Mopar Muscle Association UK

I'm after some ideas on how long or rather mileage before any real full throttle high rev driving since my light engine refresh please.

I'm running the same cam, lifters, rods and rockers. I replaced the main and big end bearings, timing chain and gear and all piston rings, so I was just wondering if there's a rough guide or train of thought on running an engine after this?

Cheers, James.

It's mainly the rings that will need to bed in.I'd reckon 500-1000 miles with plenty of running at varied speeds without any high loads. I'd also change the oil/filter at 500 and again at 1000,then back to normal use.

if you have a new engine dyno'd, how do they get round the 'Running in' as that seems to be balls out after a few pulls????

I thought once the the cam was broken in you should drive it like you stole it, to get the rings bed in.

By the time the cam is broken in the rings should be bedded in also so personally it's drive it like you stole it time. Personally I'd change the oil & filter before 500 miles. This is another one of those questions where you'll get 500 different answers...

I'm a firm believer that the old "running in" routine was just a load of nonsense.

Blue wrote:Personally I'd change the oil & filter before 500 miles. This is another one of those questions where you'll get 500 different answers...

I'm a firm believer that the old "running in" routine was just a load of nonsense.

I'm pretty much aligned with Blue on this one...

I personally would change the oil not long after the cam has bedded in. I agree during the initial fire up, you want good fuel mix ratio, to ensure no bore wash, etc. This is the time the rings really bed in.

If you follow the 'running in' process, then surely they would 'run out' as quick 😊

Geof Hauser told me to fire it up (roller cam so easier, but it is not an issue on this occasion) wait for the oil pressure to stabilise (i.e. drop) and then give it large.

I did that and then gave the car a gentle (high 10 second) pass and then nailed it thereafter. No issues at all.

I am a firm believer in early oil and filter changes though, however Geof gave their Super Pro-ET car 19 passes on break in oil before a change.....

Same cam so agree it's just bedding the rings. You need load (intermittent yes, but you need load) to do that so in the car on the road, or on a dyno. Also depends on the type of rings & the appropriate hone some bed quickly. But def worth getting them properly seated. Listen to this lot who've been there and done it a lot, then as said Bananarama! mercilessly. Production engines in a car factory don't get 500 miles, they get fired up, run in, then good to go. Once the rings have sealed (or not sealed, hopefully not) you've got what you've got!

Thanks as ever chaps

I did get two filters for the rebuild so I could change fairly soon if needed, judging by the advice, that looks to be a good call

I'll do some launches soon then and see what happens, I want to see what happens now I've got a higher stall converter in

Also depending if it's a new unit with warranty and guarantees so you would normally stick to the engine builders strict code of advice normally 500 miles.
I know I did with my new engine after all you break it you paye for it so what's a few extra miles breaking it in carefully.
It's your wallet.

Gone are the days of 50mph at these rpm blah blah blah

Get it up to temp and give it some right foot

I built my engine and broke the cam in on a Saturday and the next Friday drove tot he Nats and laded down 20 passes and that engine is still going strong.
After came break in change oil and filter and have some fun.