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?)

[Superhawk996]

I’m not going to comment too much on the Tangerine relief since I don’t know what pressure he has it set to. It clearly has a place if the engine relief bore is worn and/or if the spring has become weak.

I did a quick measurement of spring rate, distance between the relief passage and closed position and the piston size of my low mileage engine GA000099. I calculated it was something like 80-84 psi needed to bypass the cooler so I’m not worried about my relief valve opening prematurely when engine is warmed. Since that engine is not yet assembled I can’t comment on how accurate my calculation turned out to be. I will say that I wouldn’t hesitate to use the Tangerine relief replacement if I have any signs of unusually low oil pressure.

The bottom line is too much pressure isn’t good for stock cooler longevity and will blow out the seals / leak if pressure is too high. Where that system goes tilt is an unknown and why I’d like to eventually build up a pressure test rig - just for my own learning and verification of T4 pumps.

If running an aux cooler with hard plumbed fittings there would be no oil cooler seals to blow out.