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X/F Smokin' !! (a tad!).


genneton4

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Hello,
I have recently, finally got a 1990 1700 crossflow Prisoner car.  Is seems to be using a little oil.  Is this normal'ish ???   
I have owned 2 crossflow's before this one and haven't noticed any blue smoke before.
The blue smoke (tad, (whiff)) seems to occur when it's been sitting for a few minutes (at railway crossings etc) and then setting off.  Not bad at all ... but it's there, in the mirrors (ugh !). 
Plugs are not oily.  Oil pressure is the best I've ever had - 50psi and 25-30psi on tickover.  I have just serviced the car and it seems a little more noticeable.
It doesn't have an unleaded head - I run with additive. I do top up with a bit of oil but only every couple of months, maybe 1/4 pint. There is no catch tank.
Keith 
 

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Sounds normal(ish) for a X/flow with a bit of wear/ use either ignore it or time for a rebuild, might be worth taking the head off and converting to unleaded and changing the valve stem seals.

if that doesn’t work you still have a good head and know it’s the bottom end that needs work

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Just like to add that I have only just started using additive.  I was under the impression that the car could run on unleaded but have since seen lots of blogs saying all crossflow can't run on unleaded. ???  Hence the additive.

Have seen another blog this morning that says that if the crossflow engine number has a 'UL' prefix it is ok for unleaded.  My engine No. has a 'UL' prefix (well suffix actually).

So, if it is ok for unleaded ??  Do the valve guides seem to wear out at 10k miles ??  

Keith

 

 

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I've never seen a Crossflow suitable for unleaded without modification. Stem seals may indeed be a problem, but so might valve guide/valve wear. Most likely though, if you have standard Supersprint pistons, is that the rings have given up. They are seriously overstressed with this state of tune and generally last only around 15,000 to 20,000 miles. The best solution for this is forged pistons with a modern ring pack.

Wear issues associated with unleaded are the valve seats (exhausts specifically), valve guides and valve stems. Many Caterhams were fitted with quite good quality valves which were unfortunately only marginally compatible with the standard cast iron guides. Best solution here is either to line the guides with a bronze faced liner, or fit separate, bronze guides.

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  • 9 months later...

Hello again 'club'.  
I am resurrecting this thread (or hope I have). I have cogitated for almost year now about what to do about my whiff of smoke from my 1700 Supersprint.
Car has excellent oil pressure. And is working brilliant - went to Portmeirion and back, no problems.
Have now noticed the car is seeping a little oil from number 4 cylinder exhaust flange (toward starter motor). 
I realise that there could be a deeper engine problem as mentioned before (by RK) but I am trying to sort this out as economical as possible - I just want to fix the whiff of smoke.
I don't want a racer, I just want fast countryside (smile) car for my latter years.
As I said before, oil pressure seems quite impressive in my eyes.  Did a compression test (with a 1970's  'push on meter') and got 192, 187, 195, 197. (197 was No 4 cylinder).
Would I be right in thinking that my piston rings could be ok and that the real problem is with the head ??????????  Valve guides or seals or both ???
I can get the head sorted here in Nottingham by an old school engine reconditioner.  Maybe unleaded at the same time.
Seeking help and reassurance ......
Keith - Notts.
 

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Certainly can, engines are designed to use a specific grade of oil at it's operating temperature, using a thinner oil allows oil to get through seals where the thicker oil would not go at the same temperature.

As per the previous advice, most X/Flow owners run on Valvoline VR1 20w50 

 

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I will take on board the change of oil to w20/50 suggestion but I doubt it will be the answer to my problem.
I think w20/50 was in the car before this last oil change because I can't remember seeing exhaust oil seepage - it was still smoking but very, very slightly (admittedly a lot less than it is now). 
 
I did research the site for the correct oil to use for a crossflow Supersprint and it was nearly all w15/40. Is this advice now wrong ?

I don't want this link/conversation to get bogged down and staIled with the 'wrong' grade of oil advice. I will use w20/50 next, I just can't see how this alone can solve my problem. 

The real question I need help with is, with my compression figures of 192, 187, 195, 197, could that mean the the pistons and rings are in ok'ish nick and I should channel my attentions on getting the head converted to unleaded and to fit new valve guides and stem seals ??  
Is my logic reasonable. ?  ie if this course of action doesn't fix my problem and it is the block/rings then I have only wasted a cylinder head gasket set ?

Thanks very much

Keith
 

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The engine has compression rings and oil control rings. Good compression tells you very little about the state of the oil control rings and bore crosshatch patterns. I had a problem with my (K Series) engine burning oil due to worn pistons rocking and glazing the bores, leading to loss of oil control. Oil consumption was huge - 1.7 litres per thousand miles. Compressions were perfect and a more sensitive leakdown test found nothing. At the risk of sounding like a broken record ... change your oil grade!
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