Melling oil pump

[Joe L.]

Re: Melling oil pump

I wanted to post some pics of the drain plug repair on my oil pan while everything is apart. After talking to the time-sert people and getting the price for a kit to install this time-sert I decided to use a heli-core to repair. The complete process took five minutes and I am very happy with the repair.

As far as the rear main cap and damaged dowel pins, I went to the machine shop and we removed two dowel pins from a junk block so I twisted the old pins out, broached the oil pump mating surface and installed the new pins to the correct depth. They fit nice and snug so everything good there.

I am going to have the pick up screen tack welded or brazed to the oil pump cap before assembling the oil pump.

Tim------


The repair looks fine. The reason I recommended a Thread-Sert over a Heli-Coil is that I like the locking feature of a Thread-Sert over a Heli-Coil for an application like this where the drain plug is regularly removed and re-installed. However, I think this will work out fine.

If it were me, though, I think I would have been strongly tempted to use a metric 12X 1.75 thread insert so that I could use the later style GM drain plug and gasket. This set-up works perfectly for preventing oil leaks at the plug. So far, I've never found any sort of gasket that works with the original drain plug that will stop leaks 100%. Sal Carbone has suggested a NAPA plug of 1/2-20 original thread size and gasket and I've obtained that but I have not tried it yet.

[Clem Z.]

Re: Melling oil pump

i have used these on oil pan plugs with great results. http://webcache.googleusercontent.co...&ct=clnk&gl=us

[Joe L.]

Re: Melling oil pump

i have used these on oil pan plugs with great results. http://webcache.googleusercontent.co...&ct=clnk&gl=us

clem-----


From what I can see of them, these look like the GM oil plug gaskets, GM #14090908. These work very well, but there is still enough oil that gets by them to coat the area surrounding the plug and the bottom of the pan. Not a drip, by any means, but just enough to be an annoyance. Of course, these might seal better than the GM part.

The new metric GM plug and seal eliminates it 100%.

[Timothy B.]

Re: Melling oil pump

I am going to reuse the original GM pick-up screen, it cleaned up very nice and I don't believe it's available anymore and could not find it in the aftermarket.

I am making a 5/8" ID home made pipe tool to set it home inside the pump cover and thinking about using a little J B Weld to seal and lock the assembly circumference.

I would like everyones thoughts on the J B Weld as I can't imagine it ever coming apart, it seems very tight as is without anything.

[Clem Z.]

Re: Melling oil pump

I am going to reuse the original GM pick-up screen, it cleaned up very nice and I don't believe it's available anymore and could not find it in the aftermarket.

I am making a 5/8" ID home made pipe tool to set it home inside the pump cover and thinking about using a little J B Weld to seal and lock the assembly circumference.

I would like everyones thoughts on the J B Weld as I can't imagine it ever coming apart, it seems very tight as is without anything.

if it is tight you should not need anything. here is a tool i made to install the screens. put the end of the tool against the ridge on the screen tubing and tighten the hose clamp around the tubing and hammer it home. if you want to make sure it does not move i would use loctite but get the screen in position before the loctite set up

[Joe L.]

Re: Melling oil pump

I am going to reuse the original GM pick-up screen, it cleaned up very nice and I don't believe it's available anymore and could not find it in the aftermarket.

I am making a 5/8" ID home made pipe tool to set it home inside the pump cover and thinking about using a little J B Weld to seal and lock the assembly circumference.

I would like everyones thoughts on the J B Weld as I can't imagine it ever coming apart, it seems very tight as is without anything.

Timothy-----


I would recommend using a new pickup screen. The GM piece, GM #3830080, is now discontinued. However, an exact duplicate is available under Melling #55-S3 or Sealed Power #224-14227. These should cost about 10-15 bucks.

The thing is that after one of these tubes is removed, it loses its proper interference fit when re-installed. If I were to re-use the tube, I'd use Lock-Tite green sleeve locking compound and I would do exactly as you mention and use JB Weld to further lock the tube to the pump cover. I've used JB Weld for this many times when I install a NEW pick-up screen. The JB Weld has never degraded even after long service in this application.

[John G.]

Re: Melling oil pump

Another method to holding the pickup tube in place is to drill and tap a small hole in the oil pump boss that accepts the pickup tube end. A lock-tited set screw secures the works in place.

When I did mine a straight edge was used to measure the oil pan depth from pan bottom to the mounting rail. IIRC, this measurement was 8 inches. Laying the straight edge across the engine block pan mounting rail the pickup tube screen was set at 7 and 3/4 inch. I believe the pickup screen 'gap' range is from 1/4 to 3/8 inch.

[Timothy B.]

Re: Melling oil pump

To update my progress, I installed a new Sealed Power oil pump pick up and the fit is about .006 larger. After measuring from pan ralls to bottom then from block to the screen lip I positioned the pick up to allow 3/8" from bottom. When the gasket is installed, this measurment will increase by approx 1/16" so it's probably closer to 1/2".

I used the tool at the machine shop to set the pick up into the pump, it's like a impact driver that has a custom fit end to fit exactly over the 5/8" dia. tube and with a hammer drove it on. It's TIGHT.. There is nothing like using the right tool !!

Thanks Joe Lucia for the part # of the screen, I feel much better knowing the screen is new..

In my 63 shop manual the main cap bolts are called out for 60-70ftlbs. torque and oil pump bolt 45-50 ftlbs. I have read here in archives different torque specs, keeping in mind this is a 67 car are these specs still good to use. I think the main cap bolts in 1967 are 11/16 wrench size and my 63 is 5/8" but I think the thread is the same.

All comments are appreciated..

[Joe L.]

Re: Melling oil pump

To update my progress, I installed a new Sealed Power oil pump pick up and the fit is about .006 larger. After measuring from pan ralls to bottom then from block to the screen lip I positioned the pick up to allow 3/8" from bottom. When the gasket is installed, this measurment will increase by approx 1/16" so it's probably closer to 1/2".

I used the tool at the machine shop to set the pick up into the pump, it's like a impact driver that has a custom fit end to fit exactly over the 5/8" dia. tube and with a hammer drove it on. It's TIGHT.. There is nothing like using the right tool !!

Thanks Joe Lucia for the part # of the screen, I feel much better knowing the screen is new..

In my 63 shop manual the main cap bolts are called out for 60-70ftlbs. torque and oil pump bolt 45-50 ftlbs. I have read here in archives different torque specs, keeping in mind this is a 67 car are these specs still good to use. I think the main cap bolts in 1967 are 11/16 wrench size and my 63 is 5/8" but I think the thread is the same.

All comments are appreciated..

Tim-----


The main cap bolt thread size was always the same for small blocks----7/16-14. Torque on these bolts should be 70 lb/ft. The oil pump bolt is also 7/16-14 and is torqued to 65 lb/ft.

[Timothy B.]

Re: Melling oil pump

Thanks for the reply, Joe. I looked in my 1967 shop manual and it calls for 80ftlbs on the main bolts and 65 ftlbs for the oil pump. It's interesting the difference in torque settings between the 63 and 67 service books. The main cap bolt for the 67 is 11/16" socket size and 63 is 5/8" FWIW..

I always go to the 63 manual first probably because it's only Corvette and faster to get to the info..

[Timothy B.]

Re: Melling oil pump

I wanted to post results after getting my 67 running again. I am using the M-55 Melling oil pump and after making gear end clearance at .001-.002, the engine carries very good oil pressure. This engine had good pressure before this so I don't know how much I improved it.

The hot pressure is approx 30lbs at 600rpm idle and it will peg the gage at 60lbs above 2500rpm. I am concerned that the bypass in the oil filter is opening letting unfiltered oil into engine. I called Melling tech and they told me M-55 pump has a relief spring pressure of approx 55-60lbs. My next question is why not the 45 lbs like a GM standard pump. He assured me the M55 standard volume standard pressure pump is 55-60 and probably closer to 60 which is what I observed.

After talking to him he said they make a 49lb spring for this pump and he would send me one. He stated that he receives calls from restorers concerned about loosing judging points because of high oil pressure.

It's still a very nice pump...

Sorry for the long winded but I thought everyone using the M-55 would like to know this. Another good reason to look carefully at the original pump for possible reuse, I am not happy about the excess pressure because I don't believe it's needed.

[Clem Z.]

Re: Melling oil pump

I wanted to post results after getting my 67 running again. I am using the M-55 Melling oil pump and after making gear end clearance at .001-.002, the engine carries very good oil pressure. This engine had good pressure before this so I don't know how much I improved it.

The hot pressure is approx 30lbs at 600rpm idle and it will peg the gage at 60lbs above 2500rpm. I am concerned that the bypass in the oil filter is opening letting unfiltered oil into engine. I called Melling tech and they told me M-55 pump has a relief spring pressure of approx 55-60lbs. My next question is why not the 45 lbs like a GM standard pump. He assured me the M55 standard volume standard pressure pump is 55-60 and probably closer to 60 which is what I observed.

After talking to him he said they make a 49lb spring for this pump and he would send me one. He stated that he receives calls from restorers concerned about loosing judging points because of high oil pressure.

It's still a very nice pump...

Sorry for the long winded but I thought everyone using the M-55 would like to know this. Another good reason to look carefully at the original pump for possible reuse, I am not happy about the excess pressure because I don't believe it's needed.

other than start up till the oil reaches the other side of the by pass valve disk the oil pump will not open the filter by pass valve. if you are still worried just remove the spring and fiber disk from the filter adapter and tap the hole for 1/4" NTP thread and install a allen wrench type pipe plug. the by pass valve opens every time you start the engine till the oil pressure is in the oil galleries. since the unfiltered oil reaches the rear main first that is where you will see scratches when you tear down the engine.

[Timothy B.]

Re: Melling oil pump

Clem,

I understand better now, never thought about the oil on the other side of the disc. So at operating pressure this disc will stay closed unless there is a pressure differential between both sides of the filter. When this pressure differential overcomes the disc spring pressure, unfiltered oil enters the engine. This situation would only occur if the filter gets clogged.

I am upset about this melling pump not built to GM specs as far as relief spring pressure. There M55A (standard volume, high pressure pump) has a relief spring pressure of 65-70lbs. Anyone building a SHP engine should use a regular M-55.

[Clem Z.]

Re: Melling oil pump

Clem,

I understand better now, never thought about the oil on the other side of the disc. So at operating pressure this disc will stay closed unless there is a pressure differential between both sides of the filter. When this pressure differential overcomes the disc spring pressure, unfiltered oil enters the engine. This situation would only occur if the filter gets clogged.

I am upset about this melling pump not built to GM specs as far as relief spring pressure. There M55A (standard volume, high pressure pump) has a relief spring pressure of 65-70lbs. Anyone building a SHP engine should use a regular M-55.

it also occurs when you start your engine till pressure builds up in the engine oil galleries to keep the disk from popping open. you can tell if a engine has the bypass valve because the oil pressure jump up as soon as the engine starts. with the bypass plugged all the oil has to go thru the filter and you can see this on the gauge as the pressure comes up slowly