Tapping oil pump cover for turbo oil return

[Judo]

The turbo oil return hose is 5/8" ID and because it shouldn't be joined to the vac pump return (high volume of oil?), I'm planning to tap the oil pump cover like others have done. I was thinking 1/2" NPT would be best as it's only a small step down from 5/8", however it appears 1/2" NPT is almost an 18mm hole to give 1/2" ID? Surely 1/2" NPT doesn't fit? If I can go smaller than 1/2" from the 5/8" hose, then how small can I go? What size did you guys tap?

This is an 18mm spanner. Clearly I can't drill a hole that big!

https://www.aulro.com/afvb/images/imported/2013/12/354.jpg

[Judo]

P.S. While I'm here.... The oil feed is obviously on top and the return on the bottom of the turbo, but both are at about 45*. Any problems with that angle??

[Bush65]

P.S. While I'm here.... The oil feed is obviously on top and the return on the bottom of the turbo, but both are at about 45*. Any problems with that angle??
Yes, you need to rotate the turbine housing. IIRC you can be out about 5*, but nowhere near 45*.

Remove the housing before trying to rotate it as some have a dowel pin that has to be removed before they can turn.

[bee utey]

A 3/8 NPT or BSP by 5/8 steel hose nipple would be my choice as the ID could be drilled to about 13-14mm without risk. 3/8NPT is around 17mm OD max. Ford used to list one that I bought for a range of jobs, can't remember the part number now.

Failing that I'd be looking for an old steel 5/8" heater pipe end and either pressing (or silver soldering) that into the cover, the same way Ford V8 water pumps used to be done.

[Adrian18]

I didn't like drilling in to that oil pump plate so I went in beside the breather in the aluminum cover plate easy

[Judo]

I didn't like drilling in to that oil pump plate so I went in beside the breather in the aluminum cover plate easy
All of a sudden this is sounding easier... I might take the breather cover plate off and check the thickness then make my choice... :)

[flagg]

I looked at the cover too, but didn't think it was thick enough for a tap and I didn't want any oil from the drain getting into the breather..

[Judo]

I looked at the cover too, but didn't think it was thick enough for a tap and I didn't want any oil from the drain getting into the breather..
Well true, but I can't imagine I'll have more oil in my breather than Dougal. Sounded like he had some air in his oil breather. :p

Did you tap a 1/4" or bigger? Is your turbo oil return 5/8" or smaller? I have a feeling mine might be bigger than most...

[Judo]

P.S. This is my reference to Dougal's provent.

http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/143774-provent-question-dr-ben.html

[flagg]

1/4, with 8an drain. I had to put 45deg elbows in both ends to get around the breather but it drains fine.

Note that the oil requirements for mine may differ from yours. borgwarner vs garret etc.

Yes I read and re read that thread many times.. My Provent is mounted high up, with the check valve and I have a 90deg elbow in the breather before the Provent.. No oil in it.. Just mist residue. Seems to be doing what it should.

[flagg]

You have probably already seen it, but this 1/4 ntp.

https://www.aulro.com/afvb/

Don't think you would want to go much bigger...

[Judo]

Yep agreed, looking at that 1/4" is the biggest that can be safely tapped there.

Without knowing the specifics of my turbo I don't think I'm comfortable with a 1/4" drain. That's less than half the size of the drain barb on the bottom of my turbo.

Thanks for the info. I'll look for a new drain point for the moment.

[Vern]

When mike did his at my place, I'm fairly sure he drilled and tapped a half inch hole in the centre

[flagg]

What about tapping the factory turbo drain location ?

[flagg]

When mike did his at my place, I'm fairly sure he drilled and tapped a half inch hole in the centre

I didn't think that was possible as it would foul the breather above and interfere with the shaft below.. Guess I should have put more thought into it :)

[Vern]

iirc he put a 45 degree fitting in it.

[Judo]

When mike did his at my place, I'm fairly sure he drilled and tapped a half inch hole in the centre
:eek: I guess it might be fine, but I sure don't fancy that! Hard to explain without more photos, but that sounds sketchy to me. The shaft below slots into the centre hole of the cover. Not a fan of potentially altering it's movement... Plus draining onto that shaft wouldn't leave much room for the oil to drain properly from what I can see....

[steveG]

When mike did his at my place, I'm fairly sure he drilled and tapped a half inch hole in the centre

If thats what he did then I'm surprised that he ever got it to drain well enough as the shaft blocks that hole completely once the cover is fitted (apart from a few thou clearance for it to run in.

I know I had discussion with Mike as to what size he was using, but it could have been over the phone or PM if its not in his thread.
Watch out for the internal bore of the fittings you use Judo - as some have very thick walls and small bores. Drill them out if necessary.

I think bee utey's suggestion of fitting a pipe end using silver solder or pressing would be the most practical to get the largest bore in the limited space available.

Other option is the breather cover as someone said earlier. I think Rovercare took that option with his 120 build. I think that's where my provent drain goes and IIRC there was reasonable thickness to do it.

Steve

[Vern]

Hmm may be I glazed over it, but I just remember him saying something about tapping a bigger hole in it and that he could only get a small hole if he put it off centre like in judo's pic. I really didn't take that much notice:)

[Bearman]

All of a sudden this is sounding easier... I might take the breather cover plate off and check the thickness then make my choice... :)

Another way you can go is drop the sump and drill a hole in the pan above the oil level and weld/braze a 90 degree elbow in. That way you can use the size drain you want. This is what I have on mine as the turbo is on the drivers side and the drain goes directly to the sump via the above elbow.

[Judo]

Agree it's a good solution Brian (although having it above oil level might be tricky on a wingless sump?), but my aim is for a solution that I can implement without a welder. Also, I have just finished putting my new sump on. No way I want to take it off again if I can help it! ;)

Here is some further info on the side covers.

Behind the silver breather cover.

https://www.aulro.com/afvb/images/imported/2013/07/702.jpg

The cover itself, which shows the best spot is at either end, or you will no doubt be spraying oil into the breather outlet. I don't own a caliper to measure the thickness exactly, but the cover seems to be just thick enough to safely tap considering there won't be any great force applied to it. It is aluminium (or potentially an alloy, but it's not magnetic at least).

https://www.aulro.com/afvb/images/imported/2013/07/703.jpg

With most stuff I'm doing, it's the first time! I'm assuming these are push rods for the tappets in the top cover? Would oil drain down here during operation?

https://www.aulro.com/afvb/images/imported/2013/10/1003.jpg

This is what is seen down the centre hole. Oil pump gears, but also plenty of space for drainage.

https://www.aulro.com/afvb/images/imported/2013/07/704.jpg

To the left of the breather cover is also this cover/plate. Holding it in my hand it feels much heaver than the other one and is made from steel. I would say similar thickness, but if the hose routing suits, this will be my choice for tapping.

https://www.aulro.com/afvb/images/imported/2013/07/705.jpg

Behind it is identical except down the centre hole there is no oil pump gear. Looks like a shaft goes past there, but again, plenty of space for oil to drain.

https://www.aulro.com/afvb/images/imported/2013/10/1004.jpg
https://www.aulro.com/afvb/images/imported/2013/07/706.jpg


Unless anyone sees issues with the above, I would say these provide a lot of simple options for drain location and sizes. :)

[steveG]

Forward cover is just thin steel (1.6mm or less) and too thin to tap (but would be fine with a tube brazed/welded in.
Rear alloy cover is definitely thicker and should be OK to tap but I wouldn't be keen for a large diameter fitting.
Avoiding welding, my advice would be to stick with the tried and true method of tapping the oil pump cover and make sure you keep the internal diameter of any fittings as large as possible. Use a slight reducer between the fitting and the drain tube from your turbo if you have to.

Steve

[Judo]

You don't think going from 5/8" on the turbo to 1/4" ID at the other end is too much? Seems like a big reduction...

[steveG]

I'm sure that I got bigger than 1/4" into mine. Think I drilled the internal diameter hole all the way through, and then put the tapping drill for the thread in just deep enough to be able to tap a secure thread.

Here's another idea that I haven't looked into in detail. What about fitting a bolt on flange like this (http://www.ebay.com.au/itm/Turbo-oil-drain-flange-Garrett-T3-T4-T04-GT40-GT50-GT55-to-1-2-NPT-/170992604895) - either to the oil pump cover, or possibly onto one of the tappet covers.

Steve

[Adrian18]

As said before mines in the alloy cover I put it as far as possible away from the breather hole and low down never had a prob with oil ...I drilled and tapped 5/8 or so hole ... cheers

[Judo]

I'm sure that I got bigger than 1/4" into mine. Think I drilled the internal diameter hole all the way through, and then put the tapping drill for the thread in just deep enough to be able to tap a secure thread.

Here's another idea that I haven't looked into in detail. What about fitting a bolt on flange like this (http://www.ebay.com.au/itm/Turbo-oil-drain-flange-Garrett-T3-T4-T04-GT40-GT50-GT55-to-1-2-NPT-/170992604895) - either to the oil pump cover, or possibly onto one of the tappet covers.

Steve
Brilliant idea Steve. Cheaper too, as I don't need to purchase the rather expensive drill bit and tap for 1/2" NPT.

HOWEVER, neither of those cover plates have a flat surface that size. The black steel cover has a curved face. Sealed with RTV silicone might be enough to deal with the curve, but could result in a leak...

[steveG]

Ebay is your friend for taps - either NPT or BSP in 1/2" can be had for around $15.

Although I said I wasn't keen on tapping a large hole in the alloy tappet cover, since Adrian18's is working fine just run with that.

Just careful you don't end up in the situation that I did with looking at each problem in isolation, then having to re-do things to solve the next issue. Think about where you're going to run all your provent, exhaust, and intercooler ;) plumbing before committing to anything.
You might find that getting a tube welded into the sump becomes an attractive option....

Steve

[Bush65]

Another option is to replace one of the covers with a flat steel plate of 5 to 10 mm thickness.

[Ancient Mariner]

Forward cover is just thin steel (1.6mm or less) and too thin to tap (but would be fine with a tube brazed/welded in.
Rear alloy cover is definitely thicker and should be OK to tap but I wouldn't be keen for a large diameter fitting.
Avoiding welding, my advice would be to stick with the tried and true method of tapping the oil pump cover and make sure you keep the internal diameter of any fittings as large as possible. Use a slight reducer between the fitting and the drain tube from your turbo if you have to.

Steve
Just measured the steel cover in the boat 3.2mm or .125" thick good enough to tap and if unsure Locktite a backnut on .A better solution would be a SS socketwith a birdmouth cut to go over the rounded section TIG welded on as any vertical angle will drain better

AM

[Adrian18]

Here's my set up the black rubber is the turbo oil dump the shiny pipe is the crank vent I re routed it to the intake side after turboing

[flagg]

Just buy a TIG already ! :-p

[Judo]

Another option is to replace one of the covers with a flat steel plate of 5 to 10 mm thickness.

Also good thinking, although:


Just measured the steel cover in the boat 3.2mm or .125" thick good enough to tap and if unsure Locktite a backnut on .A better solution would be a SS socketwith a birdmouth cut to go over the rounded section TIG welded on as any vertical angle will drain better

AM

I don't see a problem in tapping 3.2mm. Either way...


Here's my set up the black rubber is the turbo oil dump the shiny pipe is the crank vent I re routed it to the intake side after turboing

Thanks Adrian.

Lots of options... :)

[Judo]

Just buy a TIG already ! :-p
OK! :angel:

[Vern]

When mike did his at my place, I'm fairly sure he drilled and tapped a half inch hole in the centre

Well, whilst looking at my spare motor, I discovered the oil pump cover has a bolt in the centre of it. It appears to have been tapped:mad:. I keep finding a few things that are ****ing me off:mad:

[Bigbjorn]

Ebay is your friend for taps - either NPT or BSP in 1/2" can be had for around $15.

Although I said I wasn't keen on tapping a large hole in the alloy tappet cover, since Adrian18's is working fine just run with that.

Just careful you don't end up in the situation that I did with looking at each problem in isolation, then having to re-do things to solve the next issue. Think about where you're going to run all your provent, exhaust, and intercooler ;) plumbing before committing to anything.
You might find that getting a tube welded into the sump becomes an attractive option....

Steve

I am your friend for taps, not e-bay. Brian's Retirement Sale, best prices in Australia. Haven't you seen my ads in Restored Cars, just Bikes, Just Cars. PM me for prices.

[Bigbjorn]

The tapping drills for 1/2" NPT are:-

with taper reamer 11/16"

without taper reamer 45/64"

[Bush65]

...

With most stuff I'm doing, it's the first time! I'm assuming these are push rods for the tappets in the top cover? Would oil drain down here during operation?

https://www.aulro.com/afvb/images/imported/2013/10/1003.jpg

...

https://www.aulro.com/afvb/images/imported/2013/10/1004.jpg

...
Just because I'm a pedantic bas...

You appear to have made the common mistake of confusing rocker arms and tappets. This is understandable if the engine has overhead cam shafts, and also because the adjustment for the "tappet clearance" is often a screw and lock nut in the rocker arm, however many engines (not the 4BD1) have hydraulic tappets that don't need adjusting.

The tops of two tappets are visible protruding from the block in the last photo in the above quote.

The tappet runs against the camshaft lobe transfers the cam motion to the push rod and the push rod operates the rocker arm to control the valve opening/closing.

The oil used to lubricate the rocker gear and valves, drains back down through the holes for the push rods into the tappet chest.

[Judo]

The tapping drills for 1/2" NPT are:-

with taper reamer 11/16"

without taper reamer 45/64"
Shame I didn't realise you were selling taps a while back Brian. Who knows when I'll need more tho!

I googled 1/2" NPT drill size and ended up with 23/32 (although there was varying results). It worked OK anyway, plus I brazed the fitting on after I screwed it together so no biggy if it's a fraction out.

[Judo]

Well, whilst looking at my spare motor, I discovered the oil pump cover has a bolt in the centre of it. It appears to have been tapped:mad:. I keep finding a few things that are ****ing me off:mad:
As long as it's not interfering with the shaft that fits into the centre of the cover, does it matter? Where are you draining your turbo to?

BTW, do you have a build thread for the rangie? :) I can never remember if you've covered these points already...

[Vern]

Nah I don't have time for a build thread, just get it done when I can:). My Turbo drain goes back into the rear tappet cover, I drilled and tapped a 1/2" bspf thread and screwed a 1/2" 90 degree fitting into it. Now I just need to sort my Turbo feed, thinking of double banjo fitting at the vac pump.

As for the oil pump cover, I think I wasn't supposed to notice that had been done to it, because I definitely knew I'd seen one that was centre tapped, I also noticed one of the bolts had been snapped off on my good engine:mad:
Never helping anyone again;)

[Judo]

Nah I don't have time for a build thread, just get it done when I can:). My Turbo drain goes back into the rear tappet cover, I drilled and tapped a 1/2" bspf thread and screwed a 1/2" 90 degree fitting into it. Now I just need to sort my Turbo feed, thinking of double banjo fitting at the vac pump.

As for the oil pump cover, I think I wasn't supposed to notice that had been done to it, because I definitely knew I'd seen one that was centre tapped, I also noticed one of the bolts had been snapped off on my good engine:mad:
Never helping anyone again;)

I see.. :(

[walahbro]

Hi guys after reading through all the above, is there a concensus for where the best/easiest place to run oil drain hose? Took off the cover below the the oil breather hose is, and doesnt look like the right spot, am i meant to just aim for the middle of the plate and into that circular thingy? (Technical term)80884 80883

[walahbro]

Sorry not sure why but tapatalk doubles up on photos

[Judo]

It depends how big you want the drain. From flagg's photo the biggest you could manage without interfering is a 1/4". The centre of the cover holds the shaft in place that you can see looking into the block.

http://www.aulro.com/afvb/attachments/isuzu-landy-enthusiasts-section/56916d1361267554-not-so-budget-turbo-install-dsc_3373.jpg

[walahbro]

My cap looks different it's completely flat see the pics.

When tapping this do I want the barb to sit in centre of the cylinder or just outside it? And should I going the barb flat so it doesn't come into contact with the cylinder

[Judo]

So it is. What year is your engine? That's definitely different to most of the County Isuzu's.

Judging by the photo, it looks like the oil needs to go slightly down the side? Wherever you think it will get to the sump the easiest! The angle of the barb is just the best you can so you can connect a relatively straight hose to the turbo drain.

[walahbro]

Engine is an 88/89, but it's a perentie so it may have had a heart transplant somewhere along the way. Judo I've got a turbo just like yours think the oilike drain is quite large and there's not much room down the side of that cylinder could probably get a large barb and cut it flush with the plate but probably get only a few turns into it

[rar110]

Engine is an 88/89, but it's a perentie so it may have had a heart transplant somewhere along the way. Judo I've got a turbo just like yours think the oilike drain is quite large and there's not much room down the side of that cylinder could probably get a large barb and cut it flush with the plate but probably get only a few turns into it

The Perentie engine has a diamond shaped plate held by two bolts, just in front of the starter motor. That's where turbo motors drain to.

[walahbro]

Awesome thanks rar110, this will do nicely, large diameter hole into engine

[Judo]

^ do that!

[Dougal]

Awesome thanks rar110, this will do nicely, large diameter hole into engine
Lucky you, turbo spec block. If you ever have the sump off check for piston squirters.