TheSamba.com :: View topic - a little help w/ external oil cooler fittings?

Tue Oct 14, 2008 2:30 pm

since i'm not that familiar with all the variations of types of connections used with my 'soon to be installed' external oil cooler for the 2.0L A/C
i thought i'd tap the vast wisdom of the forum before i order the needed fittings and lines to install it

below are a couple of pics of what i currently have
in the back: a mesa style 72 plate cooler with what i can guess to be NPT female connections (measured to be 3/4")
on the left: a mocal thermosatat sandwich plate http://www.racerpartswholesale.com/product/2972/Mocal_Sandwich_Plate
and required special fittings for it (1/2" x -10 ORB fitting / AN Male to BSP Male Union - huh???) http://www.racerpartswholesale.com/product/3282/826
on the right: an inline 180 degree thermostat switch (to control the cooler fan)

now here's the 'rub'...
the smallest inside diameter seems to be the inline switch at about 3/8".
next is the sandwich plate fittings at about 1/2"
so it sounds like i'm going to be using 3/8" ID hose

what i'd like to do is plumb reusable AN(?) fittings and hose (so it can be taken apart if needed) instead of dedicated barbed hose connectings that the thermo switch currently has...

anybody out there 'the god' of this stuff?...
i'd like to get my order for fittings and hose right the first time

as always...
my thanks for the help ahead of time

Tue Oct 14, 2008 5:57 pm

-10 is a bit large but won't hurt anything.
It looks like the inline thermostat switch is -8 (does not fit the AN/BSP fittings - correct?).
Oil cooler looks like 1/2 NPT female - yes/no?

Here's what I'd do, based on my assumptions from the photo -
-Replace the AN/BSP fittings with the same but for -8 size.
-Buy AN/NPT adapters to thread into the cooler (probably -8 to 1/2NPT)
-Thread the switch adapter on at the Mocal inlet or oil cooler outlet (edited to agree with tencentlife below)
-Connect it all together with -8 braided hose and the appropriate ends.

My Wahler/Volvo oil cooler adapter was the limiting factor on my turbo diesel at about 3/8" minimum hole size so the -8 (1/2") hose was a step up.

Chris

Tue Oct 14, 2008 6:54 pm

AN-10 is overlarge, but you should go with AN-8, 1/2" ID hose, not 3/8". Just because the smallest opening is 3/8" doesn't mean you want the whole circuit to be that small.

The Mesa cooler terminates with FPT fittings, most likely 1/2". You can use 1/2"MPT to 1/2" flare fittings to adapt to your AN-8 hose-end fittings. Flare fittings have the correct bevel angle for AN's to mate to. You can find them in brass in a plumbing shop.

You can use the same on the Mocal adapter instead of the BSP's if you want, being careful not to overtighten, but the BSP's are actually the correct fit. Can't tell which AN size those BSP's adapt to, but you should have AN-8 there. RPW does have both -8 and -10 to BSP.

That thermoswitch has AN-8 inlet and outlet. You can screw the body of it directly onto an AN-8 male and your AN hose female to the other end. Be very careful when tightening the switch into the body, the probe is a tiny threaded pin that would be easy to shear off. Put a little thread sealant on the small threads so it will seal without much torque.

It's best to put the thermoswitch on the return side, either the cooler outlet or sandwich inlet. That way the fan comes on as needed only if the cooler isn't able to dump enough heat on its own. If you take temp on the cooler inlet side instead, the cooler might overcool the oil. When cooling oil, think like Goldilocks: ow! this is too hot; Yuk! this is too cold; this (180F) is just right! Too cool oil is just as bad as too hot.

Tue Oct 14, 2008 7:17 pm

Brass fittings at the local hardware store are generally SAE and have a 45 degree flare. The AN flare (JIC) is 37 degrees, common to steel hydraulic type fittings. Don't mix'n'match unless you can confirm the correct flare angle.

Using a NPT fitting in a straight thread application (BSP for instance) is bad. You'll be lucky to not crack your cooler adapter.

NPT = nat'l pipe taper (self-sealing, tapered threads)
BSP = British straight pipe (straight threads, requires an external gasket to seal)
AN = Army/Navy and is interchangeable with JIC

Chris

Wed Oct 15, 2008 5:39 pm

Yeah, you're right, Chris, I forgot the plumbing flares were a slightly different angle than the JIC flares. Thing is they do work just fine; they're airtight with very little torque.

But get the right ones if you have time, 82WM, and seeing as how those BSP's look like AN-10 you'll be dealing with RPW again anyway, so get the NPT-to-AN adapters you need when you do. I guess that won't hold you up since you're in the midst of a big engine job. My suggestions were coming from someone who works in a remote location, so we learn to make do to get the job done. In a big town, you can probably drive to a place that has what you need; not so around here.

Also best to use the BSP's on the Mocal outlets, but once again the MPT's will work with no problems unless you overtorque them. They warn against it, but you would really have to yard on them damn hard to pose any risk of damage, and they'll seal perfectly well long before that. Frontier mentality again. Funny thing is, I've bought the Mocal adapters from RPW several times and when I first bought one they didn't even offer those BSP's; they got hip to that later.

Wed Oct 15, 2008 8:16 pm

Hey westyman, just go to your local hydraulic shop and take all the parts with you. They should be able to hook you up with all the fittings and take the guess-work out of the project. If you have a Parker store near you, try them. I bought my hose and fittings from them for my set up. I have some pictures of mine in my gallery if you're interested. Bottom line...your engine will be a lot happier.

Thu Oct 16, 2008 1:08 pm

Well, looks like the problem is solved
(could have sworn I responded to the suggestion about the Parker Store early this morning [5 am}over my first coffee but I must not have hit the submit button... either that or I was still asleep... lol)
Went to the Parker Store and for $5, got two brass fittings and now all I have is two the same off the sandwich plate and two the same from the cooler.
Once I get the engine in, I'll have a couple of custom hoses made and I should be in business
(I wanted threaded hose connections instead of barbed fittings so they would be easily removable in the future)
The Parker Store was great, I highly recommend them

...so, what's the best sealer to use on the pipe threads into the cooler to ensure there's no chance of a slight leak there?
No sure good old fashion teflon tape would stand up to the hot oil environment

Thu Oct 16, 2008 2:36 pm

Not teflon tape! It's not suitable for hot oils and solvents. Not much good for anything if you ask me. I only use it on airtool fittings where a little leakage doesn't matter, because I surely expect some. NPT fittings do need to have some sealer on the threads. Use TFE paste or Rectorseal.

Barb fittings suck, badly. You're doing well by avoiding them. Those AN fittings are great, they seal well with minimal torque and are easily serviceable again and again.

Thu Oct 16, 2008 2:38 pm

thanx again 10cent...
so can if find TFE paste or Rectorseal at the local HomeDespot or am I hunting for a specialty store again?
and thanx for confirming my choice away from barb fittings, i like to be able to take things part again... we are talking a vanagon here... lol

Thu Oct 16, 2008 2:47 pm

Yep, check the home fixit stores, they'll have either of those sealants in the plumbing dept.

Thu Oct 16, 2008 2:48 pm

danka... again

Thu Oct 16, 2008 8:30 pm

Hey westyman, the parker store has the hose too. It's rated at 300 degrees and uses the clamp-less fittings. So far so good with mine.

Tue Oct 28, 2008 5:47 pm

For thread sealant, here's what you're looking for:
Permatex #14, Thread Sealant with PTFE. Item # 80631. You should be able to find it at most auto parts stores. It's available in 1oz., 4oz., and 16oz. sizes.

Tue Oct 28, 2008 6:51 pm

Weird, I just brought my Mocal to Oil Filter Services in Portland, and the guy there said the sandwich plate is definitely not machined for an ORB, but requires a British tapered pipe thread. The difference being that the ORB must have a proper place for the o-ring to seat and seal. My mocal (SPTF1) has no such surface. I put the fittings in just this afternoon with Permatex 14 and it looks like the tapered thread fits the sandwich plate correctly.

Marc

Tue Oct 28, 2008 7:39 pm

They're British Straight Pipe thread and require an seal-ring. No dope. It's not an o-ring, actually, but a special double-lipped sealing washer.

But, an MPT also fits, even though the Mocal isn't a taper. It happens that the thread pitch is a prefect match, though, so the tapered male thread wedges in and seals. Within the reasonable torque needed to attain a seal, you're not putting the sandwich plate in danger of cracking.

The BSP is the correct hardware, but a 1/2" MPT works.

Tue Oct 28, 2008 8:01 pm

tencentlife wrote: They're British Straight Pipe thread and require an seal-ring. No dope. It's not an o-ring, actually, but a special double-lipped sealing washer.

But, an MPT also fits, even though the Mocal isn't a taper. It happens that the thread pitch is a prefect match, though, so the tapered male thread wedges in and seals. Within the reasonable torque needed to attain a seal, you're not putting the sandwich plate in danger of cracking.

The BSP is the correct hardware, but a 1/2" MPT works.

Looks like I'm making another trip back to Oil Filter Services. :evil: Thanks.