I am replacing a 6bolt crankshaft that crankwalked on me...see here:
6-bolt crankwalk - 0.065" endplay

I have a replacement 6bolt crankshaft that I am not able to date, i.e. I cannot determine the date of the engine manufacture that the crankshaft came from. I am ordering all bearings and seals online. Two sets of everything are available for the 6bolt crankshaft. One for engines/crankshafts made up to March 1992 and then for crankshafts made starting April 1992.

For example, the rear main seal for crankshafts manufactured AFTER March 1992 measures I.D. 85mmx103mm O.D. x8mm wide and the rear main seal for crankshafts manufactured PRIOR to April 1992 measures I.D. 80mmx96mm O.D. x9mm wide.

Furthermore, the Engine Main Bearing Set is rated as Standard (STD) for crankshafts manufactured AFTER March 1992 and the Engine Main Bearing Set for crankshafts manufactured PRIOR to April 1992 is said to be 0.25mm undersize.

The motor these parts, including the crankshaft, goes into was manufactured in March 1992. What criteria do I use to purchase the correct seals and bearings for this project? The size of the replacement crankshaft or the March 1992 engine block the crankshaft goes into?

One is a 6 bolt and ones a 7 bolt. That's the split when then started using 7 bolt blocks.

Dstarperformance01 said:

One is a 6 bolt and ones a 7 bolt. That's the split when then started using 7 bolt blocks.

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The 6 bolt/7 bolt split happened in 1994 if I am not mistaken. I am dealing with Mar/Apr of 1992 differences.
...however, I wonder if the information on the website I am looking this up is incorrect and what they meant was up to March 1994 and after April 1994 instead of 1992; in essence their typo. needless to say, they are pretty consistent across other parts/products and distinguishing b/w the date Mar and Apr 1992.

Previous poster was correct. 92 was the switchover to 7 bolt motors. That's the difference your seeing in parts.

MindBlowin03 said:

Previous poster was correct. 92 was the switchover to 7 bolt motors. That's the difference your seeing in parts.

Click to expand...

yes, correct; that was my bad research.
1G 1990 to Mar 1992 turbo eclipes & talons have 4g63 6-bolt.
1G Apr/1992 to 1994 have the 7-bolt 4g63.
2G 1995-1999 have the 7-bolt 4g63 and 2G block.

Furthermore, other than the extra bolt, it appears that the crankshaft size has not changed - at least the journal and pin diameters:

1G 1990-92 crankshaft:
Journal O.D.: 2.2433-2.2441"
Pin O.D. 1.7709-1.7717"

2G 1993-94 crankshaft:
Journal O.D.: 2.2433-2.2441"
Pin O.D. 1.7709-1.7717"

Any other changes on the bottom end b/w 6 and 7 bolt? As this answered my question.

I believe all 1g (6 and 7 bolt) will have the same internal parts aside from what's been mentioned. The 2g 7 bolts have thinner big rod ends iirc, so you can't mix 2g crank with 1g rods without machining, or vice-versa.

I believe the rear main seal has already been mentioned.

This is all conjecture and I haven't done any significant research lately.

When the cranks switched from 6- to 7-bolt, the rods and pistons did as well. It appears via ASA that the bearings, both mains and rods, were the same in 1G 6-bolts and 1G 7-bolts, but the 7-bolt rods in a 1G are the same as 7-bolt rods in a 2G. The 1G 7-bolt pistons are different than the 2G pistons as they still provide a 7.8:1 compression ratio like the 6-bolt pistons, but are of a different geometry to match the 7-bolt rod.