Brand new rebuilt engine

Hi Andre,

Is there anything that I should do differently when I am creating a road tune with a brand new rebuilt engine?

It is a bit out of left field, I am running a Zetec Silver top engine out of a 2 litre mondeo. The engine has been fully built with rods,pistons, cam etc and also with quad throttle bodies and turbo charged.

Tuning a freshly built engine does present some issues as it's important not to let the engine sit and idle for long periods as this can affect the ring seal. At the same time there is going to be a run-in period where we don't want to apply high load or rpm.

Generally I approach this by getting the engine running and then coarsely adjusting the mixtures so that I can get the engine driving and apply some light load quickly. At this point just coarse adjustments to the whole fuel map to keep the AFR within a reasonable range is sufficient. Once you've got the engine driving at highway speed, you can start focussing your energy on being a little more accurate.

There is a lot of talk about engines needing a 'run-in' tune for 1000 or 2000 or I've even heard of 5000 km before you push it hard. In my experience this simply isn't true. With modern rings and honing techniques, 90% of the bedding process occurs in the first 20 km of driving. This is why it's so important to get light load on the engine quickly. The rings will continue to bed for a little longer but beyond about 200 km of driving, I'm afraid the engine is as run in as it's ever going to get.

When you're driving with a fresh engine it's important to vary the rpm and load. Brief periods of light load will force the rings against the bore to help bedding. Backing off the throttle helps draw oil up the bore to cool and lubricate the rings.

Just a note if you haven't already got it sorted - With the multi throttle and turbo arrangement, you're going to need to use a 4D mapping technique comprising both TPS and MAP. There is a webinar on how this works if you need more info.

Hi Andre,

Thank you for your reply.

I will look up the 4D mapping webinar.

When running an engine in, is it worth using running in oil. I was specifically thinking of the oil made by Royal Purple?

Thanks,

Nathan.

I used to use a specific running in oil but more recently I've just used a regular mineral based oil of the correct grade. The only real key is to ensure you don't use a really high grade full synthetic oil as it is too slippery to allow the rings to bed properly.

When I do run the engine in and tune it. What fuel should I use? I will eventually run the car mostly on E85, but I will also flex fuel tune it.

Should I do the initial tune on E85 or Premium 98 Octane?

The most common way of tuning flex fuel is to treat pump gas as your primary fuel and tune for that first. E85 then becomes your secondary fuel and you would tune for that after completing the pump gas tune. In my opinion it depends on what you expect your primary fuel to be, as well as how your ECU deals with the flex fuel component - There isn't specifically a right or wrong way of dealing with flex fuel.

I'd probably run the engine in and tune on 98 first since you're going to be doing a few km's with this fuel it's likely to work out cheaper than using E85.