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]

You might look closer at that valve...

I was EXACTLY like you in my original assessment. Needed for damaged stuff!

My T4 core has a FLAWLESS relief valve bore.
The valve itself is perfect...
I was planning on reusing it till I saw the bit regarding changes to flow rate between cold and hot and how hot high pressure could do EXACTLY what you referenced.

One of the differences between the Tangerine valve and stock specifically addressed this issue.

At that point it became "must have at pretty much any price" for me.

The fact that it's less than a hundred bucks makes it easier to swallow.

I'll have to look at one closely when I purchase but that one design difference (if it works like it was described!) could be the WHOLE MOTOR in a worst-case scenario.
The Tangerine valve should have been that way the Germans designed it from the get-go in my book.

TRs getting my money!
At least once...