Herc engine oil pressure.

[motto]

I have a NOS JXD universal engine block which would make it late war production I believe. The universal block had provision to mount the fuel pump on either side. It only has gravity oil feed for the camshaft bearings so it appears the statement in the Studebaker TM that they were supplied by cross drillings from the main bearings is incorrect. It looks as if this was considered at one time however as there is a thickening in the crankcase web between the main and camshaft bearing positions to allow it.
Bottom line is, camshaft bearing condition does not affect oil pressure.
For what it's worth I've found reference to oil pressure in the Studebaker TM 10-1565 and it states:- ' The specified oil pressure is 35 to 40 lbs at 35 miles per hour or 2200 engine revolutions per minute.' That's about what I would expect to have.

David

[rsjon]

I have now fitted the new oil pump which seems to have improved the pressure.
However we are going for a run in the vehicle this afternoon to fully warm it up and then check the oil pressure again.
There is, of course, the option then of adjusting the relief valve.
Upon inspecting the insides of the engine, this engine does have bearings for the camshaft.
I have also inspected the oil filter housing but it appears to be different to the one mentioned earlier with the ball (missing).
Pictures to follow.
Jon.

[rsjon]

OK, oil pressure has improved a small amount.
When hot and cruising the op is now about 22 - 23 psi, not good enough.
We are running the vehicle to a few shows carefully and hope we can get the year out of it in the present condition.
I think probably another strip is required next winter.
As to what is wrong....I suspect wrong mains and/or big end clearances, though god knows they were checked enough, or camshaft or aux shaft bearings.
Not a good result, very disappointing.
Here are the pics of the oil filter housing, like I said quite different to the one posted earlier.

IMG_4621 (Large).jpg (72.07 KiB) Viewed 806 times

IMG_4622 (Large).jpg (87.99 KiB) Viewed 806 times

IMG_4623 (Large).jpg (110.74 KiB) Viewed 806 times

Regards, Jon.

[dgrev]

Jon

That is the correct oil filter cannister for a Greyhound.

Which brings me back to my query. Why shouldn't I use silastic where the inner
dome plate rests against the cannister wall?

Regards
Doug

[motto]

The filter canister seem to be the correct 'military senior' standard unit used on the JXD. These were definitely a bypass filter which means the oil that goes through the filter bypasses the rest of the system and is dumped back into the sump. The amount of pump output diverted through the filter is controlled by the size of the hole where it passes into the hollow tube the lid retaining bolt screws into. A very small hole will be found in the side of the tube not far down from the top. The size of this hole is critical as if it is too large then too much of the pump output goes through the filter with a resultant drop in oil pressure. Are you sure that nobody has opened up this hole Jon? Stranger things have happened.
Another possibility is a faulty gasket where the filter mounting bracket bolts to the side of the block. A leak path here between pressure and dump ports would reduce oil pressure.
Doug, I would not use silastic on an engine as it doesn't seem to stick that well. If you wish to seal around the edge of the retainer plate I would recommend using a reputable brand of automotive gasket cement.

David

[dgrev]

The size of this hole is critical as if it is too large then too much of the pump output goes through the filter with a resultant drop in oil pressure. Are you sure that nobody has opened up this hole Jon? Stranger things have happened.

My issue is the 40 seconds it takes to indicate oil pressure after starting. Once pressure is up, it is fine. So in my case I think the hole is correct size - it certainly is small!

>.Another possibility is a faulty gasket where the filter mounting bracket bolts to the side of the block. A leak path here between pressure and dump ports would reduce oil pressure.

Yes. A bit of porosity in the casting, gasket failure or improper fitment......

When you study it, combining oil and water into the one bolt on casting was on the stupid side of being clever. Just too much chance of a gasket failure resulting in the
2 getting together and ruining the engine.

> Doug, I would not use silastic on an engine as it doesn't seem to stick that well. If you wish to seal around the edge of the retainer plate I would recommend using a reputable brand of automotive gasket cement.

Thanks, I will investigate. I was worried that if I use gasket goo (set hard type), it could start to flake off as it is designed to be sandwiched rather than surface exposed to oil.

Regards
Doug

[armoured_smiler]

Hi Doug,

What was you fix in the end for the oil draining back around the 'washer' in the filter cannoster?

Regards
Paul

[dgrev]

Paul

Short answer is no.

Long answer is that it is on the to do list, hopefully in the next few months. My gut instinct is to go with silastic on the top side of the dome at the bottom of the cannister.
Someone suggested that I use gasket goo, but that worries me that it will break up and go through the system.
Where as silastic if I put it in as one big loop will hold together even if it loses adhesion to the metal.
The silastic would have to go around the edge of the dome and also under the flange on the tube that comes up through the centre of the cannister.

The warning about using silastic is valid I think in any location where it could come off and go through the oil system. But in the cannister on the inlet side of the
filter I just cannot see how it would be a risk, even if it did come loose as the filter would stop it.

Any thoughts anyone?

Regards
Doug

[armoured_smiler]

Doug,

Actually I thought the outside edge of the washer is on the return (IE been though filter?). I assumed the following the oil comes up the centre shaft, goes though the .006" hole almost at the top fill the inside of the filter, goes through the filter to the outside, then goes through the hole/tube down the side, into the bottom section and then the return hole?

Anyway I have now decided (after looking on the internet/forums to go through making (out of gasket material) a strip of gasket (about 15") to wrap around the bottom edge of the washer and compress it between the rolled edge in the filter cannister wall and 'the washer' which is held down with the 1/1/4" nut in the centre.


Regards
Paul

[dgrev]

Paul

I would need to go back and check, but I think the oil flow is into the bottom of the cannister (on the underside of the dome plate), up the side tube and into the main body of the
canister, through the filter and then through the tiny hole into the centre tube and back into the sump. ie, the opposite direction to what you state. To the best of my knowledge most filters collect
the crud on the outside folds of the element and drain to the centre. If the dirty oil flowed from inside to outside there is much less area as the oil only has a roughly 1" diameter x 6" long gallery and it would block much quicker. Whereas outside in, the area is huge.
Try cutting open a filter and spread it out and you will see what I mean.

I considered the option of making a gasket for the dome, but as the dome is very rough on the edges and the face slopes inwards (like a funnel) I could not see how I could put the gasket in, then install the dome and know that I had been successful because as soon as the dome goes in, you have lost sight of the gasket.

In short, it isn't much of a design.

See attached photo of interior of canister. As far as I know, oil flows from hole A to hole B, both of which are below the dome plate, B is the bottom hole for the side tube. Item marked C is the rolled groove in the canister body.

See attached photo, note how rough the edge is on the dome.

I do wonder just what required that dome to be so massively thick. That thought keeps niggling at me that I am missing something in my assessment of the design.

The American English spell checker on this site really does dislike my British English typing!

Regards
Doug

Doug,

Actually I thought the outside edge of the washer is on the return (IE been though filter?). I assumed the following the oil comes up the centre shaft, goes though the .006" hole almost at the top fill the inside of the filter, goes through the filter to the outside, then goes through the hole/tube down the side, into the bottom section and then the return hole?

Anyway I have now decided (after looking on the internet/forums to go through making (out of gasket material) a strip of gasket (about 15") to wrap around the bottom edge of the washer and compress it between the rolled edge in the filter cannister wall and 'the washer' which is held down with the 1/1/4" nut in the centre.


Regards
Paul

[armoured_smiler]

Hi Doug,

Yeah I know it is rough, but I assume the 'seal' is on the bottom 'edge' against the 'rolled semi-circle', so the actually the sides do not have to be smooth only the bottom edge.
Mine has a rough side, but the bottom 'edge to side' part of the washer seems to have been machined.

And you're right I assumed the oil would have to go though the .06" hole first (IE up the centre shaft), but hunting around on the internet about the Purolators shows what you said )IE outside first. This would explain that after I made this mod(I made sure the width of thew gasket was wide enough that you can see once the washer is installed that the gasket was visible all round the top edge of the washer (just). This would explain that after my gasket mod why the oil pressure (within seconds) went to it's cold pressure (before it took at least 10 secs), IE the oil has to go through the side pipe only now and not up or down the sides of the washer.

Regards
Paul

[dgrev]

Paul

I did not realise you had already done this.

So do tell, how did you get the gasket to stay in position against the rolled semi-circle when you inserted the dome?

Regards
Doug

Hi Doug,

Yeah I know it is rough, but I assume the 'seal' is on the bottom 'edge' against the 'rolled semi-circle', so the actually the sides do not have to be smooth only the bottom edge.
Mine has a rough side, but the bottom 'edge to side' part of the washer seems to have been machined.

And you're right I assumed the oil would have to go though the .06" hole first (IE up the centre shaft), but hunting around on the internet about the Purolators shows what you said )IE outside first. This would explain that after I made this mod(I made sure the width of thew gasket was wide enough that you can see once the washer is installed that the gasket was visible all round the top edge of the washer (just). This would explain that after my gasket mod why the oil pressure (within seconds) went to it's cold pressure (before it took at least 10 secs), IE the oil has to go through the side pipe only now and not up or down the sides of the washer.

Regards
Paul

[armoured_smiler]

Hio doug I mad sure the width of the gasket was in the range of 1/2", shaped it off the vehicle/bent it over the edge and weighted down to form a 'L' shape. SIbnce the canister comes off placed it doen the 'tube' making sure it was 'in place. put this ontot the base (carefully) then put the 1/1/4" central nut and tighten up.

Regards
Paul

[dgrev]

Paul

Very well done. Interesting how you came up with a totally different idea to what I had assumed.

Do I take it from your description that the gasket goes all the way inwards to the central tube?

How did you get over the "pucker" issue where you turned the edge of the gasket up to get the "L" shape - soak in water, form and then let dry?

Any photos?

Regards
Doug

Hio doug I mad sure the width of the gasket was in the range of 1/2", shaped it off the vehicle/bent it over the edge and weighted down to form a 'L' shape. SIbnce the canister comes off placed it doen the 'tube' making sure it was 'in place. put this ontot the base (carefully) then put the 1/1/4" central nut and tighten up.

Regards
Paul

[armoured_smiler]

Hi Doug,

No not all the way just about 1/4"-3/8" under the washer (doesn't need to reach the centre nut) just enough to be able to see/alter the gasket to know that it is sealing the rolled edge to the washer.

And the forming of the gasket I just held it around the edge of the washer with a rubber band and placed it on my straight plate and weigh it down overnight to basically form the shape so I could slide it in the filter Body (my filter body has a quite a bit of gap between the washer and the inside diameter), I can actually slide my 'washer' end on in and turn it at the bottom to miss the two inlet/drain tubes that stick in slightly.

Regards
Paul