No HTwo O

What are the proper break in steps after a fresh top end overhaul?

Thanks for the help!

LAT

As with most air cooled motors a couple of heat cycles is all you need.

IOW, bring engine up to operating temp with low to mid loads and then cool completely a few times then drive it like you stole it.

Felix

Depends on what was done. On these engines it may well include new rings and even conn rod bearings in which case 1000 miles without high revs or high boost is probably sensible.

DM993tt

Who did the work? Dare I ask what it set you back? I might be looking to do one. What prompted you to do it? What was the leakdown prior?

bb993tt

As with most things, Phelix is probably right here. I had mine done by RUF, Germany, as part of the turboR conversion. The initial run-in and tuning were done via their engine dyno, then road tested at high speed, after which the final tuning was done. When I got it back it was good to go and I was red-lining it in the lower gears the following weekend.

No HTwo O

Thank you Phelix. Your response makes a lot of sense. Do people also change the oil after the break-in period?

TB993tt

FWIW I think 1000 miles is wayyyy too much.... When RS build new engines (like my last one) they run them in on the engine dyno before sustained load mapiing takes place (think 7000rpm for 1 minute whilst parameters are optmised) I just can't see them having a 1000 mile simulation for break in it would take forever and dyno time is too expensive...

My humble guess would be a few heat cycles like LAT said and gradually bring the loads up over 100 miles or so then nail it

Geoffrey

You need to get load on the engine if there are new rings. This will help seat the rings. I generall use a dyno and run some good load at various RPMs. From there, we run (or race) them normally.

WHB Porsche

What does the person who did the work say?

dbf73

if this is a true top end - just valves, guides, seal etc but not rings, bearings or turbos, I'd at most do a couple of heat cycles and let it rip.

Felix

Shops with engine dynos have the luxury of using that as the break-in method; isn't checking the leakdown figures after the rebuild and then after running in one way of confirming the rings have seated?

But if you're doing it in the car and on the road you have to use more conventional methods,