Engine oil level ,with external filter

[JohnBM]

This subject has been on my mind for a while & I had put question out on one of the Grey motor sites without success . Q: a couple of years ago i fitted a external AC oil filter to my FE , (grey motor ) so when I change the oil , do I fill it to the normal full mark on the dipstick, or add extra to allow for the additional capacity of the filter can ?  If after going for a run does the oil drain back down the inlet hose thru the oil pressure switch to the sump ? I know there is a simple answer, I’d hate to think the engine was a bit short of oil , though the oil pressure gauge light would light up . Thanks in advance , cheers .John.

[my8thholden]

good question John ,I am interested to know the answer on how the AC external oil filter works also ,I will follow this and learn ,I would imagine though the unit would hold its own oil ,and level on the dip stick is level ,it will be interesting to see how to drain it come oil change time also ...Vern ..

[Maco]

When I have carried out an oil change & opened up the filter canister it is always full, the oil has not syphoned away.
Cheers
John

[Harv]

The aftermarket bypass oil filters do not return the oil directly to the sump. They return the oil to the camshaft gallery. The oil then has to force it's way past the cam bearings before dribbling into the sump. This is a pretty tight path when the cam is static and the oil is cold, so very little flow happens (the restricter on the filter lines helps make that path tight too). This is why the oil filter is normally chock-a-block when you open it (and the reason the cam doesn't run dry when it is sitting around idle).

Remove filter, install new one and fill the filter housing up with as much oil as you can without making a mess. Bolt down filter top and run engine. Check for oil level, and top up as needs be.

Cheers,
Harv

[JohnBM]

Thanks people , what I have been doing when changing the oil is get the engine hot with a run , then take out sump plug . The two or three times I’ve changed the oil the filter can is empty, I’ll go out shortly & check the dipstick level (cars been sitting overnight) & take off the filter canister top off to see what the oil is doing .if the dipstick level shows on the full mark , & the canister is full of oil . Then to me it would be running slightly high in volume of oil ..just me probably worrying about something I shouldn’t be . Thanks for the feedback. Cheers .John .

[JohnBM]

Further to the saga . Just checked dipstick oil level (cold) it was showing overfill , & the filter canister was empty. The penciled arrow in photo shows where level was. So as I see it all should be well once the engine is up & running. any thoughts. (apart from , have a cup of tea & a nanna nap) cheers . John .

[Rod]

Hi John,

Many years ago I fitted an external filter but have since removed it preferring to change the oil more regular since it is not a full flow filter. I may refit in the future but it would be for looks on.

I found if I filled the sump up first and then filled the filter, if I left it for some time the level on the dip stick would rise. ie: canister drained back into sump. I was always a little sure on what to do. Only fill sump and therefore reduced capicity or overfill. I found that I had more tappett noise initially on start as the oil canister filled. I don't think I was over thinking things.

With this in mind I spoke to some fella at enzed and we put an appropriate pressure relief valve on the canister drain. This allowed me to fill sump and canister to correct levels without drain back. I think it improved tappett noise on start up as the canister didn't have to refill. I was a little unsure on this because if the relief valve was too strong it wouldnt allow for circulation. ie: pointless having filter on. However when doing each oil change there was definite circulation as the oil was dark and there was evidence on the filter of circulation.

As I dsaid I ended taking filter off because the benefits were probably minimal and with the relief valve it didn't look original anyway.

This is where I started my reseach.

http://forum.fefcholden.club/index.php?topic=2629.0

Cheers

Rod

[Patrick_R]

Some good points there Rod.

As it was only an accessory, it’s not really needed as long as the oil is changed as per the book.

In most cases it looks like a horrible afterthought, which what it actually is.

I think you made the best decision to remove it, as I don’t like the sound of a noisey engine when it’s trying to fill something while the oil is not where it is really needed during start up which is the most critical time.

[my8thholden]

the lesson for me so far is the negatives are outweighing the positives ,it certainly does not seem right that the oil filter reservior should drain and refill on start up ,yet Harvs experience suggests it to be different ,later engines with spin on filters have a internal non return valve ,that would have been for exactly that reason,also manuals will give a sump capacity with filter change and without filter change,indicating to me level on the dip stick is level ..regular oil change seems the answer ,there used be a kit available where you just syphon/vacuum the sump out ,I think it fed down the dipstick hole ,some one will know ..Vern ..

[Fraze]

I have Fram accessory oil filters on both of my Greys. The way the Fram is made is that the oil return hole in the centre tube is some way up the tube. This means that oil always remains in the cannister and cannot drain away. This is a bit of a nuisance when doing an oil/filter change because to complete the job the cannister has to be emptied. I bought a Kinchrome "sucker" to suck the oil out. This is like a bicycle hand pump in reverse. When refilling, I put the new filter into the cannister and pour in oil till it fills up, then refit the cannister lid. tThen fill the sump in the usual fashion. Oil level always stays correct. Fraze     PS I also have a Porsche 356 and it uses exactly the same set up.

[Patrick_R]

Gents,

We also have to remember, that when this accessory was brought out, these cars were used every day, if not many times during the same day, so the very slight drain back through the cam bearings would probably be almost nil between start ups.

This way, yes it worked very well and as intended.

The problem now is, that sometimes these cars are not driven for days, weeks or even months, so all oil has completely been removed from upper areas including the add on filter, this then leaves it horribly void of oil during that critical start time.

The Fram filter sounds a whole lot smarter than the original accessory.

[Rod]

I am with Vern. Being bypass doesn't have the same effects as a full through filter. There has been some great threads somewhere where full through filters have been fitted to the grey.

We do need to remember that the engine service interval was / is 2000 miles (3220 km) which is low by todays standards. Yes technology has advanced significantly but one thing to remember oils have improved during this time as well. Using current oils with old service intervals I am sure will see little benefit of fitting a filter.

Honestly, for me the only reason for me now to install it comes down to looks. I may very well do it again but I would be blocking off the plumbing somehow.

Cheers

Rod

[Harv]

Don't forget that the grey has a self-filtering design feature. They all leak like a sieve, and you then keep topping them up 

Cheers,
Harv

[JohnBM]

I spent about 15 minutes earlier replying but  it must be wizzing around in cyberspace. Thanks to all for the input ,very interesting. Cheers John

[Patrick_R]

Good One Harv,

I've just fixed my oil leak, so now I will have to change my oil more regular.

[Errol62]

Just drive it a few times and should come back Ric. Chuckle, chuckle......


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[Harv]

If there ain’t no oil under it, there ain’t no oil in it.

Cheers,
Harv

[Patrick_R]

You’re probably spot on there mate.

Like the typical pommy bikes and cars, the owners say they run better when they leak :-)