54 replies to this topic

[Terry Haines]

I guess many owners have had the same problem we have over here..spun big end bearings. So lets hear what happends..

*Std 2.5 V6's..how many and at what miles?

*ST200 2.5 V6...same as above..

*3.0 V6's ST220 etc..


I'd like to giet a few facts here as, at one time, I had around 12+ SVT 2.5 engines in our shop all with spun big ends.

I know the pattern and have done some extensive measurements/digging into this problem.

What is the info from you lot???

[percybigun]

over here only the mk3 mondeo's got the 3.0 V6, only a small handful of people have fitted them into mk1/mk2 mondeo's.

i havent known of anyone on meg who has had a 3.0 bottom end failure, or HG failure. also the 2.5v6's in the mk3 mondeo's dont seem to have these problems.

i have seen a few 3.0 v6's in mk3's on ebay which had knackered bottom ends, but that could have been down to neglect/abuse.

also i remember a few st200's had engine failure at low miles when they were only 1 - 2 years old but got replaced at ford under warranty.

[Terry Haines]

..OK, I'm curious re Con Rod part numbers.. Have the late engines that have not failed, the same finis/part number as the early con rods? 3.0 and 2.5 should take the same rod butv the later engines your mentioned may have a revised rod number,can you check please?

[Chris_mitton]

Isn't there a baffled sump pan fitted on the later engines?

[Terry Haines]

Forget the revised sump..even engines with this fitted have spun the big ends..This is not a lube issue..I will explain more when we get a bit more info here..

[Simonty]

I've heard of one or two, but you could be waiting a while before those posters see this thread.

Simon

[Terry Haines]

..thats OK. Just tring to finish the 'picture' of yours vs ours on spun big end bearings..and I think it could be a very messy picture..but we will leave that untill we see a bit more info eh!!

[percybigun]

No idea on the conrods. There's been quite a few on here in the past with ticking and knocking, some ticking issues have been HG related. Very few on here have had their
Engines stripped and repaired, most people put another engine in or scrap the car at that point.
I'll find some links of old threads for you.

[Terry Haines]

Thank you , any past posts/info will help.

From my experience over here with Contours with V6 spun big ends it goes a bit like this...

*2.5 SVT V6's , the ones that go, seem to spin bearings between 60> 80,000 miles.

*Non SVT V6's that go usually fail at around 100>120,000 miles..

* The engines that don't seem to spin bearings are the Non SVT 95>96 V6's..

There is a pattern here..along with the fact that even some later 3.0 V6's that have been put into Contours with and without 'revised sump' or retained the Taurus sump..have still spun bearings...

I can furnish a lot more info but suffice to say that Ford SVT/SVE testing on a new car over here,on a track with 'sweeping curves' etc was NEVER able to replicate the spun bearings...Can post the previous posts if you wish are just drop me a PM message with them..Thanks.

[GarethST220]

There was a 2005 ST 220 in the workshop a few weeks back with spun bearings. Was making a knocking noise, had covered less than 40k. Warranty covered it. Needed an oil pump aswell, lots of black gunge despite oil changes on the button and the car was very well looked after.

Be interested to know what is actually causing this. Too thin oil? Design fault?

It was the first 220 they had ever seen with big end failure. Generally, they seem to be very reliable engine wise.

[percybigun]

heres a few old posts of people who have had bottom end issues, some are a bit vague.

- mk1 http://www.fordmonde...hp?post/820662/

- mk2 http://www.fordmonde...p?post/1304051/

- mk2 http://www.fordmonde...p?post/1696831/

- mk2 http://www.fordmonde...p?post/1775601/

- mk1 http://www.fordmonde...php?tid/184032/

- mk2 http://www.fordmonde...php?tid/188205/

[Terry Haines]

Thank you for the info..

[GarethST220]

No thoughts on the reasons why this is happening, as per my previous post? I'm lucky, my car has had 7 oil changes in its life and has gone no longer than 8k between them! Hopefully thats gone some way into helping preserve the bearings.

[Terry Haines]

40K is quite low for such a failure. I will get to the issues with con rods,bearing nip/crush etc..It will be a long post but yours just sounds like a bad build.

[GarethST220]

Mines ok, touch wood! This was a customers car in the garage i do work for. The technician did say that it was a bad rebuild that had caused the failure. There are far less Duartec 30's here than in the US, so maybe thats why the failure rate is less.

Yes very interested to have the full info on your findings.

[Terry Haines]

OK, lets kick this off..
First off we have two schools of thought..
One thinks the issue with bspun big end bearings is caused by yje lube system..
Others,like me,do not subscribe to that but fell and have seen that it could be caused by another issue..

First off let me ask if everyone understands how the big end bearing liners/shells ,are retained in the big end and what prevents the bearings spinning..
Do we all understand what bearing 'nip & crush' is when any bearing shell is fitted to a con rod or main bearing??
Lets go from there, I will explain all the technical / engineering sides to this as we go..
Just open your minds a bit and think 'outside the box' from what you have read in the past...

[WagonWheel]

Terry

I understand all the terms but I've not built an engine for 10 years!

I'm ready for a refresher - There's a wide range of experience on here and this has the makings of a top topic. People on here arent afraid to ask about the basics - makes it a good forum.

3.0 conversion is the way I want to go with my Mk2, anything that helps with its well being will be valuable

W.W.

[GarethST220]

Spoke to a Ford tech today, and he did a few of these engines in the past. It was suggested the fault was casting sand left in the oil galleries, which obviously wrecks havoc to the oil pump and bearings.

I understand how shells are retained, are you saying the retaining tags have not been lined up correctly allowing the shell to shift slightly within the big end, it then runs unevenly on the crankshaft journal, causing it to go oval and then eventually getting worse till it knocks?

[Terry Haines]

The csting sand issue was mainly on 3.0 block but think of this..the oil pump should not have any damage as the main oil galler with the sand is after the oil pump in the lube circuit..

On bearing liners/shalls..all the 'tags' do is position NOT retain the shell/liner so..does anyone know whatt nip/crush is and how it relates to shell bearings??

[Terry Haines]

'Nip & Crush'

It is the nip/crush that is the only thing that holds the bearing shell/liner in the rod/cap etc on both main and big end bearings and it works like this.

Fit a bearing shell into a 'normal' con rod half,forget the V6 cracked rod but a normal rod with a flat mating face of cap to rod.
Notice that even with one end of the bearing liner flush with the flat face the other end is just a bit proud..what wrong?
NOTHING..this 'stand prod is the nip/crush.  THINK..when the two halves of the bearing, rod and cap ,are mated the nip /crush puts RADIAL PRESSURE of the bearing into the rod/cap to force the liners tight into the housing. Withouit that 'stand proud'/ nip/crsh the the bearing would not resist the rotation of the crank etc and spin..So..time to think boys!!..Forget lube issues..What would cause the nip/stand proud to go and allow the bearing liner to spin???