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Author Subject: Big End Bearings Gone - Advice Needed
itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

Posts: 789

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Post #1
Hi Guys,

I've got a suspected big end failure with my 6, searched on here and from the threads i can find it points to that rather than being the head tappy as it doesn’t do it when cold and only when warm.

My car isn’t standard it’s got ITB's, Newman ph2 cams and management. The redline is 7900rpm but this happened at about 7000rpm, and i never take it past 7500rpm anyway.

There has always been plenty of oil in it since I’ve had it, never run it dry. It’s got Castrol Magnitec GTX oil in it at the moment, and plenty of coolant in the rad. My question is, if i get the crank re-ground, and new standard bearings fitted, what’s the likelihood of this happening again? And can you get "stronger" than standard bearings to stop this from happening?

Any help would be appreciated, cheers.
Posted 28th Nov 2010 at 17:51
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allanallen

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Location: Buxton

Registered: 01 May 2007

Posts: 1,399

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Post #2
I've recently bought a six that tapped it's bo***cks of when it got hot, I checked the normal stuff (loose plugs,injectors etc). Dropped out the magnatec and replaced with some real synthetic oil and hey presto no tap!!

If a big end has gone it would normally knock from cold, it's not a difficult job to whip the sump off and check the bearings though.

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Posted 28th Nov 2010 at 17:50
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rich_w

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Location: Havant, Hampshire

Registered: 29 Jul 2004

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Post #3
Hi,


I can supply uprated big-end and main bearings which are a lot more durable than the standard items.

They are of lead / copper composite, rather than the standard bearings which are aluminium tin.

I have them in standard and various undersizes.

When you've rebuilt it I would look at the oil your using - the chances are this failure is down to lack of oil film strength, causing metal to metal contact between the bearing and crankshaft journal, the failure stems from there.

I would look at using a high viscosity fully synth motorsport quality oil - something like Silkolene Pro S or Pro R, or the Royal Purple XPR oil we use in the supercharged cars. Go for a 20W50 grade.

Hope this helps,
Rich

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Posted 28th Nov 2010 at 18:14
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itchytrigafinga

Senior User

Location: Sidmouth

Registered: 21 Mar 2008

Posts: 789

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Post #4
rich_w wrote:
Hi,


I can supply uprated big-end and main bearings which are a lot more durable than the standard items.

They are of lead / copper composite, rather than the standard bearings which are aluminium tin.

I have them in standard and various undersizes.

When you've rebuilt it I would look at the oil your using - the chances are this failure is down to lack of oil film strength, causing metal to metal contact between the bearing and crankshaft journal, the failure stems from there.

I would look at using a high viscosity fully synth motorsport quality oil - something like Silkolene Pro S or Pro R, or the Royal Purple XPR oil we use in the supercharged cars. Go for a 20W50 grade.

Hope this helps,
Rich


Hi Rich,

Thanks that helps a lot.

Not sure if this is a dumb question but bear with me as I’m not a mechanic!

What’s the difference between big-end and main bearings?

Also, how would one know what size would be correct, is the determined on how much the crank is ground?

I have a sneaky suspicion that this is why it failed; the oil was something like, 0-30w or 0-40w.

Cheers
Posted 28th Nov 2010 at 18:30
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welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,838

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Post #5
big end is the bearing at the end of the rod, main is the main bearing the crankshaft itself runs on.

I certainly would investigate asap, to determine the size of bearing required you would get the crank pins/journals measured, if they were out of spec for a standard bearing you would need the crank ground for oversized bearings which are 0.30mm thicker.

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Posted 28th Nov 2010 at 18:43
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itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

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Post #6
Bit worried if i get this repaired it would happen again, can you get uprated oil pumps for these engines?
Posted 1st Dec 2010 at 18:04
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welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,838

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Post #7
no, short of a dry sump that is.

I wouldnt be worried, it's lasted ten years+

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 1st Dec 2010 at 19:25
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

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Post #8
Pumps won't be the issue, oil temp, lack of film strength and surge are the real engine killers. Once you have fixed you engine, fit a decent cooler and an accusump if you are serious about keeping oil going where it's needed.

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Posted 1st Dec 2010 at 19:50
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itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

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Post #9
Ok i did think that. Had the car inspected today, apparently only one of the shells has gone, and it hasn’t damaged the crank, I’m still going to get it all done as i don’t want to risk it happening again. I did think it had lasted 10 years and done about 110,000 miles (can’t have been easy miles either it being a GTi model) But I’m just a bit paranoid that it would happen again!

The garage seemed to think that the oil valve or the oil return valve at the bottom of the engine had got stuck or blocked and starved the bottom end of oil effectively, this plus the engine age, oil strength and rpm at the time contributed to the bearings breaking down.

Does that sound about right?
Posted 1st Dec 2010 at 22:49
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buzzbrightyear

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Location: hiding all receipts for car

Registered: 09 Jul 2008

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Post #10
yes it does

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Posted 1st Dec 2010 at 23:33
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welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,838

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Post #11
more likely to be simple oil surge and bottom end wear plus low oil film strength.

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need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 1st Dec 2010 at 23:36
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willygti

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Post #12
If they're doing all the shells/big end bearings now then ask them to keep the old ones. Also i'm struggling to see how a bearing can 'go' and not damage the crank Wink

Who's working on it? Lee??

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Posted 1st Dec 2010 at 23:53
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itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

Posts: 789

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Post #13
willygti wrote:
If they're doing all the shells/big end bearings now then ask them to keep the old ones. Also i'm struggling to see how a bearing can 'go' and not damage the crank Wink

Who's working on it? Lee??


? Why would i need the old ones? No, Lee isn’t doing it as they can’t do it until middle of January; i need it done before then.
Posted 2nd Dec 2010 at 00:01
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willygti

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Location: Exeter

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Post #14
So you can see they have definately done it and the damage/scoring to the old ones.

Oh and we (Sidmouth Garage) could do it - would take a couple days fitting it around other stuff but yeh...

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Team Ducati 748
2003 Subaru Impreza STi
Posted 2nd Dec 2010 at 01:57
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ryangti6

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Location: Pontypool

Registered: 01 Sep 2006

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Post #15
itchytrigafinga wrote:
willygti wrote:
If they're doing all the shells/big end bearings now then ask them to keep the old ones. Also i'm struggling to see how a bearing can 'go' and not damage the crank Wink

Who's working on it? Lee??


? Why would i need the old ones? No, Lee isn’t doing it as they can’t do it until middle of January; i need it done before then.


For peace of mind that they have acually been done probably, this is why I always ask to see my old parts if I have to use a garage to do work anyway.

________________________________________

Ryan
Posted 2nd Dec 2010 at 01:59
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itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

Posts: 789

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Post #16
I’m just going to get it repaired and then sell it i think. I know the garage and know they will do a good job so....
Posted 2nd Dec 2010 at 02:11
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smegal

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Location: Leeds

Registered: 26 Dec 2005

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Post #17
Keep it mate. Put some good oil in and enjoy. If you are going to sell it you may as well break it now as they are worth f*ck all at the mo.

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Ex SC-6

Now in a Megane R26
Posted 2nd Dec 2010 at 02:51
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itchytrigafinga

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Location: Sidmouth

Registered: 21 Mar 2008

Posts: 789

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Post #18
Ahh i dont know what to do now you guys keep making me change my mind!

Do you have to remove the engine to fit a new crank + bearings?
Posted 2nd Dec 2010 at 03:46
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smegal

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Location: Leeds

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Post #19
No but you have to remove the box.

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Ex SC-6

Now in a Megane R26
Posted 2nd Dec 2010 at 05:12
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