red external full flow oil filter plumbing?

[cassiewoofer]

I'm plumbing in the red full flow oil filter in to the UMB engine and I'm having trouble understanding the plumbing.
    It would seem sensible to plumb it directly after the old filter and straight into the main bearing oil supply gallery pipes. (in series as it were with the old oil filter.
    However when I removed it from the old engine my diagrams show it to be feeding it's filtered oil into the port near the camshaft chain.
    All photographs I have found of the weller engine also show this arrangement.
    Can anyone explain the reason behind this, (possibly so as not to reduce oil pressure to main bearings) but I can't see how thre's any benifit.
    Any photographs or diagrams of the plumbing would be much appreciated.
    Keith.
    Also, I undestand some people run engines with just the old oil filter in place, would I be risking too much by doing this for a short time just to turn the engine over?

[Robin A Woolmer]

The pressure relief valve is situated just before the existing filter housing so to take oil before this would be at maximum pump pressure, it follows therefore that it is best to take the output feed after the existing filter housing, into the new full flow filter head then to the engine block feed position. You are best to remove any filter/strainers in the exising filter housing as this only causes a pressure drop before the new filter which is to be avoided.
   Your pressure gauge should be connected to the output side of the new filter so you know the actual pressure entering the engine, it may be necessary to adjust the pressure relief valve based upon the reading you get from the new position.
   Unfortunately the pressure relief valve should ideally be positioned after the filter as there is always a pressure drop going through the filters, the less obstruction the better. One can also have pressure drops through the pipework which is not very large on AC engines.
   The key is ensuring good oil flow at sensible pressures & taking pressure measurements as close to the input to the bearings as possable.
   By the way there are several differances in the range of sumps produced for the engine over the years!
   
   I hope this assists.
   
   Robin

[cassiewoofer]

Thanks Robin that's very helpful.
   I will try and locate one of the images I've seen of the out let from the full flow filter feeding into the rear of the engine where the cam chain is housed.
    This (I think) will explain my confusion.
    Keith.

[Robin A Woolmer]

Keith
   It may be that the oil filter you refer to had a pressure relief valve incorporated which then fed the relieved oil back to the sump via the chain housing instead of fitting a return to the sump direct!
   My new design of filter housing has the valve after the filter cannister & feeds relief oil back to the sump on my new sumps or if retrofitting to an existing engine a return fitting to the sump or as you describe to the chain housing.
   The important thing is to locate the pressure relief in the correct position which is best after the filter & just before entry to the main bearings!
   
   Robin