Broke and Knackered

[James Arnold]

My 1700 Xflow is doing what I understand is a classic sign of maturity. Compression is down and I’m getting a lot of gas through the breathers. It is also leaking heavily out the rear crank oil seal.

I understand that this is due to the standard pistons not being up to the job. I have had the head off and there is no noticeable wear on the bores. I’ve seen the threads on the great Roger King, alas I can’t afford to do the job properly at the moment, so I was planning on just sticking in another set of piston and replacing the rear oil seal. If it holds out for 10k miles, that should last me a year or two, and then I will probably do a proper job.

Does it make sense to replace the pistons with out a re-bore? And does it matter where I source the them from? Is one +090 piston the same as another?

To do the crank oil seal I need to pull the engine, I understand that leaving the g/box in is the easiest move. Everything looks straight forward - anything I should watch out for?

 

From a personal perspective, I think all you guys chasing horse power have missed a trick. I find that a ten year old set of Pirellis, which have clearly gone rock hard, mean that I already have rather more horse power than is sensible. Despite my best efforts to use rear wheel steering on every roundabout I encouter, the tyres never appear to wear out.

 

J.

 

[Rory McLeod]

At the very least hone the cylinders.

[Jason Plato]

Rory

What on earth are you doing up a that time of the morning ??

 

Not searching commaoil.co.uk AGAIN !!??

 

dave

[Rory McLeod]

Dave J: If I tell you I have to kill you. :)

 

 

 

MI7 PTS

[John E]

James, I have sent you an e mail.

[CHRIS CLARK]

You left your 'PPK' here again!!!

[Anna Rexia]

What's a PPK?

[excess baggage]

Anna,

 

Piss poor knowledge, but you shouldn't be here anyway. This is a mens site.

[Jules Martin]

Wow, someone's living dangerously!

Jules

 

 

[Roger King]

James,

 

Your scheme for another 10k miles seems good to me. This is about the average mileage to show the symptoms you describe, depending on how you drive it.

 

There is only one +.090" piston available - part no 18647 - and yes you would be well advised to hone the bores. If the bore is beyond this (unlikely) you have no choice but to rebore and fit forged pistons at 83.5mm bore (or liner the bores back to +.090" - v. expensive and not worth it). You will also need to machine the piston valve pockets deeper than standard.

 

If bore condition is basically good, you may be able to get away with 'flexhoning' the bores in situ. If not, you will have to strip the block to hone with stones.

 

Check out valve guide condition too. A new set of stem seals would also be a good idea.

[Michael Peterson]

What milage can a x-flow cover before it needs a tear down? I know this is dependent upon state of tune and driving habits, but just how strong are these motors?

 

Michael

[Dave H]

James,

You don't need to take the engine out to do the rear oil seal. Last time I did mine I used the following process:-

 

Disconnect propshaft from diff,

Remove carpet from transmission tunnel,

Remove access plate on tunnel,

Disconnect gear lever,

Remove starter

Remover Gearbox/chassis bolts,

Diconnect clutch cable,

Undo engine/bellhousing bolts,

The gearbox should now be able to move about a foot back down the transmission tunnel, which give surprisingly good access to the flywheel/clutch/back of the engine, and is a damn site easier (and quicker) than taking the engine out.

 

 

[Roger King]

Michael,

 

You're right that state of tune and driving style have a huge influence on engine longevity, but a Crossflow to Sprint spec or below will last a hell of a lot longer than a Supersprint - probably 50 000miles +.

 

The Supersprint tends to suffer failure in a couple of areas, namely pistons/rings and valve guides/valves.

 

The piston used in the Supersprint was never intended for this type of use or power output (it's from a 1300cc Escort) and this is the reason that the rings start to breathe so early (typically 15 000 miles). The valves in a Supersprint are of very high quality, but suffer from a material compatibility problem with the cast iron valve guides. This often leads to accelerated wear. Later engines appear to have a chrome plated valve stem which cures the problem.

 

If stronger pistons of more modern design are used, and materials are changed in the valve guide department, there is no reason that a carefully built engine shouldn't last 50 000miles + (lots of track driving will reduce this, but the same applies to all other engine types too).

 

In other words, the Crossflow isn't inherently shorter lived than other types.

[SLR No.77]

James,

 

Surely if you end up taking up all the above advise, and are taking the engine out, then in addition to buying the pistons (& rings), gasket set, new oil, honing the bores, etc., you might as well pay the relatively small amount extra and have the bores done properly. It doesn't seem worthwhile to go to all the trouble for 10,000 miles extra. As long as the crank & big end journals are in good condition you could set yourself up to last for many more miles without any worries.

 

Just a thought?

 

Stu.

[James Arnold]

Stu,

Given the advice from Dave (ta), it now seems that I dont even need to remove the engine. I should be able to sort the rear crank leak with the lump in-place.

Removing the head and sump should allow me to change the pistons and flexhone the bores - err although I must admit that I'm not an expert on that bit.

Did I say that bodge-it is my middle name?

If I go for a re-bore I have to strip the block fully and take it to a machine shop (hence over-run my long week-end plan). The motor is already +090, I believe that means that any further re-boring is going to take me out of the cheap and cheerful Ford parts bin.

Did I mention that my other middle name is broke?

J

 

[SLR No.77]

Good point.

 

Welcome to the pist'n'broke 7 owners club!

 

Stu.