Richard Fridd
Permanent resident
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« on: 06 September, 2023, 07:27:22 PM » |
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Petrol in oil sump. Can this be caused by incorrect valve clearance? Posted on behalf of a LMC Kent member who is not yet registered on this forum.
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« Last Edit: 07 September, 2023, 07:54:14 AM by Richard Fridd »
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Richard Nevison Fridd Happy Lancia, Happy Life
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GG
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« Reply #1 on: 06 September, 2023, 08:02:19 PM » |
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check fuel pump pressure, both at idle and at speed. Too much pressure can push fuel past needle valves and wash the cylinder walls.
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B20 s.2, Appia C10, Flavia 2000
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Richard Fridd
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« Reply #2 on: 06 September, 2023, 08:43:25 PM » |
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I think it's possibly a mechanical pump. High fuel level dripping down ?
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Richard Nevison Fridd Happy Lancia, Happy Life
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Mikenoangelo
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« Reply #3 on: 07 September, 2023, 07:03:19 AM » |
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Some mechanical pumps use a diaphragm which can fail as I found on our Jowett Bradford about 60 years ago. A sudden "pop" and the dipstick flew out!
What kind of pump is it?
Mike Clark
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Richard Fridd
Permanent resident
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« Reply #4 on: 07 September, 2023, 08:12:52 AM » |
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A diaphragm pump. Would I be correct in thinking that petrol would enter the oil system only via the piston rings, due to carburettor floats allowing an excessively high petrol level, overflowing into the piston bores or via the fuel pump mechanical linkage between fuel and oil systems?
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Richard Nevison Fridd Happy Lancia, Happy Life
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lancialulu
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« Reply #5 on: 07 September, 2023, 08:32:47 AM » |
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The Fulvia mechanical fuel pump diaphragm can split allowing fuel to enter the engine......
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Its not the winning but taking part! or is it taking apart?
Lancias:
1955 Aurelia B12
1967 Fulvia 1.3HFR
1972 Fulvia 1600HF
1972 Fulvia Sport 1600
1983 HPE VX
1988 Delta 1.6GTie
1998 Zeta 21. 12v
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davidwheeler
Permanent resident
Posts: 1475
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« Reply #6 on: 07 September, 2023, 08:37:36 AM » |
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...via the pushrod. Time for an electric pump + pressure regulator conversion?
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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fay66
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« Reply #7 on: 07 September, 2023, 09:04:02 AM » |
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About £35 for a new pump from Omicron, a fairly easy fit, I have an electric pump that is only used to prime the carburettors , to save all that churning over to drag up fuel, this is turned on by a switch on the dash, and is fitted underneath by the fuel tank. It's also available to use if the mechanical pump fails. Belt and braces! Brian 8227  |
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Own 1966 Fulvia 2C Berlina since 1997, back on road 11-1999.Known as "Fay"
2006 Renault Megane 1 5 Dci Sports Tourer
Dedra Technical Adviser
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Richard Fridd
Permanent resident
Posts: 3435
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« Reply #8 on: 07 September, 2023, 09:11:18 AM » |
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Pump reported to be ok, but maybe worth replacing the existing mechanical fuel pump as an immediate precaution. A low cost item including the gasket I assume, involving only two threaded fasteners and two hose fasteners . Another oil and filter change being further time and materials. If there is nothing apparently with the existing it could be put in the spares box. Peace of mind with a new item + a spare. Apart from oil contamination the pump could fail to pump petrol if the diaphragm is deteriorating.
Richard
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Richard Nevison Fridd Happy Lancia, Happy Life
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Richard Fridd
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« Reply #9 on: 07 September, 2023, 09:16:18 AM » |
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Just to clarify, when it comes to the oil contamination, valve clearances are an unintentional red herring but obviously correct valve clearances are one solution for poor compression. £35 mechanical pump sounds reasonable Brian.
Richard
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« Last Edit: 07 September, 2023, 09:45:56 AM by Richard Fridd »
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Richard Nevison Fridd Happy Lancia, Happy Life
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nistri
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« Reply #10 on: 07 September, 2023, 10:25:54 AM » |
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Fuel in the oil will quickly damage the big ends. Necessary to change oil and filter.
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Andrea Nistri
Ardea S2
Appia S2
Fulvia GTE
Fulvia Sport 1.3 S
Fulvia Montecarlo
Fulvia Coupe 1.3 S
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Kari
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« Reply #11 on: 07 September, 2023, 02:13:14 PM » |
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In WW2, aircraft had a system called oil dilution for cold weather operation. Before stopping the engine, when a cold start was anticipated, petrol was introduced into the oil circuit. Depending on ambient temperature, the dilution was up to 30%. When the oil went cold, it remained thin and helped to start a cold engine. While warming up the engine before take-off, the petrol in the oil evaporates.
However, I agree, that it is no good when petrol leaks into the oil sump on a car.
Karl
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fay66
Permanent resident
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« Reply #12 on: 08 September, 2023, 09:06:38 AM » |
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Just to clarify, when it comes to the oil contamination, valve clearances are an unintentional red herring but obviously correct valve clearances are one solution for poor compression. £35 mechanical pump sounds reasonable Brian.
Richard
Richard, I checked online and the Omicron price was better than anyone else, and some were double for exactly the same pump. Brian |
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Own 1966 Fulvia 2C Berlina since 1997, back on road 11-1999.Known as "Fay"
2006 Renault Megane 1 5 Dci Sports Tourer
Dedra Technical Adviser
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chriswgawne
Permanent resident
Posts: 2050
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« Reply #13 on: 08 September, 2023, 12:06:36 PM » |
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My father who was non mechanical and an ardent VW Beetle fan - the car could do no wrong - , once became very excited that his engine oil level was increasing. He thought it was a miracle......and then I changed the mechanical fuel pump for him, drained the oil and found it was mostly fuel.
Chris
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Chris Gawne
Mobile: 07778 216552
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Spider2
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« Reply #14 on: 11 September, 2023, 11:46:06 AM » |
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Got to be the mechanical fuel pump diaphragm leaking fuel into the sump. can't be much else. You will have to change oil and filter so take off air filter box and carb trumpets. This gives much better access to the oil filter and fuel pump from the engine bay. No need for crawling underneath. I always keep a spare in the car.
Whilst you are at it you can now give the carbs a quick balance check with a manometer.
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