I've heard of such problems on modern engines in general, in any numbers I'd call it common.

And you've measured these engines ? What sort of ranges are you talking about ? What symptoms that lead you to measure ?

Excessive end float can never be due to "normal" thrust washer wear, as these should last easily a few hundred thousand miles. So if you're saying these are massively worn at only 20k, that is not in any way normal.

[Maxdecel]

I've seen it before but it's so long ago I can't recall the engine, looking at the comments Vauxhall Seem to have problems.

[drosser]

GreenV8S said:

I'm not familiar with that engine, but if that's the one getting worn then I would assume that's the one which has the thrust bearing.

As to why it's affecting this engine, perhaps this engine has a particularly heavy clutch or tends to be driven in environments which encourage drivers to ride the clutch or has a thrust bearing which is slightly under specced, or doesn't allow much wear before contact occurs elsewhere..

Unfortunately, I have no specific information on the type of driving (or driver) inflicted on the engines highlighted on other forums. As a very popular family car, I don't think that clutches should be any heavier that other, equivalent manufacturer models. Similarly, I see no reason for VX to use inferior spec material in the thrust washers relative to other manufacturers. As mentioned, I have only come across the reports recently when I started to consider buying an Astra with a 'Whisper Diesel' engine as driving reviews on YouTube were favourable. I was hoping that someone on this forum may have experienced the issue and could share their technical findings.

[Castrol for a knave]

NURBY said:

Can someone please explain the causes, cures and symptoms of crankshaft end float

Specifically, I'm after the causes in relation to manufacturing defects although I'm sure there are many

I've also heard that poorly aligned throwout bearings can have an effect

Also, what symptoms would a car suffering the early stages have

Thanks in advance

Rennlist 928 forum is the answer.

Symptoms of thrust bearing wear are overheating and difficult, laboured hot starting.

On the 928 it is the torque tube /flex plate clamp migrating forward.

[stevieturbo]

Maxdecel said:

I've seen it before but it's so long ago I can't recall the engine, looking at the comments Vauxhall Seem to have problems.

That's a LOT of endfloat.

[Maxdecel]

stevieturbo said:

That's a LOT of endfloat.

Isn't it, I think the one I vaguely recollect was a BL engine; the crank webs had done a fine job of machining the side of the crankcase.
Suppose lengthy periods stationary with the clutch disengaged might cause the failure but I'd like to think there was enough oil fed to the thrusts to prevent it.