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]

Ok we're in business and you guys are to thank. @cgnj you're right, my "spec sheet" was bunk. @Superhawk996 I ordered the Tom Wilson book - will be here in a few days.

Today I went to HF (I know, I know) to pick up a set of micrometers and a telescoping gauge set. I measured the main journals, and #1 bearing torqued in the case (all I had time for). I also plastigage'd #2 with the case torqued to spec. And I'm definitely in the ballpark.

(IMG:http://www.914world.com/bbs2/uploads_offsite/media.giphy.com-23760-1703899586.1.gif)

I got:

• Main journals came in at 2.361" for #1-3 and 1.574" on #4, which is right on-spec
• Plastigage on #2 came in at around 0.076 (or 0.0029") which is within the 0.0012" - 0.0035" spec that @cgnj posted
• My telescoping gauge measured #1 just over 2.362" which represents a gap of just over 0.002" which, again, is within the spec @cgnj posted of 0.0016" - 0.0039"

So all-in-all today's gut-check felt good. Thank you all again.

Also (I'll probably catch a lot of flak from you all on this) my stroker crank wasn't clearancing the case so I ground a bit of it off so that it clears ¯\_(ツ)_/¯

(IMG:http://www.914world.com/bbs2/uploads_offsite/media.giphy.com-23760-1703899586.2.gif)

I'm going to spend more time this weekend measuring the clearances on #2, #3, and #4, as well as roundness on all bearings in the torqued case with my dial bore gauge.

Once the Tom Wilson book arrives, I'll have some light reading to occupy my time :-)

Next step: More measuring, reading, and finding a machinist for balancing the rotating assembly!