Quote:

---

Anyone can make a mistake...Ever been gaping a ring and forget were you are on a particular ring gap cause you got side tracked a few seconds?
LOL....

---

LoL, I have to start on the second ring due to the fact that it grinds so much faster than the top ring and if I start on the tops first, the very first second ring I do ends up a bit larger gapped than I woulda liked..

Quote:

---

After each engine build we like to do a spot check of a least one rod and one main bearing with plastigage to check and confirm our clearence measurements during the build,surprizingly it come up very similar.At the construction co.on in chassis(frame)rebuilds on the big diesal Cat,Cummins,Detroits and etc,its the only way we can check the mains.These engines see over 300,000 miles and 7000 hours between rebuilds.

---

I'm surprised that you even have plastigauge in the
shop Bob

Quote:

---

Quote:

---

After each engine build we like to do a spot check of a least one rod and one main bearing with plastigage to check and confirm our clearence measurements during the build,surprizingly it come up very similar.At the construction co.on in chassis(frame)rebuilds on the big diesal Cat,Cummins,Detroits and etc,its the only way we can check the mains.These engines see over 300,000 miles and 7000 hours between rebuilds.

---

I'm surprised that you even have plastigauge in the
shop Bob

---

It's a great checking tool,keeps Chaz,Donny and Curt Jr on their toes.

Quote:

---

you better pull that crank and take it to get miced. and forget abot the plastic guage in this case.

---

Quote:

---

Quote:

---

you better pull that crank and take it to get miced. and forget abot the plastic guage in this case.

---

I have used snap gauges,dial bore gauges and plastigauge in the past. Done correctly they will all show pretty close. Done incorrectly any of these methods can be inaccurate. My question in this case is this. If the lower bearing bore of the rod was not perpendicular to its centerline,how would this have been checked with a dial bore gauge? Yes the rod could be checked on a surface plate or with a checking fixture. With a "home build" careful assembly practices and plastigauge located a problem. I use any and all resources to locate problems during any build,engine ,trans,or chassis. Not trying to argue techniques here. Just trying to show that there are many resources available to locate a problem. I applaud Bob for careful assembly practices for catching a problem before it cost him. So many guys I see don't take the time and then can't understand why there stuff breaks or runs slower than there buddy's "exact same combo".
Doug

---

In this case if the rod is believed to be twisted
(just a IF) you could mount 2 rods on the journal
and try putting a wrist pin into both rods(1 pin
both rods)

Quote:

---

OK
Just got home....I figured out the problem...
Looking at the rod cap, it has the same misalignment regarding the bearing offset as seen in BG part II thread.

---

Quote:

---

Quote:

---

OK
Just got home....I figured out the problem...
Looking at the rod cap, it has the same misalignment regarding the bearing offset as seen in BG part II thread.

---

It will be interesting to know if the problem was with the bearing shells, or the rod locating tang slot.

If it was the bearing, I don't see how the machinist would have caught that. Unless he marked each bearing with each rod when he checked clearances. If it was the rod tang slot location, he might have seen it, may not.

---

This is the case where plastigage is a savior.Everything may have miced up perfect and the rod may have incurred an issue after the fact like maybe got tweaked in the rod vise while torqueing the bolts or what ever.We have a similar issue years ago,it was so stupid it was hard to believe.When we installed and torqued the cap it almost locked up the engine.We did what Bob did and plastigaged it and found it was clamping on side tighter(no clearence)We checked the rod and there was no problems.By accident we found some tiny bumps on the back of the bearing shell that you cound hardly see with the naked eye.It was like and oxidation in the coating.We changed the insert and the problem went away.

Quote:

---

This may be a long shot,but I seen guys hit the crank counterweight while installing the piston and rod causing a little burr on the rod that will tighten up your rod to rod clearence.Like I said it's a long shot.

---

Like ya say... could be anything

Quote:

---

with usinf plastigage for checking. didn't we argue about this with another builder a while back but once an issue is detected it's time to pull it out and do some serious checking.

---

No arguement,just different schools of thought. We can have 3 different people get different reading on a micrometer,Chaz has feather fingers,Curt Jr has vice grip and Donny is King Kong with all thumbs.Every tool has it's place.Some of us do some don't.As far as Bob's issue I would not be in a hurry to take the crank out till I pinpoint the exact problem.