2270 Build thread, Looking forward to making all of the mistakes! Options

[vjb206]

Hey folks! I've got...

• Case halves from an old 1.7 (cleaned as best I could)
• 2270 crank + P&C kit
• #163/86b Web Cam
• 2.0 heads with 44X36 valves, where I'll be installing dual springs and 38mm exhaust valves
• Upgraded oil pump and other goodies

So my first question for the community has to do with ensuring the rotating mass is spinning freely/correctly…

I started by measuring all of the the main journals on the crank and I got a range from 2.358” - 2.360” (I used a digital caliper and I'm pretty sure I did this correctly).

Then I “dry-fit” Silverline STD/STD main bearings into the case (sans crank), torqued everything down, and got 0.003” in radial play (I used a cylinder bore dial gauge for the first time, and I think I did it correctly).

The spec-sheet says radial play should be between 0.06” - 0.10” (0.03” - 0.09” for #2); and I have 0.003." I'm a MINIMUM of 0.057" off, is that normal? What's my next step?

1. Stop pretending I know what I'm doing and take it to a machinist for test-fitting and honing (I'd like to keep cost down so this is my less preferred option)
2. DIY: hone 0.06" off all bearings (what's the right honing tool / approach here?)
3. Order different bearings (if so, which?)

[vjb206]

Measurements are in MM. Excuse me while I––––

(IMG:http://www.914world.com/bbs2/uploads_offsite/media4.giphy.com-23760-1702315305.1.gif)

[Superhawk996]

Measurements are in MM. Excuse me while I––––

(IMG:http://www.914world.com/bbs2/uploads_offsite/media4.giphy.com-23760-1702315305.1.gif)

(IMG:style_emoticons/default/lol-2.gif) Trust me I've done that too. Just gotta' be sure you know what the spec is and how its measured.

Here's a tip: If the measurement is only two significant digits (.06) it's probably in metric. Three or Four significant digits (.024 or .02364) is probably inches. This is because a miilimeter is such a small fraction of an inch, it only takes two significant digits to get you into very small numbers with high precision.

[vjb206]

Measurements are in MM. Excuse me while I––––

(IMG:http://www.914world.com/bbs2/uploads_offsite/media4.giphy.com-23760-1702315305.1.gif)

(IMG:style_emoticons/default/lol-2.gif) Trust me I've done that too. Just gotta' be sure you know what the spec is and how its measured.

Here's a tip: If the measurement is only two significant digits (.06) it's probably in metric. Three or Four significant digits (.024 or .02364) is probably inches. This is because a miilimeter is such a small fraction of an inch, it only takes two significant digits to get you into very small numbers with high precision.

Hey folks - Merry Christmas and a Happy New Year! I'm back at measuring and have some more accurate figures (see below on method). Bottom-line is that for all of the bearings I have either zero clearance (like literally 0.00mm radial play), or at most I have 0.03mm.

(IMG:http://www.914world.com/bbs2/uploads_offsite/media.giphy.com-23760-1703704167.1.gif)

Bearings as follows:

• #1: 0.01mm radial play
• #2: 0.03mm radial play
• #3: 0.00mm radial play
• #4: 0.00mm radial play

@Superhawk996 , @Montreal914 , @930cabman : Assuming this is normal, my next step will be to call my friendly neighborhood machinist to take the required amount of material off each bearing so that the tolerance sits on the low end of the radial play spec. Does this sound right to you?

Thanks for everyone's input so far, I truly appreciate it.

///// Process /////

1. Measure main journals. They all came in on-spec: #1=59.98mm, #2=59.99mm, #3=59.98mm, #4=39.95mm. Call this A
2. Set bore dial gauge to nearest constant. Mine worked out to be 61.13mm. Call this C
3. Dry fit bearings and torque case
4. Measure how far "in" the dial bore gauge measured for each of the bearings. Call this D
5. Radial play for each was (C-D)-A
6. Note: For #4 my dial bore gauge didn't fit (was too big even at its smallest setting), so I didn't get torqued figures, but it all came out to 0.00mm play so ¯\_(ツ)_/¯