Refitting the Oil Return Tube

[Tmac897]

I am in the final stages of the engine rebuild, and I’m refitting the sump, front, and rear covers, in preparation for refitting the head.

Don’t want to screw things up at this stage, and i need to refit the oil return tube. Nothing in my shop manual. From where it emerges from the block, at least some portion of it fits into a recess on the oil pump housing. And the end of the tube nearer the bend seems to be flared a little bit, and won’t easily fit inside the bore in the block.

Several questions emerge:

1) What is the orientation, I.e., is the bend and shorter side toward the oil pump, or toward the sump?

2) How much, if any, of the tube protrudes into the oil pump?

3) Is that flare meant to be the “stop” as the tube goes into the block?

I’ve included a picture of mine, which I bought used.

Thanks,
Tony

[elangtv2000]

The only oil return tubes I've ever seen have been straight, not bent like yours.

[Tmac897]

Well, seems straightening it out is #1, and that answers two other q’s.

Is the oil pump end flush with the block, or does it protrude slightly into the pump body?

[elangtv2000]

Hi Tony,
I have a 1967 S3 SE Coupe as well! Also an S4 DHC.
Here's a photo of the BD engine I built recently; the return pipe is driven into the block (maybe 1/2" or so?), not the pump. Am I understanding your question properly?
I used 3/8" hydraulic tubing, and left the flare at the end for a nice termination, but normally it's just a straight cut end.

[Tmac897]

Hi Tony,
I have a 1967 S3 SE Coupe as well! Also an S4 DHC.
Here's a photo of the BD engine I built recently; the return pipe is driven into the block (maybe 1/2" or so?), not the pump. Am I understanding your question properly?
I used 3/8" hydraulic tubing, and left the flare at the end for a nice termination, but normally it's just a straight cut .

Actually that’s really helpful! Yes, I was asking about the insertion into the block. Mine is obviously in pretty bad shape as one end slips into the block with room to spare, while the other end is flared and doesn’t fit at all. So I was thinking that I’d have to insert it into the hole at the side of the block and then pull it up into the sump. If I can’t get mine straightened out properly, I can try the hydraulic tube route.

Just wondering, is your ‘67 a 4-bolt crank or a 6-bolt?

[elangtv2000]

Post photos of the block oil holes and your pickup/strainer, please. What do you mean by "pull it up into the sump"? It fits tightly into the hole in the block, and is long enough to be above the bottom of the sump by maybe 1/2" or less.
Fair point perhaps; mine is 6-bolt with later style oil pickup/return. Is yours 4 bolt with earlier pickup? It's been a decade since I've been inside a 4-bolt so I can't really recall whether the return pipe differs.

[2cams70]

You can buy those tubes new from QED.
Most oil pumps these days are copies of the later Ford design with the oil return connected direct to the pump inlet. If that's the case you only need this tube for the mechanical purpose of retaining the inlet pipe mesh filter and not for returning bypassed oil back to the sump.

https://qedmotorsport.co.uk/product/oil-return-pipe/

[Tmac897]

You can buy those tubes new from QED.
Most oil pumps these days are copies of the later Ford design with the oil return connected direct to the pump inlet. If that's the case you only need this tube for the mechanical purpose of retaining the inlet pipe mesh filter and not for returning bypassed oil back to the sump.

https://qedmotorsport.co.uk/product/oil-return-pipe/

I have the older style sump, which is a flatter, larger diameter pickup tube, and it has no connection to the return tube. If I’m not mistaken, the end of the oil return tube should be below the level of the oil in the sump, to prevent air bubbles/frothing in the sump. The older pickup tube has an inherent oil starvation problem, so I don’t want to make that worse.

Thanks for the info on QED. I’m in the US, so I’d rather try and find something local, so I can move this along. Probably R Dent or DBE, if the hydraulic tubing doesn’t work.

Best,
Tony

[2cams70]

If you've got the large pancake type mesh filter you probably don't need the oil return tube in that case. Check your oil pump to see if there is a port between the pressure relief valve and the pump inlet. If so the return tube will not be required or functional.

If you have the earlier cartridge filter pump or the early spin on type (701M casting number) these did not have this port in which case it's best to have the return pipe. Ford 731M casting number spin on filter pump and most of the pattern pumps which are copies of the 731M design do not require the return tube as the opening on the block is blanked off by the pump body when you fit the pump.

[Tmac897]

If you've got the large pancake type mesh filter you probably don't need the oil return tube in that case. Check your oil pump to see if there is a port between the pressure relief valve and the pump inlet. If so the return tube will not be required or functional.

Thanks, this is helpful info. The engine was disassembled many years ago, and I don’t remember having to pull out a return tube. I’ve been going from the parts books to determine what I’m missing after 30 years of neglect, and some of the parts listed don’t indicate some of the differences between engine iterations. So I will double check if it’s required for my configuration.

[Tmac897]

I was able to straighten out the tube without compressing it. Flared out one end for a better friction fit, and inserted the tube about 1/2” into the block. S/B good to go.

Thanks everyone for your help.