[TRADERMIKE 2012]

We finally removed the Crank and Pistons from the 428 ci YK Block and as Lou and I deduced (using the stethoscope from Harbor Freight) that the noise was emanating from the # 7 Piston/cylinder Crank Pin "not" From the Piston slap, so confidently diagnosed by many Forum members, that was etched in stone.

This is why I take my time and gradually use the process of elimination to solve the various issues that I am experiencing at any time. The Piston slap prognosis was optional and was going to happen eventually, if not next.

The # 7 cyl Crank pin Journal was worn the most and is rough running my finger nail across the etched lines in the Journal. In addition, the Crank Pins need to be turned, if I decide to keep it. I would need matching Rod Bearings. The Crank itself also needs to be turned and new matching Bearings to suit.

The Piston Skirts were measured at the lowest point on the Skirt as well, measurements appear on the document that I am supplying with photos of the actual parts. You can look at the information in the upcoming attachments in order to let me know your thoughts.

Most of the upper compression rings were broken into 30%-70% two sections, can someone explain the reason for that? Originally the # 2 Piston had the groove in the Piston top orientated toward the front of the motor and all the remaining ones pointed toward the rear. Once we removed the group of Pistons and lined them up on a flat table, we could see that the Spurt holes were not lined up facing the intended lower Skirts/Wrist Pin or Cam area.

Both halves of the Rod and Cap were marked accordingly from number 1-8/Piston, where they join using a through bolt. I elected to orientate the Pistons, with the spurt holes up and let the Piston pointing groove fall where they may, for the time being. I noticed that the # 1 & 2 Piston grooves pointed forward and the other six faced toward the rear of the motor. You will see this in the photos soon. The engine builder that modified this Engine in 1968 had the Piston Grooves pointing toward the rear for race reasons according to my vast documented research, only to leave the Spurt holes pointing in the wrong direction, I recently learned.

However, the aftermarket Bearings don't have the necessary channels to flow the oil anyway, or so I just read in my new book. Perhaps that is the reason he built the Motor, the way it is today. I re-orientated the Piston/Rod with the Spirt hole up and pointing the oil to the opposing Pistons Wrist Pin and under Skirt to see what that would look like and I found out that is the way it is supposed to be. This means I will have to remove six of the wrist Pins and install the pistons the opposite way, that is the way to have the Thrust load as Pontiac meant it to be. Do you agree with my Theory?

Note: On these Rods, there is no bevel or camphor, one larger or smaller than the other that would clear the weights on the Crank, as was explained to me over the forum. The only difference we found was on one side of the Rod, on the lower half @ the webbing, is a raised portion, that resembles 1/16" diameter dowel x 3/16" high, cast in mark, perhaps for strength or maybe it depicts direction. For now, I base the orientation of the Rods by the Spurt holes only and the Pistons by the groove etched in the Piston edge top. I can only feel that since these Rods don't fit the description that was given to me, that maybe these are Forged ones? One could only hope! Let me know, they have an "H"- shape to them.

What if I want the Spurt holes to work as Pontiac had before, where am I going to get modern bearings to work like the old ones, are they special? Can I get away without the Bearing/Spurt hole Bearings that supply the oil to under the Piston Skirts and Wrist Pins, without this oiling system will the motor fail before its time? I have to wonder if that is the reason my existing Top compression rings cracked /Broke in the first place?

Butler sells a kit with Forged 455 ci Crank stroker, Forged Rods and Pistons. New Bearings, etc... From what I am reading in this new book that the price to turn and polish the existing Crank, Rods have to be sized, Crank turned, Pistons checked, Rods shot peened, nitride this and that, I might just start new. JMO

Lots to weigh out, this is a good start, as far as I can tell the Block is reuseable and just needs TLC.

[Kenth]

Originally Posted by TRADERMIKE 2012

1. The Piston Skirts were measured at the lowest point on the Skirt as well, measurements appear on the document that I am supplying with photos of the actual parts. You can look at the information in the upcoming attachments in order to let me know your thoughts.

2. Note: On these Rods, there is no bevel or camphor, one larger or smaller than the other that would clear the weights on the Crank, as was explained to me over the forum. The only difference we found was on one side of the Rod, on the lower half @ the webbing, is a raised portion, that resembles 1/16" diameter dowel x 3/16" high, cast in mark, perhaps for strength or maybe it depicts direction.
For now, I base the orientation of the Rods by the Spurt holes only and the Pistons by the groove etched in the Piston edge top. I can only feel that since these Rods don't fit the description that was given to me, that maybe these are Forged ones? One could only hope! Let me know, they have an "H"- shape to them.

1. You are measuring at the wrong spot.

2. All rods has a chamfer to leave room for the bearing to the radius on crank. Look closer. Also the rods are offset and needs to be positioned with the notches towards radius on crank. You can NOT just look at the spurt holes.
If there are no notches on rods (aftermarket) you need to check how the bearing sits in the rod, side with more room goes towards radius on crank.
Your 1967 and earlier rods are cast I-beams. 1968 and later rods are reinforced at the big end as shown on my picture.

[TRADERMIKE 2012]

Originally Posted by Kenth

1. You are measuring at the wrong spot.

2. All rods have a chamfer to leave room for the bearing to the radius on crank.

Look closer. Also, the rods are offset and need to be positioned with the notches towards radius on crank.

You can NOT just look at the spurt holes.


If there are no notches on rods (aftermarket) you need to check how the bearing sits in the rod, the side with more room goes towards radius on crank.


Your 1967 and earlier rods are cast I-beams. 1968 and later rods are reinforced at the big end as shown on my picture.

Mikes reply:

Thank you for the visual, it helps, it is hard to see the Beveled edge/champhor on the large side of the Rod, perhaps I should pull the Bearings out and inspect the area.

One easy way to determine the side of the Rod that goes toward the radius of the Crank or that faces each other is to associate the Rods marker @ the top of the Rod Pin area that has the two-digit number over it and orientate that visual, that I understand and point that out to me, the marker faces inside adjacent to the Rod that shares a Rod Pin or outside toward the Crank Radius?

You said:

"How the bearing sits in the rod, the side with more room goes towards radius on crank.

Mikes reply:

It seems to me that one side looks wider than the other with the Bearings installed in the large side of the Crank pin.

I will go back and study that again, but still answer the above request, that marker is in the location for a reason, so let's use it, please, to confirm the orientation of the surfaces in question.

[TRADERMIKE 2012]

Originally Posted by Kenth

1. You are measuring at the wrong spot.

2. All rods have a chamfer to leave room for the bearing to the radius on crank. Look closer. Also, the rods are offset and need to be positioned with the notches towards radius on crank. You can NOT just look at the spurt holes.
If there are no notches on rods (aftermarket) you need to check how the bearing sits in the rod, side with more room goes towards radius on crank.
Your 1967 and earlier rods are cast I-beams. 1968 and later rods are reinforced at the big end as shown on my picture.

Mikes reply:

I just got through studying your photos and if they are correctly drawn to Pontiac specs this is how I read the information, in simple terms:

Hopefully I get this rite, The ID Boss on the large end of the Rod to Crank Pin is orientated toward the Radius side of the Crank Pin.

The Piston Notch always points forward.

The Spurt holes always point toward the Cam, up and are supposed to get oil to the opposite Pistons Skirt, wrist pin and under the Piston Rod area.

The non-boss side of the large end of the Rod to Crank Pin is orientated toward the center and is adjacent to one another.