The V8 Owners Forum -

fitting a serp front cover to 3.9 engine, i have lined it all up an have sorted parts, just need correct cam.


i think the 4.2/4.6 this came off maybe had an oil cooler?? as it has a few take offs which i hope to block up, (ones in the dark blue path).

the oil obviously goes in the red direction through the pump plate, it would be able to freely take the dark blue path, but the direct route which i want to use in light blue seems to i have maybe a pressure release valve in it?? or maybe a 1 way valve? either way i cant blow throw it. then it goes up the green path and in tot he engine.

do i need this pressure release valve? or is it just there to make the flow go throw an oil cooler???

if i block the blue path should i remove what ever the restriction is in light blue path???


Ralph

The dark blue path I believe to be for an external oil cooler with thermostat. When the stat closes, the valve in the light blue path opens to permit oil to still flow.

On my setup, I put a cover on where the oil filter sits (after removing the threaded piece which holds the filter. Then I blocked permanently the light blue path to force all the oil along the dark blue path (and through my remote filter).

Which seems to work for me, but I do have concerns that my oil pressure is in the region of 60-70psi!, so I might have misunderstood some subtle aspect of how it is supposed to operate.

Chris.

Hi, If you just want to run with no cooler on a serp cover, then just plug the cooler ports, m18 or m20, can't remember which as I sit here but can be got from hydraulic shops. When you fit the cooler, the fittings have a special set of ends with internal o-rings that block and expose the right oilpaths. Was going to post some pics on here about a year ago for someone, must do it!!!

pitmole wrote:Hi, If you just want to run with no cooler on a serp cover, then just plug the cooler ports, m18 or m20, can't remember which as I sit here but can be got from hydraulic shops. When you fit the cooler, the fittings have a special set of ends with internal o-rings that block and expose the right oilpaths. Was going to post some pics on here about a year ago for someone, must do it!!!

M18x1.5 or 1.25, which makes it odd size

m18 x1.5 or the other are standard ish threads, im sure i can get bungs, work next door to a hydrolic place, hopefully they can get light weight ali ones.


i will remove the presure valve thing then, i had that idea to chris about if i need to run a remote filter, hopefully i wont need to tho.


Ralph

I think the 'coolers' are oil/water in the rad so stats aren't required - which is the gotcha if you want to run oil/air coolers.

That cover is off a p38 model, i'm unsure which 3.9 you've got - but you'll have to have a cam without a 'nose' if you get what i mean. (due to the cover not having a dizzy hole).

I was looking at fitting one of these covers to my 4.2, but had other issues with the timing chain touching the casing (i'm running a roller duplex chain).

If your engine is dizzy'less, then ignore me

G

There is no thermostat in the front cover.

There is a pressure relief valve in the cover which cause some portion of the oil flow to bypass the oil filter(back to the sump) if it is filled with "dirt". Dirt creates resistance. resistance creates larger pressure differention before and after the filter media. Access to the pressure relief valve is via one of those holes not quite visible in the photo. you can up the pressure in the system by putting a 7/16" OD washer behind the pressure relief spring.

There is a specific type of fitting in the upper port to get the oil to flow thru the cooler lines. The tube in the upper cooler line fitting has a cross hole drilled in it. No cross hole in the tube = no oil cooler line flow.

Not sure...but if you block the flow thru the light blue passage, then you may be completely bypassing the oil filter or the pressure relief valve. That might cause the oil pressure to be very high. It is not easy to figure these things out. Oil is flowing in so many directions. If you look down the various ports, there are numerous passages.

Randall

Hi
I'm new so excuse me if I'm procedurally incorrect here but I was following your chat on rover v8 front cover oil porting and am literally in desperation to obtain the male screw in pipe ends which would go to and from the oil cooler.
It's a late 90's serpentine engine bored out to 5 ltrs.
The ports are 20mm 1.5 pitch
These screw in ends I understand are extended and have O rings to facilitate diversion of the oil flow
Finally I've Ben round most of the suppliers to no avail and I'd include a photo if i could figure out how (no I don't want a remote filter)-----HELP

The oil ways in a P38 (4.6/4.0 ) non dizzy cover work in a totally different way to the 3.9 type serp covers with a dizzy.

The P38 covers have the pressure relief valve (not the one in the light blue route)on the opposite side to the filter behind a washer retained by a circlip whereas the dizzy serp covers have a similar pressure relief valve on the filter side.

In a p38 cover, some of the oil will flow via the light blue route when the oil is cold and thick when resistance through the cooler is greater. As the oil warms more will pass through the cooler.

The special ended fitting on the cooler pipes only apply to the 3.9 serp dizzy type covers and blanking off the cooler point with an M20 bunk is acceptable and is common on many TVR's.

On a p38 non dizzy cover it would be wise to remove the valve in the light blue route if you are bunging the oil cooler holes so as to get free flow into the filter. The actual pressure relief valves (returning to pump inlet) on these covers is a separate item on the opposite side of the cover from the filter near piston no 1 and has nothing to do with the light blue route.

Much appreciated Devonman. A lot of good gen there. I was unaware of most of it as my only experience so far has been the 3.9 which I presume is the basis of my new engine. That is something I will confirm on Monday.
By the way I presume dizzy is Discovery?
So all things being so, fitting an oil cooler using the afore -mentioned ports should be good??? And, quoting"Dizzy" cooler oil pipes would be adequate for identification purposes to any budding supplier.
Thanks again Devonman
P.S. Still trying use this "image insertion" stuff [/img][/url]

Username wrote:Much appreciated Devonman. A lot of good gen there. I was unaware of most of it as my only experience so far has been the 3.9 which I presume is the basis of my new engine. That is something I will confirm on Monday.
By the way I presume dizzy is Discovery?
So all things being so, fitting an oil cooler using the afore -mentioned ports should be good??? And, quoting"Dizzy" cooler oil pipes would be adequate for identification purposes to any budding supplier.
Thanks again Devonman
P.S. Still trying use this "image insertion" stuff [/img][/url]

No. Dizzy means distributor. ie Front cover with distributor or front cover without a distributor.

Front covers with distributor are on 3.9 interim engines and covers without a distributor are on P38 4.6 or 4.0 engines. The picture with the colour marking at the start of this thread is a non distributor P38 type.

Right; mine has blanked off "dizzy"hole, therefor is a 3.9 front plate ( and looks like my old one anyway)
All I've got to do is obtain 3.9 spec cooler pipes\ fittings and Bobs your uncle.
I'm sorry your having to deal with such a thickco but I'm obliged to you and il get there in the end

i think i have some M20 x 1.5 plugs if you want them,

Ralph

Thanks very much Ralph for generosity but I have them plugged at present and want to use them to fit an oil cooler. I don't want to fit a sandwich plate (not just because I'm a tight northerner ) to achieve this.
I hope I've found suitable O ring equipped fittings/pipes at Island 4by4
Thanks again folks