Oil Spray Bar Question

[2002#3]

'70 2002 with '75 block 

 

As many other FAQ'ers have done, I am investigating a low OP issue at start-up and an irregularly flickering OP idiot light at idle.  I am using an OTC OP gauge (photos 1 and 2).  (I know about the difference between the 7 psi VDO and 14 psi OEM sender minimums.)  Many FAQ posts which have addressed similar/related low OP issues have suggested checking the oil spray bar efficiency/pattern.  I removed the VC and cranked over the engine for a few seconds.  Yes, it was a little messy; not too bad.  As near as I could tell during that short time, the only place oil was being sprayed (quite nicely) was at the TC end of the spray bar.  I assume the remaining holes in the bar would produce/spray as the oil heats.

 

Q:  Is the TC end supposed to spray to assure good TC lubrication or not supposed to spray and, therefore, is leaking? See forceps indicating end of spray bar (photo 4).

Q:  Am I to assume a leak here would (1) reduce oil spray elsewhere on the bar and (2) and show up as less pressure downstream at the OP switch?

Q:  Is that a plug of some sort?  Bolt?  How to repair, tighten, plug, replace if such is needed?

Q:  Is it time to remove the spray bar, clean the bar and the central banjo fitting (center, photo 3), and replace the crush washers and TC plug?  If so, an easy work order?

 

* Data using an OTC gauge (photos 1 and 2) :

• initial idle (bottom blue):  25-30 psi (never in the hallowed 80+ range) (THIS IS WHAT MIGHT BE TROUBLING.)
• few minutes idle (mid blue):  60 psi
• more minuets (top blue):  15 psi 
• warm (3:00) idle:  15 psi  
• warm (3:00) and highway:  60-70 psi (depending on rpm) (See photo #2 for driver's view of ad hoc OP gauge for very brief highway use.  Cool, huh?)

 

Thanks for your thoughts and comments.

 

Larry

 

 

[halboyles]

There should be amble oil dripping from the five holes in the bottom of the oil pipe.  Also make sure while you are in there that there are seal/spacer rings on both sides of the oil pipe where the center bolt goes through.

[Einspritz]

My knee jerk response is to see if the plugs at the ends of the rocker shafts are leaking. Old OE shafts had a plug much like a freeze plug that can become loose. What you can't see is the shaft end at the distributor and would then need to remove the fitting to check.

 

I think that this is the replacement part:

11331266400

which is a solid aluminum plug with serrations so that it does not loosen.

 

Your pressures seem to be "OK" as the idle pressure S/B 11.4-17.1 psi at idle, 57 psi (4 Bar) at 4000 rpm, which "may" change depending on which oil viscosity you use, and the temp of the oil. Remember that those specs were for oil that was available in the '70s.

 

And too, "at speed" the volume of the oil pump may be sufficient to override any ill fitting plugs but not enough to overcome it at idle.

 

Nonetheless, it may just be a lazy sending unit, bad wire connection, or sufficient corrosion / resistance in the sender wire to the gauge to create a situation where the oil light comes on.

 

I always shim the relief spring at the pump to gain increased pressure over the rpm span (I think its 30 psi at idle using an analog VDO gauge) ever watching the pressure until the engine is hot.

 

1 hour ago, 2002#3 said:

Q:  Is the TC end supposed to spray to assure good TC lubrication or not supposed to spray and, therefore, is leaking?

 

I don't think so, but you can use your finger to see if there is a hole, or I can check later today.

 

HTH

[Schnellvintage]

+1 to the above.

 

I have also seen, on high mileage engines and neglected oil change intervals, the oil pump pressure relief piston gets stuck and does not move freely, and unfortunately it gets stuck in the relief position.   Look at oil pump diagrams in repair manuals to see photos.  I don't have one handy right now.

low oil pressure sucks!!!

Matt

Edited June 20, 2019 by Schnellvintage
added info

[TobyB]

If you're chasing low oil pressure, it's not the drip bar's fault.

 

The usual causes apply, plus, the o- ring on the oil pump where Schnell's overpressure

valve attaches can blow out, and cause both long pressure build times and low idle pressure.

 

t

the tube's likely a symptom, not a cause.

 

 

[Einspritz]

I checked yesterday to find that there are holes at either end about 1 cm in.

[kbmb02]

An example of something you don’t want to see at the spray bar banjo bolt (this, on a car I just took in to revive and prep). -KB

 

[2002#3]

Hal, Ein, Schnell, Toby, and kbmb,

 

Thanks for the comments, suggestions, and guidance.  Bar appears to drip oil nicely where it should and leak only at the plug on the forward end.  Going to live with what appears to be decent OP at all time/temp combos, except for low OP at initial start-up.

 

Q:  How does one remove the old plug and re-plug the end of the spray bar?   

Q:  Can be above be performed with the bar in place?

Q:  Does the bar have to be removed and, therefore, head bolts, too?

 

Larry

 

 

 

 

[halboyles]

I've actually never taken one apart but it appears that the plugs at both ends are crimped into place.  The plugs must have a groove in them that the crimp grabs on to.  But in checking about a half a dozen of those pipes just now it turns out that about half of them have one end just crimped flat without a plug.  So maybe you could just remove the round plug and crimp the end together.  See pics.

[2002#3]

Hal,

Mine definitely has a fore plug and an aft crimp.  Not sure I could sufficiently crimp the fore end of an in-place bar.  I have found plugs on Ebay.

Larry

[kbmb02]

1 hour ago, 2002#3 said:

Q:  How does one remove the old plug and re-plug the end of the spray bar?   

Q:  Can be above be performed with the bar in place?

Q:  Does the bar have to be removed and, therefore, head bolts, too?

 

 

Not long ago I changed one in a race engine, and only needed to remove the center banjo bolt (it slid out of the ‘holders’, did not need to remove head bolts). -KB

[Einspritz]

Do you need one?

 

I have probably one extra but don't know which style.

[2002#3]

Thank you, sir.  I appreciate your offer.  Let's wait for now.

I ordered a new bar ('83 head on a '75 block in a '70 body).  Only $20.  We'll see how it works.  I also ordered a new hollow bolt for the bar and new crush washers for the bolt.  While I am in there I might as well spiffy up a few accessible parts.

Larry

[KFunk]

I’ve actually (quite stupidly) drove for several weeks, or months, and maybe a track day, and at least one autocross, with no oil spray bar at all.  Nope, just an open hole there.  No oil lights, not even with the sensitive Vdo sensor, no issues.  Eventually found the bar sitting around and realized,  oops, maybe I needed that? Removed a few head bolts, put bar back on, re-torqued.  

 

So yeah, like Toby said, look for your problems elsewhere.

Edited June 24, 2019 by KFunk

[TobyB]

Quote

 the hallowed 80+ range

 

that proves your pump bypass valve is stuck,

 

 Is all that does. 

 

60 psi at 2500 rpm after a 1/2 hour drive is fine.

 

15 psi at idle is a bit low, but we've all run engines 

like that, and they've lasted years that way.

 

You actually don't want to see 80 psi. 

Except maybe if you're running 15-60w, and

you're in Minnesota and it's below 0.  fahrenheit.

 

 

The oil drip bar is metered by the center cam journal,

so it receives pressure for only a fraction of each cam rotation.

It's not a high- volume delivery system.

 

t