Simon
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| posted on 26/12/08 at 11:14 AM |
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Air from/into dipstick hole...
with dipstick in place.
When I run toy car (the one with the R V8 and pair of turbos - for those that don't know!) - after shut down I can hear air either being sucked
into or blown from dipstick.
Now, I'm sure it shouldn't be doing this, so does anyone have any suggestions why?
Don't forget this is a Heath Robinson affair, done by Heath Robinson himself and is in the ealy stages of development
ATB
Simon
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clairetoo
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| posted on 26/12/08 at 11:25 AM |
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Sounds like your getting a build-up of pressure in the crank-case ? Have you got enough in the way of breathers , and are they clear ?
Its cuz I is blond , innit
Claire xx
Will weld for food......
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jollygreengiant
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| posted on 26/12/08 at 12:53 PM |
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Or the engine is hot and as it cools it sucks air into the sump to equalise the pressure.
OR
you get a small and slow leakage out of the cylinder that is on the compression stroke past the piston ring.
in either case I would not worry too much.
If you must worry then first clean out the breather system. Start the engine and get it hot. Then take out the spark plugs (not forgetting to
disconect the coil/ignition system) and do a compression test, keeping the throttle wide open. Compare readings, if one is significantly down on the
others then that COULD be a problem with the compression rings on that cylinder. Alternatively when cold you could perform a cylinder leakage test,
this would take you about 8 hours on a V8, but is more diagnostic.
Otherwise, - If it isn't broke don't fix it. Just enjoy the driving.
[Edited on 26/12/08 by jollygreengiant]
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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mark chandler
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| posted on 26/12/08 at 12:58 PM |
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As Rv8 injection has minimal venting, tiny filter on the back of one rocker cover and tube to the front of the plenum butterfly on the other, this is
common problem when the tube into the plenum gets gunged up, excess pressure.
Result if left alone is a buckled valley plate which will eventually spilt and leak oil everywhere.
You need to whip off the rocker covers and weld in some fat tubes with a baffle in front and take these to a catch tank.
If you leave the dip stick a bit loose you will probally see it rise as the pressure builds, its not unusual to see the dip sticks held in with
springs!!!
Good to see you are back on it Simon.
Regards Mark
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stevec
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| posted on 26/12/08 at 02:23 PM |
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If you are using a special breather pipe one way valve because of your turbo set up maybe the breather gasses cant get into the inlet manifold.
Steve.
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Paul (Notts)
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| posted on 26/12/08 at 07:14 PM |
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PCV
what type / method of crank case ventilation are you using. I have a pcv valve conected to the flame trap then onto the carb.
This gives me a good drop in pressure in the block so when I switch off you can hear the air being sucked in for 10 to 20 seconds.
This crank case drop in pressure cured all my oil leaks.
Paul
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Paul (Notts)
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| posted on 26/12/08 at 07:41 PM |
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JUST A THOUGHT ...
Turbo---- Is your turbo blowing air into the plenum chamber and then straight throught this via your rocker cover ventilation into the block.
I thought that if you have a turbo then at times the MAP will be above atmospheric pressure so you cant uses this to vent the block.
Paul
Please ignore this if its a load of rubish.
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mr henderson
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| posted on 26/12/08 at 08:22 PM |
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Yes, you definitely want a bit of vacuum to pull the air out of the crankcase. It's not unknown for RV8s to leak oil excessiely if the carnkcase
pressure is too high. OTOH you don't want to much vacuum, hence the use of a PVC valve with a carb set up such as Weber 500
John
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