Big End Shells

[steige 1 1 Cars]

I had inspected 3 of the 4 big end shells on the second hand engine i bought recently. There was only slight wear on these. I just removed the oil pump to check the last one and found the shell sitting at 90 deg to where it should be and the damage you can see in the photo's. There is very slight marks on the crank as well.

 

http://img.photobucket.com/albums/v512/steige/PICT2226.jpg

http://img.photobucket.com/albums/v512/steige/PICT2224.jpg

 

Would oil surge have caused this to happen?

 

Will I now need a crank regrind or re-placement?

Edited December 9, 2005 by cybernck

[Pugnut 9 1 Cars]

you,ll need the crank checked for sure , reground and appropiately sized bearings.

 

it wasnt cylinder no 2 by any chance (from flywheel end?)

[steige 1 1 Cars]

you,ll need the crank checked for sure , reground and appropiately sized bearings.

 

it wasnt cylinder no 2 by any chance (from flywheel end?)

 

It was the one right above the oil pump whichever that is. the crank has been re-ground already and had +30 bearings fitted. I've just bought new bearings to suit as well. How much would it be to check/re-grind the crank?

[Mongo 0]

It was the one right above the oil pump whichever that is. the crank has been re-ground already and had +30 bearings fitted. I've just bought new bearings to suit as well. How much would it be to check/re-grind the crank?

 

Apparently theres a good place in falkirk for this, i will get the number from my mate, as i need to get my spare mi16 crank and new shells too....

[Kev-G 1]

Apparently theres a good place in falkirk for this, i will get the number from my mate, as i need to get my spare mi16 crank and new shells too....

 

JEM in Camelon..

[Anthony 1,000]

found the shell sitting at 90 deg to where it should be and the damage you can see in the photo's

Spun shell? Certainly doesn't sound promising for that crank being serviceable, especially if it's already been reground once before...

[steige 1 1 Cars]

Spun shell? Certainly doesn't sound promising for that crank being serviceable, especially if it's already been reground once before...

I'm no expert but i just had another look at the crank and ran my nail across it. There are no grooves at all and it had just discoloured slightly in two rings around it if you know what i mean. I guess the tolerances are tiny in this department though.

 

What would have caused this?

[Miles 331 1 Cars]

If the shells spin the cranks normally go oval which makes them U/S, I's sure there are some Derv bearings with a +60 size available.

Thats a good condition one from what I normally see, The problem is the big end's are to small and the crank angle doesn;t help matters, Look at any other engine and the width of the big end is allot more.

Oil surge might have had a part to play but if the engines done over 70k this is quite normal and the reason why I keep saying that the big ends always need frequet replacement

[ablister 31]

andersons engineering in kirkcaldy are £15 + vat to check the crank plus polish i think and £85+vat to re-grind it

[B1ack_Mi16 67]

If the shells spin the cranks normally go oval which makes them U/S, I's sure there are some Derv bearings with a +60 size available.

Thats a good condition one from what I normally see, The problem is the big end's are to small and the crank angle doesn;t help matters, Look at any other engine and the width of the big end is allot more.

Oil surge might have had a part to play but if the engines done over 70k this is quite normal and the reason why I keep saying that the big ends always need frequet replacement

 

I have found some that makes +100 size main bearings here!

They also make +80 on the big end bearings.

http://www.king-bearings.com/cat/panel/pan79.htm

 

Btw.. about the bearing width and journal diameter.

 

The E30 BMW M3 engine (which I uses bearings from) are also 20mm wide, like the Mi16 ones, and have less diameter on the big end journal too.. Not that I know the stroke of those engines.. Btw.. Honda engines seem to have lots of stroke too (2.0 and 2.2) at least, and still rev very high, I think the big ends on these only are 45mm diameter!

 

Also XU9J4 in my 405, bottomend untouched and now @ 212500miles.. and I usually take it to the limiter and very high revs almost all the time, still seem to work very well too

[PumaRacing 1]

If the shells spin the cranks normally go oval which makes them U/S, I's sure there are some Derv bearings with a +60 size available.

Thats a good condition one from what I normally see, The problem is the big end's are to small and the crank angle doesn;t help matters, Look at any other engine and the width of the big end is allot more.

Oil surge might have had a part to play but if the engines done over 70k this is quite normal and the reason why I keep saying that the big ends always need frequet replacement

 

The bearings are not too small and in fact bigger than many/most other engines of similar capacity. The reason the big ends fail is because they are lead/copper, very hard and not tolerant of poor lubrication. Fine for well maintained race engines but not the right choice for road ones. In conditions of marginal lubrication they pick up against the crank and spin where an aluminium or white metal bearing would embed the debris and carry on quite happily. That's why Peugeot abandoned the lead/copper bearings for later engines and why I use softer ones in all mine.

[Miles 331 1 Cars]

All the engine's I;ve found in 205 GTi's use the Aluminium bearings which are not good enough, Unlike the early type of as you said Lead/copper type which like all things have been banned due to rules & reg's, In the race engines I do all use the Lead type of bearing as I can still get hold of them.

Change of subject, I need to contact you at somepoint as I need a couple of valves for a head of yours

[steige 1 1 Cars]

If the shells spin the cranks normally go oval which makes them U/S, I's sure there are some Derv bearings with a +60 size available.

Thats a good condition one from what I normally see, The problem is the big end's are to small and the crank angle doesn;t help matters, Look at any other engine and the width of the big end is allot more.

Oil surge might have had a part to play but if the engines done over 70k this is quite normal and the reason why I keep saying that the big ends always need frequet replacement

The shells had spun but they stayed together and both moved round. They were not overlapped at all. I've heard of this happening which i guess is fatal for the crank. The shells have also changed shape slightly and are now a smaller diameter if you know what i mean.

 

Does this make any difference to the outcome of my crank?

[ALEX 98 1 Cars]

Those bearings in the picture should go back in and give you no problems.

Looks like the result of oil starvation. Runnuning low on oil lately? wangging it around bends too fast?

They need to be a lot worse than that to start giving you problem with oil pressure though.

While they're out I'd fit a new set of bearings, as they arnt that expensive.

By looking at the shells I would imagine you crank is fine too.

[steige 1 1 Cars]

Those bearings in the picture should go back in and give you no problems.

Looks like the result of oil starvation. Runnuning low on oil lately? wangging it around bends too fast?

They need to be a lot worse than that to start giving you problem with oil pressure though.

While they're out I'd fit a new set of bearings, as they arnt that expensive.

By looking at the shells I would imagine you crank is fine too.

Ok getting mixed opinions here. I bought the engine second hand and it has been fitted to a track car so it probably was going round the bends too fast.

I have bought new bearings already to go in, but i'm just not too sure about the crank!

[ashlee205gti 1]

If you have brought new bearings then fit them, i dont see the point in putting the old ones back in. As for the crank, if it is damaged then its going to ruin the new bearings in double quick time. Have you got pictures of the crank? Maybe its worth getting someone to have a look at it before you re-assemble.

[pacey205 2]

Get the crank checked for peice of mind at least. Theres no point in just whacking it back in without knowing if its going to be OK, especially as its obviously spun the shell.

 

Michael

[Anthony 1,000]

You need to get the crank checked properly - either by an engineering / engine building firm, or you can do it yourself if you've got accurate enough verniers. No ifs, no buts.

 

If it's been reground as well, you might want to get that looked at as well, as apparently some companies regrinding of cranks leaves alot to be desired shall we say...

[ALEX 98 1 Cars]

Has anyone used a Plasti gauge that Haynes talks about.

Engineering shops I've talked to around me haven't heard of the stuff.

Even the Peugeot Specialist didn't know about it.

The Idea is to trap a thin strip of plastic between the bearing cap and crank and measure how flat it's been squashed with a gauge.

Sounds like a good Idea as you don't have to remove the crank to check the clearance.

[steige 1 1 Cars]

You need to get the crank checked properly - either by an engineering / engine building firm, or you can do it yourself if you've got accurate enough verniers. No ifs, no buts.

 

If it's been reground as well, you might want to get that looked at as well, as apparently some companies regrinding of cranks leaves alot to be desired shall we say...

Ok thanks for the replies. I will get it checked out. No point in going to all the bother of fitting the engine if its only going to last a few thrashes! I just wanted to gauge some opinions.

 

Cheers

[PumaRacing 1]

Gauging opinions is only of use if the opinions are correct. If the bearings have spun then the crank will probably be worn undersize and the rod will probably be worn oversize or be seriously oval. They both need checking. No ifs, buts or maybes. You can't spin metal against metal at high speed without grinding some material away.

 

Those bearings in the picture should go back in and give you no problems.

Looks like the result of oil starvation. Runnuning low on oil lately? wangging it around bends too fast?

They need to be a lot worse than that to start giving you problem with oil pressure though.

While they're out I'd fit a new set of bearings, as they arnt that expensive.

By looking at the shells I would imagine you crank is fine too.

 

Don't be daft. Those bearings are absolutely buggered and the locating tangs have been pounded flush. There's no way on god's green earth they can be reused and the crank is extremely unlikely to be fine as indeed nor will the rod probably be.

[DrSeuss 0]

Has anyone used a Plasti gauge that Haynes talks about.

 

Yes, its quite hard to come by though. Little red strips that are compressed by clamping them up. The width of the squished plastigauge indicates the clearance.

 

Get all the bits checked, stupid to throw good money at something which might be knackered.

[steige 1 1 Cars]

Gauging opinions is only of use if the opinions are correct.

Good point!

 

I'm fairly new to the workings of the spanners so just wanted to get some thoughts.

 

I would never have re-fitted the originals as they look fecked to me!

[JERAM 0]

Those bearings in the picture should go back in and give you no problems.

Looks like the result of oil starvation. Runnuning low on oil lately? wangging it around bends too fast?

They need to be a lot worse than that to start giving you problem with oil pressure though.

While they're out I'd fit a new set of bearings, as they arnt that expensive.

By looking at the shells I would imagine you crank is fine too.

 

 

utter nonsense

 

stevie, i'll pop up and measure the crank and rod while you are away if you want, let her in doors know

[Kev-G 1]

Yes, its quite hard to come by though. Little red strips that are compressed by clamping them up. The width of the squished plastigauge indicates the clearance.

 

Get all the bits checked, stupid to throw good money at something which might be knackered.

 

Do Burton not sell it?

 

I'll certainly got some in the garage..

 

You get Red and Green (maybe more) for diff. clearances.