Oil Pressure concerns

There was a discussion on this a while ago, but I am pretty sure there isn't supposed to be a gasket between the block and oil pump. I ran into this on my '68 200. There wasn't one when I tore it down, there is no part number for one, and I've never actually seen one on any car with a similar flange for the oil pump->block union. I suspect what you've got is a gasket cut out of gasket material, rather than a purchased part. I would check that flange with a straightedge & feeler to be sure it's flat (that is, make sure that gasket wasn't intended to solve a problem), then clean that pick up screen and bolt the oil pump right back on there sans gasket. A gasket in the sump is just a liability. If anything, a light smear of suitable RTV should go there.

There is indeed a torque spec, but I don't know if off the top of my head... there are several FSMs on falconfaq.dyndns.org as well as a couple posted to scribd (http://www.scribd.com/doc/54682662/1968 ... hop-Manual is one I used!). I'm sure on of 'em will have the spec for you.
 
I grabbed this off a Mustang site for '66 200. I'd check a Ford service manual too, just to be sure. I don't know what year your engine is, but I doubt that it makes any difference.

"Shaft diameter for the main bearings was between 2.2482 inches and 2.2490 inches, and between 2.1232 and 2.1240 inches for the rod bearings. Clearance for the main bearings was between .0005 and .0022 inches, and between .0008 and .0024 inches for the rod bearings."

You'll need the green Plastigage:
http://www.autozone.com/autozone/ac...lastigage/_/N-25xn?itemIdentifier=202588_0_0_

It might just be the mounting surface leaking, but I'd open up the pump, clean it real good and give every part a thorough inspection. Pay particular attention to the rotor (sides and faces) the outer rotor (again, sides and faces) and the housing. Also, chekc the mating surfaces of the relief valve seat and plunger. If it's good, you don't have to replace it - you can re-use the parts or you can get a rebuild kit for about $25 at AZ. I usually pack an oil pump with petroleum jelly or white lithium grease to aid in priming the system.

Glad to hear you're not in a hurry to get it back together. That way, you won't overlook any possibility.

-Stu
 
Hey Stu did you read same guys comment about a gasket between the block and oil pump? I have already bought a new pump but I might just open up the old one to see how it works. You guys are sure brave. My bro in law worked for ford for 33 years and wouldn't recomment me doing some of the engine work you guys do. IYO if bearings are damaged would I be able to hear or feel a vibration?
 
Nothing wrong with a new pump, but definitely open up the old one. We all want you to find something wrong. If it's scored, plugged or otherwise damaged, they you know you found the problem. If it's all good inside, you still don't know for sure.

Go ahead and mount the new one without a gasket - I'd use a light coat of suitable RTV type sealer. Follow the torque spec, alternately tightening the bolts. If you're concerned about them coming loose, some blue Loctite on the threads is okay.

Venturing into the unknown isn't as daunting when you have the support from these guys on the forum. I ask a lot of questions and continue to learn from others. I bet the quality of your work is top notch, because you ask questions and think the process through. It may take a little longer, but the result of being informed and cautious is worth it. I learned a lot about oil pumps when I rebuilt the one on my AMX 390. AMC parts are hard to come by, and at the time, the aluminum housing wasn't available. Even with new gears, the only way to restore oil pressure was to manually lap the housing and cover to obtain the original clearances. I used a pane of glass and some 400 grit sandpaper to "suface" my oil pump housing. Every few strokes, I'd assemble it with test shims and a new gasket, torque the 7 cover bolts and measure the torque required to turn the shaft. Once it was right, it came apart one more time to remove the shims. The housings are now re-popped, but at the time, that was the way to get it right.

You probably wouldn't feel vibration or have any early warning of bearing failure besides loss of oil pressure. When you remove the bearing caps, wear would be very apparent. Since the bearings are made of several very thin layers of metal, the different colors become visible in the wear pattern. I consider the Plastigage more for checking machine work and bearing size than for wear.

Good luck.
-Stu
 
I am not sure which way to go at this point because my bro in law tells me not to mess with the bearing covers because they need to be torgued by a hi quality torgue wrench which machine shop have. Has anyone removed them? I only have a harbor freight torgue wrench which clicks when it hits the lbs it was set on. I've put the whole engine in installed flywheels pressure plates hydraulic throw out bearings ball joints tie rods is this in the same league as that? If any parts are damaged would the debris show up in the oil or the filter? Also if I examine one does that mean the other 12 are in the same condition or do I need to look at them all?

Stu thanks for the encouragement.
 
:unsure: One thing that no one has yet mentioned.Are ALL of the oil galley plugs installed?
And most importantly,are they installed PROPERLY?
Good luck.Have fun.Be safe.
Leo
 
Just bolt the new oil pump to the block, you do not need to add sealer.
I've seen many cases where excessive sealer blocks the oil pump screen or any orifice.
Sometimes to get a box wrench on the new pump fasteners there is not enough clearance between the oil pump & the box wrench. Just take a file or a rotary grinder & relieve a small amount of the oil pump so you can get a box wrench or socket on to fasten the pump.
The gasket that comes with the pump goes between the screeen flange & the oil pump housing. Make sure too long a bolt is not installed to hold the screen to the oil pump cover otherwise it will hit the internal oil pump gear & or rotor.
 
Mr Comet":24db6mqv said:
I am not sure which way to go at this point because my bro in law tells me not to mess with the bearing covers because they need to be torgued by a hi quality torgue wrench which machine shop have. Has anyone removed them? I only have a harbor freight torgue wrench which clicks when it hits the lbs it was set on. I've put the whole engine in installed flywheels pressure plates hydraulic throw out bearings ball joints tie rods is this in the same league as that? If any parts are damaged would the debris show up in the oil or the filter? Also if I examine one does that mean the other 12 are in the same condition or do I need to look at them all?

Stu thanks for the encouragement.
Click to expand...

First, let's hope that the old oil pump is visibly trashed inside. Then you won't need to worry about the bearings.

Secondly, I'm sure you realize that it's a gamble that the pump sealing surface was the problem. If it was indeed leaking, then you'll fix that when you install the new pump. But it would sure be nice to find a definite cause.

I understand what you're saying - checking the bearings adds a lot to the project. The only reason I'd want to pull the caps is that they're accessible right now. It would be a bummer to find out later that the pan needs to come off again. Often, only one or two bearings go bad and the rest are okay, so you'd have to check them all.

An accurate torque wrench is important. Your HF model might be accurate but who knows? I use a relatively cheap Craftsman (it goes on sale for about $70, but I check it against a good Snap On at work, where they test/calibrate/certify them every year. Mine has stayed accurate for a few years, in part because I treat it nice and store it correctly.

Good luck. And let us know what you find.
-Stu
 
My chilton manual was left to me by my father when he died of cancer 8.5 years ago. It was printed in the 60s. It says rod bearing cover torque 19-24 ft lb. The main bearing cover 60-70 ft lb. Anybody have newer data on this or opinion? Will the lower half of the bearing fall out when the cap is removed?
 
I removed the cover of the oil pump and I could not see any visable damage to it. Everything appears nice and smooth. But I can see how that wouldn't be decisive because if there is too much viriance between the two rotory parts this could cause a lack of pressure. Since the oil appears thinner and runs quicker hot then cold would this explain the reason the pressure falls off as the engine gets warmer?
 
Yep, you're correct about what's happening when the oil gets warm. Thin oil goes through the passages easier, so pressure is harder to build and maintain. Although that characteristic is normal, it's more exaggerated when something else is wrong.

As for the old pump, if the surfaces are smooth inside, it's probably not worn. Wear would likely show up as grooves, scratches, burnished areas, etc. Another thing to check on the old pump is the relief valve. If it has crud in it, that could be keeping the valve from closing and letting pressure build. It's also possible that the spring is weak or even broken. Again, that would prevent oil pressure from building.

The torque values in the Chilton's book sound right for the mains. I assume that the rod bolts are 5/16" so that sounds right, too. That wide torque range allows for minor inaccuracies in the torque wrench and tightening technique. Shoot for the middle number and you have an 8-10% plus/minus range. That's a comfortable margin, but you still need a pretty accurate wrench. Tighten the caps in at leaast two steps, alternating back and forth between the two bolts. Be careful doing this on a "dangling" engine!

The bearing half usually stays in the cap and you don't have to remove it to inspect it. If it stays on the crankshaft, just careully remove it and check it. Going back together, install the bering half in the cap and then install both parts together. There's a small tab on one end of the bearing half that locates it in the cap - that's important. If the lower bearing half is okay, Don't worry about the upper half, just leave it in place. If a bearing is spun or damaged by debris, it pretty much takes out both halves.

-Stu
 
I have removed only one rod bearing at this point #2 next to the pump. There is oil on both surfaces. The bearing color looks milky white with fine lines on it but nothing noticable to the touch like a groove. Should I get the plastigauge (green)? The crank area is pristine and absolutely shinny, not sure of spelling but I hope all will allow me this error.
 
Bubba's list of 8 issues which could effect the pressure #5

There is NO gasket between the pump and the pickup tube with screen. Now as dear old dad always said and he was a plumber. A pump works a whole lot more to suck then it does to push. That's why there are submerible pumps in wells today.

To review we have a gasket between block and pump we do not need with one bolt looser then other, screen with small amount of debris in screen and no gasket between the pump and intake tube with screen. All of that is enough reason to do this repair. But since im inside the lower half of the engine what else can I do so I can close this baby up with confidence of a good job done?
 
Sounds like that bearing isn't damaged, but I'd Plastigage it, and here's why:

Let's say the crank was turned for "10 under" bearings (bearings that are .010" smaller diameter). A couple of things can happen

- Maybe it was turned too far - more than .010 was taken off. Even with the right bearing, the clearance would be excessive. The bearing wouldn't wear out immediately, but the excessive clearance would kill the oil pressure. The condition might be on only one journal, might be on all of them. Only way to tell is Plastigage.

- The other possibility is that it was turned to a perfect 10 under, but was assembled with "standard" bearings (same size as original). The desired clearance of 1 to 3 thousandths is now 11 to 13 thousandths. This probably wouln't last long at all and might even exhibit some noise, and definitely would have no oil pressure once the oil is warm. Again, there could be one oddball bearing, not necessarily all of them, especially if it was assembed at a big commercial rebuilder.

This isn't a real frequent occurance, but it does happen. I always Plastigage a motor when I assemble it, and most conscientious machinists recommend it, just as a final check.

(ALERT! Here comes another one of my stories!)
I rebuilt a low mileage 327 Chevy that had supposedly never been apart. The crank was nice and didn't need to be turned, just polished. The machine shop sold me "standard" size rod and main bearings. When I Plastigaged the bearings, I had HUGE clearance on the rod journals. Turns out, the crank was standard on the mains, but 10 under on the rods. Not sure whether that was from the factory or a previous repair.

Sorry to add complication to your task, but it's still kind of a mysterious situation. The more you dig into it, the less likely that it will have to come apart again. Bottom line, no one will be as careful with your motor as you will be. Some may have more expertise and experience, but they can't possibly care as much.

-Stu
 
Mr Comet":xlkmra0i said:
Bubba's list of 8 issues which could effect the pressure #5

There is NO gasket between the pump and the pickup tube with screen. Now as dear old dad always said and he was a plumber. A pump works a whole lot more to suck then it does to push. That's why there are submerible pumps in wells today.

To review we have a gasket between block and pump we do not need with one bolt looser then other, screen with small amount of debris in screen and no gasket between the pump and intake tube with screen. All of that is enough reason to do this repair. But since im inside the lower half of the engine what else can I do so I can close this baby up with confidence of a good job done?
Click to expand...

Bubba, you make a lot of sense. It's a tough call. I'm a little obsessive about checking out every detail, but in the end, there is always a risk I've overlooked something. When I light up a new engine for the first time, my stomach is always in my throat.
 
I'll get the plasti gauge with more other supplies either later today or tomorrow when it comes in. Ill let you know when I have some more info.
 
In your detective work on the bearings since you all ready have it off, take the half out of the rod cap and look at the back to see what it says. If it's STD then is standard if you see FoMoCo in an oval than could still be the factory bearings, other brands will have their name. If you see .010,.020,.030,.040 etc. these are oversize s and crank is turned under. X2 since you have it apart you should check clearance with the Plastigauge so you have an idea were your at. I think you can trust your old Chilton's book on the torque specs and sounds right to me, but if you like can look it up in on of my old Motors books. One other thing if the bearings are still standard then they probably just did a quick'y type overhaul on your engine not a true rebuild. ie rings, bearings, valve job, and some gaskets. Nothing wrong with that if all the parts are still in factory spec.

(ALERT! Here comes another one of my stories!)
I rebuilt a low mileage 327 Chevy that had supposedly never been apart. The crank was nice and didn't need to be turned, just polished. The machine shop sold me "standard" size rod and main bearings. When I Plastigaged the bearings, I had HUGE clearance on the rod journals. Turns out, the crank was standard on the mains, but 10 under on the rods. Not sure whether that was from the factory or a previous repair.
Click to expand...

LOL in the tear down of old engines you can find many strange things. When I started out Plastigauge had not been invented yet so you needed to check parts just like a machine shop does with a Micrometer, I still do it's the most accurate way Plastigauge is a great budget way to check though. One way we used to be able to tell if a Ch--y had been apart and worked on was to look for numbers or punch marks on the rod and main caps factory built engines don't have them.

I think since you have it apart and have a new oil pump you should go ahead and replace it especially if it's an old one. You can clean you oil pickup tube by soaking it in some carb cleaner. Good Luck
 
Bubba

If you pm me your e mail I can send you a copy of the invoice for the engine. They did show some machine work done. I bought a new screen piece anyways just to start all new. Do you agree with wsa111 about not using any RTV on the gasket between the pump and the screen intake piece? Just a side question Is the over 10, 20, 30, 40 I see is that thousands of an inch of the honing of the cylinder wall? Is 40 the most it can be widened? THanks Denny
 
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