RobBrown
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| posted on 17/3/03 at 08:46 PM |
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Crankcase ventilation
I seem to remember reading somewhere that if you replace the standard carb on a pinto with sidedraft carbs, as I have done, then you end up with oil
coming out of the oil filler cap, like mine.
The solution is to recreate the ventilation which sucks air through the oil filler cap, through the engine, out of the Crankcase vent valve.
How? since there isn't the same vacuum in the Dellorto manifold as there is in the standard Ford one?
Rob
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Stu16v
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| posted on 21/3/03 at 08:10 PM |
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Pretty much impossible to do with twin carbs.
Weld two breathers onto the rocker cover. Plumb the crankcase vent into one, and run the other to a catch tank, et voila, problem solved. Make the
breather pipes (sensibly) large, and dont be tempted just to 'T' them together.
Converted my Xflow from an oil spitting smoky horror into a luvverly little engine just by doing the above.
One last point. the breather from the rocker cover to catch tank may have to be carefully positioned on a pinto, due to the extra oil araound the
camshaft, either that or make a baffle in the cover internally.
HTH Stu.
Dont just build it.....make it!
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RobBrown
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| posted on 26/3/03 at 10:24 PM |
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What size breather pipes should I use.
Does anyone know the best position to put them?
My engine is smoking quite a lot as well, I I thought it might have been the valve seats needing to be replaced?
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Stu16v
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| posted on 29/3/03 at 11:09 AM |
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quote:
What size breather pipes should I use.
As large as (sensibly) possible. Older engines (pinto, xflow) need to 'breathe' properly, as due to the fact their design is
'getting on a bit' they tend to build up a lot of crankcase pressure when revved. I would suggest 1/2 or even 5/8 bore if poss.
Is the engine smoking all the time, just on initial start up/idling for a bit or when it is thrashed?
Dont just build it.....make it!
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CairB
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| posted on 29/3/03 at 07:19 PM |
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I'd check / replace the valve stem seals. Often a source of smoking engines in the wrong sense. It's happened to me a couple of times when
the head gets a little warm due to low water due to leaks. This then makes the stem seals a tad crispy.
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RobBrown
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| posted on 30/3/03 at 07:05 PM |
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That's probably what it is, since I have had the engine running, without much coolant. I did make some attempt not to let the engine get too
warm. Oops.
Gives me a good excuse to take the head off and now convert the engine to unleaded.
With the breather pipes, where is the best location to stop too much oil ending up in the catch tank. I thought maybe the back of the rocker cover,
just behind the cam, not too much splashing around of oil there.
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david walker
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| posted on 30/3/03 at 10:00 PM |
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Back of the rocker cover is a good place to put the breather, but you must do as Stu has advised and fit a good baffle otherwise, if you don't,
you'll empty all of your oil into the catch tank very quickly.
As a rule of thumb, if you get a big cloud of smoke on start up, then it's stem seals. (oil runs past stem seals, down valves and into
combustion chamber - burns off as engine starts - so big cloud of smoke). If you have a steady blue haze when engine is warm then it's rings /
bore wear.
What makes stem seals "a tad crispy" is old age. If you have been running with too little water, you'll have more problems than stem
seals.
Pintos' and X'Flows suffer less with stem seal problems than other Fords, ie DOHC and in particular, the whole of the CVH range.
If you going to trouble of having head off for u/leaded conversion then, if bore wear isn't too bad (ie no lip at top of bore), then at least
glaze bust bores and fit new piston rings.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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