Big end bearing failure? Replacement question?

[Dean_Doherty_1990]

So last night was driving and my car started to sound like a bag of nails, I believe its my big end bearings, I thought I could just drop out the sump and replace the bearings but ive been told I need a whole new bottom end rebuild, reground crank etc or just get a 2nd hand bottom end

So?? Whats your opinions on this?

 

[starletburkie]

more than likly the crank is damaged so id buy a 2nd hand bottom end and rebuild it

 

[Nick@TD.co.uk]

If it is bearing failure, then alternative size bearings are available.

You'd need to remove the crank and have the journals checked for damage and whether it is servicable still.

Same with the rods/caps and main caps.

Cheers

Mike Jones
Tuning Developments Ltd

 

[AdamB]

As above, you would have to check the bearings and mains journals, take it to a machinest and get an expert opinion on it, it may just need a polish or a regrind, where you can throw in some oversized bearings. Worse case is the crank is out of tolerence and is good for the bin only.

 

[Dean_Doherty_1990]

Thanks for the info lads, this is one thing I know very little about, I was told I could just replace the bearings so didnt think it would be that expensive..now looks like it going to cost a fortune

 

[AdamB]

You might be lucky and just get away with a set of bearings. What's the oil level on the dipstick read? 9/10 it's oil starvation that kills off the bearings, so you could have a oil pump on it's way out or a leak. I wouldn't drive it anymore until the crank has been looked at otherwise it can cause more damage.

 

[weeJohn]

Thanks for the info lads, this is one thing I know very little about, I was told I could just replace the bearings so didnt think it would be that expensive..now looks like it going to cost a fortune

You could just replace the bearings if the crank journals have not been damaged, you need to get the sump off and the caps off and check it. Dont even run it until you do or its only going to get worse.

 

[Skalabala]

Everyone is worried about the crank?
4EFTE has a steel crank, you can have bearings laying in the sump and the crank will still be ok.
But what I have experienced is that the conrods gets damaged. So have them checked also.

 

[weeJohn]

Everyone is worried about the crank?
4EFTE has a steel crank, you can have bearings laying in the sump and the crank will still be ok.
But what I have experienced is that the conrods gets damaged. So have them checked also.

Funny that didnt happen with mine, it needed a regrind due to scoring. Its steel after all, metal, its not indestructible!

 

[Skalabala]

How bad did you hit bearings John buddy?
Scoring due to heat because of oil starvation?

 

[Iain@CRD]

Everyone is worried about the crank?
4EFTE has a steel crank, you can have bearings laying in the sump and the crank will still be ok.
But what I have experienced is that the conrods gets damaged. So have them checked also.

I have to disagree with what you've said. It only takes a moment of oil starvation and this is what you get up with.

 

[Skalabala]

I was talking about the normal bearing knock that you can still drive the car not a thrown rod

 

[Iain@CRD]

I was talking about the normal bearing knock that you can still drive the car not a thrown rod

Luckily we never threw a rod on that particular one :haha: very close tho!

Normal drivable bearing knock will eventually score journals on the crank, i done bearings on one where it was caught early and luckily done no damage to the crank at all but ive seen cases where others arent so lucky

 

[Skalabala]

Luckily we never threw a rod on that particular one :haha: very close tho!

Normal drivable bearing knock will eventually score journals on the crank, i done bearings on one where it was caught early and luckily done no damage to the crank at all but ive seen cases where others arent so lucky

Hmmmm, well I guess that oil starvation should be able to eat the crank.
But I guess all the cases I have seen was of poor maintenance and high mileage.
The one engines bearings was in the sump(not the complete shell!!) crank was good
Other one, bearings were tore to the steel backing of the bearing and crank was 39.950 to 39.930 a bit oval

If another car was to hit bearings like some 4EFTE engines then the crank would go through the exhaust

 

[weeJohn]

When a bearing is worn enough to cause it to knock, there is excessive oil clearance between it and the journals. Its that extra clearance that prevents the oil forming a film between the 2 surfaces and working as a barrier between the 2 and providing less friction. You rub any 2 pieces of metal together and either one or both will wear some, wearing causes fragments of metal to separate from the main body and these cause scores.