- Posts
- 11,024
- Location
- North of the Wall
Are you talking about the HPP oil inlet pipe, Mick?
The return pipe, in theory, is at atmospheric pressure. ie not under pressure This is to the best of my knowledge
Any Fluid Dynamics Experts?
- Thread starter Al2O3
- Start date
This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
The return pipe, in theory, is at atmospheric pressure. ie not under pressure This is to the best of my knowledge
Guys, first of all I greatly appreciate you taking the time to think about this because I'm obviously not going to work it out myself.
I've tried different 'brands' of aftermarket oil return pipes, but non of them fitted well. When the nut on the block is tightened down, pulling that fitting square and then the flange on the turbo CHRA is bolted down, pulling that fitting square, the pipe developed a kink. Presumably enough to restrict the flow? I've now got the new (25 year old) genuine LR return pipe.
I thought I'd do the calculations because I know area can increase/decrease by a surprising amount when shape dimension vary a little. Even though I'm now using the genuine pipe I thought it might help to look at dimensions to try and get an idea of the effect of a small restriction. For example if there is an unnoticeable deformation of the return pipe by 1mm, so at one point in the pipe the ID is down to 11.5mm instead of 12.5mm, that reduces the cross sectional area by 16%.
A restriction in the oil return seems to be the cause of this problem, according to YouTube videos created by Turbo servicing companies. When the oil goes down that pipe it just drops in to the sump. I can't see there being any other cause of a restriction other than the pipe?
When I rebuilt the engine the new rotor looked as though it was going to work fine and yes I filled it with vaseline on assembly.
I've asked the question about inlet pipe pressure/flow being affected by aftermarket pipes and have seriously considered going down the pressure regulator route. I've shelved the idea for now based on; nobody else needs one and they can stick (apparently) starving the turbo of oil.
I've sent pictures of the return pipe fittings, with measurements on, to a pipe fittings company to see if they think it's an AN-8, AN-10 or any type of fitting they know. Rather than bodge something with jubilee clips I'm thinking I could make a decent custom return pipe with an ID nearer to 15mm to rule out a restricted return once and for all.
See this video, notice what the guy says at 3.00 mins about AN fittings!
Are you talking about the HPP oil inlet pipe, Mick?
The return pipe, in theory, is at atmospheric pressure. ie not under pressure This is to the best of my knowledge
Im guessing because I’m no expert, but the oil will have “some” pressure, otherwise it wouldn’t flow.....would it? I think that’s correct anyway.
- Posts
- 11,024
- Location
- North of the Wall
All the videos I've seen like this state the same causes. He's suggesting 3/4" min return pipe ID. This is why I'm thinking of trying to increase mine. The only reason I'm asking about AN fittings is because all of the pipe fittings sites I've found sell them
I'd never heard of them before! That has left me wondering if the fitting on the block is an AN fitting, which is why I asked the question, but nobody seems to know what it is. That's why I've messaged a pipe fittings supplier on ebay. I'd no idea the inside of AN fitting could be smaller, but if I'm aiming for a custom 15mm ID pipe then hopefully that would be better than my current 12.5 mm one, if if it's slightly restricted. Maybe I should be looking at a 17mm or 18mm ID pipe? The limiting factor there would be the block fittingI could take this one out. But again, I've no idea what thread is in the block or what type of fitting this is or even if you can get something that will screw in with a bigger diameter hole in the middle.
- Posts
- 11,024
- Location
- North of the Wall
I think it's supposed to drain faster that it's being pumped in at the top, so it just returns to the sump by gravity rather than being pushed.
All the videos I've seen like this state the same causes. He's suggesting 3/4" min return pipe ID. This is why I'm thinking of trying to increase mine. The only reason I'm asking about AN fittings is because all of the pipe fittings sites I've found sell them
View attachment 232286
I could take this one out. But again, I've no idea what thread is in the block or what type of fitting this is or even if you can get something that will screw in with a bigger diameter hole in the middle.
That looks like it’s a basic NPT or BSP(T/P) adaptor. If you have a vernier and a thread gauge, you can work out what thread it is. Also measure the bore diameter as BSP is measured by the bore, as in a 1/2” BSP thread isn’t 1/2” OD, it’s 1/2” bore.
If your dead set on increasing the size, you could remove that adaptor and drill out the hole for a larger tap. I think that’s a bit extreme though, maybe drilling the fitting bore slightly will give you the size you want?
Edit: I have just zoomed in on the photo. That looks like a basic hydraulic fitting, which is why it has the radius on the inside, as that’s a sealing face. Knowing the rough age of the engine and the tech, I would guess it’s at 1/2” BSP to 1/2” hydraulic (I think it’s a DIN fitting).
- Posts
- 11,024
- Location
- North of the Wall
Ahh, good info. I know of British Standard Pipe, but not NPT. I've just Googled that though
I don't have a vernier or a thread gauge, but maybe I could work it out counting threads over a quarter inch or something. I was only thinking AN fittings because all my Googling about oil pipes talked about AN fittings It not so much I'm dead set on increasing the the size, it's just all info out there, like the Youtube video lynall posted before, say restricted oil return causes the problem I've got. (insert pulling my effing hair out emoji)
Ahh, good info. I know of British Standard Pipe, but not NPT. I've just Googled that though
It not so much I'm dead set on increasing the the size, it's just all info out there, like the Youtube video lynall posted before, say restricted oil return causes the problem I've got. (insert pulling my effing hair out emoji)
Yeah counting the threads over a known distance will give you an idea, but it’s not perfectly reliable. I think AN fittings are a relatively new thing, and probably not the sizes on the TDi engines, the TD5 and Puma may have them though.
- Posts
- 11,024
- Location
- North of the Wall
In my message to the pipe fittings company I did suggest that a 1996 Land Rover may well not have AN fittings, thinking it was more likely to be some olde worlde English thread
- Posts
- 11,024
- Location
- North of the Wall
Pipe fittings company wrote back to say no vehicle have AN fittings as standard (apart from some kit cars) So it's down the BSP and NPT route next.
In the meantime I thought why not port the return pipe? Couldn't think of a reason not, so I did.
That's got to help the oil flow more smoothly in to that pipe! Will it solve the problem.......highly unlikely I think it's a straw worth clutching at though!
In the meantime I thought why not port the return pipe? Couldn't think of a reason not, so I did.
That's got to help the oil flow more smoothly in to that pipe! Will it solve the problem.......highly unlikely
I think it's a straw worth clutching at though!
- Posts
- 11,024
- Location
- North of the Wall
We had our summer here a few weeks ago, which was when I took the opportunity to swap the CHRA! Gorgeous it was anorl, warm with a clear blue sky. Actually, it was skies because it lasted two days, which is twice as long as our standard summer......lush! Anyway, we've had snow, hail, rain and a lot of frosty mornings since then. Got out okish this afternoon, so thought I'd fit my ported oil return pipe. Was the usual struggle to get one end to line up and fit once the other end was fixed. It's easier to fit the big nut on the block first otherwise it's impossible to tighten. Struggled to fit the flange end on the turbo and there's the very real risk of ripping the gasket, so decided to drop the manifolds off to give me more wriggle room. Eventually got it on. I'm sure it shouldn't be such a struggle! The turbo has to be in a fixed position relative to the block, so no matter how long I stare at the setup I can't see why my return pipe is such a struggle to fit. Anyway, it on. I'll give myself a few days thinking it might be fixed, before I try the turbo playing on to the wings test.
A definite positive from this afternoon is that I found out where this plate came from.
It used to live on the inlet manifold here.
Held on by two small bolts.
I have to loosen it and swing the plate out of the way to get to the bottom inlet manifold bolt on this end. I mustn't have put it back last time and so it's vibrated off during one of the turbo wing test.
I presume it must have been an identification plate at one time but the ID bit has snapped off. Any one else got one?
A definite positive from this afternoon is that I found out where this plate came from.
It used to live on the inlet manifold here.
Held on by two small bolts.
I have to loosen it and swing the plate out of the way to get to the bottom inlet manifold bolt on this end. I mustn't have put it back last time and so it's vibrated off during one of the turbo wing test.
I presume it must have been an identification plate at one time but the ID bit has snapped off. Any one else got one?
- Posts
- 1,205
- Location
- The Flat lands of Cambridgeshire
I have one on mine mate, it should have a heat shield attached will send a pic tomorrow when i am at that the workshop
- Posts
- 11,024
- Location
- North of the Wall
Brilliant, cheers.
- Posts
- 11,024
- Location
- North of the Wall
Found it in the parts catalogue! part number ESR2422 That must have disappeared when the first owner had it.
What's it shielding the heat from?
- Posts
- 11,024
- Location
- North of the Wall
jamesmartin
Well-Known Member
- Posts
- 91,879
- Location
- louth lincs
inlet hose ,most have rotted off and hasnt caused any issues
- Posts
- 11,024
- Location
- North of the Wall
Ahh, air inlet! That shield has never been on in the 15 years I've had the Landy and it's still on the same air inlet hose. Looks grand too. It's done 130K miles in that time too.
- Posts
- 1,205
- Location
- The Flat lands of Cambridgeshire
- Posts
- 11,024
- Location
- North of the Wall
It seems to be doing ok without it. Thanks for bringing it back to my attention.
I wouldn't care, I'm not that old
- Posts
- 11,024
- Location
- North of the Wall
Decided to try my ported oil return pipe this afternoon.
This is the result
Lynall was right, it made sod all difference.
This is the result
Lynall was right, it made sod all difference.
