I serched around for info and found a long answer from /6Dan on the topic of the '60-'62 being installed with the reverse orientation of the '63 and later rods. Early rods have the oil hole pointed away from the cam.

So, I have a '62 and as I was installing my 2nd piston assy this eve, decided to check the oil hole as assembled as a formality (they never seem to get it wrong at this particular shop). Low and behold, they are pointed backwards from the '62 FSM instructions.

Sooooo, since the opposite orientation worked in '63 up, has anyone determined that it would be satisfactory in the '60-'62 engines to point the con rod oil holes towards the cam side? Is the oiling hole pointed at a different angle on one vs the other?

Tnx in advance for any comments.

FYI, here are the pertinent portions of that prior post:
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The rods were not installed "backwards" in '60-'62 engines, but the rod orientation was flipped 180° starting in '63. This was done to improve oiling, not to fix a problem that "led to oiling issues and premature failure". For reasons I haven't dug deeply into understanding, the TSBs and FSMs and MTSC brochures that talk about this change all make it very, very clear, with uppercase letters and boldface type, that '60-'62 engines and aluminum-block engines of all years including 1963 are to use the "old" connecting rod orientation, and not the "new" one.

So-

All 1960-1962 iron engines, plus 1961-1963 aluminum engines: Connecting rods installed so that the squirt holes face away from the camshaft.

All 1963-up engines, except aluminum block: Connecting rods installed so that the squirt holes face towards the camshaft.

I bet Doc can tell us more detail about what changed (logic says it was a change to the block casting itself) and what the consequences would be of using the '63-up rod orientation in a '60-'62 iron engine. But for now, don't worry about it. If your rods were installed per the FSM, with the squirt holes facing away from the camshaft, you did it right and should leave them be.

I believe the piston pins are offset. If you install the rods backwards then the offset on the pistons would be the wrong direction. I am not sure if that will cause any long term problems or not.

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12.70 @ 104.6

Isn't the offset only in the piston and offset in a direction perpendicular to the pin axis? I was not aware that the offset involved the con rod at all; I always thought that the con rod pin hole is centered in the con rod axis.....thus would be the same if you flipped the rod around...????

Now yer gonna make me have to look LOL

From your earlier post, you aren't changing the pistons offset or direction, it remains in the same orientation as with the notch pointing toward the front as it should. What you are doing amounts to basically putting the rod on the piston backwards so the "spit" hole is pointing opposite the camshaft. We have several GM and Ford engineers with us over on Inliners that actually worked with R&D on their inline engine divisions through the 60's, 70's and 80's. Many of those engines had OEM rods that also had "spit" holes at some point thru their production years, but at some point were deleted from the rods altogether. It has always been misunderstood by the public as to the true purpose of those oil holes to begin with, and there is a lot of previous discussion by these now retired engineers as to their real purpose. The fact that they were all deleted from the rods eventually suggests that they really didn't serve or fulfill the purpose they had intended them to. So whether you install these rods to the factory manual directions or not won't really matter since it essentially has the same effect as deleting the hole by changing its original purpose.

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There's no such thing as too much cam....only not enough engine!

Yes I believe that is correct. So as long as the notches are still to the front that should be fine.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

On one of my first race engines I assembled the rods according to the picture in the 1962 Shop Manual that I was using. That engine would, as Tom Hoover used to say, "Make smoke and look dumb". I always attributed it to spraying too much oil on the cylinder wall at high RPM, I always used full groove mains which would have aggravated the problem. After that I always pointed the hole towards the cam with better results. I always thought that early shop manual was just wrong but apparently early engines came that way from the factory. Since they changed the orientation in 1963 and the fact that it might not make any difference anyway I would always point the hole towards the cam. Don't know about the aluminum engine, there might be some good reason to follow the early book there.

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If you didn't drive it there, it's not a street car.

WARNING: LOONG POST (Sorry, I got on a roll.....)
OK, thanks for the replies. As for the holes dissappearing in some later inlines, that info is pretty interesting. But I have to wonder if the oiling could have been supplemented by other changes; so that seems somewhat vague info for this particular question.

I assume that the peak of the 'squirting' takes place when the oiling passage to the rod journal lines up with the squirt hole and the pressure to the squirt hole spikes up...??? In my '62, this happens when the piston/rod assy is near TDC (if the rods are assembled as per the '62 FSM, with the squirt holes away from the cam) and with the squirt pointed right at the cylinder wall. Kinda like it was actually designed that way.....

With the rods flipped with the squirt towards the cam, then any 'squirt peak' will occur with the hole about 90 degrees before TDC. and the squirt peak will shoot towards the block wall below the cam. When the squirt hole passes the cylinder area near TDC, the rod oiling passage will be far away from the squirt hole, so squirt pressure would be low.

The lower end of the rod oiling passage will not be over a grooved portion of the main bearing when the squrit hole is anywhere near to TDC so that pressure peak to the squirt hole will presumably be limited. That would perhaps explain why Exner saw high levels of cylinider oiling when using full grooved mains; he had the highest possible pressure exposed to the squirt hole when it passed by the rod oiling passage and was at TDC and pointing right at the cylinder wall. He had cylinder oiling to the max! (But that assumes something else.... as below...)

But that also leads to the question of: when the rod orientation was flipped in '63, were the crank oiling passages also changed so that the main squirt still occured near TDC? So who is the expert on crankshafts versus model year of production? My '62 crank casting # is really hard to read; I vaguely see '2264479' but only the '447' is distinct enough to be sure. (Update: My old parts interchange listing shows the same service crank PN for '60-'65: 2268442. So I guess they are all the same but would appreciate any other confirmation.)

Some lesser questions:
Is the hole through the rod at the same angle in the rod the later rods? (The hole location has to be the same as the rod bearing PN is the same.) It is also angled very few degrees from the plane of the rod. Are the later rod holes the same? (I am hoping somone will pick one up and share their observations .... I have a photo but can't see how to post here.)

2 other small things I can think of that would effect the amount of cylinder oiling:
- With the old orientation (towards the driver's side), the squirt hole will always be almost vertically oriented with the slant's normally inclination, and the hole will be almost horizontal when the rod is rotated around and the hole pointed towards the cam side. It would not change the holes general angle towards the cylinder walls, but gravity might 'arc' more of the oil away from the cylinders when pointed towards the cam.
- And looking at a cutaway illustration of the engine, the piston pin offset angles the con rod towards the cam. That DOES angle the squirt hole a few degrees lower (3 or 4 degrees change). So that might lessen any oiling to the bores with the rod squirt hole towards the cam.
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Info about what Ford and Chevy did will be a real help next time I build one o' them rare and elusive, seldom-seen Ford or Chevy slant-6 engines, but I don't think that info will be very helpful next time I'm building a Chrysler slant-6 engine with connecting rods that stubbornly insist on having squirt holes no matter how many times I look again. (On further thought, I guess I could use that info if my goal were to drag my slant-6's durability down to Chev/Ford levels).

Crank oiling passages were not changed. It would be interesting to know why the factory went out of their way to specify that '60-'62 cast-iron engines and all aluminum engines are to be assembled, after service, with squirt holes facing away from the camshaft, even after the change was made for '63+ iron engines. But pending that knowledge, the fact that they made that announcement, knowing it would be easier to just say "whenever you take apart a slant-6 engine, put it back together the new way", tells me they really meant what they said.

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Too many people who were born on third base actually believe they've hit a triple.

Your last statement about what the TSB's and such empahsized in regards to keeping the original orientation on the older engines is what is giving me pause. Is there a good technical reason, like for the AL blocks in particular, or was it to avoid some sort of liability? ("AHA, they changed the oiling hole orientation after 3 years so there MUST have been a problem." Consumer protectionism was coming along at that time so that does not seem too far fetched).

Well, I have messed around with this and a few other small engine tasks all day Sunday, and so I guess it'll be back to the machine shop on Monday AM to get them 'properly' oriented. I can imagine the questions and the eye-rolling already ..... LOL

I waffled back and forth to an 'executive' decision.....LOL. We're sticking with the newer rod orientation on the '62. The final decider was that there is some risk anytime a piston pin is pressed out to crack the piston; great logic hunh... Since I can't figure up any solid reason why the later rod squirt hole orientation would work with newer engines and not the older ones ('cept the AL block) as the crank, rods, pistons and lower block area are the same, it seems like it would be OK. The only other thing I can think of that is oil related and that changed going to '63 would be the PCV (vs the older open breather), and I can't imagine how that would interact with the squirt hole operation.

We will find out.....the tension builds.....

I agree with your decision and it is what I would have done.

FWIW, I have a set of K1 rods in my new 270 HP 64 Dart engine and they have NO squirt holes. So far it has about 30-40 drag passes, 3-4k miles, and some spritied street driving and no issues. Pretty early days though...

Lou

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Home of Slant6-powered fun machines since 1988

The issue with the aluminum blocks was they developed more cylinder bore clearance when they reached operating temps because of the greater expansion rate of the aluminum vs. cast iron. With more cylinder wall clearance comes more oil consumption. That coupled with the extra oil spraying from the "oil hole" just added that much more to the already overwhelmed oil rings causing more problems. That was probably why the aluminum blocks were so short lived. Turning the "oil hole" in the other direction didn't solve it completely but helped because it wasn't spraying directly at the cylinders saturating the rings more.

So at best they were back to square one with an engine that used more oil than they liked it too, and eventually dropped it from production because of the potential comebacks and warranty issues.

In all race shops today, an aluminum race block has to be prepped differently than a cast iron block because of the differences in thermal expansion between the two of them. Bearing clearances, ring gap, piston clearance, deck height, valve lash and other dimensions all have to be compensated for because of this.

I've witnessed first hand on many occasions engines on the dyno that had the oil pans dropped and the oil pumps powered by a drill. The shear volume of oil spray that comes from around the sides of the rods at the journals and out from around the mains and cam journals with only 30 psi of pressure is huge. All of the other engineers in these other brands realized that also, and found that the "oil hole" in the rods just isn't necessary. It actually in most cases "over" oils and causes more problems than it fixes.

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There's no such thing as too much cam....only not enough engine!

Where did you get this notion? Is that documented somewhere, or is that a homegrown idea? Because remember, the aluminum slant-6 engines have cast-iron cylinders (and cast-iron main bearing caps, upper and lower). This is not the half-baked excuse for an aluminum engine that GM put in the half-baked excuse for a car (Chevrolet Vega), nor is it a design wherein the pistons and bearings run against aluminum.
No, the aluminum blocks weren't mechanically short-lived for that or any other reason. The issues with them were corrosion-related (people didn't reliably use corrosion-inhibiting coolant in the early 1960s; common practice was to run straight water all or part of the year) and the head gaskets weren't as reliable as those of the iron engine. Neither issue has anything to do with cylinder bores or oil squirt holes.
You've got things backwards in your mind here. The aluminum engine's connecting rods weren't "turned in the other direction" -- they, and the '60-'62 iron engines, had the squirt holes facing the original direction. The iron engines starting in '63 had the squirt holes facing the other direction. There is not a single page of documentation—not a single line of text—suggesting a change was made to "help" the aluminum engines, probably because they didn't actually have a problem such as you describe.
I will be very interested to see where this idea came from, too. Can you point us at any Chrysler engineer, any TSB, any text in a service manual, any MTSC booklet, anything at all supporting this claim? I have a very extensive library and have worked closely and talked at great length with the engineer who was in charge of the whole thing (might have something to do with my having been an original discussion partner on his history of the Slant-6 engine and copyeditor on his comprehensive history of Chrysler engines) and nothing such as this claim ever came up. I think you're guessing.
Nope, didn't happen that way. Why make stuff up as you go along, when the actual info is readily available? They dropped it because aluminum cost so much more than iron that the production cost savings in longer tool life was overwhelmingly countervailed by the raw-materials cost, and the aluminum casting technology of the day meant a higher reject rate out of the foundries than for the cast-iron engine at a time when they were having trouble keeping up with the demand for slant-6 engines, and the weight savings wasn't a big enough advantage to the consumer to overcome the cost and production issues. This is very well documented by the chief engineer on the slant-6 engine project, Bill Weertman. I think his version is more believable.
Oh, absolutely. But we're not talking about the kind of aluminum block you seem to have in mind. I wonder if you've spent much (any?) time with an aluminum slant-6 engine, because it sounds like you have not.
All of the other engineers in those other brands did a bunch of things on the engines they were designing. On this board we mostly talk about slant-6 engines designed by Chrysler engineers. You may think "Chevy and Ford engines don't have an oil hole, so Chrysler slant-6 engines don't need one either" is reasonable, but I don't.
It looks like you're turning what you've generalized ("in most cases") and guessed ("it over-oils") from what you remember having seen on non-slant-6 engines on a dyno, and turning it into advice about a particular kind of engine you don't seem to have much first-hand knowledge of. I'm not sure how that's supposed to help anyone. :shrug:

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Too many people who were born on third base actually believe they've hit a triple.

Dan, i'm not speaking in a generalized fashion, I am speaking from actual hands on experience working in the racing machine shop industry and seeing first hand what is done on a wider platform by many automotive brands. Not just the Chevy Dodge Ford variety of powerplants, but also the top shelf BMW, Ferrari and every other brand worth mentioning. Sure the aftermarket aluminum blocks also take different procedures than the cast iron versions, but also the aluminum OEM blocks also do too. Also, quite a few aluminum OEM blocks with liners take even further procedures than aluminum OEM blocks without them in some cases. For instance, a Ferrari block has to have a torque plate in place to even cleanup hone the cylinder bores, as well as resize them to the next oversize. A cast iron block isn't required to have that done. Some of those other brands do have printed literature to document rebuild procedures info printed on these procedures and it is common knowledge to those that work in that industry.

Also, I know everyone here is proud of their Mopar heritage, but don't think those engineers didn't converse with engineers from other brands and came up ideas all on there own. Sometimes they did , but sometimes it was on the golf course or at lunch with their Chevy or Ford cohorts.

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There's no such thing as too much cam....only not enough engine!

...on aluminum slant-6 engines? Probably not. I don't question your knowledge and experience in general, but you don't seem to know a lot about the particulars of the aluminum slant-6, and when you try to guess at it, you're getting it wrong.
The last few aluminum 225s I looked at were Chrysler blocks, actually.
Yup, Chrysler engines are the same way: lots of printed literature to document rebuild procedures. And we're even fortunate enough to have extremely detailed firsthand accounts of the development and evolution of this engine from the engineering side. That's how come I know you're saying stuff that doesn't apply to the aluminum slant-6. (And come to think of it, the aluminum slant-6 doesn't really apply to this present discussion, because that's not the kind of engine being built in this thread.)
Of course they did. And yet, for some strange reason, those Chrysler connecting rods in that Chrysler slant-6 engine still have squirt holes in them, in total disregard of the unholed connecting rods you say can be found in Chevs and Fords and Toothgnasher Superflash XLE Series III Twin-Cam Deluxes. Maybe the Chrysler engineers weren't invited to that particular golf game.

It just seems weird to step up and start putting out guesses and generalizations to "contradict" known and documented facts and procedures for a particular, specific engine. Seriously, the facts are known. Not "almost known", not "mostly known", not "pretty well understood", not "largely reconstructed by careful examination", they're known. So what's the point of posting imaginary stories about how the aluminum slant-6 failed early because of an oiling issue that they didn't and don't actually have? What's the point of made-up statements about how the factory "turned the connecting rods around to help solve the problem, but then the engines used more oil"? How does this help anyone? :shrug:

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Too many people who were born on third base actually believe they've hit a triple.