D1 Engine Oil Cooler line thread size

[bsa_m21]

I'm building a 1996 Disco /Series coiler hybrid. I have a rad from a pre-1996 V8 Defender. The oil cooler lines from the Disco engine to the Defender rad have different thread connections. The Rad has these 3/4" flare (14tpi) / pipe thread adapters that screw into it.:


The Disco rad had welded on threaded adapters and the oil lines have this connection:


It seems to be a metric fitting o-ring fitting, also about 3/4" dia, but about 18 tpi. Anyone have an idea of what I might need for an adapter?

Thanks.

 

[bsa_m21]

Well.... The 1/2inch tube was some kind of metric tube fitting. The rad fittings turned out to be 3/4" BSP (14tpi) / BSP pipe thread. BSP and NPT are pretty much interchangeable. So, I ended up cutting off the end of the pipes and mounting 1/2" flare SS compression fittings, with standard 3/4" flare / pipe thread adapters. Works perfectly.

 

[best4x4]

Pic's would be great as I have a project I might attack which is similar

 

[Icannap1]

Well.... The 1/2inch tube was some kind of metric tube fitting. The rad fittings turned out to be 3/4" BSP (14tpi) / BSP pipe thread. BSP and NPT are pretty much interchangeable. So, I ended up cutting off the end of the pipes and mounting 1/2" flare SS compression fittings, with standard 3/4" flare / pipe thread adapters. Works perfectly.

Does your setup still use the o-ring or is it eliminated with the compression fittings?

 

[bsa_m21]

Sorry, I forgot to take pics of the final setup. Will try to get some tomorrow. No o-rings in he rad fittings now.

 

[bsa_m21]

Here is the final setup. Hmmm. I'm going to have to add a heat shield of some kind between the hoses and exhaust manifold.


The angle of the pic makes it appear that there is little space between the rad and the engine, but there is actually about 2". More than enough to change the fan belt in a pinch.

 

[CORover]

DEI makes some great heat shield products.

 

[simondewing]

You may have an issue assuming that BSP and NPT are interchangeable the pitch (angle of thread cut) is 55 degrees on BSP threads 60 degrees on NPT.
Net result they fit together but have little contact area and tend to undo themselves with vibration.
Have a similar issue with oil lines as am currently installing a Disco Bosch/Thor 4.0 V8 into my 110 in place of the original 3.5 carb V8.
Currently leaning towards some custom oil cooler lines with 90 degree bends so they run closer to the radiator and away from the exhaust.

 

[bsa_m21]

Actually, for most applications, BSP and NPT are interchangeable. The thread count is identical - 1/2" 14tpi. Also, because they are both tapered threads, they will lock and not vibrate loose, especially with pipe sealant on them (being careful not to let any get into the rad).

The 3/4" flare / pipe thread adapters are much harder steel than the threaded hole/nut in the rad (a file skates off them) and rated for a ridiculously high PSI. With only a 5 degree difference in the thread angle, I'd lay odds that the rad threads will deform to match the NPT adapter thread. And, your rad is rubber mounted and the lines are part rubber. I seriously doubt that the adapters will vibrate loose - but it wouldn't be the first time I was wrong.....

Re running the oil lines closer to the radiator and away from the exhaust - I'm with you there. I'm looking at heating and re-bending my steel lines to get more space to the exhaust. I should have cut the steel pipes shorter as well. Oh well, the compression locking rings are not reusable, but I might be able to buy new interlocking rings. If not, the complete fitting isn't expensive (~$12 ea).

 

[simondewing]

BSP - NPT - Metric thread adapters all available on interweb if you want to do it properly.
Actually 2 versions of BSP threads exist, parallel and tapered BSPP and BSPT, BSPT is far more common and usually just referred to as BSP.
Like you say thread counts are similar but BSP is a whitworth 55 degree thread form similar to the vast majority of UK "vintage" thread types.

New pipe "olives" available from McMaster Carr and other engineering suppliers.