... post your stories/experiences of bottom end failures. I guess what I am fishing for is do crossflow cranks fail and how?

or rod big ends coming apart.

most engine failures seem to be cam belt snapping, valves trashing piston resulting in con rod making its way through the block.

It's well known that many bottom end failures occur after a bad curry

My only experience has been starving a bearing of oil, it catching, spinning into a lovely mush and making my engine sound like someone shaking a quality street tin with a lump hammer inside it.

So I guess, what I'm saying is, if you are going to get a custom crank made, then you're talking custom bearings and custom journals.

Mike

I had 2 Xflow failures. The first one was with my dads 1.6 xflow mk2 cortina estate. He had the engine rebuilt and about 30k later when I was driving the car down the recently opened (at that time) M27 on our way to my brothers. The car was FULLY (could not see out of the rear view mirror) loaded and I think it had a 4.4 diff, I was cruising at about 55 when this Fiat 131 super mirafiori went past me. The road was empty and my folks were asleep, so I did the only thing a 19 year old would do. I kept up with it at about 90mph. About a mile from the end of the motor way there was this funny noise very closely followed by a bang and a total loss of power closely followed by a nasty metalic rattling noise which woke my dad and mum. When we stopped at the bottom of the slip road of at the end of the motorway we looked under the bonnet. There were holes in both sides of the block. When it was stripped at a local garage later the only useable parts were the manifolds and the rocker cover. Diagnosis Little end failure. They had not been done when overhauled. I was only doing 55 when this noise started honest dad.

The other failure was due to the early type cam followers being fitted in later type block.

Had a fair few but my stupidest.....

Grass track days, racing on a shoe string and some and finally got together a Atmo cosworth motor, in an attempt to save money (a whole fiver maybe) I fitted an oil filter from work (fork truck stores) it was the same thread i thought all would be ok, it wasnt, lost oil pressure lost engine, season over.

Slightly o/t well o/t but one of my most spectacular incidents was at Mamby showground in the early 90's, lost a rear whee which accelerated away from me like an exocet, it hit trye wall, flew god knows how far into the air, cleared spectators and went straight through a caravan roof, straight in no messing.........l

Most Kent engine bottom end problem were sorted out a couple of years before the xflo came out. The pre-xflo 1200 was very prone to oil starvation of the bigend bearings due to clogged oil ways --- quite normal for big end bearings to start knock at 20,000 to 40,00 miles. This was fixed by better quality oils, a bigger oil filter, and some attention to the oilways in the casting.

The 5 bearing engines starting 1500 were always more or less proof against this type of failure but in the early days con rod breakage was not unkown, this was fixed with the 125e co rods that were developed for the 1558cc. Lotus Twincam.

The short lived 1600 pre-xflo and the 1600 xflo envolved from this starting point and to get problems with a kent 1600 engine you have to rev it pretty hard then in order you start to run into big end bolt failure, con rod failure and crankshafts snapping at the main bearings, cure for all these is using all steel bottom end --- Ford traddionally use SG cast iron for cranks. and rods.

The big weakness on the xflo is of course the weight and height above the gudgeon pin of the pistons.

I managed to shear all 6 flywheel bolts on my 1600 X/Flow, and then on the way home from having that fixed, the bolts rattled out of my vernier pulley, mushing my brand new piper cam, all of my pushrods, all the cam followers, and then spat some nice shards of metal through my sump!

quote:

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Originally posted by alexdj125
I managed to shear all 6 flywheel bolts on my 1600 X/Flow, and then on the way home from having that fixed, the bolts rattled out of my vernier pulley, mushing my brand new piper cam, all of my pushrods, all the cam followers, and then spat some nice shards of metal through my sump!

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What is going to be your design rev limit? and what is your expected BHP?

The crossflow when bored to near 1700cc and with the crank safe to 7500 possibly 8000 if you are brave will give 135 to 145bhp but there are a lot of bits that need changing, rod bolts, duplex cam chains etc.
Get the Burton performance catalog, it lists in small paragraphs for all the ford engines from pre crossflow to duratec what bhp to expect for what mods.

170 to 180 bhp can be made from a full race clubmans xflo but at a cost.

In contrast a Zetec or K series can do that without too much trouble.

cheers for repsonses.

so as I thought, crank snapping at the big end ournal is quite uncommon.

doesn't surprise me as I would expect Ford to make the crank more than strong enough to last 100,000 miles or more.

also looking in the book, the b-e journal can be gound up to 1 mm undersize so caps can be bought for that - having it offset would give 23 cc more.

doing some sums about reduction in b-e area and consequently strength, 1.5 mm offset giving 68 cc more is 88 % of original area.

special rods probably would not be needed as long as oversize b-e shells can be found.

oh, and just because I throw open a topic for discussion, it does not necessarily follow I go trhough with it as my wallet is not of inifinite capacity.

and before you ask why am I considering twatting around like this, it is to be able to use a 1300 block but as much cc as possible and still be under the 1500 higher road tax bracket.

You are re-inventing the wheel 1500 kent cranks were made by Ford.

I think perhaps you want to stop and re-consider the practicality of what you are proposing, what is the point of building a very expensive engine to save just a few pounds road tax.

Just stick a more modern 1.4 in -- a K16 1.4 will give 104 bhp as it comes out a Rover.