Hemi crankshaft caps

[AR67GTX]

Pulled the oil pan on my 426 Hemi to replace the oil pan gaskets. First inspection up there found an interesting observation, the middle 3 main caps are stamped 1, 2 and 3 on the bottom but 1 is at the back, 2 is up front and 3 is in the middle? Were caps stamped at the plant during assembly? Motor seems to be fine, good oil pressure, cylinder walls good, no strange noises. Guess I’ll just hope it was align-honed without regard to the original cap positions or lucked out.

 

[69Bee]

Mopars have their cap position "Cast" into the cap, not stamped. If they are stamped, someone else did it, and stamped them out of order.

 

[AR67GTX]

Thanks, guess I’ll look for the cast numbers but I don’t plan on going past the entrance to this rabbit hole.

 

[69Bee]

The pic with just the caps are BB mopar, and the red is obviously a SB Mopar, but you can see the cast-in numbers for an idea of what to look for.

 

[70rcode]

Hey 67GTX, ....You got a very strange hemi issue going on.....Despite seemingly conflicting advice,....my factory assemble Hemi Does have dual 10mm tall numeral stampings on the cap bottom near the bolt hole locations with Bottom of numeral towards the oil pump side..... Except caps # 2 & 4, most production Hemi caps # 1 thru 5 are uniquely different.....# 3 ( the Thrust bearing Cap). Must go in the middle counting from the crankshaft snout end with both sides relieved for the Thrust bearing flanges to Match the block saddle reliefs ......Cap # 5 is Very similar to cap # 1 except it (#5) has a shallow relief cut on the rear main seal side to clear the flange.....Unless you cut a 1/4" off both ends, there's No way to fit a # 2, 3 or 4 cap into block position 1 !! At least this is how my production Hemi arrived off the transporter.....

 

[pnora]

That motor must of been rebuilt at some time. Number 3 is the thrust and can not go anywhere else. where were the other two positioned and numbered? A cap is a cap. One line bored it is mated to that block. You would think a quality machine shop would re-stamp all 5 in a 1-5 order.

 

[70rcode]

Unless you have a very early 1966 & maybe '67 Hemi block,.....All production Street Hemis came with factory semi--forged main caps with No casting #'s possible.....Most factory hemi Main caps have No iron casting appearance like the pictured RB assembly shown......

 

[pnora]

Another thing is the Hemi has 2,3,4 with cross bolts. so only 2 and 4 could be correctly swapped and line bored.

 

[Beekeeper]

I always thought #2,3 and 4 on original hemi caps do have the numbers stamped in them Just like these
that Meep-Meep sold here sometime back

and these originals from an internet pic.

these are mine and looks exactly like the stamping on the caps in the first pic above although mine have been drilled to make pulling the caps much easier. well my pic is blurry but they are there.

 

[AR67GTX]

False alarm - the caps are stamped on both side and I was only looking at the one side where the #4 cap strike was very light and looked like a 1 so I had 2, 3, 1 thinking only the 3 middle caps were stamped. But the other side is clearly struck as a 4 and shows all caps 1-5 in proper order. I just looked at it too briefly before I broke for lunch. So never mind - operator error.

I guess I need to do something about this rear main seal because the pan was on tight and I don’t think leaking. I think some through drilled holes for things like the motor mounts may be seeping. I have a few drips from higher up but surprisingly the valve covers do not seem be seeping oil. I can run a paper towel all around the gasket edge on both sides and pick up zero sign of oil. I’m afraid what they may be stuck on with. But I’m getting something around the rear and of the transmission input vs the rear main, common sense tells me it’s probably the main. I would have expected to find more oil and wetness inside the bellhousing though.

 

[70rcode]

Yep,....2 thru 4 Stamped.....#'s 1 & 5 not usually numeral stamped, but different enough on rear side to identify & mate correctly with block bearing saddle if you look real closely....

 

[AR67GTX]

I always thought #2,3 and 4 on original hemi caps do have the numbers stamped in them Just like these
that Meep-Meep sold here sometime back
View attachment 1305644
and these originals from an internet pic.
View attachment 1305646

these are mine and looks exactly like the stamping on the caps in the first pic above although mine have been drilled to make pulling the caps much easier. well my pic is blurry but they are there.
View attachment 1305648

Yes, at earliest glance I didn’t think 1 & 5 were stamped but they are. Other than #4 was lightly stamped on one side they look just like those.

 

[Beekeeper]

False alarm - the caps are stamped on both side and I was only looking at the one side where the #4 cap strike was very light and looked like a 1 so I had 2, 3, 1 thinking only the 3 middle caps were stamped. But the other side is clearly struck as a 4 and shows all caps 1-5 in proper order. I just looked at it too briefly before I broke for lunch. So never mind - operator error.
View attachment 1305655View attachment 1305656View attachment 1305657View attachment 1305658

I guess I need to do something about this rear main seal because the pan was on tight and I don’t think leaking. I think some through drilled holes for things like the motor mounts may be seeping. I have a few drips from higher up but surprisingly the valve covers do not seem be seeping oil. I can run a paper towel all around the gasket edge on both sides and pick up zero sign of oil. I’m afraid what they may be stuck on with. But I’m getting something around the rear and of the transmission input vs the rear main, common sense tells me it’s probably the main. I would have expected to find more oil and wetness inside the bellhousing though.

If it was dry in the bell housing I would bet its the pan leaking at the rear because the back of your flywheel doesn’t look oily. Is the inside of the inspection cover oily?

 

[AR67GTX]

That what’s bothering me, it’s a little grimey but not wet. Oil is collecting in between the flange of the bell housing cover and bell housing after just a few miles. I’m going to look at it a little closer and see if I can figure anything out.

 

[Beekeeper]

That what’s bothering me, it’s a little grimey but not wet. Oil is collecting in between the flange of the bell housing cover and bell housing after just a few miles. I’m going to look at it a little closer and see if I can figure anything out.

That’s sounds like a pan leak to me

 

[pnora]

Make sure the rear of the intake is not leaking. Also is it the picture quality or does that screen on the pickup look bad?

 

[Beekeeper]

Make sure the rear of the intake is not leaking. Also is it the picture quality or does that screen on the pickup look bad?

Which brings up the question what oil pan was on it?

 

[AR67GTX]

Stock oil pan. Picked up a Mopar Performance or Milidone (or similar) pickup sometime in the past. Screen is a bit pushed in but it’s clean otherwise. I’m going to check height before I put the pan back. Back of intake is a question mark - hard to see or even feel back in there.

 

[pnora]

Stock oil pan. Picked up a Mopar Performance or Milidone (or similar) pickup sometime in the past. Screen is a bit pushed in but it’s clean otherwise. I’m going to check height before I put the pan back. Back of intake is a question mark - hard to see or even feel back in there.

Mirror works good.

 

[AR67GTX]

I have a mechanics scope I can use, maybe an oily surface will show up on it.