Oil Filtration

[trikesrule]

This 12:1 engine (used in speedway) I recently pulled the head off had oil that felt real gritty around the base of the pushrods. This led me to think this can't be good and I wondered if the oil filter is not doing it's job. Whats your favourite filter and what are your thoughts guys? One of local gurus(?) recommended Fram but I've never used them before........trikes

[knighty]

hello again trikes

possibly a load of casting flash / sand which has been washed out of a cylinder block/head crevice and is now making friends with your oil

or - is your crank case breather pipe filtered? - or open to atmosphere?

is the oil filter a bypass type or full flow?........by this I mean if you cut the filter open it might feature a bypass valve - the bypass valve is there for 2 reasons.

1) When the paper is clogged with crud and soot, the valve opens and lets UN-FILTERED oil through to keep the engine going.

2) when the engine is cold and the oil is like honey-thick, the oil has real trouble going through the filter paper, so the valve pops open and UN-FILTERED oil gets into the engine........

sounds horrific I know - but the vast majority of standard fitment spin-on oil filters are like this.......if the valve is not in the filter - its normally in the engine.

For race engines its common to convert the oil system to "full flow" by running oil filters without bypass valves, therefore all oil must go through the filter and there is no risk of contaminating your expensive motor.

The BEST oil filters are from Mann+Hummel......Fram aint nothing special but are OK.....WIX from Dana are OK......all are made on high volume automated equipment so are good on quality......I should know as I have visited all of the above oil filter manufacturibng sites when I was responsible for lubrication systems at Ford Diesel Engineering.......just avoid cheap hand-made crap from china/god-knows-where.

[275 GTB-4]

Originally Posted by knighty

hello again trikes
is the oil filter a bypass type or full flow?........by this I mean if you cut the filter open it might feature a bypass valve - the bypass valve is there for 2 reasons.

1) When the paper is clogged with crud and soot, the valve opens and lets UN-FILTERED oil through to keep the engine going.

Some people disable this function with a suitable bolt

Some people use rare earth magnets strapped around the filters to grab particles.

[trikesrule]

Gidday Ian and 275. This 12:1 engine has the by-pass in the pump. Local Pro-builders don't recommend blocking off the bypass on these engines - don't know why I'll ask one. The crankcase breather vents to the atmosphere. Probably should have some sort of filter on it - Yes? Ian I'll look for Mann+Hummel Filters....trikes

[Tim Falce]

Originally Posted by trikesrule

Gidday Ian and 275. This 12:1 engine has the by-pass in the pump. Local Pro-builders don't recommend blocking off the bypass on these engines - don't know why I'll ask one.

If you block the bypass off the pressure will go too high and maybe blow the seals out or as happened with my mate when his bypass valve stuck it pushed the filter base off the mating face of the mount.
On my race engine I have a high pressure relief valve and flowed oil pump, I also run Valvoline 20/50 racing oil which is like treacle when cold. I can't rev the engine much above 3K for a lap or so until the oil gets warm or the pressure goes off the gauge.

[graham bahr]

it strikes me ther could be some confusion here between the pressure relief valve and filter by pass valve,

personally i would not by pass a filter by pass valve, that said the oil should only by pass the filter if the filter gets clogged, which i wouldnt expect to find on any race engine, as they usually get more oil changes than they really need.

an oil pressure relief valve should never ever be blocked or bypassed

[GORDON STREETER]

You are right Graham the filter bypass will only bypass the filter !
If you dont watch it from cold you can easily blow the filter ring out.
I only use thin full synthetic oil for short clubbie races now, but in the past had a kettle element in the dry sump tank and gave it a warm up for 15 mins.

[Tim Falce]

Originally Posted by graham bahr

it strikes me ther could be some confusion here between the pressure relief valve and filter by pass valve,

personally i would not by pass a filter by pass valve, that said the oil should only by pass the filter if the filter gets clogged, which i wouldnt expect to find on any race engine, as they usually get more oil changes than they really need.

an oil pressure relief valve should never ever be blocked or bypassed

Correct, sorry for the misunderstanding. I was going off my engine that has the bypass/relief valve, call it what you want, in the filter mount.

[trikesrule]

Thanks guys. I've contacted Mann to find out if there is an Australian Distributor but no reply yet. I won't ever bypass the pressure relief. I've seen first hand how one of the guys made a big mess in his engine bay when it blew the O'ring out. Another chap in another class actually blew the bum out of the filter in the pits causing a oil fire. Boy the #%^& hit the fan that time. But better filtration for dirt racing is a must.......trikes

[knighty]

yes you should not get the main pressure relief valve (PRV) and the bypass valve mixed up........they are two very different parts.........the main pump PRV is designed to crack open at a very specific pressure depending on the engine type - normally about 4 bar..........the bypass valve - sometimes called the safety valve - is designed to crack open at about 8 bar........blocking the main PRV on any engine is a ludicrous thing to do - you will blow a filter for sure.........

the best solution is as stated above - remove the bypass/safety valve and have a kettle element in the oil tank to give it all a bit of heat to get you started.......but to be honest - its alla bit OTT for this sort of engine - I have worked on many high level race engines (BTCC, WRC & LeMans) and we never ran an oil warmer element....thats more for F1 and F3......you will be OK without it.

anyway trikes - I think the root cause of your problem is the oil breather being open to atmosphere - fit a breather filter ASAP..........If you cannot find a Mann+Hummel filter do not lose sleep over it - fit a Fram and be done with it.

[GORDON STREETER]

Knighty you are correct in what you say it is all a bit ott. When I said that I used an element , that was some time ago when I was using thick mineral oil. Every racer will use his chosen brand for whatever reason but personally
I now use a 10w60 fully synthetic with ZX1 and dont have any problems.

[GordonG]

But isnt unfiltered oil better than no oil at all?

The filter bypass valve will only operate if the filter is clogged or the oil is too thick, which would cause a great pressure drop across the filter element. So a normal filter bypass would allow unfiltered oil to go into the engine, whilst blocking the valve would reduce the oil (and the pressure of that oil) possibly to a large degree.

The ultimate solution is to use a big enough filter, the right grade of oil, change both frequently and dont thrash the engine till its warm. But if all that fails, I think I'd rather have oil that *might* have some bits in it in preference to no oil at all.

G

[trikesrule]

Anyone ever seen or used those little stumpy oil filters? A chap that does the mechanical work for our car yard suggested one (a GM product) as he said it was pretty important to get oil pressure up quick in a race engine. What are your thoughts guys? PS I've fitted a Fram and the engine psi has dropped a little cold and hot. The Engineer I bought it from said this was to be expected as the Fram has less pressure drop.....trikes

[trikesrule]

Last Saturday night at the Speedway the Sprintcars line up in front of where my class parks. I had a wander up and down the Dummy Grid looking to see if their was a preferred filter. Easily the most favoured was the Fram (over half the field) followed by K&N and the rest don't matter. I fitted a Fram to that 12:1 engine that had those head gasket problems. The owner / driver noticed a drop of about 10-12lb on his guage.......trikes

[GORDON STREETER]

trikesrule . Are you taking the oil pressure gauge line off the main oil gallery and is it dry sump ? You dont need to have tons of oil pressure for a race engine as it only absorbs hp . As long as you use a decent type of racing oil and the pump can supply a constant flow things should be ok. It is always best to fit the biggest oil filter you can . I use a remote filter and run 60 psi
hot at big revs . After the race the oil light will come on and the gauge will drop to 20 psi at low revs .

[trikesrule]

Hi GS. The oil line taps into the block. I believe the pressure feed is from the cam bearings. Sump is wet. The engine shop that sold me the filter said to expect a psi drop as the Fram dosen't filter the fine bits hence the psi drop. Hot race is 50-52 (was 65) and hot idle 18. Acceptable I think. What do u think? I know the car owner is happy at the moment........trikes

[GORDON STREETER]

Trikes
Were you having a problem before ? as the old saying if it ain't fxxx! dont fix it
comes to mind . Did you simply fit a different filter because some of the others were ? To my mind a bigger filter should be better as it also has more capacity . If someone said "we" run our tyres at 5psi would you do the same?
I have been told many times "your carburettors are to big" ok maybe they are
but I dont notice many cars ahead of me at the end of the race ! I would stick with what you know works .

[Tim Falce]

I dont quite get the point of bigger filters on a race engine. As they would be changed frequently does the capacity matter providing it will do enough filtering for a given amount of time, or have I got it wrong as usual?

[GORDON STREETER]

Tim that extra capacity along with an oil cooler and piping could well hold another litre or so that might well save your engine in a long race. Andy Bacon used 5 litres of oil in a race at Spa in his Camero ! He knew the engine was on its last legs . My engine will use over a litre of oil in a 1 hr race, also a bigger filter will flow faster . I will stand by my comment on the first line to Trikes in post 17 Oil and fiter change ? I thought that was every 12 000 miles !

[trikesrule]

Hi GS. Back in compression vs headgasket I mentioned that when the head was off I found gritty oil at the bottom of the pushrods / tops of the lifters. Back then I wondered if this oil filter was doing it's job and thought I may as well ask what is a good and popular filter. After last Saturdays racing I whipped a pushrod out to 'feel' the oil. Much better. So all I can assume is the Fram is doing a better job than what was in there before.....trikes