Mi16 Bottom End Death

[pablo 0]

Hi guys - after about 10 laps on the first track day the 205 Mi16 has developed bottom end death. Nice rattle from in the depths.

 

Anyway I hope you dont mind me asking a few Qs:

 

1. can the bottom end bearings be swapped with the engine still in?

2. how much for the parts to do the job?

3. Is it DIY for an intermediate mechanic type lad(s)?

4. Anything else worth doing while in there?

 

Appreciate any advice on this guys!

 

cheers

-pablo

[Jonmurgie 2]

1. can the bottom end bearings be swapped with the engine still in? - YES

2. how much for the parts to do the job? - Not that much, probably around £25 for all the bearings

3. Is it DIY for an intermediate mechanic type lad(s)? - Yeah, I'd say so... it's more messy than anything as it's sump off etc. Just be careful and methodical like any other engine job.

4. Anything else worth doing while in there? - There's not much more you can do with the sump off... maybe stick in an uprated oil pump spring...

[pablo 0]

1. can the bottom end bearings be swapped with the engine still in? - YES

2. how much for the parts to do the job? - Not that much, probably around £25 for all the bearings

3. Is it DIY for an intermediate mechanic type lad(s)? - Yeah, I'd say so... it's more messy than anything as it's sump off etc. Just be careful and methodical like any other engine job.

4. Anything else worth doing while in there? - There's not much more you can do with the sump off... maybe stick in an uprated oil pump spring...

 

wow best answers on all fronts Does the box need to some off? I hear its a bit of a pig!

 

thanks for the prompt reply!

[Alastairh 47]

Box can stay on.

 

Yes a pig of a job, but its all fun at the end of the day

[Anthony 1,000]

Chances are that if the bottom end is knocking then the crank will need a regrind - Mi16s are notorious for knocking out their bigends on track thanks to oil starvation

 

In my opinion it's easier to remove the engine if you've got to remove the crank. It *can* be done in situ, but the gearbox/clutch/flywheel/pulley/cambelt/sump/oilpump all need removing and that's really not much fun lying underneath the car.

 

Big-end and main bearings come to about £70 for the set.

[pablo 0]

Chances are that if the bottom end is knocking then the crank will need a regrind - Mi16s are notorious for knocking out their bigends on track thanks to oil starvation

 

In my opinion it's easier to remove the engine if you've got to remove the crank. It *can* be done in situ, but the gearbox/clutch/flywheel/pulley/cambelt/sump/oilpump all need removing and that's really not much fun lying underneath the car.

 

Big-end and main bearings come to about £70 for the set.

 

yeah I think thats what happened ok - a baffled sump would be on the shopping list ok like.

 

any way of knowing if the crank is fubar with the sump off before taking the lump out? Im guessing dropping an Mi out isnt a walk in the park

[Miles 331 1 Cars]

More bad new's I'm afarid,

Worst case the crank pin's can go oval and also bugger the connecting rod as well which means a engine rebuild, Again I;ve seen this allot on any XU engine,

I wouldn;t just change the bearings without checking it all first

[pablo 0]

More bad new's I'm afarid,

Worst case the crank pin's can go oval and also bugger the connecting rod as well which means a engine rebuild, Again I;ve seen this allot on any XU engine,

I wouldn;t just change the bearings without checking it all first

 

trail it out then is the way forward? If I replaced the bearings just and ran it and it turned out to be worse would be much worse than it is now? (ie need a bigger rebuild)?

 

in other words for the sake of a few quid for bearings and some time is it worth a gamble?

 

thanks all for your advice!

[easypug 0]

trail it out then is the way forward? If I replaced the bearings just and ran it and it turned out to be worse would be much worse than it is now? (ie need a bigger rebuild)?

 

in other words for the sake of a few quid for bearings and some time is it worth a gamble?

 

thanks all for your advice!

 

If you just replaced the bearings then the problem could get worse, more wear on the crank, stress on the rods etc.. These items would then have to be considered in the rebuild where as if you check the crank now and it turns out ok then you will save these potential costs in the future.

 

It depends if your a gambling man i guess, i would take the safer route of checking the crank at least.

[pug_ham 242 3 Cars]

Chances are that if the bottom end is knocking then the crank will need a regrind - Mi16s are notorious for knocking out their bigends on track thanks to oil starvation

Also for bending the crank when the spin a bearing so a strip is most wise to check for this. A new crank & rod for the effected cylinder wil be needed if thats the case.

 

Graham.

[littlemike 0]

- Mi16s are notorious for knocking out their bigends on track thanks to oil starvation

 

 

Is it right or left hand bends that cause this?

[Anthony 1,000]

- Mi16s are notorious for knocking out their bigends on track thanks to oil starvation

Is it right or left hand bends that cause this?

To be honest, atleast in my experience, both.

 

Left hand bends stop the oil returning to the sump properly, so causes the oil pressure to slowly drop as there's less and less oil in the sump for the pump to pickup. Right hand bends cause the oil to be forced to the opposite side of the sump to the oil pump pickup, and causes much more sudden/instantaneous oil pressure loss (much worse when you've not got the oil level topped up to maximum and/or have a baffled sump)

[pablo 0]

ok guys here is the plan:

 

- pull the sump off and inspect the shells/crank.

- if the crank isnt too bad reshell it and keep fingers crossed

- if the crank is bad pull the engine out and rebuild

 

if it gets reshelled then we might buy another lump and rebuild it in parallel so we have it on standby and alternate the two lumps lol

 

So if we do go ahead and reshell what parts do I need need and where do I get them from? A rebaffled sump will be a must also.

 

Thanks for all your advice in this - much appreciated!!!!

 

-Paul

[pug_ham 242 3 Cars]

Ideally to check the crank isn't bent you'll have to remove it totally from the engine & might as well get teh bearings surfaces polished at least whilst its out.

 

Graham.