Race Motor - Engine Run-in?

[FWDRacer]

Morning All,

Race engine run in yesterday using a cheap 20/50 - started with restricted rpm and by the end of the day was using briefly the sort of rpm I'd be seeing for every gearchange under race conditions. Pulled the head last night after running a compression test (consistent at 180psi across all 4-cyls) but there are still some cross hatch makings from the hone. Have the rings bedded fully and can the engine be given full beans? I'm tempted to leave the sh**te oil in for one more session (qualifying at first meeting of the season) and then do an oil change onto the usual Valvoline VR-1 prior to racing. I reckon I've probably only done around an hours running so far...

What are peoples thoughts - could I leave the API-SF spec oil and race on it or would it be foolhardy? Would it guarantee a fully bedded motor that subsequanetly doesn't have blow by/consumption issues. Risks? The engine has just had new shells and crank/B/E's are in good condition but not freshly reground. It's a venerable A-Series and peak rpm is about 8.5K.

Gents - your thoughts.

edited for smellink.

Edited by FWDRacer on Wednesday 16th April 13:03

[Snake the Sniper]

A mate once brought a gold seal engine for his minor which had done 15K miles since it was rebuilt. You could still see the cross hatching on that, so as long as the pressures are what you expect, they should be bedded in. Maybe give another 30 mins to an hour if your not sure though.

[MattYorke]

I thought the cross hatching was meant to remain because it helps hold the oil film onto the bores.
I understand the point of using a mineral oil to induce some wear to bed the rings in - but I also thought that modern honing was slick enough that it wasn't really necessary.
Happy to stand corrected on either point though.

[stevieturbo]

Most Subarus in good order that Ive seen, still have excellent cross hatch visible at 100,000 miles.

If the engine isnt breathing heavily, then Id say you are fine.

[Boosted LS1]

^ I agree, the crosshatching takes many miles to wear away and once it's gone the engine's well worn. Your rings are bedded in by now so just drive it as normal.

[neiljohnson]

My rs turbo 1800 zvh engine was still showing its honing marks after 12k and knackering it's rings so i would'nt worry that you can still see them, They are there for oil retention so if they disappear then there is wear on the bores.