12 replies to this topic

[mike.]

I'm having a new clutch fitted on my mini at the moment and today got a call from the garage. Apparently the oil seal had gone and the clutch was full of oil. So hes fitting a new seal and a new clutch so thats fine.

But he also said that theres a fair bits of play in the crankshaft - I believe thats known as the end float measurement?

Anyway looking at the haynes it should be no more than 5 thou - The mechanic wreckons theres 40 thou of movement.

How serious is this?

Is this the play of the actual bearings the crank turns on thats being measured?

Thanks...

[minidaves]

engine strip down and measure and replace thust washers as a minium

if left engine failure

dave

[Dan]

He might just be talking about primary gear endfloat which will be simpler to repair. In either case excessive end float is serious, this needs fixing.

[mike.]

Which parts does he actually mean though? The 3 main crankshaft bearings in the block?

Anybody got a diagram - I'd just like to know whats actully worn.

[Dan]

If it is crankshaft end float then it will be the crank thrust washers that are worn out. If it's primary gear end float then it will be the primary gear thrust washer. End float is taken up using thrust washers. Generally if they are set properly when the engine is assembled the crank thrusts will last longer than the main bearings so it's unusual for there to be such a large clearance opening up in a running engine. 40 thou of wear would probably mean the bearing surface of the thrust was gone completely and the backing was starting to do damage to the crank. The primary gear thrust does tend to see a lot more wear in normal use than the crank thrust and between the primary thrust and the top hat bush there could easily be 40 thou of slack developed.

[mike.]

hmm.

I don't really want to spend any money on this 998 engine anyway to be honest. I'd rather fit a 1275 just for future potencial and driveability.

So will this new clutch thats being fitted to the 998 fit a 1275 engine if i can get hold of one? As long as its a verto?

Then at least i won't have wasted so much money on the clutch

Edited by minimadmike, 24 September 2008 - 11:32 PM.

[mike.]

Bump

Anybody know if my new 998 clutch will fit a 1275? As long as both engine have verto set-ups?

I'm hoping this 998 can struggle on until maybe easter when i can find a new engine to replace it with!

What will happen to the engine driving it like normal (i.e. hard) in the condition its in?

[Guess-Works.com]

yes

and driving it hard as it is, depending on what the problem is Crank or primary... exessived end float on the primary will cause the primary bushes to heat up, eventually fail and take pretty much the side of the engine with it... Failing thurst bearings will again eventually fail, possibly dropping out into the gearbox, then the crank possibly over heating and either snapping or seizing...

So basically, if you want to keep the engine going, fix the problem..

Edited by GuessWorks.co.uk, 25 September 2008 - 01:28 PM.

[mike.]

Well i've been driving it like that for god knows how long.

I'm at uni at the moment so haven't got the time to rebuild my engine, plus the cars not with me here at uni so i'll only be using it the odd weekend, xmas and easter. So hopefully if i don't rev it too much when i do use it i can get it to last.

Then by the time i finish for summer i'll have a half decent 1275 to swap it for.


Another thing - My dad said that with that much play you would expect it to develop a knocking sound or if its as serious as it sounds then it could be hard to turn over or not turn over at all. But obviously the car runs fine, makes no unusual sounds, revs freely and is great to drive. So i'm just wondering if you would expect it to make any tell tale sounds when these thrust washers go?

Thanks

[Dan]

One of the pinned threads in the technical section is called something like 'Read before posting' and the last post in that thread reads:

If you've already decided what type of answers you will believe, made up your mind what you want to hear, don't want to spend the money to keep your car running properly or are in any other way not prepared to listen to the advice that experienced people will offer you here when you ask a question.....

Don't bother asking!

It will save us all a lot of time and frankly it's getting really boring now.

Including your mechanic four people have now told you that based on the evidence, your engine is almost certainly on the verge of expensive and very possibly dangerous failure. You don't know how long you've been driving it in this condition because you've only just had it measured. Wear isn't strictly cumulative rather it tends to be exponential, the rate of wear increases over time. Especially with bearings and thrusts because once the load bearing surface is gone what's left behind rapidly destroys whatever it wears against. It may have only been in this condition for a week, you can't tell. You have to at least get this investigated, if it's just the primary gear thrusts it can be fixed in a couple of hours with the engine in the car and won't cost a fortune. Excessive end float won't make it knock, or slow down or drive badly. Not until the very last few minutes of its life. It will however destroy all the parts involved and prevent the engine being re-biult in the future. If it's going to fail it may just do it, quite suddenly and without any real warning. Then several heavy pieces of hot steel turning at several thousand RPM will make a bid to join you inside the car. The flywheel or diff parting company with the engine is not a pleasant experience, neither is a con rod finding its own way out of the block. Hope is not the most mechanically sound form of maintenance that I can think of.

[mike.]

Yeah fair enough dan, i see your point. Its just hard to accept that i've just spent nearly another £1k on a car that i won't even be able to enjoy, in the very little time i have to enjoy it during uni holidays

I'll get my dad to ask the garage if its the primary gear or the crank thrusts. I've looked at the thrusts on minispares there only cheap but its just the fitting process and time more than anything. The 998 doesn't have the power i really want anyway so i don't really want to spend the time on it when i could spend the time buying and checking over a 1275 to replace it with.

So if its the primary gear thrusts - How are they accessed?

[haz]

well its deffo a clutch off job, not 100% if you have to split the box from the block but it would certainly make it easier to remove the primary, then you just slide off the old washer and slide a new one on. If its the main thrusts, then its a total strip and rebuild, crank and pistons out.

[mike.]

Just had some news from the garage from my dad. Apparently it was the primary gear endfloat and after checking in the haynes the amount of wear is fine for that end float - so theres no problem at all really, just the garage being cautious!