FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: olman on December 15, 2018, 06:03:23 PM
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I have a C6ME-A 390 block with a 7C29 casting date from DIF . Removed all the expansion plugs from the block to clean the oil passages. Is it common to find a block that that is not tapped for 1/4 inch pipe plugs on the rear of the block around the cam plug. All 10 galley holes had expansion plugs. Just curious.
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I'm sure someone knows more about it than me, but I know they don't all come tapped because my machine shop just did it on my 428.
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Very common.
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Barry, I ordered a brass core plug kit from Elgin for the FE blocks and brass plugs are marked 1 3/4" on plugs. In your book you recommend to use 1 49/64. Which manufacturers kit comes with the correct size. I see in your book you have a Pioneer PB-110-B kit but I don't know if it's 1 49/64 or
1 3/4" Did an internet search for them but none show the size of the core plug.
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I like the larger plug. Those holes do not get smaller in diameter after a few plugs get pounded in and out over the past fifty years....
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Those holes do not get smaller in diameter after a few plugs get pounded in and out over the past fifty years....
So many comments to make, so little time ;D
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Ah Doug did we skip the meds again!?
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I thin k Doug has taken the opportunity to go off topic.... ;D
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Those holes do not get smaller in diameter after a few plugs get pounded in and out over the past fifty years....
So many comments to make, so little time ;D
ROFL
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Some math can be reassuring here.
A 1/4" dia. press fit plug at 100 psi will have only 5 lbs of pressure pushing against it.
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Those holes do not get smaller in diameter after a few plugs get pounded in and out over the past fifty years....
So many comments to make, so little time ;D
:o ;D ;D ;D ;D ;D
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Some math can be reassuring here.
A 1/4" dia. press fit plug at 100 psi will have only 5 lbs of pressure pushing against it.
Can one of you engineering types verify this? For some reason I think its off a bit ... F=P/A?
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Pressure equals force over area. P=F/A
So F = PA
Force (lbs) = 100 lbs/in^2 * .049 in^2 = 4.9 lbs.
Seems counterintuitive, doesn't it?
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P=F/A
If you solve for F, then F=PA
The area of a .250 circle is only 0.049087385212341 square inches.
If the pressure is 100 psi, then actual force against the surface of the cup should be just under 5 lbs.
F = 100*0.049087385212341
F = 4.9 and change
What I don't know is what the pressure is to push the cup back out, likely not much, but in terms of hydraulic pressure, that does work in the thousands of PSI, the oil galleys aren't pushing that hard and have plenty of leaks enroute as pressure backs up
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Great minds think alike...scary one of them has a business degree :)
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Barry, I ordered a brass core plug kit from Elgin for the FE blocks and brass plugs are marked 1 3/4" on plugs. In your book you recommend to use 1 49/64. Which manufacturers kit comes with the correct size. I see in your book you have a Pioneer PB-110-B kit but I don't know if it's 1 49/64 or
1 3/4" Did an internet search for them but none show the size of the core plug.
Many comments online about the 1 3/4" poping out. I have had two or three myself.
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Pressure equals force over area. P=F/A
So F = PA
Force (lbs) = 100 lbs/in^2 * .049 in^2 = 4.9 lbs.
Seems counterintuitive, doesn't it?
OK - got that.
I am really, truly NOT an engineer - but I have some interest in this stuff because I see things happen and wonder why.
I generally break stuff until it stays broke and then fix it until it stays fixed...street racer deal...
And I am "going somewhere" with this - just not sure if its gonna end up where I expect it too...
With "only" five pounds of force - why do plugs ever come out? Heat expansion, block distortion pressure pulses beyond the simple gauge readings we see?, Even Ford chooses to use screw in plugs on many of the builds, especially on the higher performance applications. Since there is (hopefully) no movement in the system, is friction the only opposing force holding the plug in place? How much friction do we have and how much do we need to be safe?
Might be fun to hang weights from a plug & see exactly how much it takes to move a plug out of position. Should not be too hard of a rig to concoct for somebody with a little spare time. Probably learn how much better the simple common old school tweaks that I see all the time could make the press in galley (and core) plugs work - stuff like the pin or stake punches around the perimeter, epoxy glues, larger diameters, and the like.
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I hear ya, didn't sound "logical" to me either.
I imagine that it follows the same rule as your core/freeze plug rule.....over time, being knocked out, knocked in, knocked out, knocked in, etc., the hole changes shape and you lose some of your press fit. I've even heard of the larger lifter passage crossover plug in a SBF pushing out and causing a leak. Obviously it's a larger plug, but still.....it happens.
I just tap the holes and I'm done with it.
Even if you look at a freeze plug.....take for instance a 14-16 psi radiator cap....if you have 14 psi pushing on a 1-3/4-ish plug, you're still only looking at 34 lbs. Think about how hard you have to hit your freeze plug driver to get a freeze plug to go in....
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Oil pressure can "spike" pretty high sometimes. A sticky relief valve, or just an anxious foot with a cold engine/oil can split an oil filter, even a "good one, and likely could start a press fit plug.
(I have never seen an OEM gallery plug come out, but my experience is pretty much limited to working in a Ford dealership and a rebuild shop years (50!) ago. I always had to drill and tap the plugs then use a small slide hammer to remove them)
I think in threading those holes you need to use some special tools to get it "right". The female threads are NPFS ( fuel, straight) and the plugs are NPTF, (tapered, fuel) SAE short. (Note also there are two tapers available 7/8 per inch and 3/4 per inch) These male plugs with threads designated "F" will seal using an interfence at the sharp crest of the thread when they are flush with the surface. This class of threads is more precise than NPT threads.
(Obviously you can use standard NPT "pipe" threads but getting the tapered depth correct requires some fussing and sealant (the root and crest of NPT thread is "open" and leaves a void for sealant)
more here;http://www.ring-plug-thread-gages.com/ti-NPT-vs-NPTF.htm
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Every time I have knocked in a 1-3/4 plug (which is hardly ever compared to the builders on here) I am always scared I am going to break the block. They have always gone in real hard.
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Having a pre-64 block 390HP, 406, 427 with Oil relief Valve in rear just under the center Galley would be too scary for me to try to tap for pipe plug, that wall between them is way to thin. Seems those cup made it kind of a pain to tap many at all. Also up dateing to Cam Thrust Plate up front, you need to be careful not to block the distributors pilot oil with the plate s lower bolt, your bolts thread don't start till after the welch plug bore ends....JMO
(https://i.postimg.cc/nLqZ3nph/DSC-0006.jpg) (https://postimg.cc/2qjP6R1s)
(https://i.postimg.cc/QNYLkF1q/IMG-0291.jpg) (https://postimg.cc/LhP0m6yq)
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On the other hand, if you've ever had a plug come out...
While you have an engine apart, it's a relatively easy sort of thing to get out your tap set and...
KS
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Some math can be reassuring here.
A 1/4" dia. press fit plug at 100 psi will have only 5 lbs of pressure pushing against it.
Can one of you engineering types verify this? For some reason I think its off a bit ... F=P/A?
It's fun when designing pnuematic or hydraulic systems on boats for things like brake rams, steering, etc.
150psi air pressure over an 8 inch piston, or 1400psi hydraulic pressure over a 6 inch piston
(7540lbs and 39,579lbs of force in this example)
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So, engineering types help me here too
However, a cup plug should not come out easily unless something is wrong. Size of the plug, size of the hole, extreme temps, etc.
I'll have to measure, which I will do today because I am prepping one of the 461s, but by driving it in, you are effectively compressing a cylinder (or a ring), that ring likely has some taper (although I am not sure of that, will check that today) but it also is pushing outward, because like a keystone on an arch, that extra material has no place to go when you push it in, so it is exerting force trying to keep it's size.
So you have friction, you have a ring in compression, and you have clearances designed for the planned heat of the materials. In some cases, as Ken has noted, guys also use adhesive or bonding agent on top of that. I think Ken mentioned JB Weld, but I have never done that
My guess is that when a plug comes out, it was a damaged hole, the wrong size plug, a damaged plug or in some odd cases an overheated hole. Remember, holes open with heat, when you drop a bearing on with heat with a shaft about the same size as the freeze plug, you only need 160-180 degrees and it slides right on. A bearing like that will hold an axle even when tossing the car around curves. Not saying a cup plug will grip like that, but the cup plug, although it has different levels of compression it also has less pressure exerted on it and should behave in a similar manner, and that part of the block doesn't likely get hot enough for the level of interference fit.
For me, the 15 thou difference in the 1 3/4 versus 1 49/64 is significant based on that interference. With steel plugs, likely not as much of an issue, but when you add a softer brass plug, the combination of less OD and less resistance to compression and distortion adds more variables.
For the small oil galley plugs, I think there is a reason when one pushes out. People beat the centers in, which changes the OD and makes them out of round, guys chisel the old ones out damaging the hole, sometimes people pound them into the step which likely distorts them, not to mention, little plugs generally just frustrate me anyway, so I drill every one for NPT. It's just so much easier. I didn't know about the fine thread plugs, might have to look into that, but never saw them used.
Last thing, diesel guys will understand this, but it applies to all engines. There is a shock wave from combustion and it can cause localized effects on inside surface of the cylinder wall, generally not to the extent of a very high compression diesel under load, but it is there. In fact, diesel coolant has to be designed and tested regularly to make sure it can handle it. Along with that pressure, a thin cylinder wall could have localized steam spots that can take off like bubbles, especially with straight water, and when bleeding a cooling system, an air bubble can do some damage, I have seen heater cores blown apart due to a big burp before the thermostat opens. . Depending on how these "burp" there can be spikes of pressure in a cooling system, but in a gasoline engine, they shouldn't be enough to blow a plug out either, unless there was another contributing factor
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I am really, truly NOT an engineer - but I have some interest in this stuff because I see things happen and wonder why.
I generally break stuff until it stays broke and then fix it until it stays fixed...street racer deal...
And I am "going somewhere" with this - just not sure if its gonna end up where I expect it too...
This truly describes me!
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https://www.summitracing.com/parts/rnb-565-036
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FYI just to circle back, no measurable taper on a freeze plug. A little deformed right at the top edge, but certainly doesn't look to be on purpose
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I didn't know about the fine thread plugs, might have to look into that, but never saw them used
(perhaps you are refering to my use of NPTF?)
The " F " in NPTF indicates "fuel" and a completely different thread profile. The crests of the thread are sharp and an interference fit with the mating component. It is a different tap (and die).
(https://imgv2-1-f.scribdassets.com/img/document/110081400/original/ab36714fda/1544091494?v=1)
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I didn't know about the fine thread plugs, might have to look into that, but never saw them used
(perhaps you are refering to my use of NPTF?)
The " F " in NPTF indicates "fuel" and a completely different thread profile. The crests of the thread are sharp and an interference fit with the mating component. It is a different tap (and die).
(https://imgv2-1-f.scribdassets.com/img/document/110081400/original/ab36714fda/1544091494?v=1)
Sorry, I remembered the F but forgot you pointed out it was for fuel ...very good stuff
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I recently ordered but yet to receive a set of freeze plugs and oil galley plug kit. Not sure why it takes a week to even get such small parts in the mail.
I asked what taps are needed and was told they where just regular NPT. The reason for asking was I had it in my head that some people use the NPTF but apparently not the case with POP plug kits.
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Ross you are describing cavitation, I don't think it'd be as much of an issue with gas engine cylinder walls.
Either way, when air is in the system it'll collapse the the depression can poke holes in things.
We fight this with certain diesels as they can blow pinholes in the liners over time, normally an SCA additive fixes the issue.
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Ross you are describing cavitation, I don't think it'd be as much of an issue with gas engine cylinder walls.
Either way, when air is in the system it'll collapse the the depression can poke holes in things.
We fight this with certain diesels as they can blow pinholes in the liners over time, normally an SCA additive fixes the issue.
Exactly, thanks, and yes, like I said I didn't think the issue happened at the compression ratio a gas engine ran, but there still can be localized heating and an air bound engine during a fill can certainly put a shock in a system
In the end, I really have never seen a good plug push out, I have seen them pushed out when frozen (and usually take the block with it) but trying to look for some possible explanation for discussion. To me, plug failures like have a reason and not pressure
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As Drew mentioned, the cavitation erosion you see on some diesels isn't as common in gas engines although it can happen. The other thing to consider, is that just like in the oil system the cooling system is exposed to pressure spikes and the core plugs are exposed to more than the 14psi system pressure at times. With a good water pump and high RPM you can see 30+ psi in the block and pressure spikes depending on what type of thermostat you run. I really dislike the normal "disk" style thermostat. A rolling sleeve style is both better at controlling temp, but they also don't slam shut and pop open like a typical thermostat will.
A properly sized cup/welch plug shouldn't come out, but in more demanding uses they can fail.
I've never used JB weld for a sealer, but I have used Permatex aviation sealer or something similar (whatever I had handy). I always figured it would be hard to hurt anything with the sealer and it might help.
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WOW! I've created a monster post!