Adding turbo oil return to n/a common block

[Turbulence]

Given that the oil return in turbo blocks is pressure fit, what does one do to add an oil return to an n/a common block, other than "let the machine shop do it". Do I need to find a large tap? 5/8 big enough or 3/4?

I don't want to add drain back to the oil pan.

Thanks,

Martin
89 Horizon

[contraption22]

I would say a 1/2 npt port would be large enough.

[turbovanman²]

Factory is 5/8" so you can either drill and tap it for a brass fitting or drill it for the stock pipe. It just slides in with a bit of help with a hammer.

[SebringLX]

What's wrong with doing it this way? ;)
http://projectz.home.bresnan.net/turbo%20006.jpg

[Turbulence]

What's wrong with doing it this way? ;)
http://projectz.home.bresnan.net/turbo%20006.jpg

Nothing wrong with that, I just feel the axle is a bit too close for comfort, and since there is a place in the 2.2/2.5 common block for it I might as well use it.


Factory is 5/8" so you can either drill and tap it for a brass fitting or drill it for the stock pipe. It just slides in with a bit of help with a hammer.

Thanks Simon. I may just do that.

Martin
89 Horizon

[Turbulence]

Factory is 5/8" so you can either drill and tap it for a brass fitting or drill it for the stock pipe. It just slides in with a bit of help with a hammer.

Any idea what size drill bit to use?

Martin
89 Horizon

[cordes]

Any idea what size drill bit to use?

Martin
89 Horizon


Here is the chart

http://www.korit.com/tapndrill.htm

[4 l-bodies]

Factory is 5/8" so you can either drill and tap it for a brass fitting or drill it for the stock pipe. It just slides in with a bit of help with a hammer.

Yeah, but the factory return flows directly into the spinning #4 rod and crank. Not ideal if your concerned at all about windage. If you have equal length axles, putting the oil return in the oil pan is of no concern, as the driveshaft while turning, is not going to hit the oil return line. FYI- the Masi 16v cars plumbed the oil return in the bottom of the pan.
Todd

[BLUE BY YOU]

I agree with using the pan, not to mention a much cleaner approach if the block isn't going to make a trip to a machine shop.

[Turbulence]

Not something I am concerned with at this point. Point taken though.

Martin
89 Horizon



Yeah, but the factory return flows directly into the spinning #4 rod and crank. Not ideal if your concerned at all about windage. If you have equal length axles, putting the oil return in the oil pan is of no concern, as the driveshaft while turning, is not going to hit the oil return line. FYI- the Masi 16v cars plumbed the oil return in the bottom of the pan.
Todd

[Turbulence]

Here is the chart

http://www.korit.com/tapndrill.htm

Thanks, there is also a tap and drill index in the T-M Knowledge Center. I was unclear. I was asking about the drill bit size for pressure fitting the stock tube in the block. the two closest sizes of drill bit below 5/8 are 19/32 and 39/64. The former bit is about $26 and the latter is $29. I would prefer to only purchase one of them if I can get away with it. Thoughts?

Martin
89 Horizon

[turbovanman²]

Thanks, there is also a tap and drill index in the T-M Knowledge Center. I was unclear. I was asking about the drill bit size for pressure fitting the stock tube in the block. the two closest sizes of drill bit below 5/8 are 19/32 and 39/64. The former bit is about $26 and the latter is $29. I would prefer to only purchase one of them if I can get away with it. Thoughts?

Martin
89 Horizon


Get the one thats just a shade smaller than 5/8. Can't you take them back if you don't use them?

[Turbulence]

Yes can take them back unused. I bought the 39/64 today and got almost through the block (doing it slowly, don't want shavings everywhere, greased drill bit, shop vac hose inside the block) and the bit snapped in two...wtf? I didn't feel it jam. I had drilled the hole up to 1/2 and then moved to 39/64. I'll take the bit back tomorrow.

And I discovered the hole actually needs to be 5/8 or maybe even one size over that(?). My oil return tube won't even start in the 39/64 hole. The 39/64 bit is quite lose in the oil return hole on a old common block I have here. Might have to buy a few sizes up and return the ones I don't use. Darn, should have thought to use the return hole in the old block to test fit the bit. Live and learn I guess.

Martin
89 Horizon


Get the one thats just a shade smaller than 5/8. Can't you take them back if you don't use them?

[turbovanman²]

Yes can take them back unused. I bought the 39/64 today and got almost through the block (doing it slowly, don't want shavings everywhere, greased drill bit, shop vac hose inside the block) and the bit snapped in two...wtf? I didn't feel it jam. I had drilled the hole up to 1/2 and then moved to 39/64. I'll take the bit back tomorrow.

And I discovered the hole actually needs to be 5/8 or maybe even one size over that(?). My oil return tube won't even start in the 39/64 hole. The 39/64 bit is quite lose in the oil return hole on a old common block I have here. Might have to buy a few sizes up and return the ones I don't use. Darn, should have thought to use the return hole in the old block to test fit the bit. Live and learn I guess.

Martin
89 Horizon

Hahhaaa, yeah, that would have been a good idea, didn't know you had a spare block kicking around, ;)

[Turbulence]

Hahhaaa, yeah, that would have been a good idea, didn't know you had a spare block kicking around, ;)

Yeah, sometimes I think my purpose in life is to do things the hard way and twice, or three times, or... sound familiar ;) ? (couldn't resist, sorry).

I know I have a vernier caliper somewhere. Time to dig it out and do it the correct way :o

Martin
89 Horizon

[Turbulence]

For anyone that is interested. The size of the oil drain back hole in the block that worked for me was 43/64ths

Martin
89 Horizon

[WickedShelby88]

I'm very much debating to drill the hole and make a shield to direct the oil or just make the drain go to the pan and at least that way it will be easier to get at if I have to remove the head in the future. Good info on the drill size. I will try and see if I've got a reamer at work that size as well that way I can drill it then ream it out even so I know its smooth.

[Turbulence]

I installed the tube today. Nice snug fit. Pulling the 3.5 cylinder motor out of the hor this weekend hopefully.

Martin
89 Horizon