Drilling block for oil feed?
 

So I've just been swapping out the engine on my '93 1.6 due to a crank issue, built up the new engine almost ready to drop into the car again. Last thing on the list was the turbo oil feed..... But the hole I had on my old block (hotside by flywheel) doesn't exist on this new one!

After doing a bit of research the later UK cars didn't come with them which is a bit of a bummer. I have found out you can T off of the pressure sender on the other side of the block but seeing as I already have my line sorted and the engine out the car, can I just drill and tap into where it should be?

Please say you can!!

Thanks in advance :D

T off the sender...
/ thread.

I have the oil line and a tap already. If I went for the other option I'd need a whole new line with new fittings and everything. Hence the question!

good luck.


/thread.

Well, you may have had it sorted for your old block.

:ohnoes:
:burncash:

Get a new line and fittings from FM or find the parts yourself, because if you ---- this up and drill into the water jacket or something we're just going to laugh at you.

You would need to drill and tap several inches in at the perfectly correct angle or else you have a good chance of hitting other things in the block. Joe Perez even says it is not worth attempting to tap.

You shoulda done a 1.8.

Oh really that far in?? I was working under the assumption that it'd only be a few mm's worth of metal to go through, any more than that and I agree... It's probably not worth the risk!

Drillin' for oil in Mazdaville, eh?

Sung to the tune of The Beverly Hillbillies:
Yeah, I looked at doing this a couple of years ago on an NB block.

The casting feature to support the oil feed is actually still there, but the problem is clearance. You'd need to drill a hole about 3mm in diameter and 10cm deep, perfectly centered, with absolutely zero error in the angle of the drill. Otherwise, you'll perforate the block.


http://img37.imagefra.me/img/img37/2...wm_bf36560.png


http://img40.imagefra.me/img/img40/2...2m_7793951.png


A *really* competent machine shop might be able to pull it off, but I sure as hell wouldn't attempt doing it to my own engine at home.

JP, thanks a lot for the helpful (and mature) reply! That has sealed the deal, its a no go situation.

I already have an oil filter sandwich plate which I use to supply a temp guage, so I think I might try and utilise a port off of this for the feed instead. Hopefully Pirtek can lengthen my existing line and throw the correct fitting on for that, or perhaps I can bore out one of them to accept the m10x1.5 fitting...?

100% chance a drill that size will walk.

Darn, I wanted him to try it. :D

Just a shot in the dark. What about a high quality EDM machine or rifle bore type of machine? I'm sure someone around here has access to some crazy stuff. Not saying it's a good idea, just cool that it "could" be possible.

Yes, a gun drill would have no problem with that. It'll drill that hole exactly where you point it - the harder part, imho, is positioning the block on the milling table. If the hole is parallel to the head surface and side of the block...piece of cake. Even a regular long-reach drill bit would do the job.

By hand - no way!

--Ferdi

OTOH, drilling for water is not a problem. Done this twice already. You need to drill about one inch deep, so no big deal.

Yeah, the water hole is easy. It's a shallow cut, and more importantly, high precision is not required. There's nothing delicate that you'll hit if you're off-center or not straight, and since your target is the water jacket, it's pretty much impossible to miss.

Taking water from this location also has the advantage of permitting a hose-routing which encourages convective movement of water after the engine is shut off.

Are there any disadvantages to taking the feed from the sandwich plate as opposed to where I had it before? Aside from the obvious hassle of routing it.

I know I don't really have a choice in the matter now but it would at least put my mind more at rest if there weren't! To me it just seems like a bit of a bodge...

To the best of my knowledge, all of the commonly-available oil filter sandwich plates allow the user to draw oil from the system on the pre-filter side, rather than the post-filter side. So the oil which you're getting from it is technically un-filtered, inasmuch as it contains whatever might happen to be floating around in the oil sump prior to filtration.

That's the only potential drawback I can think of, and of course sufficiently many people have been running in this configuration without having reported any serious harm.

Tapping into the hole which supplies oil to the pressure sensor (as is done with the Bell and FM kits) will provide you with post-filter oil.

Saying that, I already have one of these:

https://www.miataturbo.net/attachmen...ine=1341522387

So once the hose is made up I could theoretically use either location?

I never considered the sandwich plate offered unfiltered oil but you're absolutely right Joe. In light of that, I believe this would be the best solution to your conundrum:

https://www.miataturbo.net/attachmen...ine=1341522686

Eaton 1/8"BNPSTWIERHJK to -4AN fitting then attach your pressure sending unit to sandwich plate and hope it doesn't leak all over the place.

A damn good shout that actually Scott!

And the oem sender is 1/8NPT yes?

Nope, stock sender is 1/8BSPT.

--Ferdi

Indeed. 1/8 BSPT.

The specs two are *really* close. 1/8 NPT is 27 TPI with a major diameter of 0.405", whereas 1/8 BSP is 28 TPI with a 0.383" major diameter.

Some folks report that the two can be interchanged, provided that one exercises caution and is liberal in the use of sealant.

Others prefer to use the correct adapters.

https://www.pegasusautoracing.com/gr...D=PLUMADAPTBSP

Use an oil safe sealant (Rectorseal5 for example) on the OEM sending unit, it will thread into a 1/8NPT standard port perfectly, you just can't install 1/8NPT into a 1/BSPT hole. Ask me how I know. Didn't even know such a thing as "BSPT" existed until Husty and some others clued me in on my thread, not that I'm a pipe fitter or anything . . .

Look a ahiity old block is like $100.

I will tap ur block bby

It is not like our block is rare am commodueit

Speaking of oil feeding.
I have an NBB so I want to run a mechanical oil guage in the car, any idea what length I need of 4AN braided going from block port through firewall to guage near steering wheel. I could measure myself but then what good is that gonna do?

what the fuk is rong with you

no. do not run mechanical oil gauge into the damn cabin. 200* oil spraying on you is fail

Hmm food for thought.

You know I had a nylon line in my VW for years but never thought about the temperature of the oil. It never leaked after years of use so I never paid the "what ifs" much attention.

I know there are people that do it, is not braided line to brass gauge fittings very very reliable?

My mechanical fuel gauge with heater hose line in the cabin has never leaked, gets a bit of fumes going after a hard run but that's all. Since I'm so busy texting I get the kids to watch the dial when I'm full throttlin'.

whatever. go ahead and live on the edge.

you may as well run the fuel gauge in your lap.

sure it didn't break before.
but just think: if it happens just 1 time there's a good chance you'll be f*'d for life.

Ha the fuel guage was a joke.

So then get an electrical guage and sender but run the braided line from the block out a few feet then connect to the sender so to avoid vibration damage to the sender unit??

run a stupid remote sensor like the rest of the 205th sentury

Pretty much.

I've never seen it happen, but there are a few horror-stories floating around about hoses (or gauges themselves) failing, with the result of 250 degree oil being sprayed into the driver's compartment at 60+ PSI. I'd imagine that this is probably an unpleasant thing to experience.

They do make diaphragm-style isolators for use with mechanical fuel pressure gauges. Not sure if I've ever seen one rated for use with oil, but they may be out there.

On the other hand, as cheap and reliable as electric gauges are, coupled with the fact that it's a lot easier to run a wire than a braided line, I'd personally stick with the electric gauges across the board. Direct-reading mechanical gauges are so 19'th century. :rolleyes:

Prosport Gauges Oil Pressure Gauge 52mm

$43 bux and some change for shipping. Don't cheap out when it comes to something safety related...

Going with electric unit.

Isn't there a reasonable amount of vibration failures associated with attaching the electric sending unit directly to the block. I had heard running some hose/line from block then the sender unit will isolate it from quite a bit of vibration and ensure a longer life.
Paranoid or overkill ?
Wait did I just go from borderline unsafe to oversafe?

Incidental: I have heard that those blackout-style gauge can be difficult to read when exposed to direct sunlight in a convertible with the top down.

Considering that the '90-'94 engines all had analog sensors mounted to the block, and they don't seen to be experiencing an abnormally high rate of failure after 18-22 years, I'd have to say that no, this is not a serious concern.


What I have heard (but never seen first-hand) is that putting the heavy analog sender on the end of a tee-adapter combination can lead to stress-induced fracturing of the mechanical fittings between the sensor and the block. This would argue for a remote fitting if your application requires intermediate hardware, such as when using the oil pressure hole for a turbo oil feed on a later-model engine.

Thanks for the tip on the blackout gauges, good point, and the leverage on the fittings when piggybacking the block port.

If a sandwich plate is used as well as the block port what is the best spot for the turbo line and pressure gauge when choosing from either feed?

Joe is correct, direct sunlight makes it a little difficult to see but not impossible.

Oil line from block, pressure from sandwich.

Okay I have a plan forming in my head, the last piece of the puzzle that Im not 100% on is if I use -3AN or -4AN line for the turbo feed? Seen them both mentioned in different threads!

-4 an.