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?)

[technicalninja]

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SuperHawk gives good advice.

I, too, use Plasti-gauge in EVERY SINGLE BUILD.

I do all the mic measuring, math, the freaking hard way FIRST.

I then (should!) know what my clearances are to the fourth decimal point.

I'm BAD-ASSED at this...

I then use the Plasti-gauge as a "quality control check".

I'm backing myself up with a completely different way of taking the same measurement!

If the Plasti-gauge show different than what I expected I'm a HONKED DONKEY!

Complete re-check from the start to see where I made a FATAL mistake...
Self-flagellate as required.



One SUPER important tip regarding Plasti-gauge!

As it ages it shrinks FAST.

6 months down the line it's not very accurate and it's useless at 1 year.

With time it will shrink down to sewing string width...

I know this from personal experience.


Buy brand new Plasti-gauge only!

I worry "how long has that been siitting on the parts house shelf" so I always buy from a mass retailer. Summit is my go-to for PG.
It always looks new and fat...

Lots of techs and machine shops have negative experience with PG and it's a bit like POR15, either you like it, or you don't. I'm betting most of the "failed when used" troubles are more self-generated than a defect in the product.

It shouldn't be used alone in my book but it's a part of it all.