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Low Oil Pressure 673


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Ok, I finally got my conversion completed today. Quite the ordeal, with lots of little hidden issues I had deal with.

SDC10855.jpg

I got the oil changed and cranked it up. I left it crank over a bit before I let it fire up to get oil moving. Things went down hill from there. I can only get 15-20 psi at idle and it won't really budge over that if I do a quick rap on the throttle. Don't want to do any damage so I didn't let it run long.

I know there are two bypasses in the housing(one on top, one at the bottom mount flange). I don't really know how I could test them? I did look at my Highway service book and the END707/711 only lists 20 psi at hot idle. This is what the housing came from. My truck had a cold idle of 50 psi, and about 20 psi hot.

Anyone have some thoughts on what I should look at?? Hate to have to mount up the old full flow canister again.

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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The valve at the bottom? Not the one above the filters.

I inspected everything before installing, it's mostly visible. Looked clean, but didn't try to move the piston as no way to do it beside removing plug on outside. Guess maybe I should have?

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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The valve at the bottom? Not the one above the filters.

I inspected everything before installing, it's mostly visible. Looked clean, but didn't try to move the piston as no way to do it beside removing plug on outside. Guess maybe I should have?

I think it should be the one on the bottom. I've seen the plunger on those gall. If the spring is weak it would let the valve relieve too soon.

"Mebbe I'm too ugly and stupid to give up!"

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Ok, I finally got my conversion completed today. Quite the ordeal, with lots of little hidden issues I had deal with.

SDC10855.jpg

I got the oil changed and cranked it up. I left it crank over a bit before I let it fire up to get oil moving. Things went down hill from there. I can only get 15-20 psi at idle and it won't really budge over that if I do a quick rap on the throttle. Don't want to do any damage so I didn't let it run long.

I know there are two bypasses in the housing(one on top, one at the bottom mount flange). I don't really know how I could test them? I did look at my Highway service book and the END707/711 only lists 20 psi at hot idle. This is what the housing came from. My truck had a cold idle of 50 psi, and about 20 psi hot.

Anyone have some thoughts on what I should look at?? Hate to have to mount up the old full flow canister again.

One time i installed the wrong gasket on the block one time and had low PSI. i dont know how many differant gaskets they make.
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Yup, same pictures in my book. I matched the existing gasket when I got the new one. I then installed it while matching up the ports. I see the note where the "tab" is on the right side. Guess tomorrow I'll make sure it's correct.

I had dreams about this happening.................and sure enough.....grrrrrrrrr.

I gave the bracket to the parts guy to get the proper filters for it in hopes that would go right.

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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Yup, same pictures in my book. I matched the existing gasket when I got the new one. I then installed it while matching up the ports. I see the note where the "tab" is on the right side. Guess tomorrow I'll make sure it's correct.

I had dreams about this happening.................and sure enough.....grrrrrrrrr.

I gave the bracket to the parts guy to get the proper filters for it in hopes that would go right.

Train I haven't followed what you have done to this engine other than the housing so forgive my ignorance !BUT there is somthing I ran across some time ago , have you looked at the compressor I ran across one of these that the compressor had babit ( WORN )style bearings on the crank and it caused the engine to have low oil preasure.

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Fred, I only replaced the big canister with this spin on set up. Engine always had great oil pressure. BTW, air compressor was rebuilt about 8 yrs ago? Used to pump oil BAD.....doesn't put a drop in the system now.

Anyhow, today I did find an issue and it might be the root cause? Won't know til I find parts. I went out today and found a stream of oil/water condensation on the floor under truck. Didn't recall that being their yesterday but with the doors being opened and the floor starting to sweat I thought it was inmaterial. BUT, I thought I'd start it one more time and recheck things. It fired, gauge went to about 25 psi(better) and so I quickly looked over the cowl to see and saw a stream of oil spurting out of guage line. Oops! Seems there was a fine hairline crack in the copper pipe back under the old cloth covering and I didn't notice it yesterday. Today it really burped out so I shut it down.

Unfortunately it's 3/16" copper(WTF?) and no big box store carries it(only 1/8-1/4") so I can't fix leak til I get to Cross truck sometime this week.

I really hope it was just a leak in the line that was causing the low reading? I hope, I hope, I hope.......

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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Fred, I only replaced the big canister with this spin on set up. Engine always had great oil pressure. BTW, air compressor was rebuilt about 8 yrs ago? Used to pump oil BAD.....doesn't put a drop in the system now.

Anyhow, today I did find an issue and it might be the root cause? Won't know til I find parts. I went out today and found a stream of oil/water condensation on the floor under truck. Didn't recall that being their yesterday but with the doors being opened and the floor starting to sweat I thought it was inmaterial. BUT, I thought I'd start it one more time and recheck things. It fired, gauge went to about 25 psi(better) and so I quickly looked over the cowl to see and saw a stream of oil spurting out of guage line. Oops! Seems there was a fine hairline crack in the copper pipe back under the old cloth covering and I didn't notice it yesterday. Today it really burped out so I shut it down.

Unfortunately it's 3/16" copper(WTF?) and no big box store carries it(only 1/8-1/4") so I can't fix leak til I get to Cross truck sometime this week.

I really hope it was just a leak in the line that was causing the low reading? I hope, I hope, I hope.......

I used 1/4 plastic air brake line for my oil presure line hadnt had any problems. Ron
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That is what was on this filter housing when I got it. I need to pull the dash and see if I can change the fitting on the back of the gauge(if I can't find parts to fix the copper line).

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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That is what was on this filter housing when I got it. I need to pull the dash and see if I can change the fitting on the back of the gauge(if I can't find parts to fix the copper line).

Good find Originally on most of the R models the trucks came plumbed with 1/4 braid from the filter head to the fire wall then plastic to the gauge head I hope ya got the fix there,Kinda bad timimg for a burst line.

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That's a definite possibility. This might help.

RHasler, Is this the gasket for the plate on the block that has the piping leading out to the filter? I'm now wondering how thick this gasket is in order to have the proper PSI. I still have the original setup and same engine as Larry. I'm assuming a person has to make this gasket?

mike

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I really hope it was just a leak in the line that was causing the low reading? I hope, I hope, I hope.......

If you are pumping oil out of the line then yeah I would think that would show lower pressure on the gauge, also a restriction or kink in the line would create pressure and could break the line. This could have been your low pressure problem to begin with and the increase in pressure from the housing broke the line where the restriction was. I would get rid of that cooper line and put a braided or plastic line in.

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RHasler, Is this the gasket for the plate on the block that has the piping leading out to the filter? I'm now wondering how thick this gasket is in order to have the proper PSI. I still have the original setup and same engine as Larry. I'm assuming a person has to make this gasket?

mike

Mike, is this the pad with tapped pipe ports that you are referring to? If so the gasket number for plate part number 368GB29D is 590GB1152B. I don't know if it's still available or exactly how thick. I would imagine it's the same thickness as the other gaskets. Thickness shouldn't have an effect on oil pressure. I'll try to scan the relevant page for you later tonight.

"Mebbe I'm too ugly and stupid to give up!"

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I am not sure you can use the spin on filter setup you have on your engine. If you have a 673 there is one oil pressure valve arrangement for that engine and it appears to be the remote mounted full flow-by pass type. I have been following this topic and have done some research.

Send me a PM, for the info.

FW

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I got the gasket for the spin on set up from Mack(590gb1298b). My original set up used 590gb1109b(if I recall correctly).

The gasket rhasler shows is for the bypass filter, not the full flow version. The gasket has no issue at all with proper pressure. It just connects the two parts and keeps it from leaking. All the relief valving is inside the housing.

fifthwheel, I did enough research and comparing of mounting pads, gaskets and ports that I'm pretty sure that it's good to go(if I get the leaky line fixed).

The U model that it came from had the exact same mounting configuration(includin lack of oil cooler and piston coolers), the ports were in the same location as mine, so I can't see why it won't work. I know I have heard/seen others that have done this conversion, only never knew what parts to get.

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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Here you go Mike, these are the pages relating to the filter pad adapter. I'm not sure it's still available, but it was in a gasket kit too, part number 126SB184 for the kit, 590GB1152B for the gasket.

Thanks rhasler for the posting of the original unit. I hope Mack still has the gasket. I've had the filter brace welded. It was broken where it was bolted to the pad in several places. It should have been mounted to the frame instead of on the engine. Also had welded one of the intake bolt holes was busted from the filter bracket too loose.

mike

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FIXED!!!!! Got the leaky line to the guage fixed yesterday and PRESTO-CHANGO there is full oil pressure. Hit the key and it went right up to 50 psi, so now I can relax and work on other things.

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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