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Author: Subject: Smokey Crossflow
Alfa145

posted on 16/4/11 at 10:08 PM Reply With Quote
Smokey Crossflow

I have a 1690 Xflow. And between 5k and 6k revs it puts out quite a smoke screen behind me, quite usefull for annoying chavs following too close but not great for my oil consumption.

I've done a compression test and all are about the 170 mark and no change to the pressure if I put oil down the bores. So I assume none of the rings are buggered.

My only thoughts are it might be the oil ring as sometimes booting it off a roundabout it smokes a bit too. Also people following say it always smells of burnt oil even when its not visible smoke and being driven sensibly.

Any pointers to what this might be? Or should I just stick new rings in and glaze bust it and see what happens?

[Edited on 16/4/11 by Alfa145]

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thunderace

posted on 16/4/11 at 10:27 PM Reply With Quote
valve guides or oil seals take off the exhaust mamafold and you shoude see if there leaking.
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Chippy

posted on 16/4/11 at 10:31 PM Reply With Quote
First thing I would do is put some new valve guide seals on, and see if that improves things. HTH Ray





To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy

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Alfa145

posted on 16/4/11 at 10:39 PM Reply With Quote
Thanks for the replies, I put some new seal on a few months back these: http://www.burtonpower.com/fp705a.html

Would knackered stem seals cause heavy smoke at 5k+ revs?

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rusty nuts

posted on 17/4/11 at 12:15 PM Reply With Quote
What fuel pump are you using? If you have done away with the mechanical pump and put on a blanking plate which type did you use? Burtons do one with a deflector to stop oil being splashed into the breather system . What breather system are you using? ., standard breather systems were never the best , the breather gets clogged and the valve can stick. Worn valve stem oil seals tends to cause the engine to smoke after a longish period of idling followed by accelerating not a constant smoke screen . My Xflow engined car using the standard breather/inlet had the same problem IF the sump was filled to maximum on the dipstick, dropping the level to halfway between the 2 marks stopped all smoking, My car now uses a breather take off with a catch tank and can be filled to the max with no problems
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avagolen

posted on 17/4/11 at 12:21 PM Reply With Quote
Second a problem with the breather.

High revs and a lot of oil moving around, a little bit of crankcase pressure and presto - oil fumes venting.

Len.





The Answer for everything, but never the last word....

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rusty nuts

posted on 17/4/11 at 12:31 PM Reply With Quote
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BREATHER ELBOW X/FLOW 711M 23.5mm
Burton Power

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David Jenkins

posted on 17/4/11 at 12:36 PM Reply With Quote
I second Mel's comment about oil level - the first time I drove my car in anger I floored it coming onto the A12 and left a 100 yard sausage-shaped white cloud of oil smoke behind me! Dropping the level to the half-way point stopped that problem.

I think that the oil was flowing back in the sump under acceleration (despite baffles) and getting into the bore of the No.4 cylinder.






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Alfa145

posted on 17/4/11 at 02:36 PM Reply With Quote
Cheers for the replies, I have a different breather to standard, a pipe from the crank case and a pipe from the rocker cover going to a catch tank then venting through a little filter, not through the inlet. So the oil has to be getting into the combustion chamber some how.

Its got a Facet pump on it so it does have a blanking plate, not sure what type, will have a look on Burtons and see what different ones there are.

Per tank of petrol it uses about a pint of oil. it has a tiger shortened sump on I believe (I didnt build it) so not fully sure what baffles it has in there.

According to the paper work its a re-con block less that 3 years old.

When I put the seals on I checked the the bores and they were all fine, no scoring at all.

[Edited on 17/4/11 by Alfa145]

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David Jenkins

posted on 17/4/11 at 03:13 PM Reply With Quote
quote:
Originally posted by Alfa145
Per tank of petrol it uses about a pint of oil.



That's way too high - I use less than a pint every few months... something's not right.






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rusty nuts

posted on 17/4/11 at 05:11 PM Reply With Quote
What oil are you using ?Xflows don't seem to like semi or synthetic oils , changing to something like Millers or Valvoline 20/50 might help?
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Alfa145

posted on 17/4/11 at 05:36 PM Reply With Quote
20/50 mineral, reputable brand (can't remeber what without going in the garage)
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Alfa145

posted on 17/4/11 at 09:05 PM Reply With Quote
quote:
Originally posted by David Jenkins
That's way too high - I use less than a pint every few months... something's not right.


Yup it is a bit too much, starting to cost a fortune in oil. Just no idea what it is thats causing it.

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David Jenkins

posted on 18/4/11 at 07:00 AM Reply With Quote
Just a thought - is the oil level correct for the shortened Tiger sump?

If the oil volume has been reduced but you're pouring the same amount in, then the oil would be hitting the crank and being thrown up into the bores (much more than is usual, that is). This is why my car used to leave smoke when accelerating; as the oil flowed to the back of the engine it came into contact with the crank.

My dipstick was wrong after shortening my sump, and I can't have the oil level at 'max' - I put a punch mark half-way between the 'max' & 'min' and try to keep the level on that.

You could try putting the oil level at the 'min' mark and see how it behaves. Don't drive too far though if you're losing oil at that rate, until you are sure what the cause really is!






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Alfa145

posted on 18/4/11 at 07:57 AM Reply With Quote
Surely no matter how much you shorten your sump the max level is always at the same point, just the amount of oil it takes to get to that level is different. I have the original 711M dipstick in so it should be correct.

I would assume if I was overfilling it then on every accelleration from lower revs it would smoke badly. where as mine only does from about 5k upwards or on the odd roundabout.

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David Jenkins

posted on 18/4/11 at 09:44 AM Reply With Quote
Fair comment - but mine was the original x-flow dipstick too!

Anyway - here are few more random thoughts!

The fact that you're getting smoke on some roundabouts suggests that the oil is slopping around in the sump - I wonder how much baffle there is in there?

A high oil level could also cause problems at high revs, as the oil would be flung further into the bores.

I'd still be tempted to run on (or just above) minimum oil level and thrash it around the neighbourhood to see what happens...

If it's not that, I'd be starting to think about the bottom piston rings - whether they're fitted correctly, etc. I'm not sure what effect they'd have on compression tests... if the bottom ring is out of sorts, would the upper rings keep the compression up while testing?

Just had a look at the Haynes Book of Lies for a Mk2 Escort (x-flow engine) for excessive oil consumption problems:

Badly worn, perished or missing valve stem oil seals.

Excessively worn valve stems and valve guides.

Worn piston rings.

Worn pistons and cylinder bores.

Excessive piston ring gap allowing blow-by.

Piston oil return holes choked.

Most of these require major engine work - head off as a minimum.

[Edited on 18/4/11 by David Jenkins]






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Alfa145

posted on 18/4/11 at 11:07 AM Reply With Quote
THanks for the help.

So the first thing to do is not top up the oil and see if it finds its own level. If it goes down to the minimum level and it doesn't stop smoking then I'll have to consider opening it up.

The block is reasonably freshly reconditioned as was the head according to the reciepts I got with the car and what the builder told me, and it looks to be true.

I've already put new seals on so should be able to rule those out, but will check them anyway.

It was running rather rich for a good 2000miles, could that have any impact on this smoking issue?

Worst case is it's going to cost me £150+ to put new rings in, thats getting close to Zetec prices......

[Edited on 18/4/11 by Alfa145]

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David Jenkins

posted on 18/4/11 at 11:17 AM Reply With Quote
If it was running rich for quite a while after the reconditioning, then maybe the excess fuel washed the oil off the bores...






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Alfa145

posted on 18/4/11 at 01:45 PM Reply With Quote
What would that mean? new rings and a hone? or something else?
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David Jenkins

posted on 18/4/11 at 03:21 PM Reply With Quote
Worst-case scenario - rebore + new pistons.

Hopefully, nothing so drastic, so don't panic! Test all the simple stuff first. The fact that you're getting respectable compression test figures suggests that everything is OK-ish with the bores & rings.

If it isn't the oil level (as suggested previously) then valve seals and/or worn valve guides are a strong possibility. Both can be fixed without too much pain to the wallet, and without taking the whole engine out of the car.

[Edited on 18/4/11 by David Jenkins]






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